Fluid handling – Systems – Multi-way valve unit
Reexamination Certificate
1999-10-07
2002-07-16
Michalsky, Gerald A. (Department: 3753)
Fluid handling
Systems
Multi-way valve unit
C137S596170, C251S129140
Reexamination Certificate
active
06418967
ABSTRACT:
The invention relates to a proportional pressure regulating valve of the 3/2 directional type consisting of a valve housing which has a regulating pressure chamber and with a pressure medium sump line and with at least two diaphragm stages with defined or definable drag of which two diaphragm stages are connected with each other according to the principle of the hydraulic half bridge.
BACKGROUND OF THE INVENTION
DE-C 44 26 152 describes an electromagnetic pressure regulating valve, especially for regulating the shift pressure of automatic motor vehicle transmission, which has a valve housing and control shift valve actuatable by a magnetic armature and connected therewith, which controls connections from a pressure medium intake to a consumer connection or a return flow or tank. The control shift valve is situated in a rear and in a front bearing point in the valve housing and is prestressed via an adjusting spring. With this pressure regulating valve there are throughout the service life no changes of the valve characteristic resulting from problems caused by dirty oil, since a pressure drop relative to a through flow, especially of the dirt-sensitive armature chamber, is prevented. In the inlet area on the bearing gap and on the outlet opening of the current path from the ventilation hole, the same velocity energy potential prevails.
U.S. Pat. No. 3,915,932 has further disclosed a valve which has two diaphragm stages connected according to the principle of the hydraulic half bridge and is used as volume governor for dividing a pressure medium flow in a main and an accessory flow.
The valves, already known, often have the disadvantage that they either reach a minimum working pressure near zero bar or that the leakage flow of the pressure medium is minimized to nearly zero when the working pressure is minimal.
SUMMARY OF THE INVENTION
The problem on which this invention is based is to provide a proportional pressure regulating valve, especially for the regulation of shift pressure in automatic motor vehicle transmissions, in which the minimal working pressure is almost zero and the leakage flow of the pressure medium in the end position of the control shift valve is minimized to almost zero with minimal working pressure and which makes possible an adaptation of the flow properties of the valve to the conditions existing during utilization.
The aforementioned problem is solved by the present invention.
The pressure regulating valve is designed as connected throttle or diaphragm system (hereinafter the expression diaphragm will be used to mean throttle or diaphragm). The connected diaphragm system consists of two mechanically of hydraulically connected regulating diaphragms. The regulating diaphragms are according to the principle of the hydraulic half bridge. Before the two regulating diaphragms can be front-mounted a fixed diaphragm. This connected diaphragm system has three connections: a pressure medium supply line (connection P), a working pressure line to the consumer (connection A) and a pressure medium sump line to the pressure medium sump (connection T). The connection P is situated on the inlet side before the first regulating diaphragm or fixed diaphragm, the connection A is situated, e.g. between the two regulating diaphragms and the connection T is located on the outlet side behind the second regulating diaphragm. Each one of the diaphragms constitutes a drag. The two regulating diaphragms are at the same time adjustable drags. The operating principle of said pressure regulated valve works similarly to the one of an electric voltage divider with two connected adjustable slide resistances or with a front-mounted fixed resistance and two connected adjustable slide resistances. Each one of the diaphragms produces a certain pressure drop. On the input side of the first regulating diaphragm or of the fixed diaphragm supply pressure prevails, while on the output side, after the second regulating diaphragm, ambient pressure prevails. The pressure between the two regulating diaphragms is adjustable, according to the opening of the diaphragms, between ambient pressure and supply pressure. At the same time, the two regulating diaphragms form inlet and outlet openings of a pressure regulating chamber and each has a sealing element for opening and closing the diaphragms. According to the invention, the sealing element of the inlet diaphragm is designed as ball, or calotte, or truncated cone, or cylinder and/or of the sealing element of the outlet diaphragm as ball, calotte, or truncated cone, or cylinder, i.e. on one hand, a sealing element in the inlet or outlet is designed as ball, calotte, truncated cone, or cylinder. On the other hand, both sealing elements can be designed as ball, calofte, or truncated cone, or cylinder, it being possible for both sealing elements to have either the same or different shape. The inflowing and outflowing characteristic of both regulating diaphragms can thus be advantageously adjusted as best as possible to the existing condition of use of the valve. The type, e.g. of each separate diaphragm as seat or shift valve and thus the shape of the sealing surface, the same as the pressure intensification through each diaphragm, is at the same time individually adjustable.
Both regulating diaphragms are connected by a control shift valve. The diaphragms, especially the sealing elements, do not have to be rigidly or integrally connected with the control shift valve, but can also be separately designed and loosely abut on the control shift valve, the contact force being produced in the pressure medium flow by the drag of a loose diaphragm. By moving the control shift valve in one direction, the cross section of the inlet diaphragm is enlarged and that of the outlet diaphragm is simultaneously reduced. When the control shift valve moves in opposite direction, the cross sections change in inverse manner. This corresponds to the operation principle of a hydraulic half bridge. Depending on the configuration of the connection, positions of the control shift valve can result in which one diaphragm is already fully open while the other still is not fully closed (negative overlapping of the leading edges). In a possible condition of operation, the inlet diaphragm is already completely open and the outlet diaphragm still not fully closed. In this condition of operation, the system of the two connected regulating diaphragms becomes reduced to a system having fixed inlet diaphragm and regulatable outlet diaphragm.
In a system of two connected regulating diaphragms with front-mounted fixed diaphragm, if the drag of the inlet regulating diaphragm is clearly less than that of the front-mounted fixed diaphragm, then the inlet regulating diaphragm for the self-adjusting regulating pressure is no longer important. The system comprised of one front-mounted fixed diaphragm with two consecutive connected regulating diaphragms becomes reduced in this operation condition to a system with fixed inlet diaphragm and regulatable outlet diaphragm. According to the present state of the art, by means of one such reduced system, e.g. mechanical shift pressure for transmission control are regulated. This means that in this operation condition, it is possible to apply the experience acquired over the years with conventional seat valves.
Compared to the system having one regulating diaphragm and one fixed diaphragm, the system having two connected regulating diaphragms has the advantage that when the outlet diaphragm is fully open the through flow is not maximal as in the system of fixed and regulating diaphragms but is minimized to zero by the sealing element of the inlet regulating diaphragm. The same also applies to the case of additionally front-mounted fixed diaphragm. The operation condition “fully open outlet diaphragm” corresponds in both systems and in the reduced system with fixed inlet diaphragm and regulatable outlet diaphragm to the minimal regulating pressure. In the system having two connected regulating diaphragms—with or without front-mounted fixed diaphragm—said lowe
Frei Walter
Gierer Georg
Mayr Karlheinz
Remmlinger Hubert
Runge Wolfgang
Davis & Bujold P.L.L.C.
Michalsky Gerald A.
ZF Friedrichshafen AG
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