GB2212229A

GB2212229A - Intermediate clutch plate with release-limiting device

Info

Publication number: GB2212229A
Application number: GB8825634A
Authority: GB
Inventors: Winfried Sturmer
Original assignee: Fichtel and Sachs AG
Current assignee: ZF Sachs AG
Priority date: 1987-11-12
Filing date: 1988-11-02
Publication date: 1989-07-19
Also published as: DE3738423A1; BR8805926A; FR2623262A1; FR2623262B1; GB8825634D0

Description

Multi-disc clutch with release distance limitation of the intermediate

plate 2212229 The invention relates to a multi-disc clutch, especially a two-disc clutch, having two clutch discs arranged between a counter-pres sure plate - for example in the form of a fly-wheel - and a presser plate and an intermediate plate arranged between the two clutch discs, which intermediate plate is loaded by the force of a spring device, while selfreadjusting release-distance-limiting devices are provided on the intermediate plate, consisting of tangentially arranged fastening plates for radially extending bolts which comprise a support system at the one end and a spring device at the other end having friction faces arranged therebetween, also a displacement device rendering possible an axially acting relative displacement, with play between two stops corresponding to the release play of the intermediate plate.

A multi-disc clutch with a release-distance-limiting device of the above-stated style of construction is known for example from German Auslegeschrift No. 1,755,032. From this prior art various examples of embodiment are known which all possess one disadvantage of principle At least one of the components which has a friction face opposite to the push member is spring-loaded and must be held in a guide with play, for readjustability in the case of wear. On reversal of the push member movement this play makes itself noticeable in that the build-up of friction force proceeds in stages. This stage derives from the fact that one of the components participating in the friction action shifts within the necessary play and during this shifting makes no contribution to the build-up of the friction force. Since however even in the case of minimum shift distances - that is in the case of minimum wear on the friction linings - a calculable displacement force must be present, in the prior art the friction forces must be set relatively high, so that even at the first stage of the staged friction force development the desired effect is present. Because however the friction force built up in this readjusting device is at the cost of the pressure application force of the corresponding clutch disc, this force should however be relatively low. On the other hand however the requirement also exists that the friction force generated here is greater than the release force acting upon the intermediate plate or upon the presser plate.

It, is therefore an object of the present invention to irprove a displacement device of the known construction style to the effect that the onset of the friction force takes place without a stage jump and in its level is subject to only slight fluctuations over the whole life of the clutch.

According to the invention there is provided a multi-disc clutch assembly comprising two presser plates rotatable about a common ax-Ls of rotation, of which a first presser plate carries a clutch cover and of which a seocnd presser plate is guided fast in rotation but axially movably in relation to the first presser plate and is initially stressed axially towards the first presser plate by a clutch spring device, two clutch discs arranged axially between the two presser plates, an intermediate plate arranged axially between the two clutch discs and guided fast in rotation but axially displaceably in relation to the first presser plate, a release spring device for the intermediate plate and at least one release-distance-limiting device on the intermediate plate with a fastening plate held on the intermediate plate in the region of the external circumference of the latter, a push member abutting through friction faces on the fastening plate and axially displaceable in relation to the fastening plate and an initial-stressing spring C> device supported on a bolt, which spring device presses the push member with the aid of the bolt against the fastening plate, two stops on one of the two presser plates being associated with the push member, which stops limit the axial release play 9f the intermediate plate, characterised in that the fastening plate is arranged between the first- mentioned push member and a second push member, whcih is likewise displaceable axially in relation to the fastening plate and likewise limits the release play of the intermediate plate in relation to the two stops, and the fastening plate rests through friction faces upon the two push members, in that the bolt is anchored on the first push member and penetrates with play a slot of the fastening plate, which slot is elongated in the pushing direction of the push members, and a hole of the second push member, and in that the initial-stressing spring device is cl,:i,mped, on the side of the second push member remote from the first push member, in between the second push member and the bolt.

