DE4448015B4 - Hydrodynamic torque converter - Google Patents

Abstract

Hydrodynamic torque converter (3) with a housing (2) and pump housed therein (7), turbine wheel (10), stator (12) and a lock-up clutch (15) with an annular piston (17), wherein on both sides of the annular piston (17) with a Oil fillable chamber (14) is formed, the annular piston (17) carries at least a first friction surface (21) which is frictionally engageable with a second friction surface, wherein radially within the friction surfaces (21) between the annular piston (17) and one second friction surface bearing member, the first of the chambers (18) is formed, in the radial region of the friction surfaces in at least one of the friction surfaces supporting or forming components channels (25) are provided, the axial flow of the friction surfaces (21) an oil flow from the second of the chambers (20) via the channels (25) radially inwardly toward the axis of rotation (27) of the torque converter (3) out towards, characterized in that at least one channel schla has a line-shaped course.

Description

The invention relates to a hydrodynamic flow converter having a pump wheel, turbine wheel, stator and lockup clutch housed in a housing with an annular piston, wherein an oil-fillable chamber is formed on both sides of the annular piston, the annular piston carries at least one friction surface that can be frictionally engaged with a counter friction surface. wherein the first of the chambers is formed radially within the friction surfaces between the annular piston and a component carrying a counter friction surface, further provided in at least one of the friction surfaces bearing or forming components channels or openings or passages are for generating an oil flow from the second of the chambers via the channels or openings or passages radially inwardly in the direction of the axis of rotation of the flow converter.

By the EP 0 078 651 is a flow converter with a lock-up clutch has become known, in which on the side facing away from the friction lining or the friction surface of the annular piston channels are provided via openings on the one hand with the axially formed between a radial wall of the housing and the annular piston first chamber and on the other hand second turbine and impeller receiving chamber are connected. An oil flow from the second chamber into the first chamber, which serves to cool the viscous coupling provided in the torque flow between the annular piston and the turbine hub, takes place via the channels.

By the U.S. Patent 4,969,453 are known hydrodynamic flow converter with a lock-up clutch, wherein the annular piston in the radial region of its friction surface or cooperating with the friction lining channels, which even with the lock-up clutch an oil flow from the second, at least the turbine wheel receiving chamber, in the first, of the annular piston and a radial wall of the housing limited chamber allow. 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 region of the friction lining or the friction surfaces.

A further lock-up clutch for a hydrodynamic flow converter with provided in the friction surface or in the friction lining channels is through the JP-OS 58-30532 known.

Furthermore, it is known to operate torque converter lockup clutches with slip, this slip depending on the design of the drive train and / or depending on the engaged gear stage and / or the operating state of the cooperating with the flow transducer drive either briefly, e.g. during switching operations, or practically over the entire operating range of the flow transducer (continuous slip) can occur. During the slip phases falls in the region of the friction lining or the friction surfaces on a power loss in the form of heat, which can be very high in certain operating conditions and can be several kilowatts. Such operating conditions are present, for example, when driving uphill with trailer, in which over a long time may incur a high power loss, and the change from unbridged to bridged state of the converter clutch, in which due to the occasional high slip in a short period of time, a very high power loss or heat quantity can occur.

As has been explained with reference to the prior art, measures are known for generating an oil flow which reduces the thermal load on the lockup clutch.

The oil flow generated by the known measures, however, causes the transmittable by the lock-up clutch torque is reduced due to occurring in the oil flow dynamic or kinetic processes. The torque transfer capacity of the lock-up clutch decreases with increasing speed and with increasing volume flow of oil. In flow converters to be completely bridged from a certain speed, thus the system pressure must be designed to be high, so that the components, in particular the piston must be strengthened and a more powerful pump is required. Furthermore, the higher pressure again increases the volume flow of oil, which causes additional losses. The mentioned reduction of the torque transfer capacity of the lockup clutch is due, among other things, to forces generated by dynamic processes, which act on the radially inwardly flowing oil and cause an increase in pressure therein. These forces create an axial component which acts on the piston in the opening direction of the coupling.

Another disadvantage of the previously known measures is that the oil flow is very dependent on the temperature or the viscosity of the oil and the pressure difference between the both sides of the converter piston pending pressures. In solutions according to the U.S. Patent 4,969,543 Thus, the flow resistance generated by the channels must be designed for the critical case, that is, even at maximum oil temperature, only so much oil must drain through the channels that the system pressure in the torque converter does not collapse to an inadmissibly low level. Also is at according to the solutions U.S. Patent 4,969,543 the flowing over the channels oil flow directly dependent on the pressure difference between the two chambers. This pressure difference is the manipulated variable for the torque of the clutch and thus can not be used to set a desired volume flow. In order to limit the losses in the flow converter to an acceptable level, therefore, the volume flow of oil present at maximum pressure difference, ie at maximum clutch torque, must be limited. As a result, the cooling oil flow may indeed be dimensioned large enough for the maximum clutch torque, but for medium and low torques, the existing volume flow is then too small for many applications due to the small pressure difference.

The object of the present invention was to improve the hitherto known hydrodynamic flow transducers with lockup clutch, in particular by increasing the torque transmission capacity and reducing the thermal load, in particular in the area of the friction surfaces of the lockup clutch. Furthermore, the thermal load of the oil should be reduced. A further object of the invention is to optimize the cooling oil flow through the converter clutch over the entire operating range of the flow converter, as well as to improve the heat exchange in the region of the friction surfaces of the lock-up clutch between the oil and the adjacent components. The measures according to the invention further aim to enable a better regulation or control of the torque transmittable by the lockup clutch or the slip present on the lockup clutch, so that the torque shocks or momentary irregularities occurring in the drive train or on the internal combustion engine are better damped by the slip which increases comfort. The hydrodynamic flow converter according to the invention should continue to be produced in a particularly simple and economical manner.

According to one of the solutions of the invention, this is achieved in that the radially inwardly directed oil flow is directed radially outwards after leaving the channels within at least one guide channel and the guide channel limiting walls or components at least relative to the axial pressure acting on them as a result of the oil pressure relative are axially supported or connected to each other so that a self-contained power flow is present. By the measure according to the invention it is achieved that the rotating forces acting on the oil due to the radial flow of the oil on the dynamic forces can be intercepted at least substantially and at least in the axial direction. As a result, it can be achieved that virtually no axial force component generated by the dynamic forces occurring can act on the piston, which would result in a reduction in the torque which can be transmitted by the lockup clutch. Due to the configuration according to the invention, therefore, the dynamic forces acting on the oil, which generate an oil pressure increase, can be at least partially neutralized with respect to their effect on the clutch closing force acting on the piston.

