Power plants – Pressure fluid source and motor – Coaxial impeller and turbine unit
Reexamination Certificate
1999-10-01
2001-05-08
Look, Edward K. (Department: 3745)
Power plants
Pressure fluid source and motor
Coaxial impeller and turbine unit
C060S367000
Reexamination Certificate
active
06226985
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is directed to a turbine wheel arrangement and an impeller wheel arrangement for a hydrodynamic torque converter comprising an outer shell connected with a respective hub for common rotation and a plurality of vanes or blades arranged successively in the circumferential direction at the outer shell. The blades are connected to an inner shell at a side of the blades remote from the outer shell. Fluid flow channels are formed between the successive of blades and in the outer shell and inner shell.
2. Description of the Related Art
Prior art impeller wheel arrangements and turbine wheel arrangements having blades arranged successively along a circumferential direction are used in known torque converters and have the problem that the blade configuration, i.e., the contouring of the blades must be adapted to different operating ranges or operating points of a torque converter to provide the respective fluid flow channels to provide operating characteristics that are acceptable over a relatively large operating range and a good torque transmission and so that the torque converter has a relatively high efficiency. For example, at the starting operating point of a vehicle a high staring conversion is required in which the turbine wheel arrangement essentially does not rotate and initially only the impeller wheel arrangement is driven by the driving means, whereas at an operating point of a vehicle where the ratio of the speed of the turbine wheel arrangement to the speed of the impeller wheel arrangement is greater than 0.8 a high efficiency is required. To completely satisfy each of these operating requirements, the blades of the turbine wheel arrangement and/or of the impeller wheel arrangement would have to be constructed with different blade contours. Since only one blade contour is possible in each device, compromises were made in the prior art devices with regard to the blade contouring for different operating points to provide an acceptable converter characteristic for the starting range as well as for the normal or approximately constant driving range. It is obvious that, based on this compromise, no approximately optimum converter characteristic can be provided in any of the relevant driving ranges.
A prior torque converter is disclosed in European Patent EP 0 846 893 A2 in which the respective blades in both turbine and impeller are constructed so as to be completely offset along a direction of flow, i.e., blade portions lying in different areas in the circumferential direction are provided. An arrangement of this type is intended to prevent separation of flow in modem torque conveners which, owing to a lack of sufficient installation space, are constructed in an axially flat manner. This is achieved by offsetting the two blade portions relative to one another at the translational area between the two blade portions. The translational area is constructed in a stopped manner and extends along the flow direction. However, no additional adapting measures are taken in this torque converter of the prior art in the area of the impeller wheel or turbine wheel which would make them especially suitable for determined operating states or for a greater range of operating states.
SUMMARY OF THE INVENTION
It is the object of the present invention to provide a turbine wheel arrangement or an impeller wheel arrangement for a hydraulic torque converter in which improved working characteristics are achieved in different operating states, especially frequently occurring or critical operating ranges, of a torque converter .
In accordance with the present invention, this object is met by a turbine wheel arrangement and an impeller wheel arrangement for a hydrodynamic torque converter comprising an outer shell connected with a respective hub for common rotation and a plurality of blades ranged in succession in the circumferential direction at the outer shell. The blades are connected with an inner shell at a side of the blades remote of the outer shell. Respective fluid flow channels are formed by blades arranged successively in the circumferential direction together with the outer shell and the inner shell.
At least one of the blades of the turbine wheel or the impeller wheel is further provided with a blade area lying closer to the outer shell that has a blade contour adapted to a first operating state such, for example, as a starting operation state of a torque converter and with a blade area lying closer to the inner shell that has a blade contour adapted to a second operating state such, for example, as a driving operation state of the torque converter.
According to yet a further embodiment of the present invention, it is suggested that at least one of the blades, but preferably all of the blades, of the turbine wheel arrangement and/or of the impeller wheel arrangement are divided into different blade working areas, with each of the different blade working areas being adapted to a different operating state. That is, the different blade working areas have shapes which are optimized for different operating states or operating ranges of a torque converter. Accordingly, for example, an area of the respective blades lying closer to the outer shell may have a contour which is optimized for the torque conversion in the swung state, while the blade area lying closer to the inner shell may be optimized for the normal driving state in which the speed difference between the turbine wheel and the impeller wheel approaches zero, but the torque converter is not bypassed by a lockup clutch generally provided in this torque converter.
According to a further embodiment of the present invention—regardless of whether it is provided for the turbine wheel arrangement or for the impeller wheel arrangement—a preferably substantially flat base area of the blade is provided and, in an end area of the blade following the base area of the blade in the upstream and/or downstream direction, a blade area lying closer to the outer shell is offset in the circumferential direction with respect to a blade area lying closer to the inner shell. As a result of dividing at least one blade into areas effective for different operating states in at least one blade end area, this end area acts differently in the different operating states, but a blade base area constructed for a very large range of operating states is still provided.
In this case, for example, it can be provided that the blade area lying closer to the outer shell and the blade area lying closer to the inner shell are offset relative to one another in the circumferential direction by extending away from the blade base area in different circumferential directions. In particular, it is possible that the blade area lying closer to the outer shell and the blade area lying closer to the inner shell are inclined and/or curved to different degrees in the circumferential direction with respect to the blade base area.
Depending on the torque requirements for which a torque converter is to be designed and on the operating states or ranges for which the different blade areas are to be constructed, it may be provided, for example, that the blade area lying closer to the outer shell and the blade area lying closer to the inner shell extend away from the blade base area in the same circumferential direction, but at a different inclination and/or with a different curvature. Alternatively, the blade area lying closer to the outer shell and the blade area lying close to the inner shell may extend away an&or curve away from the blade base area in opposite circumferential directions.
It is noted in this respect that the above also includes a construction in which the area lying, closer to the outer shell and the area lying closer to the inner shell both extend away from the base area in the same circumferential direction in one blade end area and extend away from one another in opposite circumferential directions in the other blade end area.
To achieve different contours in the respective blade areas, the bl
Sasse Christoph
Wienholt Hans-Wilhelm
Cohen & Pontani, Lieberman & Pavane
Leslie Michael
Look Edward K.
Mannesmann Sachs AG
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