GB2194835A

GB2194835A - Torsional vibration damper

Info

Publication number: GB2194835A
Application number: GB08716759A
Authority: GB
Inventors: Andreas Forster
Original assignee: Fichtel and Sachs AG
Current assignee: ZF Sachs AG
Priority date: 1986-07-19
Filing date: 1987-07-16
Publication date: 1988-03-16
Anticipated expiration: 2007-07-16
Also published as: FR2601741B1; GB8716759D0; DE3624498C2; GB2194835B; DE3624498A1; FR2601741A1

Abstract

Displacement chambers 25 act as hydraulic end stops in a torsional vibration damper. The displacement chambers 25 are connected in their middle region with a lubricant pocket 32 and a storage pocket 29 for lubricant so that only in the end region of the maximum angle of rotation of an extension 19 within the chamber is hydraulic damping effective. At the same time unhindered access of lubricant into the displacement chambers is possible, whereby for example it is also possible to use grease. <IMAGE>

Description

SPECIFICATION Torsional vibration damper with lubricant filling and hydraulic end stop The invention reiates to a torsional vibration damper, especially for installation in the drive line of motor vehicles, consisting of a hub disc with windows for the reception of springs, side discs arranged to both sides of the hub disc with corresponding windows, the hub disc being made closed all round radially outside the springs, with at least one radially outwardly protruding extension which engages in a circumferentially limited aperture of a counter-piece or ring part connected with the side discs for the formation of displacement chambers which are at least partially filled with lubricant and sealed to the exterior, while furthermore the side discs tightly surround the springs and are likewise sealed off in relation to the hub disc radially within the springs.

A torsional vibration damper of the abovestated construction type is known by way of example from German Patent Specification No.

2,848,748. In this known torsional vibration damper at every relative movement between the hub disc and the side discs a displacement operation is executed. It is here immaterial whether the rotation angle deflections are large or small.

It is the problem of the present invention to improve a torsional vibration damper of the above-stated construction type to the effect that the damping action is effective especially in the region of the maximum angle deflections even when lubricants such as viscous oil grease are used, even if air is included in the comparatively thickly liquid lubricant.

In accordance with the invention this problem is solved by the characteristic of the main claim. Due to the arrangement of simply produced storage pockets (passages) between the region of the springs and the apertures which act as end stop, the lubricant accommodated in the torsional vibration damper can flow without major resistance directly into the displacement chambers, namely by way of window-like lubricant pockets which are made smaller in the circumferential direction than the corresponding aperture. Thus the object is achieved that at smaller amplitudes of the mutual rotation practically no damping takes place and only in the region of the end stops does the introduced lubricant become effective as hydraulic end stop.At the same time it is ensured that the lubricant displaced in the region of the end stops can flow back again into the liberated spaces immediately after the return movement of the individual parts of the torsional vibration damper, so that in the subsequent vibration a satisfactory damping can already take place again. In this way it is also guaranteed that this type of end stop is also effective for example with viscous grease as lubricant and air inclusions are centrifuged away radially inwards.

For easier production of the individual parts and easier adaptation of the function it is proposed to make each side disc in two parts, while the inner disc part in each case extends parallel and close to the hub disc, comprises the windows for the springs, extends as far as the ring part and in the region of the aperture comprises windows for the entry of the lubricant and the outer disc parts tightly surround the inner disc parts and the torsion springs and comprise pockets or passages open towards the hub disc, which reach from the space accommodating the springs to the windows of the inner disc parts. Thus for the one part the inner disc parts can be used both for the reception of the springs and for the action of the springs and for the formation of exact windows for the passage of the lubricant and for the control of the end stops.The outer disc parts then take over the function of the seal to the exterior and form passages for the supply of the lubricant from the radially inner zones into the radially outer zones of the torsional vibration damper.

In an advantageous manner the axial projections of the edges, facing in the circumferential direction, of extension piece and window extend at an angle radially outwards towards one another. Thus the use of the lubricant displacement and thus the use of the hydraulic end stop become continuously possible.

In the arrangement of such a torsional vibration damper within a two-mass system the primary mess can be formed as outer disc part, and in that case the two inner disc parts and the other outer disc part together with the ring part arranged therebetween are arranged axially one behind the other and tightly connected with the primary mass. The connection can be effected preferably by riveting.

The invention will next be explained in greater detail by reference to examples of embodiment. Individually: FIGURE 1 shows the longitudinal section through a torsional vibration damper as part of a clutch disc; FIGURE 2 shows the partial section along the line il-ll in Figure 1; FIGURE 3 shows the longitudinal section through a two-mass system with corresponding torsional vibration damper; FIGURE 4 shows the partial section along the line IV-IV in Figure 3.

Figures 1 and 2 show the upper half of a longitudinal section through a torsional vibration damper 1 within a clutch disc and the partial section 11-1 1. The torsional vibiation damper 1 comprises a hub disc 3 which is connectable through a toothing fast in rotation with a gear shaft. The hub disc 3 comprises several windows 5 distributed on the circumference for the reception of torsion springs 7.

