Torque converter

Abstract

A hydrodynamic torque converter comprising a pump wheel and a turbine wheel mounted to be rotatable about an axis of rotation is disclosed. A fluid in a region between the pump wheel and the turbine wheel is provided wherein a first axial contact surface is formed on the pump wheel and a second axial contact surface is formed on the turbine wheel. A frictional connection between the pump wheel and the turbine wheel can be produced when the pump wheel and the turbine wheel are pressed axially against one another. Moreover, one of the contact surfaces is configured to be flexible in order to lie against the other contact surface under an axial pressure load.

Claims

1. A hydrodynamic torque converter, comprising: a pump wheel and a turbine wheel mounted to be rotatable about an axis of rotation; a fluid in a region between the pump wheel and the turbine wheel; wherein a first axial contact surface is formed on the pump wheel and a second axial contact surface is formed on the turbine wheel; wherein a frictional connection between the pump wheel and the turbine wheel can be produced when the pump wheel and the turbine wheel are pressed axially against one another; wherein one of the contact surfaces is configured to be flexible in order to lie against the other contact surface under an axial pressure load; wherein the contact surface configured to be flexible comprises a metal sheet that is folded over circumferentially; and wherein the metal sheet is thinned out in a region of a bending edge of the metal sheet.

2. The torque converter as claimed in claim 1, wherein the turbine wheel is connected on a radially outer side to a housing in which the turbine wheel is received.

3. The torque converter as claimed in claim 1, wherein a fold angle of the metal sheet is less than 180 so that a fold of the metal sheet is open when the contact surface configured to be flexible is unloaded.

4. The torque converter as claimed in claim 1, wherein the metal sheet is folded over a plurality of times in alternate directions.

5. The torque converter as claimed in claim 1, wherein the contact surfaces enclose a predetermined angle with the axis of rotation.

6. The torque converter as claimed in claim 1, wherein a friction element is mounted on one of the contact surfaces.

7. The torque converter as claimed in claim 1, wherein the contact surface configured to be flexible comprises a separate element connected to the pump wheel or the turbine wheel.

8. The torque converter as claimed in claim 7, wherein the separate element is connected in a fluid-tight manner to the pump wheel or the turbine wheel.

9. A torque converter, comprising: a pump including a first plurality of blades; a turbine fluidly connected to the pump and including a second plurality of blades; and a clutch disposed radially outside the first plurality of blades and the second plurality of blades, wherein the clutch includes a first contact surface mounted on the pump axially opposite a second contact surface mounted on the turbine, wherein the first contact surface or the second contact surface is flexibly mounted thereto, wherein the contact surfaces are configured to be frictionally engageable with one another, and wherein the contact surface flexibly mounted is folded over circumferentially and thinned out in a region of a blending edge of a fold of the contact surface.

10. The torque converter of claim 9, wherein the first contact surface or the second contact surface is flexibly mounted via a flexible element.

11. The torque converter of claim 9, wherein the first contact surface or the second contact surface includes a friction element attached thereto.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The disclosure is now described in more detail with reference to the accompanying figures, which show:

(2) FIG. 1 a longitudinal section through a device for transmitting torque with a torque converter; and

(3) FIGS. 2-7 variants of flexible contact surfaces on the torque converter of FIG. 1.

DETAILED DESCRIPTION

(4) FIG. 1 shows a longitudinal section through a device 100 for transmitting torque. The device 100 is designed in particular for use in a drive train, for example of a motor vehicle. The device 100 can be in particular part of a converter, a dual clutch, a starting clutch or a power shift clutch.

(5) The device 100 comprises an axis of rotation 105 about which a pump wheel 110 and a turbine wheel 115 of a hydrodynamic torque converter 120 are rotatably arranged. At a predetermined radial spacing from the axis of rotation 105, respective guide plates 125, which are axially opposite one another, are formed on the pump wheel 110 and the turbine wheel 115. Located in this region is a fluid 130, typically an oil, that couples the two wheels 110 and 115 hydrodynamically to one another. An optional guide wheel 135 is provided axially between the wheels 110, 115 for influencing the flow of the fluid 130.

(6) The pump wheel 110 is preferably connected on its radial outer side to a housing 140 which receives the turbine wheel 115 and the fluid 130.

(7) The pump wheel 110 and the housing 140 represent an input side 145 of the device 100 for transmitting torque. An output side 150 can be coupled to the turbine wheel 115 of the torque converter 120 directly or, as shown in FIG. 1, by means of an elastic element 155.

(8) A lock-up clutch 160 is provided in a region which is preferably located radially outside the guide plates 125. To form the lock-up clutch 160, a first axial contact surface 165 is formed on the pump wheel 110 and a second axial contact surface 170 is formed on the turbine wheel 115. The contact surfaces 165, 170 are axially opposite one another and can be brought into frictional connection with one another in that the pump wheel 110 and the turbine wheel 115 are moved axially towards one another and pressed axially against one another.

