US 6,742,638 B2Granted

Hydraulic torque converter

AssigneeLuK Lamellen und Kupplungsbau Beteiligungs KG

InventorsStephan Maienschein, Bruno Müller, Gunnar Back

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Abstract

Overheating of various parts of a hydraulic torque converter between the engine and the transmission of the power train in a motor vehicle, wherein the torque converter employs a bypass clutch which generates heat when it is operated with slip, is counteracted by establishing one or more paths for the flow of hydraulic converter fluid from a first plenum chamber at one side of the axially movable piston of the bypass clutch to a second plenum chamber. A first portion of each such path is defined by at least one groove in a friction surface of at least one part of the bypass clutch, and a second portion of each such path is defined by one or more throttling orifices which offers or offer to the fluid flow a resistance several times that of the groove(s).

Claims40

Dependent claims

A fluid-operated apparatus for transmitting torque from a rotary output element of a prime mover to a coaxial input element of a driven unit, comprising:

a hollow rotary fluid containing housing coaxial with and connected to the output element;
a pump connected with and located in said housing;
a turbine rotatable with the input element and being located in and rotatable relative to said housing;
a bypass clutch disposed in said housing and being engageable to connect said housing with said input element, said clutch including a piston movable axially in and dividing the interior of said housing into a plurality of chambers in the engaged condition of said clutch, a first chamber of said plurality having an inlet and a second chamber of said plurality having an outlet, said piston being movable axially of said housing to engage the clutch in response to an increase of fluid pressure in said first chamber above the fluid pressure in said second chamber;
and means for establishing a path for the flow of fluid between said first and second chambers in the engaged condition of said clutch, including a first friction surface borne by said housing, a second friction surface adjacent said first friction surface at least in the engaged condition of said clutch and rotatable with said input element, at least one of said surfaces having a groove communicating with said first and second chambers, defining a first portion of said path and being arranged to offer a pronounced resistance to the flow of fluid therethrough, and at least one throttling orifice defining a second portion of said path, wherein the fluid flows radially inwards from a boundary line between an outside diameter of at least one of the first and second friction surfaces and a neighboring surface and as the fluid flows radially inside from the outside diameter, the flow of the fluid is redirected at least once in the axial direction.

2 more elements

A hydrodynamic torque converter for use between a rotary output element of a prime mover and a rotary input element which is coaxial with the output element and forms part of a change-speed transmission, particularly in the power train of a motor vehicle, comprising:

a rotary fluid-containing housing coaxial with and connectable to the output element;
a pump disposed in and rotatable with said housing;
a turbine disposed in and rotatable by fluid in said housing in response to rotation of said pump;
an engageable and disengageable bypass clutch disposed in said housing and operable to at least temporarily connect the housing with the input element, said clutch including a piston movable axially of said housing and dividing the interior of the housing into at least two fluid-containing chambers in the at least partly engaged condition of the clutch, a first chamber of said chambers having a fluid-admitting inlet and a second chamber of said chambers having a fluid-discharging outlet, said clutch being engageable in response to admission of fluid into said first chamber at a pressure exceeding the fluid pressure in said second chamber with attendant axial movement of said piston in said housing, said clutch further having a first friction surface rotatable with said housing and a second friction surface rotatable with the input element and bearing upon the first surface in at least partly engaged condition of the clutch;
a torsional vibration damper disposed in said housing and including an input member rotatable with and about the axis of said housing at least in the engaged condition of said clutch, an output member turnable about said axis relative to the input member, and means for yieldably opposing rotation of said output member relative to said input member;
and means for non-rotatably mounting said output member on the input element of the transmission, including a first hub rotatable with said turbine, a second hub adjacent and coaxial with said first hub and axially movably carried by the input element, a set of mating gears coupling said second hub for rotation with said output member, and energy storing means for yielding biasing said hubs against each other axially of said housing.

3 more elements

Dependencies are inferred from the claim text.

Facts

Application: 10/194,085Filed 11 Jul 2002
Priority: DE 101 33 69911 Jul 2001
Published: US 2003/0010588 A116 Jan 2003
Granted: 1 Jun 2004
Term ends: Not estimatedThe source records don’t support an estimate.

Classification8 codes

F16H 45/02
Combinations of fluid gearings for conveying rotary motion with couplings or clutches: with mechanical clutches for bridging a fluid gearing of…
F16D 13/64
Clutching elements: clutch-plates; Clutch-lamellae
F16D 13/72
Details: features relating to cooling
F16H 2045/0215
With mechanical clutches for bridging a fluid gearing of the hydrokinetic type: details of oil circulation