Under guide channel are to be understood both radially extending in cross-section self-contained channels as well as annular radially inwardly extending chambers. Such an annular chamber may also be divided into a plurality of radially extending channels, which may have a self-contained cross-section. As a guide channel and a tubular member can be used, which is in communication with at least one output side of a provided in the radial region of the friction surfaces channel. Thus, the oil emerging from at least one such channel can be guided radially inwards via a pipe, the outflow side of this pipe being able to re-open into the first chamber or opening into a special oil return guide. Such an oil return guide can be formed, for example, by channels. which are provided in the output hub of the turbine and in the longitudinal direction of the transmission input shaft. The pipe guide according to the invention of the oil flowing radially inwardly when the converter lock-up clutch is closed can be provided in the first chamber or in the second chamber.

For the structure of the flow converter, it may be particularly advantageous if the guide channel is supported by a component having a friction surface, such as a housing or annular piston. Furthermore, it is expedient if the channels opening into a guide channel allow an oil flow from the second chamber into the first chamber. For this purpose, corresponding openings or passages can be provided in the surfaces adjoining the friction surfaces or in the components forming the friction surfaces. These openings or passages can be formed such that they act throttle-like or similar to a nozzle. In order to ensure optimal support of the occurring as a result of dynamic processes in the oil flow pressure increase, it is particularly advantageous if the guide channel limiting walls are axially fixed relative to each other, so at least virtually rigidly connected. To form the guide channel or the guide chamber can easily in one of the components forming a chamber a with this axially fixed radial Ölführungswandung be provided, which define with radial areas of the component at least one radially extending, the guide channel or the guide chamber forming space in which or in which the oil flow is directed radially inward. The walls bounding the guide channel can advantageously be rigidly connected to a component bearing one of the friction surfaces.

A particularly simple structure results from the arrangement of the first chamber axially between the annular piston and a radial wall of the housing. It may be expedient if the annular piston is provided axially between the radial wall of the housing and the turbine wheel. It can also be advantageous if the guide channel or the oil guide wall limiting this is carried by the piston.

The oil guide wall bounding the guide channel or the guide chamber can be accommodated in the first chamber in an advantageous manner, wherein this wall can be designed and arranged such that the first chamber is subdivided into two subchambers. For some applications, however, it may also be expedient if the oil guide wall is provided on the side facing away from the chamber of the annular piston, ie on the turbine wheel side facing the annular piston.

In the second chamber, at least the turbine wheel and the impeller and possibly the stator can be accommodated.

A particularly advantageous construction may result in that at least one of the friction surfaces bearing components having a friction lining. This friction lining can be carried by the piston or by a radially extending wall portion of the housing. The attachment of the friction lining to the corresponding component may e.g. done by gluing. When using a friction lining, it may be expedient if the channels are at least partially limited by the friction lining. For this purpose, the channels can be provided in the friction lining. The channels may e.g. be formed at least partially by embossing or cutouts or grooves in at least one friction lining. By such a configuration, a steady flow of oil between the two chambers can be generated, which is passed over the friction lining. This results in a particularly good heat exchange between the friction surfaces and the oil, so that overall, a low or lower thermal load results in both the friction surfaces forming components and the oil.

It may be particularly expedient if the inlet of the channels provided in the radial region of the friction surfaces lies radially further outwards than their outlet and these channels open into a guide channel or a guide chamber. The guide channel or the guide chamber may extend at least over 50% of the radial extent of the first chamber. The greater this radial extent, the lower the restoring forces on the piston of the lock-up clutch generated as a result of the dynamic actions acting on oil.

To feed the channels with oil, it may be advantageous if the respective inlet side of the channels communicates with an axial supply opening provided in the annular piston and / or in the oil guide wall. The outlet side of the channels may communicate with an axial passage provided in the annular piston and / or in the oil guide wall, which in turn opens into a guide channel. For channels that are formed by depressions or cutouts in the friction lining and / or in the region of a friction surface of a component, the respective outlet side of the channels can also be designed such that it opens directly into the guide channel.

In order to achieve a particularly effective heat exchange, the channels provided in the radial region of the friction surfaces can be formed in a zigzag or meander shape. As a result, the greatest possible guide length for the oil in the area of the friction surfaces can be achieved. The length of the channels and their cross-section must be tuned to the desired volume flow of oil. For this purpose, it is expedient if the grooves or cut-outs forming the channels are relatively deep, whereby upon insertion of these channels into a friction lining, this depth can preferably extend over practically the entire friction lining thickness. It is particularly advantageous in this case if the channels are formed by elongated cutouts in the covering. Advantageously, the respective inlet side of the channels in the outer edge region of the friction lining and the respective outlet side can be provided in the radially inner edge region of the friction lining. For the heat exchange between the friction surfaces and the oil, it may also be useful if the zigzag or meandering channels formed in the circumferential direction of the friction lining, so that the oil - viewed over the radial width of the friction surfaces - several times back and forth radially. The channels may for this purpose have at least two deflections, with grooves having at least four deflections have proven to be advantageous.

When using a lock-up clutch with conical friction surfaces, it may be particularly advantageous if the friction lining is produced as a cone processing, the conical shape through Merging the two ends of the cone processing is formed. However, the annular friction lining may also consist of a plurality of segmented or crescent-shaped friction elements, which together can result in an annular or frusto-conical shape. By using Reibbelagsegmenten the use of materials can be reduced, since the accumulated waste can be substantially reduced. It may be particularly expedient if the starting material for the friction linings is coated with adhesive film prior to punching, since this makes it easier to handle the finished linings.

When punched through channels or grooves in the friction lining, it is expedient if this has both radially outward and radially inward a continuous contour, as this can ensure that a virtually deformation-free handling is given and thus also when gluing the friction linings to the carrier, such as the piston, can not affect the function of the lock-up clutch deformations.

According to a further inventive embodiment of a flow converter, the oil flow flowing through the channels can be adjustable via at least one valve as a function of at least one operating parameter of the flow converter and / or of the machine driving it and / or of the transmission driven by the flow converter. Such a parameter may be formed for example by the oil temperature, by the drive speed of the engine or the output speed of the flow converter or input speed of the transmission. As a parameter can continue to be used in a particularly advantageous manner, the pressure difference between the two chambers. It may be particularly useful when the valve has a control characteristic, which ensures a practically constant flow of oil, ie a constant volume flow with closed Überbrükungskupplung over the entire operating range of the flow converter. For some applications, however, it may also be expedient to realize other characteristics for the volume flow, in particular those that are dependent on the slip of the lock-up clutch or by the amount of heat resulting from the slip. A particularly simple structure may result from the fact that the valve is designed as a flow valve, which adjusts the desired volume flow as a function of the existing between the two chambers pressure difference.

The valves according to the invention can be advantageously provided on the inlet side and / or the outlet side of the respective channels or a guide channel. However, such a valve can also be arranged in the region between the inlet side and the outlet side of a channel or a guide channel.

According to a further embodiment of the channels, they can also be formed by means of components in the material of at least one of the friction surfaces, such as e.g. Ring piston and / or housing, introduced moldings, such. Be formed grooves.

A particularly simple control of the volume flow of cooling oil can be achieved that the flow area of a valve according to the invention in response to the pressure difference between the two chambers is variable, it may be useful if the flow area of the valve is reduced with increasing pressure difference between the two chambers , Advantageously, such valves can be designed and arranged such that they have virtually no or only a very small function of the centrifugal force acting on them with regard to their function. Advantageously, the valves may further have a flow rate detection which is not proportional to the root of the pressure difference between the two chambers.

