Spring devices – Vehicle – Mechanical spring and nonresilient retarder
Reexamination Certificate
1999-06-15
2001-05-08
Oberleitner, Robert J. (Department: 3613)
Spring devices
Vehicle
Mechanical spring and nonresilient retarder
C280S124178
Reexamination Certificate
active
06227527
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a pneumatic suspension system forming a McPherson strut.
2. The Prior Art
Such a pneumatic suspension system is described in great detail in German laid-open patent specification 36 24 296.
A McPherson strut (also referred to as a spring damper) is employed as a wheel-guiding element with only one lower transverse control arm. Conditioned by the forces originating from the wheel and acting on the strut, a moment is introduced in the latter which deteriorates the suspension properties due to increased friction within the damping device.
In order to eliminate the friction, the force application lines of the wheel stand-up force, the steering force and the spring force have to extend through one point (which equals the moment zero point). By setting a steel spring in a slanted way, the friction is minimized for the most part. However, when pneumatic suspension systems are employed, inclined positioning of the pneumatic suspension bellows is possible only conditionally because of the tied-on components (pneumatic suspension pot, pneumatic suspension piston, outer guide, etc.).
SUMMARY OF THE INVENTION
Now, the problem of the invention consists in setting the active surface of the pneumatic suspension bellows (and thus the loop) in a slanted position in such a way that the frictional forces are minimized. High driving comfort is to be assured at the same time. Furthermore, the pneumatic suspension bellows is to be protected against damage caused, for example by gravel or weather influences.
The present invention solves this problem by providing a pneumatic suspension piston surrounding a damping device as a separate structural component. The outer guide of the pneumatic suspension piston has parts with cylindrical and conical surfaces that form a roll-off contour. The roll-off contour is not rotationally symmetric with respect to the damping axis. The roll-off contour is adapted to the effective diameter of the inclined loop of the pneumatic suspension bellows in such a way that the effective diameter extends substantially parallel with the edges of the roll-off contour.
During rebound and spring deflection, the inclined loop of the pneumatic suspension bellows is always completely surrounded by the outer guide. In this way, the pneumatic suspension bellows is in any position embedded between the outer guide and the roll-off contour of the pneumatic suspension piston.
The design permits, furthermore, the use of a pneumatic suspension bellows with a single-layer strength carrier extending axially with respect to the damping axis, such pneumatic suspension bellows being optimized with respect to comfort (DE-A 36 43 073).
A thin-walled protective bellows made of elastomeric material or TPE surrounds the outer guide of the pneumatic suspension bellows and also the pneumatic suspension piston, whereby its upper end is connected with the outer guide and/or with the pneumatic suspension pot, and its lower end is connected with the pneumatic suspension piston or with the container tube of the damping device.
A sealing piston receiver made of rigid material is arranged between the pneumatic suspension piston and the container tube of the damping device in the form of a fixed composite.
The roll-off contour has a constriction enlarging the roll-off space between the outer guide and the pneumatic suspension piston.
A pot-like support body is present between the damping device and the pneumatic suspension piston, said support body being arranged particularly above the container tube.
A residual pressure valve is arranged in the pneumatic suspension piston or in the pneumatic suspension pot. It is advantageous in this connection if the residual pressure valve is arranged within the pneumatic suspension piston in the region of the piston receiver.
Said residual pressure valve facilitates the installation on the vehicle and, furthermore, prevents damage during repair work or in the event of failure of the pressure system.
The pneumatic suspension piston has a receiver for a stabilizer joint, whereby such receiver is arranged particularly in the region of the piston receiver.
The edges of the roll-off contour are rounded, whereby their radius is preferably greater than or equal to the inner radius of the loop.
A process for producing the pneumatic suspension system as defined by the invention consists in cutting off the pneumatic suspension bellows along a slanted line before it is installed, whereby the slanted surface of the section is finally secured on the pneumatic suspension piston. In the operating condition under pressure, the pneumatic suspension bellows will then form with an inclined loop.
REFERENCES:
patent: 4332397 (1982-06-01), Steger
patent: 4555096 (1985-11-01), Pryor
patent: 4778198 (1988-10-01), Gold
patent: 4826204 (1989-05-01), Cameron
patent: 4911416 (1990-03-01), Warmuth, II
patent: 5009401 (1991-04-01), Weitzenhof
patent: 5449150 (1995-09-01), Watanabe et al.
patent: 5769401 (1998-06-01), Pradel
patent: 36 24 296 (1987-02-01), None
patent: 36 31 610 (1987-04-01), None
patent: 36 43 073 (1988-06-01), None
patent: 196 07 804 (1997-05-01), None
patent: 0 225 271 (1987-06-01), None
patent: 0 259 245 (1988-03-01), None
patent: 0 262 079 (1988-03-01), None
patent: 0 318 696 (1989-06-01), None
patent: 830 696 (1960-03-01), None
patent: 57-110517 (1982-07-01), None
patent: 57-129942 (1982-08-01), None
patent: 2-182512 (1990-07-01), None
Burch Melody M.
Collard & Roe P.C.
Oberleitner Robert J.
Phoenix Aktiengesellschaft
LandOfFree
Pneumatic suspension system does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Pneumatic suspension system, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Pneumatic suspension system will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2554962