By arrangement of two simultaneously actuated push members, each of which comprises a friction face opposite to a securing plate, necessary clearances which have the same function as in the prior art have no effect upon the build-up of the friction. In every case a distinct and steep rise of the friction force on the onset of the release-distance-limiting device_ -4is secured. The tendency of the bolts according to the prior art in fact to place themselves obliquely and thus to retard the build-up of the friction force is likewise completely excluded with the design in accordance with the invention.

In the single example of embodiment two push members are arranged parallel and with spacing from one another and possess the same length. This design is very simple in construction and the attunement of the two push members to equal length can be effected entirely without problem.

However a form of construction is also possible in which the two push members are made prolonged on one side and together with the presser plate form a release-distancelimiting device. In this embodiment different variants are possible. Thus by way of example two parallel-arranged push members can be used, each of which reaches with a radially inwardly angled-off flange into a radially outwardly open groove of the presser plate. The two legs of the two push members lie against the mutually facing faces and the two outer faces of the two legs work with play in the groove of the presser plate. A symmetrical and uniform force introduction to the release-distance-limiting device is ensured by the mutual abutment of the two flanges. In another example of embodiment it is provided that one of the push members engages with a flange in a corresponding groove of the presser plate and the other push member, of a thinner and thus more elastic material, is arranged fast on the one push member. A further variant proposes that the two push members are made coincident, with a correspondingly large opening into which an extension of the presser plate reaches with play. 5 The invention will next be explained in greater detail by reference to various examples. Individually: Figure 1 shows a longitudinal section through the upper half of a two-disc clutch for a motor vehicle; Figures 2 to 4 show various views and a section through jo a release-distance-limiting device in enlarged representation; Figure 5 shows the partial longitudinal section through a variant of embodiment; Figure 6 shows the partial longitudinal section through a further variant of embodiment; Figures 7 and 8 show a further partial longitudinal section through a variant, with a view from above; Figures 9a to 9d show the prior art with representation of the individual movement steps.

To clarify the problem arising in the prior art, let reference firstly the conventional components of the clutch as represented in Figure 1 are to be discussed in connection with a conventional release-distance-limiting device such as is represented in Figures 9a to 9d. Like references have been used for like parts. In connection with the components according to Figure 1, the following situation arises on the fly-wheel 1 of an internal combustion engine an intermediate cover 7 and a clutch cover or lid 6 are fixedly arranged. Within the parts 6 and 7 -6there are arranged following the fly-wheel 1 - a clutch disc 4, an intermediate plate 2, a clutch disc 5 and a presser plate 3. The presser plate 3 is loaded by a clutch spring device, for example in the form of a diaphragm spring 11, in the direction towards the fly-wheel 1, so that the two clutch discs 4 and 5 and the intermediate plate 2 are pressed against one another - for the transmission of a torque to a gear shaft (not shown) - all the parts rotating about the common axis 10 of rotation. To release the clutch the diaphragm spring 11 is moved by means of its spring tongues 11a away from the fly-wheel 1, so that the presser plate 3, through a release spring indicated at 65 and the intermediate plate 2, through a release spring indicated at 66, complete a release movement directed away from the flywheel 1. Thus both clutch discs 4 and 5 are free. On the external circumference of the intermediate plate 2 there is situated a releasedistance-limiting device 12, which extends into an opening 8 of the intermediate cover 7. In this case several circumferentially regularly distributed release-distance-limiting devices are provided. Each is secured on the external circumference of the intermediate plate 2 by means of a fastening plate 16 - as will be explained in greater detail in Figures 2 to 4. The release springs 65, 66 can be conventional tangential leaf springs which guide the parts 2, 3 at the same time fast in rotation but axially movably.