The oil flow control valves can also be designed as a solinoid.

According to a further independent idea of the invention, grooves for carrying out a cooling liquid can be introduced in the region of the friction surface of an annular friction lining of the lockup clutch of a hydrodynamic torque converter. The ratio between the thickness of the friction lining and the average depth of the grooves considered over the longitudinal extent of the grooves may advantageously be on the order of between 2.7 and 1.3. The depth of the grooves may be in the order of between 0.2 and 0.8 mm, preferably between 0.3 and 0.6 mm. The grooves can have virtually the same depth over their entire extent. For some applications, however, it may also be expedient if viewed over the longitudinal extent of the grooves, the depth varies. Furthermore, the grooves may have at least substantially the same width over their longitudinal extent. However, it can also be useful grooves that vary over their length in the width.

The throttling of the cooling oil flow can thus be carried out in accordance with the invention in the flat zigzag and substantially over the entire width of the lining extending grooves. Between the deflections of the grooves they may have substantially straight part lengths, which may have a longitudinal extent of about 10 to 40 mm. The Groove width can be on the order of 3 to 10 mm. In order to ensure a favorable for many applications flow of a maximum of about 10 liters per minute at a pending on the side facing the turbine side of the piston pressure of about 5 bar, groove depths in the order of 0.3 mm have proven to be useful. The individual zigzag or meandering grooves extending from the radially outer region to the radially inner region of the friction surface can be present in a number of approximately 4 to 12, which are distributed at least approximately evenly over the circumference of the friction lining. The pitch or the distance between two on the same radial side of the friction lining existing deflections of the grooves is in relation to the total radial height of the meandering Nutenführung preferably in the order of between 0.6 to 1.3, preferably in the order of between 0.8 and 1.1.

To improve the cooling effect pocket-shaped recesses or depressions can be introduced in the radially outer and / or in the radially inner edge region. These pocket-shaped projections which are open radially outwards or radially inwards can have approximately the same height as the cooling grooves. However, the projections can also extend over the full pad height, so that they can be easily prepared in the manufacture of the pad or by cutting. These pocket-shaped projections can be arranged in an advantageous manner - viewed in the circumferential direction - each between two adjacent deflections.

To dissipate the amount of heat generated in the region of a friction surface engagement of a lockup clutch, friction linings have proved expedient in which the ratio of the area occupied by the grooves and / or pocket-shaped projections to the remaining lining friction surface is on the order of approximately 0 , 7 to 1.8, preferably of the order of 1 and 1.5.

By introducing pocket-shaped projections into the radially outer or radially inner edge regions of the friction lining, by utilizing the drag flow, the cooling in the region of the friction engagement of the lockup clutch can be improved or increased. It can be particularly advantageous, when viewed in the direction of rotation of the friction lining, that the radially outer inlet side of a cooling groove lags against the radially inner outlet side of this cooling groove. It can be advantageous if the flow direction viewed in the circumferential direction of the friction lining through the grooves coincides with the direction of the drag flows. In a converter construction, in which the friction lining is supported by a component rotatable with the turbine wheel, such as a piston, this drag flow is generated by the component forming a counter friction surface for the friction lining, in particular the converter housing. When slip occurs in the lock-up clutch of the converter has, if a torque is transmitted from the drive motor to an output member, the converter housing has a greater rotational speed than the grooved friction lining, so that the flowing through the grooves cooling medium accelerated by the converter housing or the faster-rotating Gegenreibfläche becomes. Due to the arrangement and guidance of the groovings according to the invention, the otherwise unavoidable speed of rotation influence can be substantially reduced or largely avoided on the torque which can be transmitted by the clutch.

The friction lining according to the invention can also be pump-side or on a surface formed by the transducer housing, e.g. by gluing, be attached. The piston of the lockup clutch then has only a metallic Gegenreibfläche.

Furthermore, Nutausgestaltungen invention can also be introduced directly into the material forming the piston and / or the converter housing. In such an embodiment, a friction lining without grooves can be used. However, friction linings with grooves may also be used, which may then also be configured differently than described in the present application.

It may be particularly useful when the grooves are formed so that, viewed over the length of the grooves and for the occurring during the driving of a equipped with a flow converter vehicle pressures on the input side and the output side of the grooves in the grooves in the significant turbulent flow is present. Thus, the grooves may be formed such that the pressure difference existing between the input side and the output side of these grooves creates a turbulent flow in the grooves. The emergence of a turbulent flow within the grooves can be positively influenced by a corresponding groove or Nutausgestaltung.

According to a further embodiment of the invention may be present in a hydrodynamic flow transducer of the type described in axial contact of the friction surfaces of the lock-up clutch, an oil flow from the second chamber into the first, wherein in the first chamber, a radial wall is provided, compared to one of the first Chamber defining radial walls is axially fixed, the flow of oil radially inwardly between them two axially fixed walls is passed. These two walls can also be rotated relative to each other. The wall received in the chamber can advantageously be axially fixed relative to the housing. The latter can be done for example by axial support of the corresponding wall via the turbine hub. The wall can be connected in an advantageous manner rigidly with the turbine hub.

• -Figur I einen Schnitt durch eine erfindungsgemäße Einrichtung
• -Figur II ein Diagramm mit Drehmomentkennlinien von Überbrückungskupplungen
• -die 3 bis 5 weitere erfindungsgemäße Ausgestaltungsmöglichkeiten eines Strömungswandlers mit Überbrückungskupplung
• -die 6, 7 und 12 Ausgestaltungsmöglichkeiten eines Reibbelages für eine erfindungsgemäße Überbrükungskupplung
• -Figur 8 eine Einzelheit einer erfindungsgemäßen Überbrückungskupplung
• -die 8a bis 11 Ventile zur Regulierung des Volumenstrom an Öl sowie Einzelheiten von mit derartigen Ventilen ausgerüsteten Überbrückungskupplungen.

Based on 1 to 12 let the invention be explained in more detail. It shows

• Figure I shows a section through a device according to the invention
• Figure II is a diagram with torque characteristics of lock-up clutches
• -the 3 to 5 further inventive design options of a flow converter with lock-up clutch
• -the 6 . 7 and 12 Design options of a friction lining for a Überbrükungskupplung invention
• Figure 8 is a detail of a lock-up clutch according to the invention
• -the 8a to 11 Valves for regulating the volume flow of oil and details of bridging couplings equipped with such valves.

In the 1 illustrated device 1 has a housing 2 that has a hydrodynamic torque converter 3 receives. The housing 2 is connectable to a driving shaft, which may be formed by the output shaft, such as the crankshaft of an internal combustion engine. The non-rotatable connection between the driving shaft and the housing 2 can be done via a drive plate, the radially inward with the driving shaft and radially outward with the housing 2 rotatably connected. Such a drive plate is for example by the JP-OS 58-30532 known.

