Power plants – Pressure fluid source and motor – Pulsator
Reexamination Certificate
1999-05-03
2001-05-29
Lopez, F. Daniel (Department: 3745)
Power plants
Pressure fluid source and motor
Pulsator
C092S079000
Reexamination Certificate
active
06237334
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention is directed to a hydraulic actuation device for the adjustment or positioning of an actuation element or an element to be operated in motor vehicles. The hydraulic actuation device includes a piston-cylinder unit having a cylinder housing and a piston axially movable in the cylinder.
2. Description of the Related Art
A prior art hydraulic actuation device including a piston-cylinder unit is known from DE 196 08 132 A1. This prior art device has a cylinder with a cylinder housing forming a cylinder space. In the preferred embodiment, the cylinder is a master cylinder in a hydraulic system in a motor vehicle. A piston is arranged so as to be displaceable axially in the cylinder space and a piston rod connected to the piston in a positive engagement is guided out of the cylinder housing. In addition to the above-described solution to the problem of connecting a piston with a piston rod,
FIGS. 1 and 1
a
of the prior art reference show a cylinder space which has, along a surface line, a channel which extends parallel to the center axis of the cylinder housing and which, when the piston is displaced, produces a connection between the respective diminishing cylinder space and a primary seal to maintain the pressure ratios at the cylinder side of the primary seal at the pressure level of the medium to be compressed.
If the cylinder space and the pressure line system connected thereto are to be filled with a liquid medium which is required to be free of bubbles, difficulties are encountered if precautions are not taken. For example, the cylinder must be filled before the piston assumes its fully extended position so that a connection is formed between the cylinder space and the pressureless space located behind the primary seal. Using these precautions, any air bubbles present in the liquid may be guided to a compensation vessel through the pressureless space. However, once the prior art device is installed, it is difficult to release any air bubbles present in the liquid and may be impossible depending on the installed position of the cylinder.
SUMMARY OF THE INVENTION
The present invention proposes a master cylinder and/or slave cylinder for a hydraulic actuation device, wherein the cylinder space of the master cylinder and/or slave cylinder is deaerateable through a deaeration bore hole. The dearation may occur after the cylinder has been installed in a vehicle and the longitudinal axis of the cylinder may have an installed position that is at an angle greater than zero from the horizontal position.
Therefore, the object of the invention is to provide a cylinder for a hydraulic actuation device which is installed in a motor vehicle at an angle diverging from the horizontal and may be deaerated in an unobjectionable manner in all resulting installation positions.
This object is met by a hydraulic actuation device, comprising a cylinder housing having a surface forming a cylinder with a longitudinal center axis, a piston axially displaceably arranged in said cylinder, and a connection channel extending longitudinally along an inner wall of said cylinder and having an outer channel wall at a position in said channel located furthest from said center axis, said outer channel wall substantially following a straight line and having an angle of inclination with respect to said center axis greater than zero.
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: 741627 (1903-10-01), Conner
patent: 2531705 (1950-11-01), Schultz
patent: 4318460 (1982-03-01), Kosinski
patent: 4989498 (1991-02-01), Mori et al.
patent: 196 08 132A1 (1997-05-01), None
patent: 89/11600 (1989-11-01), None
Stampf Volker
Tulaczko Boleslaw
Cohen & Pontani, Lieberman & Pavane
Lopez F. Daniel
Mannesmann Sachs AG
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