DE112009002560B4 - Hydrodynamic torque converter with lock-up clutch - Google Patents

Abstract

Hydrodynamic torque converter (1) with a housing (2) arranged concentrically around a hub (10) and non-rotatably connected thereto, in which a pump wheel, a turbine wheel, a stator and a lockup clutch (4) with a disk pack (6) are arranged, and the disk set (6) has at least one friction surface which is engageable with a Gegenreibfläche in an end plate (6b), wherein the friction surfaces are provided with cooling grooves, and the lockup clutch (4) one of two part pistons (5a, 5b) has a composite piston (5), and the piston (5) upon pressurization of the disk set (6) via the end face of its partial piston (5b) for additional friction partner, characterized in that serving for cooling the friction partner of the lockup clutch (4) , via the torque converter (1) circulated cooling oil by means of paddle rings or pad sealing lips (18), the section W are provided between the fins (6a, 6b), forcibly and completely by the piston (5) and the cooling grooves of the plate pack (6) is passed.

Description

The invention relates to a hydrodynamic torque converter with lockup clutch having the features of the preamble of claim 1.

Hydrodynamic torque converter with friction ring or friction lining and equipped with such a wet-running clutches are by the US 4,969,543 and the US 5,056,631 known. Since the oil in known hydrodynamic torque converters from the external converter cooling circuit is not guided deliberately over the converter lock-up clutch to be cooled, hydrodynamic flow converters with a lock-up clutch are described in these two US patents, in which the engaged friction surfaces are designed such that even when closed Bridging coupling an oil flow between the chambers provided on both sides of an annular piston chambers is made possible. These hydrodynamic flow transducers have a housing in which a pump impeller, a turbine wheel, a stator and the lock-up clutch, which has the annular piston, are accommodated. Both sides of the ring piston are provided with oil-filled chambers. The first of the chambers is formed radially within the friction surfaces of the lock-up clutch and limited by the annular piston and a radial wall of the housing, while in the second chamber, at least the turbine wheel is arranged. The oil flow serves to reduce the thermal load of the components occurring as a result of slippage in the lockup clutch, in particular in the area of the friction lining or the friction surfaces.

Further, solutions are known which seek to guide the oil by communicating all possible flow paths of the cooling oil, except those paths which pass through the lockup clutch, through guide plates and sealing elements (eg disc springs between adjacent parts rotating at the same speed) provided with a high flow resistance, so that the cooling oil flow through the converter substantially leads to the lockup clutch and in combination with Nutmustern having a self-conveying effect, the cooling oil is at least partially supported by the cooling grooves. This principle is used in the DE 103 50 935 A1 described. In this solution can be optimized by appropriate measures the flow of oil through the fins of a torque converter lockup clutch. For this purpose, the flow resistance for the oil is increased in the area that is far from the converter lock-up clutch. With a second, independent measure, however, the flow resistance for the oil is reduced via the torque converter lock-up clutch.

The WO 2007/079713 shows a solution for a forced oil flow converter. Here, the oil drain is deliberately directed only via the converter lockup clutch by an attached on the side of the piston additional wall is applied to the piston, which faces away from the disk pack and thus the pressure chamber for the piston. The end of this additional wall, which is arranged near the disk pack, is applied essentially oil-tight on the surface of the adjacent disk. The other end of the additional wall, which is close to the transmission input shaft, is rotatable and in turn connected to it in an oil-tight manner.

In addition, according to WO 2007/048505 A1 known to remove the oil for cooling the converter lockup clutch from the pressure space between the piston and converter housing by a bore in the clutch piston is provided through which the oil can flow or by a leakage at the seal in the outer diameter portion of the piston is made specifically for cooling. However, this production of a processable defined leakage is very difficult, since a leak very tolerance, wear and the degree of contamination of the oil used is dependent and can not be reliably maintained over the entire life. In addition, the use of the pressurized oil for firing the clutch to cool the lockup clutch from a 3-channel converter principle makes a 2-channel converter principle and the cooling flow can not be controlled independently of the clutch closing pressure. In addition, at low torque and high slip speeds, not enough cooling flow is conducted through the torque converter lock-up clutch.

Furthermore, it is off EP 1 843 062 A2 a fluid-filled coupling arrangement is known in which an output side of a piston output side pressure space is limited at least substantially on the one hand by the output side of the piston and on the other hand by a partition wall associated with the piston, which in turn between the output side pressure chamber and a cooling space in a friction region having provided coupling.

