Fluid handling – Systems – Multi-way valve unit
Reexamination Certificate
1999-07-06
2001-10-02
Ryznic, John E. (Department: 3745)
Fluid handling
Systems
Multi-way valve unit
C137S625690
Reexamination Certificate
active
06296019
ABSTRACT:
TECHNICAL FIELD
The invention relates to a pressure medium control device for the pressure control of a consumer, with a consumer with a first pressure medium connection and a second pressure medium connection, with a pressure generating device, such as a pump and with a valve for controlling the pressures at the first and second pressure medium connection, wherein the valve has a slider which is axially displaceable inside an oblong hole bore of a housing and is axially displaceable by pressure biasing in a control pressure chamber and against the resetting force of an energy accumulator, wherein furthermore the oblong hole bore has axially spaced indentations provided on the circumference of the bore and each with one or two control edges and the slider has at least a first and a second axially spaced circumferential groove with two control edges.
BACKGROUND OF THE INVENTION
Pressure medium control devices of the generic type are known for controlling a gearbox and a torque converter lock-up clutch of a hydrodynamic torque converter through EP O 293 196. With these pressure medium control devices there is the drawback that when switching on a volume flow change-over for operating the torque converter lock-up clutch with small or negative pressures there is undesired sticking of the clutch. Furthermore with such devices of the generic kind two sliders are used wherein one slider is used for controlling pressure and a second slider is used for changing over the flow.
The object of the invention is to improve a pressure medium control device of the kind mentioned at the beginning with regard to its function whilst nevertheless retaining its simple construction. More particularly the object is to achieve with a device of simple construction of the kind mentioned at the beginning a targeted control of a positive and negative differential pressure as a function of a control pressure. Furthermore the device according to the invention is to be capable of simple fitting and able to be adapted to a variety of individual cases.
SUMMARY OF THE INVENTION
This is achieved according to the invention in that the slider has at its one end area a bore with the diameter D
3
which holds an axially displaceable piston and a pressure medium duct between a first circumferential groove of the slider and the bore produces a fluid connection and the slider has, seen perpendicular to the axis of the slider, in the axial direction right and left of the second circumferential groove two different outer diameters D
1
,D
2
and thus two different cross-sectional surfaces. This avoids an expensive construction with stepped bores with returns which are produced by means of inserted sleeves. Likewise the use of two slider valves is avoided in that the desired function is achieved through the slider of the pressure medium control device according to the invention.
Advantageously the slider has between areas with different outer diameters D
1
and D
2
a transition area with a differential surface in the area of a control edge of the second circumferential groove with the surface D
2
−D
1
which is substantially equal to the cross-sectional surface of the bore with the diameter D
3
. Advantageously the outer diameters D
1
and D
2
are measured so that the surface difference of the cross-sectional surfaces is equal to the cross-sectional surface of the bore with the diameter D
3
.
Furthermore the slider advantageously forms between areas with different outer diameters D
1
and D
2
a transition area with a differential surface in the area of a control edge of the second circumferential groove with the surface D
2
−D
1
which is substantially larger than the cross-sectional surface of the bore with the diameter D
3
. Advantageously the outer diameters D
1
and D
2
are measured so that the surface difference of the cross-sectional surfaces is greater than the cross-sectional surface of the bore with the diameter D
3
.
Furthermore it is expedient if the slider has between areas with different outer diameters D
1
and D
2
a transition area with a differential surface in the area of a control edge of the second circumferential groove with the surface D
2
−D
1
which is substantially smaller than the cross-sectional surface of the bore with the diameter D
3
. Advantageously the outer diameters D
1
and D
2
are measured so that the surface difference of the cross-sectional surfaces is smaller than the cross-sectional surface of the bore with the diameter D
3
.
It is likewise advantageous according to the inventive idea if the slider has a stepped bore arranged coaxial with the axis of the slider and having a first diameter D
3
and a second diameter D
4
wherein in the area of the second diameter a bore perpendicular thereto produces a fluid connection with the first circumferential groove of the slider.
It is particularly expedient if the oblong hole bore of the valve has a stepped bore with a first diameter D
1
and a second diameter D
2
wherein the control pressure chamber is located in the end area of the first bore with the smaller diameter. It is likewise advantageous if the oblong hole bore of the valve has a stepped bore with a first diameter D
1
and a second diameter D
2
wherein an energy accumulator is mounted between the slider and the one end area of the second bore with the larger diameter.
According to the inventive idea it is furthermore advantageous if the energy accumulator is mounted without pretension between the slider and end area of the bore such as wall. In another embodiment it is advantageous if the energy accumulator is mounted with pretension between the slider and the end area of the bore such as wall.
According to a further inventive idea it is expedient if the oblong hole bore has axially spaced indentations provided on the circumference of the bore and at least one of these indentations is connected to an inlet pipe and at least a further of these indentations is connected to an outlet pipe wherein between the inlet pipe and outlet pipe, such as inflow pipe and outflow pipe, is an excess pressure valve which opens in the direction of the outlet pipe when a predetermined excess pressure is reached. It can thereby be advantageous if a throttle is connected in in front of the excess pressure valve.
It is likewise advantageous if the control pressure in the control pressure chamber can be controlled by means of a valve connected in at the input side. In another further development it is expedient if the pressure in the inlet pipe is controllable by means of a valve connected in on the inlet side. It is advantageous if the valves are electrically controllable valves such as magnetic valves. It is further expedient if the valves are controlled by an electronic control unit with a micro processor.
It is further expedient if the oblong hole bore has axially spaced indentations provided on the circumference of the bore and at least one of these indentations is connected to a first pressure medium connection of the consumer and a least one further indentation is connected to a second pressure connection of the consumer.
It is furthermore advantageous if with the pressure medium control device mentioned at the beginning the change-over area of the pressure and the pressure rise can be set independently of the counter pressure which prevails in the outflow pipe. Since the slider regulates or controls the differential pressure it is insensitive to disturbances such as temperature fluctuations particularly at the radiator or pressure fluctuations which occur at the same time at the pressure medium connections of the consumer.
The invention further relates to a pressure medium control device for the pressure control of a consumer, with a consumer having a first pressure medium connection and a second pressure medium connection, with a pressure generating device, such as a pump and with a valve for controlling the pressures at the first and second pressure medium connection, wherein the valve has a slider which is axially displaceable inside an oblong hole bore of a housing an
Homm Manfred
Muller Bruno
Darby & Darby
LuK Getriebe-Systeme GmbH
Ryznic John E.
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