The housing 2 is by a driving shaft or the internal combustion engine adjacent housing shell 4 and a further attached to this housing shell 5 educated. The two housing shells 4 and 5 are radially outside via a welded joint 6 firmly connected to each other sealingly. In the illustrated embodiment, to form the outer shell of the impeller 7 the housing shell 5 immediately used. For this purpose, the blade plates 8th in a conventional manner on the housing shell 5 attached. The housing shell 5 is axially in the outer sleeve-like portion 4a of the housing shell 4 plugged in. Axial between the impeller 7 and the radial wall 9 of the housing 4 a turbine wheel 10 is provided, which is firmly or rotationally rigidly connected to an output hub 11, which is rotatably coupled via an internal toothing with a transmission input shaft. Axially between the radially inner regions of the pump and the turbine wheel, a stator 12 is provided. The housing shell 5 has radially inside a sleeve-like hub 13 , which is rotatably and sealingly storable in the housing of a transmission. In the interior formed by the two housing shells 4,5 14 is still a lock-up clutch 15 provided, which in effect parallel to the torque converter 3 is arranged The lock-up clutch 15 allows torque coupling between the output hub 11 and the driving housing shell 4 , Effectively in series with the lock-up clutch 15 is a torsionally elastic damper 16 connected, which in the illustrated embodiment between the annular piston 17 the lockup clutch 15 and the output hub 11 The torsionally flexible damper is provided 16 Includes in a conventional manner energy storage in the form of coil springs. The axially between the radially extending wall 9 and the turbine wheel 10 provided annular piston 17 is radially inward on the output hub 11 limited axially displaceable stored. The annular piston 17 divided the interior 14 in a first chamber 18 radially inward of the friction engagement area 19 the lockup clutch 15 axially between the annular piston 17 and the radial housing wall 9 is formed, and a second chamber 20 , in which, among other things, the impeller 7 , the turbine wheel 10 as well as the stator 12 are included.

The housing shell 4 forms a conical friction surface with radially outer regions 21 , whose fictitious cone tip axially in the direction of the turbine wheel 10 is directed away. The conical friction surface 21 is in frictional engagement with a friction lining 22 Can be brought from the conical area 23 a support plate 24 is worn The support plate 24 in turn, in turn, from the likewise drawn from sheet metal annular piston 17 carried.

In recent concepts for a powertrain, such as a motor vehicle, the lock-up clutch over at least a majority of the operating range of the flow transducer - operated with slip, wherein during the slip phases in the friction engagement area 19 a power loss in the form of heat is obtained, which can be very high in certain operating conditions and can amount to several kilowatts. Such operating conditions are present, for example, when driving uphill with trailer and when changing from unbridged to practically bridged state of the converter clutch. Such concepts for operating a lockup clutch with slip are, for example, by the German patent applications P 42 28 137.7 12 and P 42 35 070.0-12.

Inadmissibly high temperatures in the friction engagement area 19 to avoid, and thus a destruction of at least the friction lining surface and a part of the interior 14 counteract existing oil are in the illustrated embodiment means in the form of in the friction lining 22 introduced oil grooves or channels 25 provided, over which even with practically closed lock-up clutch 15 a steady flow of oil between the second chamber 20 and the first chamber 18 can be done. The oil flow is over the friction lining 22 and the friction surface 21 directed The oil channels 25 are optimized in terms of their shape in that a good heat exchange between the frictional engagement in the area 19 acting components and the oil flowing through can take place. A preferred shape of the channels 25 is still related to the 6 and 7 described in more detail.

The radially outer oil inlet end of the channels 25 stands over passages or holes 26 in the piston 17 and in the support plate 24 with the second chamber 20 in connection. The radially inner outlet end of the channels 25 stands with the first chamber 18 in connection.

The axial with the piston 17 firmly connected support plate 24 forms in conjunction with radial areas of the piston 17 a sub-chamber 18a, which serves as a guide channel for the closed lock-up clutch 15 over the channels 25 radially in the direction of the axis of rotation 27 flowing oil is used. The guide channel 18a communicates with the radially inner end portions of the channels 25 over in the support plate 24 introduced openings or holes 28 in connection. Radial inside has the support plate 24 axial markings 29 acting as a spacer between the support plate 24 and the ring piston 17 serve. Between the stampings 29 the guide channel 18a, which is practically designed as an annular chamber, is open radially inwards, whereby a connection to the between the radial housing areas 9 and the support plate 24 formed sub-chamber 18b is present. In the illustrated embodiment, the piston plate 17 and the support plate 24 in the field of embossing 29 connected by rivets. Radially outside the guide channel 18a has the annular piston 17 an annular axial embossing 30 , also as a spacer between the support plate 24 and the remaining areas of the ring piston 17 serves. By the impression 30 continues to be the deformation stiffness of the support plate 24 in the friction engagement area 19 increased. In the area of the annular embossing 30 is a radial seal between the two components 17 and 24 available. The cooling oil flow takes place when the lock-up clutch is closed 15 starting from the second chamber 20 over the passages 26 , the oil channels 25 , the openings 28 and the guide channel 18a radially inwardly in the region of the output hub 11 , This cooling oil flow can then be in the area of the output hub 11 be derived for example via a hollow shaft or via a channel provided for this purpose, preferably first in an oil cooler. From this oil cooler then the oil can be returned to a sump and from there again into the hydraulic control circuit.

The guide channel 18a forming components 17 and 24 are axially supported relative to each other such that the oil flowing radially inwardly therein does not cause an axial force component on the axially displaceable piston 17 which is a change, in particular a reduction of the torque transfer capacity of the lock-up clutch 15 would effect. This is achieved in that the forces occurring due to the radially inward oil flow in the oil, or pressure increases, the axial force component on the piston 17 and on the support plate 24 cause to be intercepted axially such that a closed power flow arises. This is in the illustrated embodiment according to 1 by the axial support of the sheet 24 on the piston 17 guaranteed.

The mentioned, due to dynamic processes in the oil forces and thus also caused by these pressure increases reduce in Strömungswandlerkonstruktionen with lock-up clutch, as for example by the U.S. Patent 4,969,543 have become known, with increasing speed of the maximum transferable torque of the lock-up clutch very strong. In the known flow converters with cooling oil flow occur on dynamic processes attributable torque losses, when the flow of oil between the radial housing wall and the piston of the virtually closed Überbrükungskupplung from radially outside to radially inside flows, these losses are larger with increasing volume flow of oil. One reason for the decrease in the torque transfer capacity of the Überbrükungskupplung with increasing speed or increasing the volume flow of oil is likely due to the acting on the oil during the flow of the oil from radially outside to radially inward Coriolisbeschleunigung due to the rotation of the flow converter in the direction of rotation on the Oil acts and a pressure increase in the radial to the axis of rotation 27 can cause flowing oil. In the present invention, due to the radial flow of oil caused pressure increases and thus the axial flow forces generated on the oil flow conductive components intercepted axially such that they have virtually no effect or at least a much smaller effect on the closing force of the lock-up clutch 15 and thus have on the transferable from this moment. These undesirable pressures or forces are intercepted axially according to the invention.

