Fluid handling – Self-proportioning or correlating systems – Self-controlled branched flow systems
Patent
1997-11-05
1998-12-22
Hepperle, Stephen M.
Fluid handling
Self-proportioning or correlating systems
Self-controlled branched flow systems
137114, 13711513, 13711521, G05D 1100
Patent
active
058508449
DESCRIPTION:
BRIEF SUMMARY
The invention relates to a pressure reduction valve for reducing the pressure in the circuits of double-acting, closed hydraulic systems with a slave activator and a master activator, when the master activator is unattended, comprising a valve housing which contains a first seat which defines two spaces, wherein the first space is arranged to communicate with the first circuit and the second space is arranged to communicate with a reservoir for the hydraulic fluid, in the first space there is provided a first valve body and a first spring, one end of which abuts against a section of the housing and the other end of which abuts against the valve body, and the valve body is arranged to be moved in one direction to sealingly abut against the seat under the influence of the force which is exerted by the pressure of the fluid in the first circuit, and the force of the first spring, and in an opposite direction under the influence of an opening body section which in turn is influenced by the pressure of the fluid in the second circuit.
Valves of this type are employed, e.g., in connection with gear shift systems for cars, where the gear shift forces are transferred from the driver's cabin to the gear box via a hydraulic system of this type.
Since the power transfer is hereby performed without any kind of servo arrangement, i.e. the pressure which is produced in the pipes for movement of the slave activator is provided by movement of the gear lever by hand, the friction between the movable components of the system must be moderate in order that the hand power required may also be moderate.
When the system is left and the temperature in the hydraulic fluid increases, an increase takes place in the pressure of the hydraulic fluid in the system's circuits. This results in an increase in the force whereby this fluid influences the packings between the movable and stationary components of the system, and the force which must be exerted to achieve movement of these movable components, which is a disadvantage.
When a valve of this kind is employed, the valve body is lifted from its seat when the pressure exceeds a defined value for the said reason. Fluid from one circuit can thereby flow to a reservoir and the pressure of the fluid in the circuit is reduced. Since the two circuits can be separated by only a piston which is freely movable in the master cylinder, a reduction also takes place in the pressure of the fluid in the second circuit.
The force required to operate the system can therefore be maintained at a moderate level.
The valve, however, creates a flow of fluid from only one of the circuits to the reservoir. If the vehicle is left with the gear lever in its neutral position, the situation can therefore arise that the gear lever is moved away from its normal position in relation to the driver's seat, and this can be uncomfortable for the driver. A further situation which can arise is that the gear lever is moved so far away from its position in relation to the gear lever housing that the desired gear can no longer be obtained since the gear lever abuts against the gear lever housing.
The object of the invention is to provide a valve whereby the above-mentioned disadvantages are eliminated.
The characteristics of the valve according to the invention are presented in the characteristic features indicated in the claims.
The invention will now be described in more detail with reference to the drawing whose only figure schematically illustrates a longitudinal section through an embodiment of a valve according to the invention.
The valve comprises a housing 1 which is circular in cross section and on the outside of which there are formed two radially outwardly open grooves, in which there are fitted respective O-rings 2,3. The valve housing can thereby be arranged for sealing insertion in a boring, e.g. in a gear lever housing or the like, since a section of the outside of the housing can be equipped with external threads arranged to be screwed into internal threads of the boring.
Approximately at the centre of the
REFERENCES:
patent: 2689583 (1954-09-01), Gardiner
patent: 2774369 (1956-12-01), Di Tirro
patent: 4463775 (1984-08-01), Wittren
Hepperle Stephen M.
Kongsberg Automotive ASA
LandOfFree
Pressure reduction valve does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Pressure reduction valve, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Pressure reduction valve will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2038428