192 clutches and power-stop control – Vortex-flow drive and clutch – Including drive-lockup clutch
Reexamination Certificate
2001-05-24
2003-03-18
Lorence, Richard M. (Department: 3681)
192 clutches and power-stop control
Vortex-flow drive and clutch
Including drive-lockup clutch
C192S212000, C060S330000
Reexamination Certificate
active
06533088
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention pertains to a hydrodynamic clutch device having a pump impeller inside a housing and a turbine impeller including a turbine shell connected non-rotatably to a turbine hub. A clutch device of this type is known in the form of, for example, a hydrodynamic clutch or a hydrodynamic torque converter and can be used in the drive train of a motor vehicle.
2. Description of the Related Art
Hydrodynamic clutch devices usually have a pump impeller, mounted in a housing, and a turbine impeller with a turbine shell, to which a turbine hub is connected nonrotatably. If the hydrodynamic clutch device is a hydrodynamic torque converter, a stator is also provided.
Hydrodynamic torque converters convert and transmit the torque produced by a machine such as an internal combustion engine. The pump impeller, the turbine impeller, and the stator are usually designed as curved shell components, and each wheel has a number of vanes. The individual wheels of the hydrodynamic torque converter run in the closed housing, which is filled with a working fluid.
In the normal case, the pump impeller is driven by the flywheel of the internal combustion engine via the housing at the rpm's determined by the engine. During startup phase, only the pump impeller turns at first; the turbine impeller and, if present, the stator, are stationary. The working fluid flows from the pump impeller to the turbine impeller and transfers its energy to it. The turbine impeller is connected nonrotatably via the turbine hub to a shaft, which, in a motor vehicle, for example, is a take-off shaft or a transmission input shaft. As soon as the torque generated via the pump impeller on the turbine impeller is greater than the resistance torque of the shaft, the turbine impeller and thus also the shaft begin to turn.
In addition, hydrodynamic torque converters also usually have a bridging clutch, which is also installed inside the converter housing. Like a friction clutch, a bridging clutch of this type has the task of producing a slip-free connection, insofar as possible, between the converter housing and the shaft, such as the transmission input shaft. Individual components of the bridging clutch are usually also connected to the hub of the turbine.
Hydrodynamic torque converters of the general type described above are already known and are used especially in the automotive industry. An example is described in DE 198 38 445. In an exemplary embodiment presented in this document, a hydrodynamic torque converter is disclosed which has a pump impeller, a turbine impeller, and a stator inside a housing. The turbine impeller has a turbine shell and a connecting element, which are connected to each other. By way of the connecting element, the turbine shell is connected to one-part turbine hub, which is connected nonrotatably to the shaft.
In the case of a hydrodynamic clutch device, the turbine hub is called upon to perform several different functions. For example, it serves, first, as a connecting site for the turbine shell. If, in addition, a bridging clutch is provided, this clutch usually has a clutch piston, as will be described in further detail below. This clutch piston must be guided and driven. For this purpose, the piston has in the past been attached to and/or guided by the turbine hub. In addition, the stroke which the clutch piston can execute must be limited, and this has also been one of the functions of the turbine hub. Finally, the turbine hub also has the job of supporting various bearings such as axial bearings, roller bearings, plain bearings, etc.
When the hydrodynamic torque converter is equipped with a bridging clutch, this clutch usually includes a clutch piston. The radially outer area of this clutch piston, for example, can be provided with friction facings, which can, as a function of a pressure difference between the interior space of the converter and a chamber formed between the converter housing and the clutch piston, be pressed against an opposing friction surface of the converter housing. In its radially inner area, the clutch piston is usually sealed off against the turbine hub by the intermediate installation of a sealing element but still retains its freedom to rotate. The sealing element can be designed as a suitable sealing ring, which is held in a sealing groove made in the turbine hub. The turbine hub thus also has the function of making available an appropriate sealing ring groove.
Because of all these various functions which the turbine hub must fulfill, and because of the fact that heavy loads act on the turbine hub during the operation of the hydrodynamic torque converter, turbine hubs have been produced in the past as one-part components, which must be subjected to additional processing steps after their production. Thus, for example, it has been conventional in the past to produce turbine hubs as sintered metal parts or forgings, which are then machined in various ways. These metal-removing machining processes create appropriate contact surfaces and guide surfaces for the seating of the clutch piston, for the seating of sealing rings, for the connection of the turbine shell, etc., on the hub. In addition, the sealing ring groove described above must also be cut into the turbine hub, which can be done by means of, for example, a lathe-turning process.
These metal-removing machining processes in particular are very expensive and therefore disadvantageous. First, machining is time-consuming, because various work steps and processes are required to bring the turbine hub into it final desired shape after its rough shape has been produced. The production of a turbine hub is therefore also complicated structurally, because the sealing ring groove in particular must be produced in a highly precise manner. Finally, the metal-removing machining of parts suffers from the disadvantage that large amounts of waste material are generated, which must be stored separately and recycled. All in all, the production of turbine hubs as it has been done in the past is highly cost-intensive.
SUMMARY OF THE INVENTION
The object of the present invention is to improve a hydrodynamic clutch device of the general type cited above so that it can be produced easily in terms of construction and also at low cost.
According to the invention, a hydrodynamic clutch device, especially a hydrodynamic torque converter, is provided which has a pump impeller; a turbine impeller, which has a turbine shell and a turbine hub nonrotatably connected to it; and possibly a stator, all installed inside a housing. The turbine hub consists of several parts and the turbine shell is designed and mounted on the turbine hub so that it takes over some of the functions of the turbine hub.
As a result of the hydrodynamic clutch device according to the invention, it is possible to avoid the disadvantages of the state of the art described above. The hydrodynamic clutch device is not limited to specific design embodiments. For example, it is conceivable that the hydrodynamic clutch device could be designed either as a hydrodynamic clutch or as a hydrodynamic torque converter. To make it easier to understand the invention, it is described below on the basis of a hydrodynamic torque converter in particular, although the invention is not to be considered limited to this concrete embodiment.
The first basic idea of the invention is that the turbine hub is no longer designed as a single part but rather as a unit consisting of several parts. As a result, the individual components of the turbine hub can be easily produced first by suitable production methods. The individual parts of the turbine hub thus produced are then assembled to obtain the completed turbine hub. By providing the individual parts with the appropriate contouring and by assembling these parts appropriately to form the complete turbine hub, it is possible to eliminate the previously required metal-removing steps such as the production of the contact surfaces, the introduction of the sealing ring groove, etc.
At
Cohen & Pontani, Lieberman & Pavane
Lorence Richard M.
Mannesmann Sachs AG
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