Power plants – Pressure fluid source and motor – Coaxial impeller and turbine unit
Reexamination Certificate
1999-08-10
2001-07-17
Ryznic, John E. (Department: 3745)
Power plants
Pressure fluid source and motor
Coaxial impeller and turbine unit
Reexamination Certificate
active
06260354
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a hydrodynamic torque converter having a hydrodynamic circuit including a pump wheel and a turbine wheel, wherein a turbine shell of the turbine wheel extends between two axial abutments for axially positioning the turbine wheel.
2. Description of the Related Art
A prior art hydrodynamic torque converter having a hydrodynamic circuit is disclosed in DE 44 23 640 A1 (see
FIG. 1
) which has a pump impeller, a turbine wheel and a stator. The turbine wheel has a turbine shell, which is formed with blading. A radially inner region of the turbine shell is connected in a rotationally locked manner to a radial flange of a turbine hub via riveting. The radial flange of the turbine hub interacts with axial abutments, which are provided on both sides and position the turbine wheel axially between a housing hub of the converter housing and the stator. Of course, this radial flange of the turbine hub must have sufficient flexural rigidity to fulfill this task.
The stator is guided via a freewheel having a supporting ring axially between it and one of the axial abutments for the turbine hub described above. The supporting ring is provided with grooving for the throughflow of converter fluid, which originates from a supply reservoir and passes via a fluidic connection to the supporting ring. The converter fluid is delivered via the grooving of the supporting ring into the converter circuit.
The above-described prior art torque converter is comparatively complicated to produce and is comparatively expensive because, on the one hand, it has a turbine hub which is complicated with regard to its shape with the radial flange and also has to be connected to the turbine shell via labor-intensive riveting and, on the other hand, the supporting ring between the freewheel and the adjacent axial abutment requires grooving for the throughflow of converter fluid. This grooving also results in a reduced contact surface of the supporting ring on the adjacent component causing an increased surface pressure on the supporting ring.
SUMMARY OF THE INVENTION
The object of the present invention is to design a hydrodynamic torque converter such that, with minimum production effort and at minimum cost, the turbine wheel is axially positioned while ensuring that the converter circuit is supplied with converter fluid.
This object is achieved according to the invention by a hydrodynamic torque converter having a hydrodynamic circuit, comprising a pump impeller wheel having an impeller shell and impeller blading connected to an impeller hub, a turbine wheel having a turbine shell and turbine blading connected to a turbine hub, an output shaft in rotary connection with said turbine hub, and axial abutments for axially positioning said turbine wheel, wherein said turbine shell comprising a wall extending radially inward between said axial abutments and wherein said turbine shell comprises stiffeners in a region of said turbine shell between said axial abutments.
The turbine shell of the present invention is formed to extend radially between the extension region of the axial abutments. No additional production effort is required compared with the designs of prior art turbine shells because the difference in production of the turbine shell between the invention and the prior art is that the die blocks for the manufacture of the turbine shells according to the invention have to be of larger radial design than for the prior art turbine shells. Because of the relatively thin wall of the turbine shell, stiffeners are provided for high axial strength, despite the comparatively small wall thickness. The radially inner end of the turbine shell according to the invention is guided between the axial abutments, thereby providing axial positioning for the complete turbine wheel. If these stiffeners are formed by axial pressed-out portions made at the wall of the turbine shell, passages may be formed either in the extension region of the respective axial pressed-out portion or circumferentially depending on the direction of the pressed out passages, in each case between two axial pressed-out portions. These passages, if they lead from the radial inner region of the axial abutments to a diameter radially outside the same and in addition are connected via a fluidic connection to a supply reservoir for converter fluid, are suitable for the throughflow of converter fluid.
In this way, the hydrodynamic circuit of the torque converter may also be supplied with converter fluid by means the region of the turbine shell that has the stiffeners. Configuration of another point for supplying of the converter circuit may therefore be dispensed with.
The radially inner end of the turbine shell has a bearing surface for mounting in position on the turbine hub. For the benefit of low surface pressure, this bearing surface, despite a small wall thickness of the turbine shell, may be designed to be relatively large if this bearing surface is created by bending the radially inner end of the turbine shell. A further advantage of such a bending is the firm connection of the turbine shell to the turbine hub via a butt weld. This may be effected with a laser welding unit and, compared with other welding processes, which require increased preparatory measures, is cost-effective and simple to produce.
A further simplification may be achieved if the turbine hub is of essentially annular design. A simple tube then suffices for the manufacture of the turbine hub.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of the disclosure. For a better understanding of the invention, its operating advantages, and specific objects attained by its use, reference should be had to the drawing and descriptive matter in which there are illustrated and described preferred embodiments of the invention.
REFERENCES:
patent: 4353444 (1982-10-01), Bionaz
patent: 5203835 (1993-04-01), Kohno et al.
patent: 5575364 (1996-11-01), Friedmann et al.
patent: 5762172 (1998-06-01), Tsukamoto et al.
patent: 44 23 640 (1995-06-01), None
Cohen & Pontani, Lieberman & Pavane
Mannesmann Sachs AG
Ryznic John E.
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