GB2168784A

GB2168784A - Divided fly-wheel

Info

Publication number: GB2168784A
Application number: GB08531520A
Authority: GB
Inventors: Bernhard Schierling; Manfred Caspar; Franz Hartig
Original assignee: Fichtel and Sachs AG
Current assignee: ZF Sachs AG
Priority date: 1984-12-22
Filing date: 1985-12-20
Publication date: 1986-06-25
Also published as: DE3447180A1; FR2575256A1; JPS61215831A; JPH0730813B2; GB8531520D0

Abstract

A first fly-wheel (1) secured to a crank-shaft (9) of an internal combustion engine is connected with a bearing extension (11) to which a bearing race ring (17) is fixed axially through a bearing (15). A second fly-wheel (25) is firmly connected with the bearing race ring (17) with interposition of a thermal insulating washer (37). The thermal insulating washer (37) thermally decouples the bearing (15) from the second fly-wheel (25). The second fly-wheel (25) is coupled rotationally elastically with the first fly-wheel (1) through a torsional vibration damper (39). <IMAGE>

Description

SPECIFICATION Divided fly-wheel The invention relates to a divided fly-wheel for securing to a crank-shaft of an internal combustion engine.

Divided fly-wheels are known from Fed. German Publication Specifications Nos. 2,826,274 and 2,931,423, in which a second fly-wheel is rotatably mounted through a bearing race ring on a bearing extension of a first fly-wheel screwed on the crankshaft. The second fly-wheel is rotationally elastically coupled with the first fly-wheel through a torsional vibration damper. The mounting of the second fly-wheel substantially directly on the bearing extension of the first fly-wheel is advantageous for the taking up of wobble forces such as are generated for example by the crank-shaft. In motor vehicles the second fly-wheel forms the counter-face of the starting and gear-change clutch and conducts the heat generated by the clutch disc directly into the bearing. The thermal loading reduces the life of the bearing and increases the bearing play.

The bearing play must remain within pre-determined limits even with maximum thermal loading.

On the other hand it must be ensured that the divided fly-wheel is capable of functioning even at very low ambient temperatures, for example in frost.

It is the problem of the invention to indicate a way in which the two fly-wheels can be mounted mechanically stably one on the other and at the same time the thermal loading of the bearing can be reduced in order to prolong the life.

A stable mounting is achieved according to the invention in that the second fly-wheel is mounted through a separate bearing race ring on the bearing extension of the first fly-wheel and a thermal insulation layer is provided between the race ring and the second fly-wheel. The thermal insulation layer thermally decouples the bearing race ring and thus the bearing from the second fly-wheel without detriment to the mechanical strength of the connection. The thermal insulation layer preferably consists of friction material such as is also used for clutch friction linings or the like. This material is easily mouldable and possesses the mechanical strength necessary for the stability of the mechanical connection, as well as good thermal insulation properties.

A further aspect of the invention concerns formations of the torsional vibration damper which render possible the above-explained thermally insulated bearing mounting of the second fly-wheel in a constructionally simple manner.

Examples of embodiment are to be explained in greater detail below with reference to drawings, wherein:- Figure I shows a partial axial longitudinal section through a first form of embodiment of a divided fly-wheel; Figure 2 shows a partial axial longitudinal section through a second form of embodiment of a divided fly-wheel; Figure 3 shows a representation of principle of a torsional vibration damper of the fly-wheel according to Figure 2; Figure 4 shows a partial axial longitudinal section through a third form of embodiment of a divided fly-wheel; Figure 5 shows a partial axial longitudinal section through a fourth form of embodiment of a divided fly-wheel; Figures 6 and7 show partial sectional views of plain bearings for use with the fly-wheels according to Figures 1, 2, 3 and 5.