However, in order to save parts and to realize a leaner coupling concept is used especially for a lockup clutch with one or two friction linings (TwinPlate) the clutch piston used to close the lockup clutch quasi as a friction partner, on the back of a heat accumulation in the oil is caused, however, disadvantageous thereby the oil can affect, since the oil is not replaced behind the piston. The consequence of this is continual warming, causing critical, oil-damaging temperatures can be achieved, which can cause a change in the coefficient of friction characteristic and thus form the basis for a judder of the clutch.

Therefore, the object of the invention is to provide a hydrodynamic torque converter with a lockup clutch, are reduced by the improved cooling of the lockup clutch, the maximum temperatures generated by the friction loss at the friction surfaces of a clutch, thereby reducing the life of the oil and the friction linings Lengthen clutch.

This object is achieved with a hydrodynamic torque converter with a lockup clutch having the features of claim 1.

Thereafter, the surrounded by a housing hydrodynamic torque converter is arranged concentrically around a hub and rotatably connected thereto. In this a pump impeller, a turbine wheel, a stator and a lockup clutch with a disc pack are arranged. The disk pack has at least one friction surface which can be brought into engagement with a counter friction surface in an end disk. The friction surfaces are usually provided with cooling grooves. Next, the torque converter lock-up clutch has a piston composed of two pistons, which is the additional friction partner under pressure of the disk set on the face of its piston part, serving for cooling the friction partner of the converter lockup clutch, circulated through the torque converter cooling oil, forcibly and completely by the piston and the cooling grooves of the disk set is passed.

In an advantageous embodiment of the torque converter, the point of introduction of the oil, starting from the piston, in the disk set is freely selectable. The same applies to the point of discharge of the oil from the disk pack.

In addition, it is advantageous that the partial piston facing the converter lockup clutch has at least one recess in the region of this converter lockup clutch. Also, a plurality of recesses may be arranged distributed over the circumference of this partial piston.

In order to produce a connection through the disk pack, it is particularly advantageous if the at least one disk is provided with at least one recess. However, a plurality of recesses may be arranged distributed over the circumference of the annular surface of the lamella, which are either arranged on the same diameter or can also be spaced apart radially.

Furthermore, it is advantageous for the formation of a space that the two partial pistons are connected to one another via at least one connection point, which is preferably located at or in the vicinity of the outer diameter of at least one of the partial pistons.

However, a connection formed as an annular curvature sealing connect the facing annular surfaces of the partial piston with each other. However, the connection between the two partial pistons can also not be sealing, but be designed so that a channel stops in the radial direction.

In a further advantageous embodiment of the invention, the disk set of the lockup clutch consists of at least one blade and an end plate. This design of the torque converter lockup clutch is sufficient to realize the positively driven oil flow according to the invention. If more axial space is available, several lamellae and one end lamella can be joined together to form a lamella package. Important for the realization of a coupling function, however, is that both the at least one lamella to the respectively adjacent lamella or to the end lamella and the end lamella again to the immediately adjacent lam has friction linings, which are traversed by cooling grooves. To ensure the discharge of the oil from the disk pack, it is either necessary that the exit of the oil from the at least one lamella takes place in the amount of the outer or inner diameter of the end plate or the end plate has at least one recess. As with the at least one lamella, several recesses may also be distributed over the circumference of the annular surface of the end lamella.

In a further embodiment, the at least one lamella can be provided with at least one recess. Advantageously, a plurality of recesses distributed over the circumference of the annular surface of the lamella are arranged on the same diameter or radially spaced from each other.

To form a channel in the disk set, it is particularly advantageous that the ends of the at least one lamella and the respective free end of the end lamella are spaced from the opposite component surface.

In an inventive embodiment of the invention, the path of the oil flow through the Lockup clutch limited in the radial direction by appropriately between the friction surfaces bearing parts of the torque converter lockup clutch and the disk pack used Belagdichtringe or lining sealing lips.

Through the formation of channels, by producing recesses in the respective components or by introducing sealing points between axially adjacent components, the path of the cooling oil from the piston via the torque converter lockup clutch is predetermined and thus forcibly guided oil flow, so that achieves optimum cooling of the oil becomes.

The invention will be explained in more detail with reference to an embodiment and associated drawings.

