Classifications

• • G—PHYSICS
  • G05—CONTROLLING; REGULATING
  • G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
  • G05D16/00—Control of fluid pressure
  • G05D16/02—Modifications to reduce the effects of instability, e.g. due to vibrations, friction, abnormal temperature, overloading or imbalance
• • G—PHYSICS
  • G05—CONTROLLING; REGULATING
  • G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
  • G05D16/00—Control of fluid pressure
  • G05D16/04—Control of fluid pressure without auxiliary power
  • G05D16/10—Control of fluid pressure without auxiliary power the sensing element being a piston or plunger
  • G05D16/101—Control of fluid pressure without auxiliary power the sensing element being a piston or plunger the controller being arranged as a multiple-way valve
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T137/00—Fluid handling
  • Y10T137/2496—Self-proportioning or correlating systems
  • Y10T137/2544—Supply and exhaust type
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T137/00—Fluid handling
  • Y10T137/7504—Removable valve head and seat unit
  • Y10T137/7613—Threaded into valve casing

Definitions

• the invention relates to a pressure control valve with a control piston movable in a valve bore according to the preamble of claim 1.
• control piston In pressure control valves according to the prior art, the control piston is held in its initial position by the action of an energy accumulator. In a direction of deflection, the pressure control valve connects a pump connection to a consumer connection. In the other direction of deflection, the pressure control valve connects the consumer connection to a tank connection by shutting off the pump connection. If the pressure at the consumer connection exceeds the predefinable setpoint, the control piston is deflected so far against the force of the energy accumulator and the flow cross section between the pump connection and consumer connection is reduced until the pressure at the consumer connection corresponds to the predefinable setpoint.
• control piston If the setpoint is exceeded accordingly, the control piston is deflected so far against the force of the energy accumulator that there is a pressure relief from the consumer connection to the tank connection.
• the control piston In the known pressure control valves it is disadvantageous that there are instabilities in the control behavior during fast control processes due to the spring-mass system, especially in the area of the control piston.
• DE 35 05 377 C2 shows a pressure control valve in which a control piston movable by an electromagnet can be moved in an axially closed distributor housing.
• DE-OS-27 00 058 shows a flow control valve in which a plunger which is axially displaceable in a bore in the control piston and forms an annular gap with the bore forms a damping device for the movement of the control piston.
• the present invention is therefore based on the problem of providing a pressure control valve which guarantees reliable and stable operation even with high dynamic control.
• the design effort to avoid the instabilities should be as low as possible, in particular the number of individual parts of the pressure control valve should be as small as possible.
• Pressure control valve with a movable control piston in a valve bore which connects and releases a pump connection with a consumer connection in the deflection direction under the action of a force accumulator and the consumer connection with a tank connection in the other deflection direction by shutting off the pump connection the problem in that, regardless of the direction of deflection of the control piston, a volume flow present between the latter and the valve bore, in particular in an annular gap formed by the control piston and the valve bore, dampens the deflection movement of the control piston.
• the volume flow is preferably small and in particular only as large as the damping requires.
• the damping takes place via an annular gap which lies directly in the pressure medium channel, and the damping volume is coupled to the pressure medium volume flow.
• the arrangement is dead volume-free with regard to the damping effect.
• the damping of the control piston by means of the volume flow or the associated pressure build-up also has the advantage that the damping effect is dependent on the share of the frictional force caused by the drag or displacement flow on the speed of the control piston and on the share of one by the pump exclusion Leakage flow flowing consumer load caused frictional force is dependent on the pressure difference between the pump connection and the consumer connection. This results in a particularly favorable damping and thus control behavior of the pressure control valve.
• Displacement flow can be set particularly easily and advantageously by the geometric design of the pressure control valve, in particular the control piston. Due to the action of the frictional forces on the outer surface of the preferably cylindrical control piston, Particularly uniform application of force and thus particularly good control and damping behavior of the pressure control valve can be achieved.
• the particular embodiment of the invention according to claim 2 has the advantage that the direction and amount of the towing flow can be predetermined, in particular that it can be specified that the towing current enters the pressure control valve at the consumer connection, which is usually lower in pressure than the pump connection.
• the special embodiments of the invention according to claims 3 and 4 have the advantage that a hollow cylindrical volume by the step formed between the two sections with different diameters of the control piston with an axial deflection of the control piston between the step of the control piston and the corresponding stage of the valve bore is reduced or enlarged, into which the drag or displacement current flowing over the larger annular gap at the consumer connection can flow in or out. Due to the geometrical design of both the step and the annular gap, the damping characteristic of the pressure control valve can be easily but precisely adjusted and adapted to different application situations. For example, the control and damping characteristics of a pressure control valve are possible by replacing the control piston.
• the special embodiment of the invention according to claim 6 has the advantage that coil springs represent reliable, inexpensive and durable energy storage and are also available in almost any desired dimension.
• other mechanical energy stores such as a leaf spring or an elastic element, or pneumatic or hydraulic pressure stores can be considered.
• the special embodiment of the invention according to claim 7 has the advantage that a reliable connection from the consumer connection to the pump connection and from the consumer connection to the tank connection can be established with simple and inexpensive structural means.
• the special embodiment of the invention according to claim 9 has the advantage that a clear structural separation between the consumer, pump and tank connection is guaranteed.
• the pump and tank connection can be provided in a star or ring shape.
• the special embodiment of the invention according to claim 10 has the advantage that the control pressure or setpoint can be changed even after the pressure control valve has been manufactured and even after the pressure control valve has been installed in a larger system.
• the special embodiment of the invention according to claim 1 1 has the advantage that the use of the pressure control valve as a screw-in cartridge allows the pressure control valve to be used and exchanged without problems even in larger pressure control systems.
• Fig. 1 shows a section through an inventive pressure control valve.
• 1 shows a section through a pressure control valve 1 according to the invention with a valve body 2 and a control piston 3.
• the control piston 3 is guided axially in the valve bore 2 in the valve bore 4 and is pressed by the coil spring 5 in the direction of arrow 6.
• the coil spring 5 is supported at the upper end on a first disk 7, the horizontal position of which can be adjusted via the threaded bolt 8 which can be screwed into the valve body 2.
• the setting is secured by means of the lock nut 9.
• the setting is preferably carried out using a hexagon socket 10 attached to the valve outer end of the bolt 8.
• the coil spring 5 is supported on the shoulder 11 of the second disk 12, which receives the control piston 3 in a central bore.
• the control piston 3 has a decreasing end at its end facing the second disk 12
• the control piston 3 has an elongated first blind hole 18 in this area, which allows a connection to the tank connection 21 by means of a first tap hole 19 and a circumferential groove 20. This connection also continues through a central bore 16 in the second disk 12 and permits ventilation of the interior of the pressure control valve 1 into the tank connection 21.
• control piston 3 has an axially extended, annular groove 22 which, with the corresponding axial position of the control piston 3, connects the radial tank connection 21 to the also connects radial pump connection 23.
• control piston 3 has a second blind hole 25 directed towards the axial consumer connection 24, which is connected by means of second branch bores 27 to the axially extended annular groove 22 and thus, with the corresponding position of the control piston 3, a connection between the radial pump connection 23 and the axial consumer connection 24 provides.
• the control piston 3 In the area of the consumer connection 24, the control piston 3 has a smaller diameter. At the transition from the smaller to the larger diameter formed by a step 26, both the section of the control piston 3 with the smaller diameter and the section with the larger diameter have a region of reduced diameter, as a result of which a hollow cylinder-like volume 28 is created. In the further course between the consumer connection 24 and the pump connection 23, the control piston 3 has three annular grooves 29 which are designed as relief grooves.
• the section of the control piston 3 located at the consumer port 24 is ground onto the valve body 2 in section 32 such that a
• the pressure control valve 1 is via an external thread 30 as
• Screw-in cartridge can be screwed into an existing pressure control system.
• the seal 31 that comes into contact with a shoulder (not shown) of the pressure control system serves to seal between the pressure control valve and the pressure control system. If the pressure at the consumer connection 24 exceeds the predeterminable target value, the control piston 3 is moved against the action of the coil spring 5 against the direction of the arrow 6 due to the excessive pressure. In this case, an oil volume is drawn into the hollow-cylinder-like, increasing volume between the control piston 3 and the valve body 2 in the area of the stage 26 via the annular gap formed by the greater clearance between the control piston 3 and the valve body 2 at the consumer connection.
• control piston 3 When the pressure at the consumer connection 24 falls below, the control piston 3 is moved in the direction of the arrow 6 in accordance with the force of the coil spring 5 acting on it.
• the hollow cylinder-like volume formed in the area of step 26 is reduced and the enclosed medium must be displaced in the direction of arrow 6 over the defined annular gap to the consumer connection 24.
• This displacement volume flow Q erdrangung can be determined using the following equation:
• ⁇ is the number of circles, since the inner diameter of the valve bore 4 in the section of the control piston 3 with the larger diameter, dt the outer diameter of the control piston 3 in the section with the smaller diameter and v ⁇ oiben is the speed of the control piston 3.
• the pressure build-up in the reduced space can be determined, where ⁇ is the viscosity of the displaced medium, I the gap length, dm the mean gap diameter and h the gap height, for example 40 ⁇ m to 60 ⁇ m.
• a force FD can be determined which is directed against the deflecting force and thus dampens the movement of the control piston 3:

Landscapes

• Physics & Mathematics (AREA)
• Fluid Mechanics (AREA)
• General Physics & Mathematics (AREA)
• Engineering & Computer Science (AREA)
• Automation & Control Theory (AREA)
• Safety Valves (AREA)
• Fluid-Driven Valves (AREA)
• Control Of Fluid Pressure (AREA)

Priority Applications (5)

Applications Claiming Priority (2)

Publications (1)

Family

ID=7872635

Family Applications (1)

Country Status (6)

Families Citing this family (5)

Citations (6)

Family Cites Families (5)

• 1998
  • 1998-07-01 DE DE19829394A patent/DE19829394A1/de not_active Withdrawn
• 1999
  • 1999-03-06 EP EP99914483A patent/EP1092180B1/de not_active Expired - Lifetime
  • 1999-03-06 DE DE59902960T patent/DE59902960D1/de not_active Expired - Lifetime
  • 1999-03-06 AT AT99914483T patent/ATE225531T1/de active
  • 1999-03-06 JP JP2000558444A patent/JP4156803B2/ja not_active Expired - Fee Related
  • 1999-03-06 WO PCT/EP1999/001453 patent/WO2000002109A1/de not_active Ceased
  • 1999-03-06 US US09/720,670 patent/US6439257B1/en not_active Expired - Lifetime

Patent Citations (6)

Also Published As

Similar Documents

Legal Events