The divided fly-wheel as represented in Figure 1 comprises a first fly-wheel 1 which is secured with necked-down screws 3, 5 on a motor vehicle internal combustion engine crank-shaft 9 rotating about an axis 7 of rotation. The screws 3 exclusively secure the fly-wheel 1 to the crank-shaft, while at the same time an annular bearing extension 11 is screwed with the aid of screws 5 to the crank-shaft 9. A dowel pin 13 centres the bearing extension 11 and the fly-wheel 1 in relation to the crank-shaft 9.

A bearing race ring 17 is mounted rotatably but axially fixedly through a rolling bearing 15 on the bearing extension 11. The rolling bearing is axially guided between an annular shoulder 19 of the bearing extension 11 and an annular disc 21 secured by means of the screws 5 on the bearing extension 11 and protruding radially beyond the bearing extension 11. Securing screws 23 hold the annular disc 21 independently of the screws 5 on the bearing extension 11. A second fly-wheel 25 is screwed with screws 27 to the bearing race ring 17 on the side axially remote from the first fly-wheel 1. An annular disc 29 is inserted between the race ring 17 and the second fly-wheel 25 and protrudes radially inwards beyond the race ring 17 and fixes the race ring 17 axially between itself and an annular flange 31 of the race ring 17 on the rolling bearing 15.The race 33 of the fly-wheel 25 facing away from the first fly-wheel 1 forms a presser face for the clutch disc of a friction clutch of the vehicle, the clutch cover of which is indicated at 35. In order to keep the friction heat generated on the second fly-wheel 33 away from the bearing 15, an annular thermal insulating washer 37 is interposed between the annular disc 29 and the second flywheel 25. The thermal insulating washer 37 insulates the race ring 17 and thus the bearing 15 thermally form the fly-wheel 25. The thermal insulating washer 37 preferably consists of a mechanically strong material of good thermal insulation, especially of a material which is also usable for friction linings, for example clutch friction linings.

The first fly-wheel 1 is rotationally elastically coupled with the second fly-wheel 25 through a torsional vibration damper 39. The latter comprises two annular side discs 41,43 rotatably enclosing the bearing race ring 17, which are firmly connected with one another by distance rivets 45 in the region of their external circumferences and distance rivets 47 arranged with radial spacing from the distance rivets 45. The side disc 43 adjacent to the first fly-wheel 1 is screwed with screws 49 to the first fly-wheel 1. Axially between the two side discs 41, 43 an annular intermediate disc 51 is arranged which engages fast in rotation with an internal toothing 53 of its internal circumference in an external toothing 55 of the bearing race ring 17.

In windows 57 of the intermediate disc 51 for the one part and axially associated windows 59, 61 of the side discs 41, 43 for the other part there are seated helical compression springs 63 which are resiliently stressed on relative rotation of the intermediate disc 51 and the side discs 41, 43 and couple the side discs 41, 43 rotationally elastically with the intermediate disc 51. The springs 63, only one of which is represented in Figure 1, are arranged in distribution in the circumferential direction on a common diameter circle radially between the distance rivets 45 and 47. A friction device 64 is arranged radially between the race ring 17 and the springs 63 axially between the two side discs 41, 43 for the damping of rotational vibrations.The friction device 65 is of conventional formation and comprises at least one friction ring effective in relative rotation between the side discs 41, 43 and the intermediate disc 51. The friction force is generated by an axially acting spring, for example a dished spring.

Variants of the divided fly-wheel according to Figure 1 are to be explained below. Parts of like effect are here provided with like reference numerals and with a additional letter for distinction. For the explanation reference is made to the description of Figure 1.

In departure from the fly-wheel according to Figure 1 the bearing extension 11a is integrally connected with the first fly-wheel 1a. The race ring 17a carries a radially outwardly protruding annular flange 67 to which the second fly-wheel 25a is secured with rivets 69, the thermal insulation washer 37a being interposed. The torsional vibration damper 39a which couples the fly-wheels 1a and 25a rotationally elastically with one another comprises two intermediate discs 51a arranged with axial spacing from one another, which are riveted to the bearing race ring 17a by means of the rivets 69 in common with the fly-wheel 25a. The side discs 41a, 43a are riveted with common rivets 71 in the region of their external circumferences to the first fly-wheel 1a.An inertia ring 73 secured at the same time by means of the rivets 71 to the flywheel 1a is used as spacer between the side discs 41a and 43a.