According to the prior art it was usual to equip the release-dis tancelimiting device 12 with a push member 19 which is arranged in the opening 8 and is made shorter in -7 the axial direction than the axial defining surfaces of the opening 8, in accordance with the desired release distance 6, I of the intermediate plate 2. Through a slot 43 of the push member 19 there extends in the radial direction a bolt 17 which is firmly connected in its radially inner region with a plate 42 and radially outside the push member 19 penetrates the fastening plate 16 with play in an opening and is braced radially outwards radially outside the fastening plate 16 by dished springs 18 which bear upon a corresponding collar. Between the fastening plate 16, firmly secured to the intermediate plate 2, and the push member 19 for the one part and between the plate 42 and the push member19 there is in each case arranged a friction element 40. Each of the friction elements 40 is fixed in the axial direction through stops 41, the friction element on the fastening plate 16 likewise having a play in relation to the bolt 17.

In Figure 9a the installation situation is reproduced. In the -fitting of the clutch the push member is brought, from the exterior by way of the adjusting opening 37, into its basic position, being brought to abut on the fly-wheel 1. Then it has a play 67 corresponding to the desired release play of the intermediate plate 2, in relation to the wall in the intermediate cover 7. Due to the push-in movement of the push member 19, as a result of the friction force the bolt 17 moves by way of the plate 42 and the corresponding friction element 40 likewise in the direction towards the fly-wheel 1, until abutment of the bolt 17 on the fly-wheel-side edge 68 of the opening 69 in the -8 fastening plate 16 takes place. This enlarged passage opening in the fastening plate 16 for the bolt 17 is necessary in order reliably to maintain the frictional clamping-in by the dished springs 18. In the first release movement according to Figure 9b the intermediate plate 2 is moved by the force of its release spring in the direction of the arrow 71 shown here away from the fly-wheel 1, until the push member 19 comes to abut on the corresponding wall of the intermediate housing 7. In this case the friction force of the releasedistance-limiting device 12 must be greater than the force of the release spring, since the intermediate plate must be held in this position. In the illustration in Figure 9b the friction forces of both friction elements 40 are immediately in action, since the push member 19 is loaded in the direction towards the fly-wheel 1 and the bolt already abuts in the "correct" region of the opening 69 of the fastening plate 16. If now after a certain wear the clutch disc 4 is engaged again and the intermediate plate 2 is brought into engagement, by the great force of the diaphragm spring 11, in the direction of the arrow in Figure 9c in the direction towards the fly-wheel 1, then the push member 19 must be displaceable in relation to the intermediate plate 2 according to the amount of the wear on the clutch disc 4, by premature abutment on the fly- wheel 1, namely facing in the direction away from the fly-wheel 1. Due to this relative displacement of the push member 19 the bolt 17 comes to abut on the opposite side 73 of the opening 69 in the fastening plate 16. During this movement of the bolt 17 with the plate 42 only the displacement force of one 1 -9of the two friction elements 40 has to be overcome, since the friction element 40 arranged on the plate 42 can accompany this release movement. In the subsequent release operation according to Figure 9d the intermediate plate 2 is moved according to the arrow 74 away from the fly- wheel 1 by the release spring, until the push member 19 comes to abut on the wall of the intermediate housing 7. In this condition likewise only the displacement force of the one friction element 40 which rests on the fastening plate 16 is effective. The lower friction element 40 on the plate 42 can come into frictional action only when the bolt 17 has taken up its play in the opening of the fastening plate 16.

The problem of the entire arrangement now resides in that for the one part the displacement force of the release- distance-limiting device 12 should be kept as low as possible, since it is at the expense of the pressure application force by the diaphragm spring 11. On the other hand for the secure release of the intermediate plate a specific lift-away force is necessary, which however again must lie lower than the displacement force, in order to hold the intermediate plate fast securely after the travelling of the release distance. The usual style of construction according to the prior art as represented in Figures 9a to 9d compels setting the displacement force, for reasons of certainty, by a friction element relatively high so that a secure release distance limitation is provided. For the other part then in case of wear twice the friction force has to be overcome by the diaphragm spring in clutch engagement, which involves an undesirably high loss of pressure application force.

The embodiments of the release-distance-limiting device according to the present invention as described hereinafter do not possess the abovedescribed disadvantages of the prior art.

