IPC분류정보
국가/구분 |
United States(US) Patent
등록
|
국제특허분류(IPC7판) |
|
출원번호 |
US-0437526
(2003-05-14)
|
우선권정보 |
DE-0030183 (2002-07-05) |
발명자
/ 주소 |
- Schiele, Peter
- Bauknecht, Gert
- Ziemer, Peter
- Dorr, Ulrich
- Ast, Ewald
|
출원인 / 주소 |
|
대리인 / 주소 |
|
인용정보 |
피인용 횟수 :
6 인용 특허 :
7 |
초록
▼
A system and method for supplying cooling fluid for frictional elements, for example multiple disc clutches and multiple disc brakes, in automatic transmissions. The cooling fluid flows through the multiple disc clutch or brake in a predefined manner radially inward or outward, whereby a defined flo
A system and method for supplying cooling fluid for frictional elements, for example multiple disc clutches and multiple disc brakes, in automatic transmissions. The cooling fluid flows through the multiple disc clutch or brake in a predefined manner radially inward or outward, whereby a defined flow through the clutch or brake packet is ensured through a defined pressure difference in the cooling fluid between the cooling fluid supply and the discharge of the cooling fluid. A preferred embodiment of device for supplying the cooling fluid is designed as a ring-shaped channel that partially or fully encloses the clutch or the brake.
대표청구항
▼
1. A method for supplying cooling fluid to a rotating, selectively engageable frictional element of an automatic transmission for a vehicle, comprising:providing a predefined radial flow path for bringing cooling fluid into contact with the frictional element; and defining a pressure difference betw
1. A method for supplying cooling fluid to a rotating, selectively engageable frictional element of an automatic transmission for a vehicle, comprising:providing a predefined radial flow path for bringing cooling fluid into contact with the frictional element; and defining a pressure difference between a cooling fluid supply and a cooling fluid discharge to ensure a desired volume flow of cooling fluid through the radial flow path, wherein said volume of flow of cooling fluid is controlled by varying said defined pressure difference, said volume flow of cooling fluid causing a dynamic pressure of the cooling fluid, and wherein said dynamic pressure of the cooling fluid is used as a control signal for a cooling fluid control. 2. The method according to claim 1, wherein the cooling fluid supply is carried through at least one circumjacent space which at least partially encloses the frictional element.3. The method according to claim 1, wherein the cooling fluid supply is disposed inside an inner disc carrier of the frictional element, and the cooling fluid flows radially from the inside to the outside.4. The method according to claim 1, wherein the frictional element comprises a plurality of discs forming a clutch.5. The method according to claim 1, wherein the frictional element comprises a plurality of discs forming a brake.6. The method according to claim 1, wherein the predefined radial flow path is radially outward.7. The method according to claim 1, wherein the predefined radial flow path is radially inward.8. A method for supplying cooling fluid to a rotating, selectively engageable frictional element of an automatic transmission for a vehicle, comprising:providing a predefined radial flow path for bringing cooling fluid into contact with the frictional element; defining a pressure difference between a cooling fluid supply and a cooling fluid discharge to ensure a desired volume flow of cooling fluid through the radial flow path; under normal conditions, electronically controlling the cooling fluid flow, and under control failure conditions, employing a dynamic pressure of the cooling fluid as a direct control signal for an actuation of the frictional element, to provide a hydraulic control mode emergency start-up capability. 9. The method according to claim 8, wherein a volume flow of cooling fluid is controlled by varying the defined pressure difference.10. The method according to claim 8, wherein a dynamic pressure of the cooling fluid caused by the cooling fluid flow is used as a control signal for a cooling fluid volume control.11. A system for supplying cooling fluid to mutually rotatable frictional elements of an automatic transmission for a vehicle, comprising a cooling fluid supply and a cooling fluid discharge, having a respective pressure difference, including a dynamic pressure caused by a volume flow of cooling fluid, said pressure difference controlling a volume flow of cooling fluid through the frictional elements, said dynamic pressure being a control signal for controlling said volume flow of cooling fluid, a maintenance of a defined pressure difference ensuring a defined volume flow of cooling fluid through the frictional elements.12. The system according to claim 11, wherein the frictional elements comprise friction pads having grooves, said grooves causing a defined flow resistance, such that a defined pressure difference between the cooling fluid supply and the cooling fluid discharge corresponding to the differential speed of the pads can be achieved.13. The system according to claim 12, wherein at least a portion of the pads are mounted on an outer disc carrier, the outer disc carrier having openings to facilitate a passage of the cooling fluid from the cooling fluid supply to the frictional elements.14. The system according to claim 12, wherein at least a portion of the pads are provided with openings to facilitate the passage of the cooling fluid from the cooling fluid supply to the frictional elements.15. The system according to claim 12, wherein the cooling fluid supply comprises an annular groove acting as a cooling fluid supply chamber, at least partially enclosing the pads, and wherein the pads comprises a set of outer discs mounted on an apertured disc carrier, further comprising baffles disposed in conjunction with the apertures of the outer disc carrier, to