The side discs 41a, 43a are rotationally elastically coupled with the intermediate discs 51a through helical compression springs 63a connected in series by pairs (Figure 3). The two springs 63a of each pair are supported on one another in the circumferential direction through a control disc 75.

The control disc 75 is freely rotatably mounted on the race ring 17a axially between the two intermediate discs 51a. The control ring 75 controls a friction device 77 which generates a friction moment on relative rotation of the control ring 75 and the intermediate discs 51 a. For this purpose the friction device 77 is axially resiliently arranged axially between the intermediate disc 51a adjacent to the flywheel 1a and the control disc 75. The relative angle of rotation of the control disc 75 is limited by the rivets 69 and 71. The friction device 77 generates a comparatively high friction moment. Since however only one of the two springs 63a of each pair is bridged over by the friction device 77, the friction device 77 comes into use only when the first-loaded spring of each pair has reached an initial stress force which can overcome the friction moment of the friction device 77.The torsional vibration damper 39a comprises a second friction device 79 which is effective at every relative rotation between the first fly-wheel la and the second fly-wheel 25a. The second friction device 79 has a comparatively low friction moment and is axially resiliently effective between the first fly-wheel la and the bearing race ring 17a.

Figure 4 shows a variant of the divided fly-wheel according to Figure 1 which differs essentially in the construction of the torsional vibration damper 39b. The torsional vibration damper 39b has two side discs 41b, 43b secured to one another with axial spacing in a manner not illustrated further which however are connected not, as in the flywheel according to Figure 1, with the first flywheel, but with the second fly-wheel 25b. The side disc 41b adjacent to the second fly-wheel 25b carries collared nuts 81 in the region of its external circumference, by means of which the fly-wheel 25b is screwed thereto. The intermediate disc 51b is mounted rotatably on the race ring 17b and screwed in the region of its external circumference to the first fly-wheel 1 b through screws 49b.Axially between the two side discs 41b, 43b again a friction device 65b is axially resiliently clamped.

The friction device 65b comprises a control ring 83 which is coupled fast in rotation but with play in the circumferential direction with the intermediate disc 51b. The friction device 65b therefore becomes effective only on exceeding of a predetermined relative angle of rotation between the intermediate disc 51b and the side discs 41b, 43b.

The friction device 65b is provided radially between the springs 63b of the torsional vibration damper and the bearing race ring 17b and generates a relatively great friction moment. A further friction device 85 is effective between the bearing extension 11b and the race ring 17b and generates a comparatively low friction moment, which however is effective in the entire range of rotation angle. The fly-wheel according to Figure 4 has, similarly to the fly-wheel according to Figure 1, the advantage in principle of being easily assemblable from sub-units and dismantlable, while the bearing 15b is thermally insulated.

Figure 5 shows a different design of a divided fly-wheel in which the first fly-wheel 1c secured by means of the screws Sc to the crank-shaft 9c at the same time forms the component of the torsional vibration damper 39c corresponding to the intermediate disc 51 in Figure 1. The bearing extension 11c carrying the bearing 15c is screwed together with the fly-wheel 1c to the crank-shaft 9c by means of the screws 5c. The second fly-wheel 25c is secured by means of rivets 87 to a radially protruding bearing flange 89 of the race ring 17c, which is rotatably mounted on the bearing extension 11through the bearing 15c. The race ring 17c is axially fixed by a radially inwardly protruding collar 31c and a radially inwardly protruding annular disc 29c riveted in between the bearing flange 89 and the second fly-wheel 25c.Again a thermally insulating washer 37c is riveted in between the annular disc 29c and the second fly-wheel 25c.