At the in 1 The embodiment shown extends the support plate 24 or the guide channel 18a radially to the output hub 11 so relatively far inward. For some applications, however, it may also be appropriate if the guide channel 18a only over a portion of the radial extent of the annular piston 17 extends, so that with increasing speed or increasing volume flow, a certain change of the lock-up clutch 15 transmissible torque results. However, in most cases it will be convenient if the guide channel 18a over at least 50% of the radial extent of the annular piston 17 runs. Furthermore, it is possible only a part of the oil flow through the guide channel 18a to guide and the rest through the sub-chamber 18b radially inward. For this purpose, the support plate 24 Connecting openings between the sub-chamber 18b and the guide channel 18a exhibit. These connection openings can be designed according to the desired effect and at a certain radial distance from the axis of rotation 27 to be ordered.

In the diagram according to 2 is the abscissa, the speed of the flow converter or the housing 2 and on the ordinate the ratio of that of the lock-up clutch 15 transferable moment to the both sides of the converter piston 17 existing pressure difference shown The line 31 shows the torque curve over the speed for a given, so constant differential pressure .DELTA.P on the piston of a conventional converter lock-up clutch, ie a lock-up clutch, in which there is no flow of oil from the one side of the piston to the other side with the clutch closed. It can be seen that in such a lock-up clutch over the speed at a given ΔP, the transmittable torque remains at least substantially constant flow converter with such a lock-up clutch, for example, in U.S. Patent 4,649,763 shown.

The line 32 represents a possible course of the from the lock-up clutch 15 transmittable torque over the speed at a given ΔP of a hydrodynamic flow transducer in which an oil flow from the second chamber 20 in the first chamber 18 is present, dar. Such hydrodynamic flow transducer, for example, by the U.S. Patent 4,445,599 and U.S. Patent 5,056,631 known. In these constructions, channels or openings are provided in the region of the friction linings and / or the piston of the lock-up clutch, which an oil flow from the second chamber, which accommodates at least the impeller and the turbine wheel, in the first chamber, which from a radial wall of the housing and the piston is limited allow. As a result of this flow of oil or oil flow, the maximum torque which can theoretically be transmitted by the converter lockup clutch for a given ΔP is reduced - as a result of flow losses in the supply and return flows and in the flow through the converter. This is off 2 can be seen, and that is at low speeds for the same ΔP that according to the line 32 transmittable maximum torque less than that of the same speed corresponding moment of the line 31 , The static losses are superimposed on dynamic losses, which also reduce the transmittable by the lock-up clutch torque. These are caused by the in the first chamber radially inwardly directed oil flow. As from the course of the line 32 can be seen, the transferable for a given ΔP from the lock-up clutch torque is significantly reduced with increasing speed by the dynamic losses.

By the inventive support of the forces occurring due to the radially inward oil flow or pressure increases in the chamber 18 it is achieved that, for a given ΔP, the torque transmittable by the lock-up clutch does not correspond to the line above the speed of the flow converter 32 falls off, but according to the dashed line 33 at least substantially remains practically constant Depending on the desired behavior of the lock-up clutch, the line 33 but also have a different course. Thus, if desired, viewed over the speed also a certain drop in the transmittable torque may be present. With optimal design of the at least one guide channel 18a for the oil flow, however, can be achieved that with respect to the torque transmission ideal case according to the line 31 practically only static losses occur.

The above approach is idealized because friction in the fluid as well as friction between the fluid and the guide walls has not been taken into account.

The embodiment according to 3 differs from the one according to 1 in that the component 117 does not extend radially outward to the outer contour of the sheet 124 and radially inside is not guided axially displaceable on the output hub 111. The sheet 124 is similar to the ring piston 17 according to 1 radially centered on the output hub 111 and received axially displaceable limited. In the embodiment according to 3 thus forms the sheet metal 24 practically the piston of the lock-up clutch 115 and the annular member 117 a stiffener for the sheet 124th

In one embodiment according to 4 the component limiting the guide channel 218a is provided in the form of an annular plate 224 on the side of the annular piston 217 facing away from the first chamber 218. The piston 217 has in the radially outer region of the guide channel 218 a passages 228, which communicate with the channels 225 in the friction lining 222. In the radially inner region of the guide channel 218 a discharge openings 234 are introduced into the piston 217, which open into the first chamber 218.

As already mentioned, the guide channels 18a , 118a, 218a be practically designed as an annular chamber. However, it is also possible to provide a plurality of radially extending channels which are in each case in communication with at least one of the feed openings 28, 288. For example, instead of guide plates 24 . 224 Also, single tubes are used, which are radially outward with one of the openings 28 . 228 communicate and extend radially inward toward the axis of rotation. Also, it is not necessary, the radially inwardly directed flow of oil into the first chamber 218 or sub-chamber 18b but the outflow for the radially inward flow of oil can also take place via a return provided for this purpose. For example, this oil flow could also be via at least one in the output hub 11 introduced radial bore, which opens into a spillway, be evacuated.

At the in 5 shown hydrodynamic torque converter 303 is in turn a first chamber 318 and a second chamber 320 present through the piston 317 the lockup clutch 315 are separated from each other. The ring piston 317 is on the output hub 311 axially displaceable centered. In the torque flow between the output hub 311 and the ring piston 317 is the torsionally elastic damper 316 arranged When the lock-up clutch is closed 315 is between the second chamber 320 and the first chamber 318 an oil stream is present in the chamber 318 directed radially inward. This is the piston 317 at least one inlet opening 326 present in the illustrated embodiment by one of the piston 317 supported nozzle or aperture 326a is formed. That through the opening 326 flowing oil is in the friction engagement area 319 between the friction surface 321 of the housing 302 and the friction surface of the friction lining 322 in grooves or channels 325 guided. On the outlet side of the grooves or channels 325 then the oil enters the first chamber 318 and flows radially inward. The oil flow is thereby radially inwardly between the housing 309 and a radial annular support plate 324 guided. The sheet 324 is on the output hub 311 attached and thus in the axial direction to the piston 317 towards, axially supported. This support causes the occurring in the radially inward flowing oil pressure increases practically not on the piston 317 Since the axial forces generated by these pressure increases from the sheet metal 324 be intercepted.

The oil guide plate or support plate 324 could instead of the output hub 311 also with the housing shell 304 be axially connected. Even then would be present in relation to the axial forces occurring in itself closed power flow.

The oil grooves or channels 25 . 225 . 325 could also, at least in part, instead of in friction lining 25 . 225 . 325 to be introduced, in the adjacent housing wall and / or in the piston of the lock-up clutch and / or for example in embodiments according to the 1 and 3 also in the support plate 24 . 124 be provided. A piston with Ölführungsnuten is eg through the U.S. Patent 5,056,631 known.

