192 clutches and power-stop control – Clutches – Operators
Reexamination Certificate
1998-12-17
2001-04-17
Bonck, Rodney H. (Department: 3681)
192 clutches and power-stop control
Clutches
Operators
C192S08200T
Reexamination Certificate
active
06216841
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention, in general, relates to a hydraulic clutch which is responsive to differences in rotation and which consists of a rotatable input casing, a hydrostatic pump within the casing, an output shaft and a friction clutch for connecting the output shaft to the input casing and, more particularly, to a hydraulic clutch provided with a chamber in which, at the occurrence of a difference in rotations between the input casing and the output shaft, fluid pressure is generated by a pump supplied from a suction chamber for actuating the friction clutch.
2. The State of the Art
Such couplings are used in different configurations in the drivetrains of automotive vehicles for the direct transmission of torque or for blocking an associated differential transmission as well as for powering wheels of an axle or for distributing drive torque between two axles. Each of these couplings utilizes a hydrostatic pump comprising an internal rotor and an external rotor which move relative to each other, and thereby generate fluid pressure, in case the rotations of the input casing and of an output shaft differ.
Hydraulic couplings of this general type are disclosed, for instance, by
FIG. 14
of WO 93/19310 and
FIG. 12
of U.S. Pat. No. 5,611,746. These couplings are provided with a hydrostatic pump inside of a hollow rotatable casing, and in each case the pump has a pressure and a suction chamber equipped with simple throttles and spring-biased valves responding to predetermined pressures to accommodate certain boundary conditions.
Such arrangements are, however, unsuited for controlling the coupling in a predictable manner. Indeed, such arrangements do not allow adjustments of the transmitted torque relative to differences in rotation or varying temperatures of the operating fluid. These couplings cannot be released when braking with ABS, when the vehicle is being towed, at high speeds or when the clutch is thermally overloaded.
OBJECT OF THE INVENTION
It is, therefore, it is an object of the invention to provide a coupling of the kind referred to which is of a simple and reliable construction and which may be quickly released and adapted to different operating conditions under a desirably patterned control.
SUMMARY OF THE INVENTION
In accordance with the invention, the above and other objects are accomplished in a hydraulic coupling of the kind referred to, the pressure chamber of the hydrostatic pump of which communicates by way of a rotary insert with a fixed housing in which there is provided a valve for controlling the pressure within the pressure chamber. In this manner, the pressure in the chamber may be modulated, with the control valve being mounted in the fixed housing of the coupling so that it poses no problems to feed it with electrical control signals from an external control module.
Preferably, the pressure chamber is formed between the rotatable input casing and an annular piston, with the hydrostatic pump being seated within an annular piston. The number of parts otherwise required may thus be reduced, and the assembly is simplified since the annular piston and the pump may be preassembled as a unit. Notwithstanding the reduction of its structural dimensions, the piston may be formed with a large active surface thereby to provide for a particularly sensitive control and for an instantaneous response of the coupling.
In an advantageous embodiment of the invention, a suction chamber is formed within the annular piston and communicates with an axial bore in the output shaft by way of a further rotary insert. Accordingly, the suction flow may also be modulated and the rotating piston of the pump may relatively easily be supplied with operating fluid.
In an advantageous embodiment, each end of the annular piston forms an annular radial surface, one of the surfaces limiting the pressure chamber, the other surface cooperating with discs of the friction clutch. The pressure chamber is, therefore, located at an end of the annular piston while the friction clutch is located at the opposite end of the piston. Accordingly, there is no need for separate clutch actuating elements. As a result of this and the large piston surface the space required for the friction clutch may be kept very small.
In a further embodiment of the invention, an annular spring may be provided between the other radial surface of the piston and the input casing for biasing the annular piston away from the discs of the friction clutch. Such an arrangement ensures a complete and, if necessary, quick release of the clutch when braking, for instance. It also defines a response threshold for the prevention of what for the sake of convenience may be called tight-corner-braking.
In a further embodiment of the invention, the valve for controlling the pressure in the pressure chamber is a proportional valve fed by a control module with a control signal which is both representative of driving conditions and dependent upon the temperature of the pressure medium.
REFERENCES:
patent: 4719998 (1988-01-01), Hiramatsu et al.
patent: 4727966 (1988-03-01), Hiramatsu et al.
patent: 4924989 (1990-05-01), Filderman
patent: 5046595 (1991-09-01), Sumiyoshi et al.
patent: 5197583 (1993-03-01), Sukai et al.
patent: 5611746 (1997-03-01), Shaffer
patent: 5827145 (1998-10-01), Okcuoglu
Bonck Rodney H.
Hormann Karl
Steyr-Daimler-Puch Fahrzeugtechnik AG & Co KG
LandOfFree
Hydraulic clutch does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Hydraulic clutch, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Hydraulic clutch will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2547508