• 1a eine Teilschnittdarstellung eines geschlossenen Kolbens (Sandwichkolben) einer Wandlerüberbrückungskupplung mit zentraler Ölzufuhr und „offener“ Endlamelle,
• 1b eine Teilschnittdarstellung eines geschlossenen Sandwichkolbens einer Wandlerüberbrückungskupplung mit zentraler Ölzufuhr und „offener“ Endlamelle,
• 2 eine Teilschnittdarstellung eines geschlossenen Sandwichkolbens gemäß 1 b, mit einer Belagdichtringanordnung für die Abdichtung der Ölzufuhr in einer ersten Variante,
• 3 eine Teilschnittdarstellung eines geschlossenen Sandwichkolbens gemäß 1b mit einer weiteren Variante der Belagdichtringanordnung für die Abdichtung der Ölzufuhr,
• 4 eine Teilschnittdarstellung eines geschlossenen Sandwichkolbens einer Wandlerüberbrückungskupplung mit weiteren konstruktiven Ausbildung für eine Ölzufuhr,
• 5 eine Teilschnittdarstellung eines offenen Sandwichkolbens einer Wandlerüberbrückungskupplung mit einer Belagdichtringanordnung wie in 2 und „offener“ Endlamelle,
• 6 eine Teilschnittdarstellung eines offenen Sandwichkolbens einer Wandlerüberbrückungskupplung mit einer Ölzufuhr wie in 4 und geschlossener Endlamelle,
• 7a und 7b eine Teilschnittdarstellung eines geschlossenen Sandwichkolbens einer Wandlerüberbrückungskupplung mit jeweils abwechselnder Richtung der Ölzu fuhr durch die Reibbeläge der Wandlerüberbrückungskupplung,
• 8 eine Teilschnittdarstellung eines geschlossenen Sandwichkolbens einer Wandlerüberbrückungskupplung mit einem Außenlamellenträger als einer weiteren konstruktiven Möglichkeit für die drehfeste Verbindung der Endlamelle und evtl. weiterer Außenlamellen jeweils mit dem Antrieb und der Abdichtung der Ölzufuhr,
• 8a eine vergrößerte Darstellung eines Ausschnittes aus 8, der den Bereich der Abdichtung der Ölzufuhr zeigt.

Show it:

• 1a a partial sectional view of a closed piston (sandwich piston) of a lockup clutch with central oil supply and "open" Endlamelle,
• 1b a partial sectional view of a closed sandwich piston of a lockup clutch with central oil supply and "open" Endlamelle,
• 2 a partial sectional view of a closed sandwich piston according to 1 b , with a pad sealing ring arrangement for sealing the oil supply in a first variant,
• 3 a partial sectional view of a closed sandwich piston according to 1b with a further variant of the pad sealing ring arrangement for the sealing of the oil supply,
• 4 a partial sectional view of a closed sandwich piston of a torque converter lock-up clutch with further structural design for an oil supply,
• 5 a partial sectional view of an open sandwich piston of a lockup clutch with a Belagdichtringanordnung as in 2 and "open" end plate,
• 6 a partial sectional view of an open sandwich piston of a lockup clutch with an oil supply as in 4 and closed end plate,
• 7a and 7b a partial sectional view of a closed sandwich piston of a lockup clutch with each alternating direction of Ölzu drove through the friction linings of the lockup clutch,
• 8th a partial sectional view of a closed sandwich piston of a converter lockup clutch with an outer disk carrier as a further constructive possibility for the rotationally fixed connection of the end plate and possibly further outer plates each with the drive and the sealing of the oil supply,
• 8a an enlarged view of a section from 8th showing the area of oil supply sealing.

The 1 to 8th show a partial section of a lockup clutch 4 a torque converter 1 with a housing 2 , wherein the designation of the same components is retained in all figures. This torque converter lockup clutch 4 consists essentially of a piston 5 , by means of two interconnected partial pistons 5a and 5b assembled into a so-called "sandwich piston" and concentric on a hub 10 with a rotation axis 3 is arranged, with which he is firmly connected. In this case, the partial piston forms 5a in relation to the lockup clutch 4 the outer sub-piston and the sub-piston 5b corresponding to the inner part pistons. Next is this piston 5 with the disk pack 6 the lockup clutch 4 in operative connection, wherein in this embodiment a blade 6a with a plate carrier 7 connected and also concentric around the hub 10 is arranged. The slat package 6 further includes an end plate 6b that in this and in the 1b in the case 2 is pressed. The faces of the slats 6a and 6b are provided with a friction lining. Both at the 1a and 1b , each a non-inventive embodiment of the torque converter 1 show, as well as the following figures is the lamella 6a on both sides, the end lamella 6b on the other hand, one-sided, provided with a friction lining, the lamella 6a is facing. This respective friction lining has depressions that follow, for example, a pattern. In this way, a positive guidance of an oil flow is generated by cooling grooves, which are used for cooling the friction partners and thus both the piston 5 as well as the slats 6a . 6b necessary is.