The inventive guide the flowing between the second chamber and the first chamber oil radially inward and the associated support or compensation of the impulse forces or pressure increases occurring in the oil is not limited to embodiments in which the oil flow directly in the region of the friction surfaces Lockup clutch takes place, but can also in such constructions, as for example by the U.S. Patent 4,493,406 and the U.S. Patent 4,445,599 have become known to find application.

In 6 is a friction lining 422 shown in a lockup clutch according to the 1 and 3 to 5 Can be used. The friction lining 422 has a radially outer circumferentially extending contiguous region 422a and a likewise contiguous radially inner circumferentially extending region 422b , In between the outer and the inner area 422a . 422b existing middle area 422c are cutouts 435 introduced, which have a zigzag or meandering course. The cutouts 435 are in the illustrated embodiment in the circumferential direction of the friction lining 422 meandering or serpentine. By such a leadership of the cutouts 435 a particularly large channel length is ensured for the oil to be passed, whereby a good heat exchange between the oil flowing through and the friction surfaces of the lock-up clutch forming components is achieved. As a result, both a low thermal load of the friction surfaces or the components forming them and of the existing oil in the region of the friction surfaces can be achieved.

The length dimensioning and shaping of the channels or punched holes 435 must be made such that the flow resistance occurring therein is designed for the critical operating case of the torque converter or the lock-up clutch, which means that even at maximum possible oil temperature only so much oil must drain from the second chamber into the first chamber that the system pressure in the torque converter does not collapse. It is useful if by the punched holes or grooves 435 Guided cooling oil flow has the lowest possible dependence on the oil temperature.

The friction lining 422 has nine evenly distributed over the circumference channels or grooves in the illustrated embodiment 435 , It is expedient if at least three such zigzag channels or grooves in the friction lining 422 are introduced.

The in 6 illustrated friction lining 422 is shown in its flat position and is glued to the frusto-conical areas of the corresponding annular piston or the corresponding support plate or the corresponding housing shell. The friction lining 422 is prepared as a cone processing, so that when joining the two end portions 436.437, a conical or frusto-conical shape is formed. A particularly low use of material can be achieved by dividing the friction lining 422 into several sector-shaped parts 438 , This is in 7 shown. The friction lining segments 438 are then glued to the corresponding carrier part. It may be particularly advantageous for this purpose if the covering material or the blank blank at least before punching the cutouts 435 coated with an adhesive film on one side. This ensures easy handling. This handling is also favored by the fact that radially outside and radially inside the lining segments 438 or the covering 422 have a continuous continuous area.

In the embodiment according to the 6 and 7 are the grooves or punched out 435 closed radially outward and radially inward. This is made possible by appropriate design of the friction lining spanning components. The configuration must be such that at the radially outer end 439 of the channels 435 the oil in the channels 435 can flow in and at the radially inner end 440 can drain again. For this purpose, in the embodiments according to the 1 and 3 to 5 corresponding holes or recesses provided in the adjacent parts, which with the corresponding ends of the channels 435 are in communication. Instead of holes or cutouts, however, the corresponding parts could also have depressions or embossments that a connection of the corresponding end 439 and or 440 with the appropriate chamber, eg 320 and or 318 guarantee. In 5 dashed line is a corresponding connection shown by a depression 441 in the piston 317 is formed. This Anformung or depression is opposite the oil inlet side 326 offset in the circumferential direction and with a radially inner end portion of a channel 325 connected.

It is useful if the channels 435 Viewed over its length at least two deflections, so at least three legs or two arches have. In the embodiment according to 6 the channels have six deflections and thus seven legs. In a sinusoidal or serpentine guidance of the channels 435 would have these six adjacent arcs.

In 8th Another way to make a connection between a radially inner end 440 a friction lining 422 and between the case 2 and the ring piston 17 formed first chamber 18 shown. This connection is made by an axial step 2a on the housing shell or on the lid 4 guaranteed. The gradation 2a is arranged such that it extends radially outwards over the end region 440 of the corresponding channel 435 extends. The gradation 2a can also be annular, so extend over the entire circumference, so that then all end portions 440 of the channels 435 a connection with the first chamber 18 exhibit.

In order to reduce the dependency of the oil volume flowing between the second chamber and the first chamber on the oil temperature or oil viscosity and on the pressure difference existing between the second chamber and the first chamber, according to a further inventive embodiment at least one means is provided which determines the volume flow depending on the oil temperature or the oil viscosity and / or the pressure difference between the pending on both sides of the piston pressures.

In the 8a to 10 is such a means in the form of a valve 542 shown.

In 8a is the valve 542 from the piston 517 carried. The valve 542 has a housing 543 that on the friction lining 522 turned away side of the piston 517 attached to the latter. In the illustrated embodiment, this has the housing 543 an annular outer shoulder 544. in a hole 545 of the ring piston 517 recorded and fixed, for example via a press fit.

How out 9 it can be seen is in the housing 543 of the valve 542 an axially displaceable piston 546 added. The piston 546 has an axial approach 547 that is axially in an outwardly open recess 548 is displaceable by axial displacement of the piston 546 becomes the cross section of the outlet 549 that is between the recess 548 and the axial approach 547 adjusts, changes. This cross-sectional change is effected by a corresponding shaping of the axial projection 547 and / or the recess 548 , The recess 548 is in the illustrated embodiment by an annular, in cross-section L-shaped socket 550 formed on the housing 543 is fixed so that the axial approach 551 in the cylinder room 552 protrudes. On the axial approach 551 is a tared spring 553 taken up the piston 546 in the direction of the housing bottom 554 applied. This ensures that at low differential pressure between the two chambers, eg 20 and 18 or between the chamber 20 and the guide channel 18a , a relatively large flow of oil can flow through the valve. The valve 542 has inlets 555 connecting the second chamber 20 ( 1 ) and the cylinder space 552 produce. The outlet of the valve 542 forming recess 548 opens or is in communication with at least one in the friction engagement area 519 provided oil duct 535 , This compound is designed such that through the valve 542 through flowing oil preferably from one end of a channel 535 is led to the other end of this channel and from there then flows radially to the axis of rotation of the corresponding flow converter.

In the illustrated embodiment has the axial approach 547 of the piston 546 a groove 556 having such a geometry or such a course that with increasing axial displacement of the piston 546 to the left the outlet cross section 549 is reduced. By appropriate design of the groove 546 and interpretation of the force-displacement characteristic of the spring 553 can be achieved that over the valve 542 over the entire range of application of the corresponding torque converter, a virtually constant volume flow flows. It can thus be achieved that a volume flow is formed which is practically independent of the difference of both sides of the piston of the Überbrükungskplung pending pressures. If necessary, however, can also by appropriate design of the approach 547 , the recess 548 and the energy storage 553 other characteristics for the volume flow can be realized. Thus, for example, via a suitably ausgestaltetes valve 542 the adjusting volumetric flow of oil increase at least slightly with increasing pressure difference or at least decrease slightly. If necessary, the volume flow from a predetermined pressure difference between the two chambers can also be completely interrupted. Preferably, the flow control valve 542 however, designed so that the volume flow is kept virtually constant and thus virtually independent of fluctuations in the inlets 555 pending supply or load pressure is. Such a flow control valve has the further advantage that it can be configured such that temperature changes in the oil can be largely compensated, which means that the volume flow is largely independent of temperature changes in the oil.