Figures 1 to 4 show the overall assembly of the twodisc clutch as already briefly described, the releasedistance-limiting device 12 being represented in greater detail in Figures 2 to 4. It consists, in substantial distinction from the prior art, of two push members 19 and which are made completely identical in this example of embodiment. In principle they possess the form of the one push member according to the prior art. They are arranged to both sides of the fastening plate 16 and comprise friction faces opposite thereto. These friction faces can be made metal on metal (Figure 1), but it is also possible - as may be seen especially from Figure 3 - for friction elements 40 to be interposed. The fastening plate 16 has a slot 27 and the friction elements 40 and the push member 20are provided with bores 28 - for the passage of a bolt 17 with appropriate play. The bolt 17 is f ixedly arranged in the one push member 19, penetrates the other push member 20 with play and is supported through dished springs 18 on the outside of the push member 20. The symmetrical friction device thus obtained acts with the same displacement force in every situation, irrespective of the play between bolt 17 and push.member 20. This is guaranteed by the fact that both push members 19 and 20 are loaded and displaced at the same time and thus all friction faces between the two push S _11members 19 and 20 and the friction elements 40 and the fastening plate 16 are immediately in engagement. It is also irrelevant here whether the friction elements 40 have play in relation to the stops 41 provided on the fastening plate 16, since the same friction is generated both between the push members and the friction elements 40 for the one part and between the friction elements and the fastening plate 16. Due to this measure the displacement force is always equally high in both directions, that is to say it can be calculated exactly and adapted to the existin g conditions of the other clutch components. Figures 2 and 4 also show different views and the installation of the release-distance-limiting device 12. Figure 2 shows a partial lateral view of the intermediate plate 2, which possesses a plurality of noses 45 on the external circumference, a radially outwardly open, opening 46 defined in U-form being formed between each two successive noses 45. This opening 46 is closed by the fastening plate 16. This has a floor 44 which extends over both openings, the two parts being firmly connected with one another through fastening screws 36. Between the floor 44 and the U-shaped opening 46 the one push member 19 is guided in the displacement direction and the guidance of the other push member 20 takes place radially outside the floor 46 by edges 48 of bent-up side parts 47 of the fastening plate 16. The friction elements 40 provided in the present case are held by stops 41 which in the present case are formed as undulatory bends. Figure 4 here represents the view from radially outside.

Figure 5 shows a partial longitudinal section with another form of embodiment. The release-distance-limiting device 13 as represented here works not with stops on the fly-wheel 1, the intermediate housing 7 or the lid 6, but with corresponding stops on the presser plate 3. Instead in this case the release force for the intermediate plate 2 is directed towards the fly-wheel 1. In the already-described U-shaped opening 46 on the external circumference of the intermediate plate 2 the fastening plate 16 is arranged in the manner as already described. It is loaded from the interior with a push member 21, which is of solid formation and reaches in the axial direction into the region of the presser plate 3., There it comprises a radially inwardly angled-off leg 29 which reaches into a radially outwardly open groove 30 of the presser plate 3, with play according to the release distance. The second push member 22 is laid from the exterior on to the fastening plate 16; it is made from a thinner and therefore more elastic material and firmly connected, for example by a spot weld 75, with the push member 21 in the region of the presser plate 3. In this way production inaccuracies between the two push members 21 and 22 are completely excluded. In the way as described above the bolt 17 penetrates the two push members, and is secured in the push member 21. The dished springs 18 ensure a friction force generation on relative displacement. In the present case no pertaining friction elements are provided. The lid 6 of the clutch is here provided with an opening 31 in order to be able to accommodate the parts of the release-movement device 13, including a radially S -13outwardly protruding region of the presser plate 3. In this case the function is as follows: The release-distancelimiting device 13 limits the release distance between presser plate 3 and intermediate plate 2. The intermediate plate 2 is loaded by a spring device in the direction towards the fly-wheel. In the fitting of the clutch the push member 21 is brought through an appropriate adjusting opening 38 and by means of a tool from radially outside into the position as represented, that is abutment in the groove 30 on the side remote from the fly-wheel. In the release operation by means of the diaphragm spring 11 the presser plate 3 moves away from the fly-wheel until the groove 30 comes to rest on the leg 29. Thus the clutch disc 5 is released. On further release movement the presser plate 3 entrains the intermediate plate 2, through the releasedistance limiting device 13, and thus also releases the clutch disc 4. In this action the spring force acting upon the intermediate plate 2 is overcome by the friction force of the release-distance- limiting device 13. In the ensuing engagement operation firstly the clutch disc 4 engages by the initial stress force of the intermediate plate 2, and then the clutch disc 5 engages. In the case of wear to the friction linings of the clutch disc 5, the two push members 21 and 22 are displaced, by the presser plate 3 and the leg 29, by an appropriate amount by the force of the diaphragm spring 11. The friction of all friction faces then comes into action at full level.