Next is this torque converter 1 on the drive side rotationally fixed with a driving disc 12 connected. Starting from this basic structure, are in the 1a and 1b both partial pistons 5a and 5b connected to each other at the outer circumference so that a circumferential groove is formed by this connection, into which a seal in the form of a sealing element 11 for sealing the piston 5 opposite the wall of the housing 2 is introduced. In addition, it is apparent from these two figures that both in the sub-piston 5b as well as in the lamella 6a several recesses distributed over the circumference 9a and 9b are provided in the form of, for example, bores, preferably on the the same diameter are arranged, wherein the recesses in the partial piston 5b With 9a and the recesses in the lamella 6a With 9b be designated. Preferably, the recesses 9a in the piston 5 in this embodiment, on the same diameter as that of the recesses 9b the slat 6a arranged so that over the length of each channel is formed. In these figures, these recesses 9a and 9b preferably on an average diameter and in the region of the disk carrier 7 the slat 6a arranged.

In 1a in which the piston 5 not yet the disc pack 6 acted upon by pressure, the path of the oil flow for cooling the friction partner is indicated by arrows. It can be seen that that for cooling the torque converter lockup clutch 4 external oil through a radial bore 13 in the hub 10 exit. From this it gets into the space of the double-walled sandwich piston 5 , flows through it in the direction of torque converter lockup clutch 4 , enters through the recesses 9a . 9b through, flows through the cooling grooves of the friction linings of lamella 6a and end lamella 6b and also flows around the inner diameter of both the lamella 6a as well as the by the inner diameter of the Endlamelle 6b to the adjacent plate carrier formed annular recess 15 to finally have corresponding recesses 14 in the lining carrier 7 and recesses 16 in the end lamella 6b in the converter room 17 to get.

In this way, the oil, starting from the hub 10 , via the lockup clutch 4 heated. It can then cool down in the converter room 16 ,

In 1b the flow for the oil is blocked by the piston 5 the disk pack 6 subjected to pressure and thus the entry of the oil to the converter room 17 through the recesses 9a closes. Thus, no oil neither the recesses 9b still the remaining recesses 14 . 15 and 16 to reach.

Unlike the 1a and 1b is in the 2 the disk pack 6 and thus each lamella 6a and 6b on the inner diameter with a pad seal 18 provided the space between the slats 6a . 6b in the direction of the hub 10 seals. Otherwise, in this figure by means of the arrow the path of the oil from the entrance into the space of the sandwich piston 5 about the recesses 9a the lockup clutch 4 with her disc pack 6 shown. Because the disk pack 6 in the direction of the hub 10 is sealed, the positively driven oil can only through the recesses 16 in the end lamella 6b in the converter room 17 get there and cool down there.

In 3 is the torque converter lockup clutch 4 , as well as in 2 , closed. In this embodiment, the recesses 9a of the partial piston 5b again congruent with those in the lamella 6a the lockup clutch 4 provided recesses 9b arranged. Besides, unlike 2 , the disc pack 6 the lockup clutch 4 in the area of the circumference of the lamella 6a sealed. This is in each case in the inter alia specified by the thickness of the friction linings between the slats 6a and 6b a pad seal 18 arranged. Thus, the oil flow passes in this case over the hub according to the direction of the arrow in this case 10 first in the space between the two pistons 5a and 5b of the sandwich piston 5 , flows through the recesses 9a and 9b of partial pistons 5b or lamella 6a To get over the cooling grooves of the friction linings of the plate pack 6 over the inner diameter both through the recesses 14 in the lining carrier as well as by the inner diameter of the end plate 6b to the lining carrier 7 formed annular recess 15 finally in the converter room 17 to get.