distribute volume flow of cooling fluid to the pads.16. The system according to claim 12, wherein the pads are mounted on respective inner and outer disc carriers, wherein apertures are provided in the inner disc carrier to permit radial flow of heated cooling fluid between the friction disc pads and the cooling fluid discharge.17. The system according to claim 16, wherein the cooling fluid discharge leads through a connection to an oil sump, the connection exhibits has a low pressure drop.18. The system according to claim 12, wherein a portion of the pads are mounted on an inner disc, the inner disc baying a tooth structure, a flow of heated cooling fluid occurring through a play of the tooth structure.19. The system according to claim 12, wherein the pads with grooves are placed on an inner disc carrier, such that at a differential speed in the frictional elements is induced in the cooling fluid supply, wherein the magnitude of said dynamic pressure is a function of the square of the differential speed.20. The system according to claim 12, wherein the frictional elements comprise pads on outer discs, having a configuration such that no hydrodynamic pressure builds up in the cooling fluid supply.21. The system according to claim 12, further comprising an actuator piston, having an outer piston diameter (r_KAD) designed in relation to the piston attack diameter (r_KA) such that a compensation of the dynamic pressure acts on the frictional elements.22. The system according to claim 11, wherein the cooling fluid supply comprises a circumferential space, which at least partially encloses the frictional elements.23. The system according to claim 11, wherein a portion of the frictional elements are supported by an inner disc carrier, designed such that the cooling fluid flows radially and in a defined manner from a center of rotation outwards through the frictional elements, further comprising a cooling fluid supply chamber, disposed inside the inner disc carrier, for sourcing cooling fluid and a cooling fluid discharge chamber for receiving cooling fluid.24. The system according to claim 23, further comprising a partition for sealing a chamber including the frictional elements in order to avoid an uncontrolled fluid discharge towards other transmission components.25. The system according to claim 24, wherein the partition is arranged outside of the frictional elements, sealing against a housing, and at an inside of the frictional elements, sealing by means of a labyrinth seal or an elastomeric seal.26. The system according to claim 23, wherein the inner disc carrier has apertures to facilitate passage of the cooling fluid.27. The system according to claim 23, wherein the inner disc carrier has a play of the tooth structure, or the frictional elements supported by the inner disc carrier have notches, to facilitate passage of the cooling fluid.28. The system according to claim 23, further comprising an outer disc carrier for supporting a portion of the frictional elements, having openings provided to facilitate discharge of the heated cooling fluid.29. The system according to claim 23, wherein the outer disc carrier has a tooth structure, dimensioned such that the discharge of the heated cooling fluid occurs via a play of the tooth structure.30. The system according to claim 23, wherein a ring-shaped channel is provided which opens into an oil sump, communicating with the cooling fluid discharge.31. The system according to claim 23, wherein a sealing of the cooling fluid supply chamber to the cooling fluid discharge chamber is provided via a support of the last outer disc to the housing in an unactuated state, and to the adjoining piston, in an actuated state.32. The system according to claim 23, wherein a sealing of the cooling fluid supply chamber to the cooling fluid discharge chamber is provided by elastomeric sealing elements on a hydraulic actuator side and on a support side or in the tooth structure of the terminal discs, respectively.33. The system according to claim 23, wherein an inner piston seal diameter (r_KID) is dimensioned in relation to a piston attack diameter (r_KA), such that the cooling fluid supply pressure simultaneously acts upon a ring surface that comes into existence between the inner piston seal diameter (r_KID) and the piston attack diameter (r_KA), which at least partially compensates for a dynamic pressure variation, depending on the surface size.34. The system according to claim 11, wherein the frictional elements comprise a plurality of discs arranged as a clutch.35. The system according to claim 11, wherein the frictional elements comprise a plurality of discs arranged as a brake.36. The system according to claim 11, wherein the frictional elements comprise pairs of friction surfaces having a mutual rotation about an axis, selectively engageable by application of an axial force to selectively transmit a rotational force therebetween, a relatative slip between adjacent discs generating heat, wherein the cooling fluid is present proximate to heat-generating surfaces of the frictional elements and has a general flow pattern in a radial direction.37. The system according to claim 11, wherein cooling fluid flows radially outward through a radial flow path.38. The system according to claim 11, wherein cooling fluid flows radially inward through a radial flow path.39. The system according to claim 11, further comprising a control for selectively controlling a pressure difference between the cooling fluid supply and the cooling fluid discharge, to thereby control a volume flow of cooling fluid.40. The system according to claim 11, further comprising an electronic control for selectively activating a hydraulic piston to apply a force pressure between frictional elements to selectively transmit a rotational force therebetween, wherein a backup hydraulic mode control is provided, in