The torsional vibration damper 39c has two side discs 41c, 43c arranged on axially opposite sides of the fly-wheel 1, which are firmly connected both with spacing with one another and with the second fly-wheel 25c in the region of their external circumferences by distance rivets 45c. Radially between the distance rivets 45 and the race ring 17c the side discs 41c, 43c are connected by additional distance rivets 47c. The helical compression springs 63c of the torsional vibration damper are seated for one part in windows 57c of the first fly-wheel 1c and for the other part in windows 59c, 61c of the side discs 41c, 43c and couple the first flywheel 1c directly rotationally elastically with the side discs 41c, 43c. The torsional vibration damper 39c comprises several friction devices which are effective in different relative rotation angle ranges.

A first friction device 91 is axially effective between the first fly-wheel 1c and the side disc 43c lying axially remote from the second fly-wheel 25c. The friction device 91 generates a relatively slight friction moment and is effective in every relative rotation between the two fly-wheels 1c and 25c. A second friction device 93 is effective between the first fly-wheel 1c and the annular flange 89 of the bearing race ring 17c. The friction device 93 includes a control ring 95 which engages with an axially bent-over tab 97 in an opening 99 of the first fly-wheel 1c. The opening 99 is wider in the circumferential direction than the tab 97, so that the control ring 95 is coupled fast in rotation but with play in the circumferential direction with the first fly-wheel 1c.The friction device 93 is dimensioned for operation under load, and becomes effective only after the overstepping of a predtermined relative angle of rotation between the two fly-wheels 1c, 25c. Moreover a third friction device 101 is effective between the side disc 43c placed axially remote from the fly-wheel 25c and the annular flange 89 of the bearing race ring 17c. The friction device 101 is controlled by control discs 103, 105 in such a way that it becomes effective only in the case of a relative angle of rotation of the order of magnitude of the maximum relative angle of rotation between the two fly-wheels 1c, 25c. The friction device 101 generates a comparatively high friction moment and damps the powerful rotational vibrations occurring on starting and stopping of the internal combustion engine.Each of the three friction devices 91, 93, 101 has a separate axially acting spring for friction moment generation.

The design according to Figure 5 is especially stable, since the second fly-wheel 25c is connected both in the region of its external circumference through the distance rivets 45c with the two side discs 41c, 43c and in the region of its internal cir cumference through the rivets 87 with the bearing race ring 17c.

Figure 6 shows an axial section through a plain bearing usable with the forms of embodiment as explained above for the mounting of the second fly-wheel. The plain bearing 15d comprises an outer race ring 107 which is axially fixed between the radially inwardly protruding annular shoulder 31d of the bearing race ring 17d and the annular disc 29d inserted between the second fly-wheel 25d and the race ring 17d. The outer ring 107 has two sliding ,aces 109, 111 inclined towards one another in the form of two coaxial cone faces which widen axially outwards away from one another. In cross-section the outer ring 107 is made somewhat V-shaped.The race ring 11d is enlcosed by two inner rings 113, 115 arranged axially side by side, which rest with complementary sliding faces on the sliding faces 109, 111 and are fixed axially between the annular shoulder 19d and the annular disc 21d. axial and radial play of the outer ring 107 can be taken up by adjustment of the axial spacing of the inner rings 113, 115. The use of a plain bearing, especially as represented in Figure 6, is expedient since the angle of rotation of the two flywheels Id and 25d is limited and the thermal insulation washer 37d thermally decouples the plain bearing 15d from the second fly-wheel 25d.