Other options for specifying the oil path are described in the following 4 to 8th shown, the lockup clutch 4 each shows in the closed state. For example, according to 4 , which is a non-inventive embodiment of the torque converter 1 shows the possibility of specifying the oil path in that the recesses 9a of the partial piston 5b so far be laid out that the inner diameter of these recesses 9a greater than the outer diameter of the lamella 6a or coincides with this. In addition, the inner diameter of the lamella 6a chosen so that this in the recesses 14 of the disk carrier 7 ends. This can be done in the space between the sandwich piston 5 located oil both, starting from the recesses 9a in the partial piston 5b over the outside diameter of the lamella 6a , From there on the cooling grooves of the friction linings of the disk set 6 , on the one hand on the end of the inner diameter of the Endlamelle 6b formed annular recess 15 and on the other hand on the in the plate carrier 7 provided recesses 14 in the converter room 17 flow.

Unlike the described 1 to 4 shows 5 Another possible design of the sandwich piston 5 which is open at the outer diameter. In this piston 5 is the partial piston 5a designed cup-shaped in its end and so to the partial piston 5b arched out, that with its encircling curvature 19 (or several vaults 19 on the same or different diameter) sealingly on the flat end face of the partial piston 5b is applied. In this way, the actual connection between both pistons 5a and 5b produced. The curvature can be just as good 19 through the partial piston 5b be generated. Through this vault / s 19 a more uniform surface pressure distribution is generated at the friction surfaces of the friction partners. In addition, in this embodiment, the outer diameter of the sub-piston 5b preferably equal to the lamella 6a , so that between the wall of the cup-shaped end of the partial piston 5a and the lateral surfaces of part piston 5b and lamella 6a a circulating channel 20 formed in the recesses provided in this area 16 the one with the case 2 caulked end fin 6b opens. Next is a channel from the recesses 9a and 9b formed radially within the circumferential seal of both sub-piston 5a and 5b as a result of the curvature 19 are introduced. In addition, turn in this channel towards the hub 10 inserted lining sealing rings 18 for a radial seal in this direction. Due to the generated seal between the two pistons 5a and 5b in the region of the end face of the partial piston 5b in the form of the circumferential curvature 19 or piston nose is the in the space of the sandwich piston 5 Forced oil forced into through the recesses 9a and 9b formed channel in the disk pack 6 to flow in, as the arrow indicates. The oil can in the outer diameter range of the friction linings of the slats 6a and 6b emerge, wherein it flows through the cooling grooves to ultimately over the recess 16 in the range of the outer diameter of the end plate 6b in the converter room 17 to get.

6 shows a further embodiment of the sandwich piston 5 who as well as in 5 , open at the outer end. Likewise, its sub-piston 5a as in 5 an annular curvature 19 in the form of a piston nose, which has a certain diameter range, to form a pressing surface for a clutch closing force introduction. These, however, opposite 5 at least in the radial direction is designed so that relative to the sub-piston 5b a channel is formed. As in the previous figures, the end plate is 6b firmly with the converter housing 2 connected. Otherwise the oil will continue according to the arrows as in 4 pointed, forcibly guided, wherein the flow of oil is deflected so that it flows through the cooling grooves of the friction linings radially inwardly. After flowing through the disk pack 6 the oil arrives again in the converter room 17 ,

The 7a that have a similar construction of the lockup clutch 4 as in 2 differs from this in that the positions of the recesses 9a in the partial piston 5b not with the positions of the recesses 9b in the lamella 6a match, so that through the lining gaskets 18 at the outer and inner diameter of the lamella 6a between Lamella6a and partial piston 5b on the one hand and the pad seal on the inner diameter of the slats 6b between the slats 6a and 6b on the other hand, a diversion of the oil within the disk pack 6 is achieved by 180 ° to the adjacent friction linings. By this deflection, the flow resistance for the oil is increased, whereby the residence time of the oil in the disk pack 6 is extended and the oil flow longer has the opportunity to dissipate heat from this claimed area of the friction partners and thus the friction surfaces bearing parts, whereby the heat from the friction partners can be better absorbed by the oil and transported away from them.

In 7b is also a deflection of the oil by 180 ° with respect to adjacent friction linings by a different positioning of the recesses 9a and 9b achieved, as can be seen in the direction of the arrows. Otherwise, the structure of this hydrodynamic torque converter 1 with converter lockup clutch 4 equal to in 3 described.