On both sides of the hub disc 3 there are arranged side discs 8 and -9 which in the present case can be made for example as castings. The side discs 8 and 9 extend parallel with the hub disc 3 and in the region of the springs 7 comprise outward bulging portions to form windows 14 and 15 for the charging of the springs 7. Radially outside the external circumference of the hub disc 3 the two side discs 8 and 9 are firmly connected with one another. Here the side disc 8 comprises for example integrally a ring part 23. As may be seen especially in combination with Figure 2, on the external circumference of the hub disc 3 there are provided preferably several extensions 19 distributed on the circumference which engage in corresponding apertures 21 of the ring part 23 with play in the circumferential direction.Here the edges 35 of the extensions 19 form with the edges 45 of the apertures 21 rotation angle limitations at maximum torque loading between the hub disc 3 and the side discs 8 and 9 (the friction linings (not shown) of the clutch disc are connected fast in rotation with the side disc 8). Seals 27 are arranged on the internal circumferences of the two side diacs 8 and 9 so that the interior space within the two side discs 8 and 9 and of the ring part 23 with the aprings 7 can be filled at least partially with a lubricant which ensures a low-wearing operation of the torsion spring system. This lubricant can at the same time be used as what is called a hydraulic end stop, in that the extensions 19 of the hub disc 3 and the apertures 21 of the ring part 23 form displacement chambers 25.

Due to appropriate small radial and axial gaps between the parts rotatable in relation to one another, on relative rotation a displacement work has to be performed in relation to the lubricant in the form of oil or grease. In order however that torsional vibrations with small amplitudes as far as possible are not damped and on the other hand however that the flow of the lubricant can take place with as little hindrance as possible into the displacement chambers, the side discs 8 and 9 are provided with passages or storage pockets 29 which are made open in the direction towards the hub disc 3 and reach in each case from the region of the springs 7 into the displacement chambers 25.These storage pockets 29 end in pockets 32 and 33 respectively which in the radial direction correspond approximately to the external diameter of the extensions 19 and are made shorter in the circumferential direction than the circumferential extent of the apertures 21 in the ring part 23.

The edges 35 of the extensions 19 and the edges 45 of the aperture 21 in the usual way extend substantially radially while the edges 37 of the pockets 33 are preferably made oblique so that the action of the hydraulic end stop on movement of the edges 35 towards the edges 45 takes place gradually. As may be seen especially from the right half of Figure 2, on rotation of the hub disc 3 to the right in relation to the main part 23 out of the position as illustrated firstly no hydraulic damping takes place since the displacement chamber 25 remains opened by way of the pocket 33.

On increasing approach of the edge 35 to the edge 45 a gradual closure of the displacement chamber 25 to the exterior is effected by the oblique edge 37 of the pocket 33 opposite to the edge 35 of the extension 19, so that in this displacement chamber the hydraulic pressure gradually rises. If now the edge 35 has run completely over the edge 37, the displacement chamber 25 is still in communication with the remainder of the interior space only by way of radial and axial throttle gaps between the hub disc 3 and the side discs 8 and 9. According to the formation of these gaps a hydraulic displacement work must be performed in order that a further relative rotation may be executed.In the reverse movement of the hub disc 3 and at the beginning of the opening of the window 33 lubricant can immediately flow into the disolacement chamber 25 and the displacement work is immediately interrupted. Here the storage pockets can be moved to extend around in the circumferential direction by way of passages 31 according to Figure 2.

According to the nature of the desired damping in the region of the end stop naturally the corresponding edge can extend radially, as represented by the example of the pocket 32.

In Figures 3 and 4 a torsional vibration damper 2 is part of a two-mass system. Functional differences from the example of embodiment according to Figures 1 and 2 are not to be encountered here. The assembly differs however in several points. The two-mass system consists of the primary mass 10 and the secondary mass 39 which are mounted rotatably in relation to one another by means of a bearing 40 and are fixed in the axial direction.

The primary mass 10 is connected fast in rotation with the crank-shaft (not known) of an internal combustion engine and forms an outer disc part of the torsional vibration damper 2.

In the axial direction the primary mass 10 is adjoined by an inner disc part 12, the ring part 24, another inner disc part 13 and another outer disc part 11. All the parts are riveted firmly and tightly with one another in the region of their external diameter by means of rivets 41. Between the two inner disc parts 12 and 13 the hub disc 4 is arranged which is connected elastically in the circumferential direction with the two inner disc parts 12 and 13 through springs 7 and is set with its radially inwardly arranged toothing 42 fast in rotation on a toothing 43 of the secondary mass 39. The hub disc 4 and the inner disc parts 12 and 13 are equipped with windows 8 and 18, 17 for the reception of the springs 7.

Windows 18 can likewise be provided in the primary mass 10. Radially outside these windows the hub disc 4 preferably comprises several extensions 20 distributed on the circumference which form rotation angle stops with the ring part 24. For this purpose the ring part 24 is provided with apertures 22.