The flow control valve 542 is arranged on the inlet side or at the beginning of the cooling flow.

That in the 9a illustrated flow control valve 642 can instead of the valve 542 be used, wherein the receptacle for the valve body on the piston must be changed accordingly, or instead of the throttle or orifice 326a , The valve 642 has a housing 643 that has a cylinder space 652 forms for the piston 646 , The open side of the case 643 is through a disk 650 that have an opening 650a partially closed. Between the case back 654 and the piston 646 is a calibrated spring 653 intended. The feather 653 is at least partially in an axial recess 646a of the piston 646 added. The cylinder space 652 is through the piston 646 divided into two rooms, with the right room 652a over the opening 650a is supplied with oil having a pressure corresponding to the pressure in the second chamber, which accommodates at least the pump and turbine wheel. The left room 652b is about one between the two rooms 652a and 652b provided throttle opening or aperture 657 supplies the bore 657 or aperture 657 serves as orifice plate for setting a pressure drop ΔP between the two rooms 652a and 652b , In series with the orifice plate 657 is a control panel 658 switched, depending on the in the chamber 652a pending pressure through this control panel 658 regulates outflowing volume flow of oil. This is achieved in that by appropriate cross-sectional adjustment of the control panel 658 the pressure difference ΔP between the two spaces 652a and 652b to a certain Value is set. In the invention, this value should preferably be constant, so that there is a practically constant volume flow The control panel 658 is through in the housing 543 introduced radial openings 648 formed, whose flow area by axial displacement of the piston 646 can be changed. Takes the pressure in the chamber 652a too, so will the piston 646 against the force of the spring 653 shifted to the left, whereby the flow area of the openings 648 is reduced. This will in turn be the one in the chamber 652b existing pressure is brought to a higher level, and it turns, in turn, between the two chambers 652a and 652b a pressure difference, which ensures that through the openings 648 the desired amount of oil flows through.

In one embodiment according to 10 becomes the friction lining 722 from the housing shell 704 carried. In 10 this is a carrier sheet 704a provided on the housing shell or on the lid 704 is fastened, via riveted joints 760 , The rivet connections 760 are by means of the material of the housing 704 formed rivet pin, which in corresponding recesses of the sheet 704a intervene, formed. The lining carrier component 704a is radially outward in the direction of axially from the radial wall 709 of the lid 704 Taken conical, so that an annular, in cross-section wedge-shaped intermediate space 761 is formed in the space 761 is a volume flow valve 742 taken up by the component 704a will be carried. The gap 761 has a connection to the second chamber of the flow converter or is part of this second chamber. The disc-like lining carrier component 704a can radially outside - viewed over the circumference - at least in places with the radially outer wall of the housing 704 have a connection, whereby the axial rigidity of the component 704a is enlarged. The piston 717 the lockup clutch 715 also has a conically positioned area 730 , which forms a friction surface, which with the friction lining 722 can be brought into engagement. With the lock-up clutch closed 715 a defined cooling oil flow flows over the valve 742 in the area of the covering 722 existing channels or grooves 725 ,

In 11 a construction is shown, which allows the individual over the circumference of the covering 822 provided oil grooves or oil channels 825 over a single valve 842 to supply with oil. This is in the illustrated embodiment on the piston 817 a component in the form of an annular cover 862 fastened, eliminating between this cover 862 and the ring piston 817 a circumferentially extending chamber 863 is formed, which has openings 826 with the respective oil inlet ends of the individual oil grooves 825 There are also several valves depending on the application 842 be provided, but the number of valves may be less than the number of individual oil grooves or oil channels 825 ,

The inventive concept according to 11 , namely several oil grooves or oil channels 825 through the same valve 842 to supply, can also in a particularly simple manner in a construction according to 1 Use, in the area of a passage 26 of the piston 17 a corresponding valve is provided. This allows over the annular space 17a and over the passages 26 in the component 24 all channels 25 be supplied with oil.

It is useful if the valves 542 . 642 . 742 or 842 are formed and / or arranged so that the influence of the centrifugal force acting on them is minimized, whereby the desired function is ensured. This can be ensured by using the simplest possible piston and by arranging the direction of movement of the piston in the axial direction of the torque converter. By the latter measure it is achieved that no component of the force acting on the corresponding valve centrifugal force acts in the direction of the valve spring. The pistons should be made as small as possible and be made of a lightweight material, such as plastic or aluminum. In the embodiment according to 11 will the sensitivity of the valve 842 reduced by centrifugal force, characterized in that this valve 842 additionally arranged on a relatively small radius.

The inventive use of means that regulate the flow of cooling oil, it is achieved that at the lockup clutch, an oil flow can be adjusted, which is not proportional to the root of the pressure difference between the pending on both sides of the piston pressures.

In hydrodynamic flow transducers such as those by the U.S. Patent 4,969,543 has become known, there is the disadvantage that when the lock-up clutch flowing over this flow rate is very speed dependent, the volume flow decreases significantly with increasing speed due to the already mentioned dynamic, or kinetic processes in the oil This significant for the function of the flow converter disadvantage can the inventive design of the leadership of the flow radially inward, at least substantially avoided. For a given, or desired system pressure in the flow converter can therefore by a configuration according to the invention, a lesser Volume flow adjusted at low speeds and thus a smaller pump can be used.

In 12 is a ring-like friction lining 922 partially shown, which meandering or zigzag grooves 935 has, extending in the circumferential direction of the friction lining 922 extend and have a similar configuration as the grooves 435 according to the 6 and 7 have. The zigzag or serpentine grooves in the radial direction 935 have viewed over their length substantially the same width and can advantageously at least substantially form a same flow area for the cooling oil over its longitudinal extent. The grooves 935 are both radially to the outer edge in the illustrated embodiment 922a towards and radially to the inner edge 922b open and not, as in the embodiment according to the 6 and 7 closed.

The in the friction lining or friction ring 922 introduced grooves or channels 935 can be introduced in the manufacture of the friction lining, so before the attachment of the friction lining on a support member, such as an annular piston or a blade. However, the grooves or channels formed in accordance with the invention can also be introduced into the friction lining during the fastening, for example by gluing, of the friction lining on a carrier component or after such an attachment. So it can quite generally the friction lining, eg 922 , Are first attached to the corresponding annular piston and during this attachment or thereafter the channels or grooves are impressed in the corresponding friction ring or friction lining.