In 8th is also a deflection of the oil by 180 ° in the lockup clutch 4 indicated by the course of the arrow, different from the previous one 1 to 7 It differs in that in this embodiment, the lockup clutch 4 an outer plate carrier 8th has, against which the sandwich piston 5 is circumferentially sealed and thus not on the converter housing 2 is applied. Otherwise, the structure of this converter 1 analogous to that in 7b ,

8a shows the section 8th in an enlargement, so that the positive guidance of the oil, represented by the arrow, through the cooling grooves of the friction linings of the lockup clutch 4 becomes clearly visible. In addition, in this figure, the spaces of the lamella 6a to the neighboring components 5b . 6b clearly.

By this in the above-described 1 to 8th forcibly guided cooling oil flow, the cooling of the friction partner of the lockup clutch 4 optimized. A self-conveying effect by the groove pattern in the friction linings by the drag effect or radial pumping action of the oil in the rotating cooling grooves, as used in the prior art, is not required in these embodiments.

If the cooling oil flow in the range of the inner diameter portion of the friction surface / n is introduced, as in the 1a . 2 and 5 , flows due to the low flow resistance of the cooling oil flow in the effective direction of centrifugal force through the cooling grooves of the lockup clutch 4 , However, as in the 3 . 4 . 7b and 8th The cooling oil flow can also be optionally introduced into the diameter range with the largest surface pressure in order to purposefully reduce the maximum friction surface temperature in this area.

In all structural designs, both the point of initiation of the clutch closing force and that of the cooling oil in the torque converter lockup clutch 4 be selected as needed. The former, to achieve a uniform surface pressure, the latter to flow through the point with the largest surface pressure with the cooler oil first.

LIST OF REFERENCE NUMBERS

1

Torque converter / converter

2

converter housing

3

axis of rotation

4

Converter lockup clutch

5

Piston / sandwich piston

5a

outer part piston

5b

inner part piston

6

disk pack

6a

lamella

6b

end disk

7

Inner plate carrier

7

Outer plate carrier

9a

recess

9b

recess

10

hub

11

Sealing / sealing element

12

driving plate

13

drilling

14

recess

15

Passage / channel

16

recess

17

transformer room

18

Surface sealing ring

19

bulge

20

channel

Claims (10)

Hydrodynamic torque converter (1) with a housing (2) arranged concentrically around a hub (10) and non-rotatably connected thereto, in which a pump wheel, a turbine wheel, a stator and a lockup clutch (4) with a disk pack (6) are arranged, and the disk set (6) has at least one friction surface which is engageable with a Gegenreibfläche in an end plate (6b), wherein the friction surfaces are provided with cooling grooves, and the lockup clutch (4) one of two part pistons (5a, 5b) has a composite piston (5), and the piston (5) upon pressurization of the disk set (6) via the end face of its partial piston (5b) for additional friction partner, characterized in that serving for cooling the friction partner of the lockup clutch (4) , via the torque converter (1) circulated cooling oil by means of paddle rings or pad sealing lips (18), the section way between the slats (6a, 6b) are provided, forcibly and completely by the piston (5) and the cooling grooves of the disk pack (6) is passed. Hydrodynamic torque converter (1) to Claim 1 , characterized in that the point of introduction of the oil, starting from the piston (5), in the disk pack (6) is freely selectable. Hydrodynamic torque converter (1) to Claim 1 , characterized in that the location of the discharge of the oil from the plate pack (6) is arbitrary. Hydrodynamic torque converter (1) to Claim 1 , characterized in that the converter lock-up clutch (4) facing the partial piston (5b) in the region of this converter lock-up clutch (4) has at least one recess (9a). Hydrodynamic torque converter (1) to Claim 4 , characterized in that over the circumference of the annular part piston (5b) a plurality of recesses are arranged. Hydrodynamic torque converter (1) to Claim 1 , characterized in that the partial pistons (5a, 5b) are connected to each other at least via a connection point. Hydrodynamic torque converter (1) to Claim 6 , characterized in that the connection point is located at or in the vicinity of the outer diameter of at least one of the partial pistons (5a, 5b). Hydrodynamic torque converter (1) to Claim 6 , characterized in that as a ring-shaped curvature (19) formed connection point, the facing annular surfaces of the sub-piston (5a, 5b) sealingly connects to each other. Hydrodynamic torque converter (1) to Claim 8 , characterized in that the annular bulge (19) has at least one channel for the oil flow in the radial direction. Hydrodynamic torque converter (1) to Claim 1 , characterized in that the disk set (6) of the lockup clutch (4) consists of at least one blade (6a) and an end plate (6b).

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