Figure 7 shows a variant 15e of the plain bearing in Figure 6. The plain bearing 15e comprises an outer ring 117 fixed axially in the bearing race ring 17e and guided radially with its cylindrical inner circumference 119 on an inner ring 121. The inner ring 121 carries at its end facing the fly-wheel 1e a radially outwardly standing annular flange 123 which guides the outer ring 117 on one axial side on a plane end face. On the side of the outer ring 117 opposite to the annular flange 123 the outer ring 117 is guided by a plane annular disc 125. The inner ring 121 and the annular disc 125 are fixed axially between the annular shoulder 19e of the bearing extension lie and the annular disc 21e.

Axial play of the outer ring 117 can be taken up by adjustment of the distance of the annular disc 125 from the inner ring 121. The outer ring 117 has substantially T-shaped cross-section so that the bearing flange 123 and the annular disc 125 are axially flush with the outer ring 117. The plain bearing 15e is likewise thermally insulated from the second flwwheel 25e by a thermal insulation washer 37e.

Claims

1. Divided fly-wheel for securing to a crankshaft of an internal combustion engine, comprising a. a first fly-wheel (1) for securing detachably to the crank-shaft (9) and connected with a bearing extension (11), b. a bearing race ring (17) mounted rotatably but axially fixedly on the bearing extension (11), c. a second fly-wheel (25) secured on the bearing race ring (17) and rotatable together therewith in relation to the first fly-wheel (1), d. a torsional vibration damper (39) having two damper parts ( 43, 51) substantially of disc form, connected rotationally elastically with one another through a plurality of springs (63) arranged radially outside the bearing race ring (17) and rotatable in relation to one another, of which damper parts one is connected fast in rotation with the first fly-wheel (1) and the other with the second fly-wheel (25), characterised in that the second fly-wheel (25) is secured on the bearing race ring (17) with interposition of a thermal insulation layer (37).

2. Fly-wheel according to Claim 1, characterised in that the thermal insulation layer (37) consists of a friction lining material.

3. Fly-wheel according to Claim 1 or 2, characterised in that the torsional vibration damper (39) is arranged axially between the first fly-wheel (1) and the second (25), in that one of the two damper parts comprises two side discs (41, 43) held with axial spacing from one another by means of spacers and connected firmly with one another and with one of the two fly-wheels and in that the other of the two damper parts comprises at least one intermediate disc (51) arranged axially between the two side discs (41, 43) and connected fast in rotation with the other of the two flywheels, which intermediate disc is supported rotationally elastically through the springs (63) on the side discs (41, 43).

4. Fly-wheel according the Claim 3, characterised in that the side discs (41, 43) are firmly connected with the first fly-wheel (1) on the side of the springs (63) radially remote from the bearing race ring (17).

5. Fly-wheel according to Claim 4, characterised in that the intermediate disc (51) is coupled fast in rotation but axially movably with the bearing race ring (17) at its internal circumference through a toothing (53, 55).

6. Fly-wheel according to Claim 4, characterised in that the bearing race ring (17a) comprises a radially outwardly protruding annular flange (67) to which one or more of the intermediate discs (51a) is or are fixed.

7. Fly-wheel according to Claim 6, characterised in that two intermediate discs (51 a) arranged with axial spacing from one another are provided which are connected through distance rivets (69) with one another and with the annular flange (67).

8. Fly-wheel according to Claim 7, characterised in that the distance rivets at the same time connect the second fly-wheel with the bearing race ring.

9. Fly-wheel according to Claim 7 or 8, characterised in that a control disc (75) rotatable in relation both to the intermediate discs (51 a) and to the side discs (41a, 43a) is arranged axially between the two intermediate discs (51 a), in that the side discs (41a, 43a) and the intermediate discs (51a) are rotationally elastically connected with one another through pairs of springs (63a) arranged in series with one another, in that the spring pairs (63a) are supported on one another in the circumferential direction through the control disc (75) and in that the control disc (75) and the intermediate discs (51a) are connected with a friction device (77) which is especially dimensioned for operation under load.

10. Fly-wheel according to Claim 9, characterised in that the control disc (75) is radially guided with its internal circumference on the race ring (17a).