It may be particularly advantageous if the one radially inner or radially outer deflection 946 of the channels 935 tangent angle, in 12 with the reference number 945 is provided, in the order between 120 and 30 degrees, preferably of the order of magnitude 45 and 70 degrees. In 12 is the angle 945 about 60 degrees. Advantageously, the individual over the circumference of the friction lining 922 distributed grooves 935 be sized so that over the length of the grooves 935 considered at least one substantially turbulent flow takes place. As a result, a better heat transfer to the cooling oil can be achieved. The turbulent flow is according to an embodiment of the invention by appropriate design of the deflection 946 along the grooves 935 achieved. Due to the multiple guidance of the grooves 935 over the radial width of the friction lining 922 the cooling caused by the cooling oil in the friction engagement region of the corresponding clutch is also positively influenced. By virtue of the guide according to the invention of the grooves or channels, a correspondingly long coolant guide can be achieved in the friction engagement region of the coupling, as a result of which good heat transfer to the cooling medium can be achieved.

To achieve a turbulent flow within the grooves 935 must in the design of the same between the inlet side 939 and the outlet side 940 the grooves 935 pending differential pressure are taken into account. In lockup clutches this differential pressure corresponds to the pressure difference between the chambers provided on either side of the piston of the lockup clutch ( 18 and 20 in 1 ).

To improve the cooling effect can pocket-shaped recesses or depressions in the radially outer and / or in the radially inner edge region 947 . 948 be introduced. These bag-shaped formations 947 . 948 can work in a similar way as the grooves 935 , getting produced. In the illustrated embodiment according to 12 are the pocket-shaped formations 947 . 948 triangular shaped. These formations 947 . 948 However, they can also have a different shape, such as moon-shaped or semicircular. Furthermore, the formations 947 . 948 , with respect to a radius 949 and viewed in the circumferential direction, also be formed asymmetrically. In the illustrated embodiment, the pocket-shaped projections 947 . 948 - viewed in the circumferential direction - in each case between two adjacent deflections 946 intended. With rotating friction lining 922 done in the pockets 947 . 948 a coolant flow which can be turbulent. How out 12 it can be seen overlap the pocket-shaped projections 947 . 948 and the channels 935 in the radial direction at least partially. Due to the design and arrangement of the cooling grooves 935 and the coolers 947 . 948 own the between these cooling arrangements 935 . 947 and 948 remaining friction surfaces 950 , also a zigzag or meander shape.

The invention is not limited to the illustrated and described embodiments, but also includes variants that can be formed in particular by combining individual features or functionalities described in connection with the various embodiments. Furthermore, individual features described in connection with the figures or functions taken alone can represent an independent invention. In this regard, reference is made in particular to the design of the friction linings, which are provided with cooling arrangements, such as grooves and / or pockets. Furthermore, reference is made to the use of valves or restrictors or orifices for controlling the coolant flow. Also, the present inventions are to be considered as part of or in conjunction with the cited prior art and this is intended to supplement the present application.

The Applicant also reserves the right to claim other features of significance essential to the invention which have hitherto been disclosed only in the description.

Claims (28)

Hydrodynamic torque converter (3) with a housing (2) and pump housed therein (7), turbine wheel (10), stator (12) and a lock-up clutch (15) with an annular piston (17), wherein on both sides of the annular piston (17) with a Oil fillable chamber (14) is formed, the annular piston (17) carries at least a first friction surface (21) which is frictionally engageable with a second friction surface, wherein radially within the friction surfaces (21) between the annular piston (17) and one second friction surface bearing member, the first of the chambers (18) is formed, in the radial region of the friction surfaces in at least one of the friction surfaces supporting or forming components channels (25) are provided, the axial flow of the friction surfaces (21) an oil flow from the second of the chambers (20) via the channels (25) radially inwardly toward the axis of rotation (27) of the torque converter (3) out towards, characterized in that at least one channel a schl has a linear course. Torque converter after Claim 1 , characterized in that the channel is open radially inwardly toward the outlet at the inner edge and radially outward towards the inlet at the outer edge. Torque converter after Claim 1 or 2 , characterized in that between the inlet and a deflection and / or between two deflections and / or between a deflection and the outlet, a leg or an arc of the channel is arranged. Torque converter after one of Claims 1 to 3 , characterized in that the at least one channel is incorporated in a friction lining (22). Torque converter after Claim 4 , characterized in that the introduction of the at least one channel in a friction lining (22) takes place by means of embossing Torque converter after Claim 4 , characterized in that the introduction of the at least one channel in a friction lining (22) takes place by means of cutouts. Torque converter after one of Claims 1 to 6 , characterized in that at least three channels are provided. Torque converter after one of Claims 1 to 7 , characterized in that the channels (25) are distributed uniformly over the circumference of the friction surface. Torque converter according to one of the preceding Claims 1 to 8th , characterized in that the channels (25) viewed over their length have a substantially equal width. Torque converter according to one of the preceding Claims 1 to 10 , characterized in that the channels (25) viewed over their length have a substantially equal flow area. Torque converter after one of Claims 1 to 10 , characterized in that the channels (25) through the friction lining (22) are limited. Torque converter after one of Claims 1 to 11 , characterized in that the inlet side of the channels (25) in the radially outer edge region of the friction lining (22) and the outlet side in the radially inner edge region of the friction lining (22) are provided. Torque converter after one of Claims 1 to 12 , characterized in that the serpentine formed channels (25) extend in the circumferential direction of the friction lining (22). Torque converter after one of Claims 1 to 13 , characterized in that the friction lining (22) is mounted on a support member. Torque converter after Claim 14 , characterized in that the carrier part with the housing (2) has a connection. Torque converter after one of Claims 1 to 14 , characterized in that the friction lining is mounted on an annular piston (17). Torque converter after one of Claims 1 to 14 , characterized in that the friction lining (22) is mounted on a lamella Torque converter after one of Claims 1 to 14 , characterized in that the friction lining (22) on a housing shell (4) is fixed. Torque converter after one of Claims 14 to 18 , characterized in that the friction lining (22) is glued. Torque converter after one of Claims 1 to 19 , characterized in that the friction lining (22) is fixed prior to embossing the channels (25). Torque converter after one of Claims 1 to 19 , characterized in that the embossing of the channels (25) takes place during the attachment. Torque converter after one of Claims 1 to 21 , characterized in that at least one of the friction surfaces bearing components having a friction lining (22). Torque converter after one of Claims 1 to 22 , characterized in that the friction lining (22) consists of a plurality of sickle-shaped friction segments. Torque converter after one of Claims 1 to 22 , characterized in that the friction lining (22) is annular and in the at least one friction surface channels (25) for carrying out a cooling liquid are present. Torque converter after one of Claims 1 to 24 , characterized in that the ratio between the thickness of the friction lining (22) and the average depth of the channels (25) is on the order of 2.7 to 1.3. Torque converter according to at least one of the preceding Claims 1 to 25 , characterized in that the depth of the channels (25) is of the order of 0.2 to 0.8 mm. Torque converter according to one of the preceding Claims 1 to 26 CHARACTERIZED IN THAT said channels (25) are configured to provide substantially turbulent flow over the length thereof and for the pressures encountered on the input side and output side of the grooves during travel of a vehicle equipped with the torque converter. Torque converter according to at least one of the preceding Claims 1 to 27 , characterized in that the channels (25) in the friction lining (22) extend in the circumferential direction serpentine and viewed over its length have a substantially constant flow area.

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