Motors: expansible chamber type – With motive fluid valve – Relatively movable serial valves
Patent
1993-12-03
1995-10-03
Lopez, F. Daniel
Motors: expansible chamber type
With motive fluid valve
Relatively movable serial valves
91459, F15B 1102
Patent
active
054542928
DESCRIPTION:
BRIEF SUMMARY
Hydraulic circuit comprising at least two double acting hydraulic piston-cylinder devices, more particularly for opening and closing of a folding roof of a vehicle of the cabriolet type, in which both of the cylinder ends of each of the hydraulic piston-cylinder devices are each connected to a conduit supplied with pressurized fluid by a common hydraulic pump and to a return fluid conduit leading to a source of hydraulic fluid.
Such a circuit is known.
Separate piston-cylinder devices or pairs of piston-cylinder devices are often required for controlling the various parts of the folding roof and for actuating a hood to close a space within the vehicle for containing the roof in the folded state. In the well-known circuit the valves associated with each piston-cylinder device or pair of cylinder devices are formed by solenoid controlled spool valves of the 4/3 type i.e. valves having four points of connection and comprising a middle position in addition to two operative positions.
In connection with the desire and tendency to house the hydraulic control equipment in a smallest possible space, in general piston-cylinder devices of a rather small diameter and consequently relatively high pump pressures are involved, whereas the size of the valves is also very small. Such valves are very expensive and are, in the middle position, incapable of maintaining the pressure in a controlled cylinder, if subsequently a next cylinder is to be controlled under a substantially lower pressure. In such a case leakage of oil via the necessary clearance between the valve bore and the valve spool when the latter is in its middle position, can hardly be avoided, due to which the pressure in the respective cylinder may decrease to a value which is substantially beyond the pressure required for that cylinder to operate. It may thus happen that a roof tensioning bow which has been lifted from the stowing space by operating a certain cylinder, will thereafter partially move back into the storing space as a result of a decrease of the pressure in that cylinder and thereby interfere with the hood which at that moment is moving under a relatively low pressure to its closed position. Attempts to avoid these undesired incidents by using a precision fit between the valve bore and the valve spool have led to situations in which the power exerted by the energization of a valve appeared to be not sufficient to shift the valve spool in its bore.
The present invention aims at solving the above drawbacks in a simple and effective manner by using valves of a simpler and therefore less expensive structure which offer better security against loss of pressure in the respective cylinders.
In accordance with the invention this aim is achieved in that the electrically actuated valves are 3/2-valves, with a check valve of the ball valve type in the surface connection for the pressure conduit.
The type of valve used in accordance with the invention is of a substantially simpler and less expensive construction, whereas the check valve of the ball valve type associated therewith is a well working one.
The invention will be hereinafter further explained by way of example with reference to the accompanying drawing.
FIG. 1 is a perspective view of a motor vehicle of the cabriolet type, the folding roof of which is shown in a partially opened position, whereas also the pairs of hydraulic piston-cylinder devices for actuating the roof are shown;
FIG. 2 shows a simplified hydraulic circuit according to the invention, with three hydraulic piston-cylinder devices;
FIG. 3A-F show six successive phases of the closing procedure with the folding roof of a vehicle of the type according to FIG. 1;
FIG. 4A-F show in a diagrammatic manner the successive phases of the opening procedure of the folding roof and
FIG. 5 shows a longitudinal section of a 3/2 valve of the ball seat type, with which--in accordance with the invention--an additional check valve of the ball valve type is used. With reference to FIG. 1 the folding roof is indicated at 1. In the closed position the
REFERENCES:
patent: 2390425 (1945-12-01), Crum
patent: 2506008 (1950-05-01), Arps
patent: 4630523 (1986-12-01), Tersteegen
Energie Fluide et Lubrification, Feb. 2, 1963, p. 31.
Applied Power Inc.
Lopez F. Daniel
LandOfFree
Hydraulic circuit comprising at least two double acting hydrauli 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 circuit comprising at least two double acting hydrauli, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Hydraulic circuit comprising at least two double acting hydrauli will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1071903