Pockets 34 are arranged in the two inner disc parts 12 and 13 approximately in the region of these apertures 22 which pockets in combination with the passages or storage pockets 30 in the outer disc parts 11 and primary mass 10 are responsible for the friction-free supply of the lubricant into the displacement chambers 26. Here in parallel with the embodiments according to Figures 1 and 2 the arrangement is made such that the edges 38 of the pockets 34 are arranged circumferentially with spacing from the edges 46 of the ring part 24 and form an angle with the edges 36 of the extensions 20. On relative rotation between the hub disc 4 and the disc parts 10, 11, 12, 13 with small angular deviation thus no damping will take place, since the pockets 34 are opened. Only when the edges 36 travel over the edges 38 will a pressure build up in the displacement chambers 28 as a result of the mutual oblique positioning, which pressure increases with increasing angle of rotation. After the edges 36 and 38 overlap this pressure will be dependent upon the throttle passages or gaps which are still present between the relatively movable parts.

It can further be seen from Figure 3 that the outer disc part 11 is made as a thin sheet metal part and radially outside the rivets 41 has a seal 44 due to insertion of an elastic 0ring. The seal in the radially inner space takes place by means of a friction device 28, friction rings being utilised as sealing elements on both sides of a hub disc 4, which rings make use of the pressure application force of a spring between the secondary mass 39 and the radially inner region of the disc part 11 for friction generation.

Claims

1. Torsional vibration damper especially fof the drive line of a motor vehicle comprising a) a hub disc (3; 4) rotatable about a rotation axis, b) two side discs (8, 9; 10, 11; 12, 13) of substantially annular disc form arranged on axially opposite sides of the hub disc (3; 4), which side discs are connected by way of a ring part (23; 24) erlclosing the hub disc (3; 4) to form a housing unit rotatable about the rotation axis in relation to the hub disc (3; 4) and accommodating the hub disc (3; 4) at least partially and a lubricant supply in sealed manner in itself, c) several springs (7) arranged within the housing unit in openings (5, 14, 15; 6, 16, 17) of the hub disc (3; 4) for the one part and of the side discs (8, 9; 10, 11, 12, 13) for the other part, which springs couple the hub disc (3; 4) rotationaily elastically with the side discs (8, 9; 10, 11, 12, 13), d) several radially inwardly open apertures (21; 22) offset in relation to one another in the circumferential direction on the internal circumference of the ring part (23; 24), in each of which there engages an extension (19; 20) protruding from the external circumference of the hub disc (3; 4) while circumferentially adjacent end zones of the apertures (21; 22) together with the extensions (19; 20) form lubricant-filled displacement chambers (25; 26) which are connected through throttle passages with displacement chambers (25; 26) in each case adjacent in the circumferential direction, characterised in that the apertures (21; 22) form, in the circumferential direction between adjacent end zones forming the displacement chambers (25; 26), lubricant pockets (32, 33; 34) open axially to the extension (19; 20) and radially inwards, which pockets are wider in the circumferential direction than the extension (19; 20) engaging in the aperture (21 ; 22) and with their end faces (37) lying opposite to one another in the circumferential direction limit the end zone of the aperture (21; 22) forming the displacement chambers (25; 26) and in that storage pockets (29, 31; 30) for lubricant are provided axially between the hub disc (3; 4) and at least one of the side discs (8, 9; 10, 11, 12, 13), which pockets extend radially away over the springs (7) and are opened radially to the lubricant pockets (32, 33; 34) of the aperture (21; 22).

2. Torsional vibration damper according to Claim 1, characterised in that the storage pockets (29, 31; 30) are formed into the side disc or discs (8, 9; 10, 11, 12, 13) and merge into the lubricant pockets (32, 33; 34).

3. Torsional vibration damper according to Claim 1 or 2, characterised in that the storage pockets (29, 31) of several springs (7) merge into one another in the circumferential direction,

4. Torsional vibration damper according to one of Claims 1 to 3, characterised in that at least one of the side discs (10, 11, 12, 13) consists of an inner disc part (12, 13) axially adjacent to the hub disc (4) and an outer disc part (10, 11), sealed off from the hub disc (4), on the side of the inner disc part (12, 13) axially remote from the hub disc (4), and in that the inner disc part (12, 13) comprises openings (16, 17) formed as windows (16, 17) for the reception of the springs (7) and the outer disc part (10, 11) contains the storage pockets (30).

5. Torsional vibration damper according to Claim 4, characterised in that the two side discs comprise an inner disc part (12, 13) and an outer disc part (10, 11) and in that one of the outer disc parts is formed as primary flywheel (10) of a two-mass fly-wheel system on which a secondary flywheel (39) is mounted and in that the other (11) of the two outer disc parts and the two inner disc parts (12, 13) are firmly riveted with the primary flywheel (10).

6. Torsional vibration damper according to one of Claims 1 to 5, characterised in that the end faces (37) of the lubricant pockets (32, 33; 34), lying opposite to one another in the circumferential direction in the aperture (21; 22), extend obliquely at an angle opening towards the rotation axis to the adjacent end face (35; 36), facing in the circumferential direction, of the extension (19; 20).

7. Torsional vibration damper as claimed in Claim 1, substantially as described with reference to Figure 1 & 2 or Figure 3 & 4 of the accompanying drawings.