11. Fly-wheel according to Claim 3, characterised in that the intermediate disc (51 b) is connected with the first fly-wheel (1 b) on the side of the springs (63b) radially remote from the race ring (17b) and the side discs (41b, 43b) are connected with the second fly-wheel (25b) on the side of the springs (63b) radially remote from the race ring (17b).

12. Fly-wheel according to one of Claims 3 to 11, characterised in that a friction device (65, b, 77) dimensioned especially for operation under load is arranged axially between the side discs (41, 43) in the space radially between the race ring (17) and the springs (63).

13. Fly-wheel according to Claim 12, characterised in that with the bearing extension (11a, b) and the bearing race ring (17a, b) there is connected a further friction device (79; 85) effective on relative rotation of the bearing extension (11a, b) and of the race ring (17a, b), the friction moment of which device is less than that of the first friction device (65b; 77).

14. Fly-wheel according to Claim 1 or 2, characterised in that the first fly-wheel (1c) forms one of the two damper parts of the torsional vibration damper (39c), in that the other of the two damper parts comprises two side discs (41c, 43c) arranged on axially opposite sides of the first fly-wheel (1c), which are firmly connected with one another and with the second fly-wheel (25c) on the side of the springs (63c) radially remote from the bearing race ring (17c).

15. Fly-wheel according to Claim 14, characterised in that the side parts (41c, 43c) and the second fly-wheel (25c) are connected with one another through common spacer rivets (45c).

16 Fly-wheel according to Claim 14, characterised in that a first friction device (91) is effective between the first fly-wheel (1c) and the side disc (43c) placed remote from the second fly-wheel (25c) and a second friction device (93) is effective between the first fly-wheel (1c) and the bearing race ring (17c) and in that the second friction device (93) is connected in series with an idle-motion device (97, 99) with the first fly-wheel (1c) and the bearing race ring (17c) and generates a greater friction moment than does the first friction device (91).

17. Fly-wheel according to Claim 16, characterised in that the second friction device (93) comprises a control ring (95) which comprises at least one axially protruding tab (97) which engages with play in the circumferential direction in an opening (99) of the first fly-wheel (1c).

18. Fly-wheel according to Claim 16 or 17, characterised in that a third friction device (101), the friction moment of which is greater than the friction moment of the second friction device (93), is effective between the first fly-wheel (1c) and at least one of the side discs (41c, 43c) on exceeding of a predetermined relative angle of rotation be tween the first fly-wheel (1c) and the side discs (41c, 43c).

19. Fly-wheel according to Claim 18, characterised in that the predetermined relative angle of rotation is selected in the order of magnitude of the maximum relative angle of rotation of the torsional vibration damper (39c).

20. Fly-wheel according to one of Claims 1 to 19, characterised in that the bearing race ring (17, a, b, c) is mounted through a rolling bearing (15a, b, c) on the bearing extension.

21. Fly-wheel according to one of Claims 1 to 19, characterised in that the bearing race ring (17d, e) is mounted on the bearing extension (ill, e) with adjustable bearing play through a multi-part plain bearing (15d, e).

22. Fly-wheel according to Claim 21, characterised in that the plain bearing (15d) comprises an outer ring (107) having two sliding faces (109, 111) inclined radially inwards in V-form towards one another in cross-section and two inner rings (113, 115) arranged axially adjustably side by side, each with a complementary sliding face.

23. Fly-wheel according to Claim 21, characterised in that the plain bearing (15e) comprises an inner ring (121) provided with a radially outwardly protruding annular flange (123), an annular disc (125), which is axially adjustable in relation to the inner ring (121), axially laterally of the inner ring (121), and an outer ring (117) guided radially on the inner ring (121) and axially bewteen the annular disc (125) and the annular flange (123).

24. Divided fly-wheel as claimed in Claim 1, substantially as described herein with reference to and as illustrated by any one of the examples shown in the accompanying drawings.