an event of electronic control failure, based on a dynamic pressure of cooling fluid resulting from rotation of transmission components, to hydraulically activate the hydraulic piston.41. A system for supplying cooling fluid to an automatic transmission for a vehicle, comprising a set of frictional elements comprising a set of outer discs mounted on a disc carrier and having a tooth structure, having a cooling fluid supply which encloses the set of frictional elements within circumferential space comprising first and second annular grooves, the first annular groove comprising a supply channel, cooling fluid within the first annular groove flowing adjacent to the set of outer discs and absorbing heat therefrom, to the second annular groove, which comprises a supply chamber, and radially inward in the direction of the set of outer discs, through the disc tooth structure, and hence into the disc carrier; and a discharge, having a pressure difference variation with respect to the cooling fluid supply which serves as a control signal to control a flow rate of cooling fluid through the set of frictional elements.42. The system according to claim 41, further comprising a seal for containing cooling fluid bathing the frictional elements between the cooling fluid supply chamber and the cooling fluid discharge.43. The system according to claim 42, wherein the seal extends between a support of a terminal outer disc to a housing or adjoining hydraulic actuator.44. The system according to claim 42, wherein the automatic transmission comprises a hydraulic actuator for engaging the frictional elements, elastomeric sealing elements being provided as seals on a hydraulic actuator side and on a support side or in the tooth structure of the terminal discs, respectively.45. A system for supplying cooling fluid to mutually rotatable frictional elements of an automatic transmission for a vehicle, comprising a cooling fluid supply and a cooling fluid discharge, having a respective pressure difference, said pressure difference controlling a flow of cooling fluid through the frictional elements, a maintenance of a defined pressure difference ensuring a defined flow of cooling fluid through the frictional elements, wherein a dynamic pressure of the cooling fluid resulting from rotation within the transmission provides a control signal for a fail-safe operating mode to selectively engage the frictional elements to transmit a rotational force therebetween.46. A system for supplying cooling fluid to mutually rotatable frictional elements of an automatic transmission for a vehicle, comprising a cooling fluid supply and a cooling fluid discharge, having a respective pressure difference, said pressure difference controlling a flow of cooling fluid about the frictional elements, a maintenance of a defined pressure difference ensuring a defined flow of cooling fluid through the frictional elements, and an electronic control for controlling the cooling fluid flow, wherein, in case the electronic control fails, an emergency control employs a dynamic pressure of the cooling fluid as a direct control signal for an actuation of the frictional elements to control a mutual rotation thereof, such that a hydraulic control mode emergency start-up capability is ensured within the scope of an emergency program.47. A system for cooling a clutch or brake in an automatic transmission for a vehicle with a fluid, the clutch or brake selectively transmitting a rotational force based on an axially applied pressure between respective pairs of discs, the discs generating heat as a result of slippage, comprising a cooling fluid supply and a cooling fluid discharge, the cooling fluid supply being concentric with the discs, a radial flow path for cooling fluid being defined, allowing intimate contact of fluid with portions of radial surfaces of the discs, wherein a flow rate of cooling fluid is controlled by a respective pressure difference between the cooling fluid supply and the cooling fluid discharge and an electronic control for selectively activating a hydraulic piston to apply the axially applied pressure, wherein a backup hydraulic mode control is provided, in an event of electronic control failure, based on a dynamic pressure of cooling fluid resulting from rotation of transmission components, to hydraulically activate the hydraulic piston.48. The system according to claim 47, having a plurality of separately operable clutches or brakes, further comprising a control for selectively controlling a pressure differential between the cooling fluid supply and the cooling fluid discharge for each clutch or brake.49. The system according to claim 48, wherein the control dynamically provides a high pressure differential for clutches or brakes subject to slippage, and a low pressure differential for clutches or brakes not subject to slippage.50. The system according to claim 47, wherein the pairs of discs of the clutch or brake are mounted on inner disc carriers and outer disc carriers, respectively, the inner and outer disc carriers having apertures permitting cooling fluid flow in a radial direction, further comprising at least one elastomeric seal for selectively containing the cooling fluid proximate to the pairs of discs and separate from other transmission components.51. The system according to claim 47, wherein the pairs of discs form a clutch packet, and a rotation of the discs induces a dynamic pressure of the cooling fluid, further comprising a piston for actuating the clutch packet by applying a pressure along a rotational axis, the piston having an outer piston diameter and a piston attack diameter, the outer piston diameter being designed in relation to the piston attack diameter to compensate for the effect of the dynamic pressure on the flow of cooling fluid through the clutch packet.
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