In Figure 6 there is represented a further variant of Figure 5. It is superfluous here to repeat the description -14 of the function, and only the differences will be discussed.

The releas e-dis tance- limiting device 14 again comprises two individual push members 23 and 24, both of which are provided in the region of the presser plate 3 with radially inwardly angled-off flanges 32 and 33. Through appropriate adjusting openings 39 the two flanges 32 and 33 are brought into abutment for the first time in the assembly of the clutch, and applied together to the groove wall which is most remote from the fly-wheel. The appropriate release play is obtained by attunement of the material thickness of the flanges 32/33 and the width of the groove 30.

Figure 7 shows a release-distance-limiting device 15, in which again two identical push members 25 and 26 are used. They are both made f lat and also reach into the region radially outside the presser plate 3. The presser plate 3 is there provided with a nose 34 which reaches into two corresponding openings 35 of the push members 25 and 26.

Between this nose 34 and the openings 35 corresponding clearance is provided. By these openings 35 it is possible to effect the adjustment of the release-distance-limiting device 15 in the fitting of the clutch, by reaching with a tool from radially outside into the openings 35 and bringing the two push members 25 and 26 into the position directed furthest away from the fly-wheel.

Figure 8 shows, for completion, a view 'T' according to Figure 7, from which the form of the two push members 25 and 26 appears. The securing of the release-distance-limiting device 15 is here effected, in accordance with the 11 embodiments as described above, by means of a fastening plate 16 and fastening screws 36.

Claims

-16C 1 a i m s l.) Multi-disc clutch, comprising two presser plates (1, 3)

rotatable about a common axis (10) of rotation, of which a first presser plate (1) carries a clutch cover (6, 7) and of which a second presser plate (3) is guided fast in rotation but axially movably in relation to the first presser plate (1) and is initially stressed axially towards the first presser plate (1) by a clutch spring device (11), two clutch discs (4, 5) arranged axially between the two presser plates (1, 3), an intermediate plate (2) arranged axially between the two clutch discs (4, 5) and guided fast in rotation but axially displaceably in relation to the first presser plate (1), a release spring device (66) for the intermediate plate (2) and at least one release-distance-limiting device (12; 13; 14; 15) on the intermediate plate (2) with a fastening plate (16) held on the intermediate plate (2) in the region of the external circumference of the latter, a push member (19; 21; 23; 25) abutting through friction faces on the fastening plate (16) and axially displaceable in relation to the fastening plate (16) and an initial-stressing spring device (18)) supported on a bolt (17), which spring device presses the push member (19; 21; 23; 25) with the aid of the bolt (17) against the fastening plate (16), two stops on one of the two presser plates (1, 3) being associated with the push member (17), which stops limit the axial release play (67) of the intermediate plate (2), 11 1 -17characterised in that the fastening plate (16) is arranged between the first-mentioned push member (19; 21; 23; 25) and a second push member (20; 22; 24;