(9) In one embodiment, the turbine wheel 115 is designed to be axially movable relative to the pump wheel 110 and the housing 140. With respect to the fluid 130 in the housing 140, the turbine wheel 115 acts in the manner of a hydraulic piston, which is pressed axially in the direction of the pump wheel 110 when the hydraulic pressure on the side axially remote from the pump wheel 110 increases. If the housing 140 is rotating about the axis of rotation 105, the fluid 130 is pressed radially outwards and effects such hydraulic pressure. From a predetermined speed of the housing 140, the lock-up clutch 160 is therefore hydraulically closed so that the contact surfaces 165, 170 come into engagement with one another and reduce a slip between the pump wheel 110 and the turbine wheel 115, ideally to zero.

(10) It is disclosed that one of the contact surfaces 165, 170 be mounted flexibly, in particular with respect to the axis of rotation 105, on the wheel 110, 115 associated therewith, so that the contact surfaces 165, 170 can lie closely against one another in an improved manner when the lock-up clutch 160 is closed. In the illustrated embodiment, the second contact surface 170 of the turbine wheel 115 is designed to be rigid or stiff with respect to the axis of rotation 105, whilst the first contact surface 165 is connected to the pump wheel 110 or the housing 140 by means of a flexible element 175. In another embodiment, as described more precisely below, the first contact surface 165 can also be rigidly mounted and the second contact surface 170 flexibly mounted. The flexible element 175 can also be omitted if the respective contact surface 165, 170 is flexibly formed on the wheel 110, 115 associated therewith. A friction element 180 can be optionally provided on one of the contact surfaces 165, 170.

(11) The surface along which the contact surfaces 165 and 170 engage with one another when the two wheels 110, 115 are pressed axially against one another can be configured in various ways. The surface can be for example planar and enclose a predetermined angle with the axis of rotation 105. If this angle is 90, the surface is located in the rotational plane. The contact surfaces 165, 170 can moreover also be concavely and convexly configured to correspond to one another. Other superimposed and expedient curvatures can also be used.

(12) In an exemplary embodiment, the contact surfaces 165 and 170 are designed such that there is as little leakage as possible between the contact surfaces 165, 170, even when the lock-up clutch 160 is stationary or rotating at low speed. The closure of the lock-up clutch 160 is facilitated by the build-up of a hydraulic pressure of the fluid 130 under the influence of centrifugal force (centrifugal oil). If the lock-up clutch 160 is closed, the contact surfaces 165 and 170 can also lie against one another in a fluid-tight manner.

(13) FIGS. 2 to 7 show variants of flexible contact surfaces 165, 170 on the torque converter 120 of FIG. 1. All the illustrations here are to be seen as schematic and as a possible embodiment in each case of the principle explained above with reference to FIG. 1. Each of the FIGS. 2 to 7 comprises an upper illustration, which is denoted by A and shows the opened lock-up clutch 160, and a lower illustration, which is denoted by B and shows the closed lock-up clutch 160. The variants shown in FIGS. 2 to 7 can be combined with one another and with the embodiment illustrated in FIG. 1. It is essentially possible in all embodiments for the design of the first contact surface 165 and the second contact surface 170 to be mutually interchangeable. Therefore, only one variant is described below; the inverse variant in each case will be readily obvious to a person skilled in the art.

(14) FIG. 2 shows an embodiment in which the second axial contact surface 170 is designed in one piece on a metal sheet, which is a component of the turbine wheel 115. The metal sheet is bent circumferentially about the axis of rotation 105, whereby a circumferential fold is formed 205. The fold angle between portions of the metal sheet on different sides of the fold 205 is preferably less that 180 when the metal sheet is unloaded (FIG. 2A). The metal sheet can be thinned out in the region of the fold 205 so that its material thickness is reduced. As a result of the geometry of the arrangement, the effective bending length of the metal sheet can be extended, thereby producing a further elastic effect of the metal sheet. The second contact surface 170 faces that portion of the metal sheet which is further away from the axis of rotation 105 along the metal sheet.

(15) FIG. 3 shows an embodiment in which two folds 205 are provided about which the metal sheet of the turbine wheel 115 is folded. The bending directions are opposed to one another here to produce the Z-shaped fold illustrated. It is preferred for both folding angles to be smaller than 180.

(16) FIG. 4 shows an embodiment similar to that of FIG. 1, although the flexible element 175 is mounted on the turbine wheel 115. The flexible element 175 can comprise in particular a metal sheet.

(17) FIG. 5 shows a further embodiment according to that of FIG. 1.

(18) FIG. 6 shows a variant of the most recently shown embodiment, in which the flexible element 175 is mounted on the pump wheel 110 or the housing 140 and supports the first axial contact surface 165. The second contact surface 170 corresponding thereto is rigidly designed on the turbine wheel 115.

(19) FIG. 7 shows yet another embodiment similar to that of FIG. 4, but with the mutually contacting contact surfaces 165, 170 (FIG. 7b) located in a rotational plane about the axis of rotation 105.

LIST OF REFERENCE NUMBERS

(20) 100 Device

(21) 105 Axis of rotation

(22) 110 Pump wheel

(23) 115 Turbine wheel

(24) 120 Torque converter

(25) 125 Guide plate

(26) 130 Fluid

(27) 135 Guide wheel

(28) 140 Housing

(29) 145 Input side

(30) 150 Output side

(31) 155 Elastic element

(32) 160 Lock-up clutch

(33) 165 First axial contact surface (on the pump wheel)

(34) 170 Second axial contact surface (on the turbine wheel)

(35) 175 Flexible element

(36) 180 Friction element

(37) 205 Fold