26), which is likewise displaceable axially in relation to the fastening plate (16) and likewise limits the release play (6M of the intermediate plate (2) in relation to the two stops, and the fastening plate (16) rests through friction faces upon the two push members, in that the bolt (17) is anchored on the first push member 10 (19; 21; 23; 25) and penetrates with play a slot (27) of the fastening plate (16), which slot is elongated in the pushing direction of the push members, and a hole (28) of the second push member (20; 22; 24; 26) and in that the initial-s tress ing spring device (18) is 15 clamped, on the side of the second push member (20; 22; 24; 26) remote from the first push member (19; 21; 23; 25), in between the second push member (20; 22; 24; 26) and the bolt (17).
2.) Multi-disc clutch according to Claim 1, characterised in that the stops are provided on the clutch cover (6, 7), in that the release spring device (66) loads the intermediate plate (2) in a direction away from the first presser plate (1) and in that the two push members (19, 20) are formed as parallel plates extending with spacing from one another and have equal lengths in the axial direction.
3.) Multi-disc clutch according to Claim 1, characterised in that the stops are provided on the second presser plate (3), in that the release spring device (66) -18 loads the intermediate plate (2) in the direction towards the first presser plate (1) and in that the two push members (21, 22; 23, 24; 25, 26) possess a prolongation which extends in between the stops (30) of the second presser plate (3).
4.) Multi-disc clutch according to Claim 3, characterised in that the second presser plate (3) has on its circumference a groove (30) forming the stops and in that one of the push members (21) comprises a leg (29) protruding radially inwards with axial play into the groove (30) and the two push members (21), 22) are connected with one another.
5.) Multi-disc clutch according to Claim 4, characterised in that the two push members (21, 22) are non detachably connected with one another.
6.) Multi-disc clutch according to Claim 3, characterised in that the second presser plate (3) has on its circumference a groove (30) forming the stops and in that the two push members (23, 24) each comprise a leg (32, 33) protruding radially inwards with axial play into the groove (30).
7.) Multi-disc clutch according to Claim 6, characterised in that the legs (32, 33) are arranged axially side by side and rest axially on one another. -
8.) Multi-disc clutch according to Claim 3, characterised in that the second presser plate (3) comprises at least one radial nose (34) which engages with axial play in openings (35) of the two push members (25, 26).
9.) Multi-disc clutch according to one of Claims 1 to 1 L 1 8, characterised in that the fastening plate (16) extends in the tangential direction of the intermediate plate (2) and the bolt (17) extends substantially radially.
10.) Multi-disc clutch according to one of Claims 1 to 9, characterised in that on both sides of the fastening plate (16) there are arranged friction elements (40) which are fixed in the direction of displacement of the push members (19, 20) by stops (41) of the fastening plate.
ll.) Multi-disc clutch according to one of Claims 1 to 10, characterised in that the fastening plate (16) is screwed to two noses (45) arranged side by side in the circumferential direction of the intermediate plate (2) and protruding radially from the circumference of the intermediate plate (2), which noses define an opening (46), and in that one of the push members (19) is arranged in the opening (46) and guided on the noses (45).
12.) Multi-disc clutch according to Claim 11, characterised in that on both sides of the other (20) of the two push members side parts (47) protrude from the fastening plate (16) in radial prolongation of the noses (45) which guide the other push member (20).
13.) Multi-disc clutch according to Claim 11 or 12, characterised in that friction elements (40) are arranged on both sides of the fastening plate (16) and in that the fastening plate (16) is provided between the noses (45) with bent-over portions (41) extending in the direction of displacement of the push members (19, 20), which bent-over portions fix the friction elements (40).

-2014. A multi-disc clutch substantially as described with reference to any of the embodiments illustrated in Figures 1-9 of the accompanying drawings.

R1 -I Published 1989 atThe Patent Office. State House, 66'71 High Holborr-.Lond, -r, WGIR 4TP. Ptirther copies maybe obtained from ThePateritolficeSales Branch, St Mary Cray. Orpinglon, Kent BR-1 3RD. Printed by Multiplex techniques Itd. St Mary Cray, Kent. Con- 1/87