Abstract:
The present invention regards a control system (1000) for an actuator cylinder (10) having a first and a second chamber (11, 12), a piston (13) separating said first chamber (11) from said second chamber (12), said system (1000) comprising: a first supply conduit (20) of said first chamber (11) of said cylinder (10); a second supply conduit (21, 22) of said second chamber (12) of said cylinder (10); wherein said first supply conduit (20) and said second supply conduit (21, 22) are connectable to a distribution valve (100) configured to control a feed operation and a discharge operation of said first supply conduit (20) and said second supply conduit (21, 22); a first check system (30) positioned along said second supply conduit (21) and configured to open a passage for a fluid coming from said distribution valve (100) and directed towards said second chamber (12) if the pressure difference between the pressure of said fluid coming from said distribution valve (100) and the pressure in said second chamber (12) exceeds a first predetermined value, and wherein said first check system (30) is connected to said first supply conduit (20) by means of a first pilot conduit (201), wherein said first check system (30) is configured to open a passage for a fluid coming from said second chamber (12) and directed to said distribution valve (100) when the pressure in said first pilot conduit (201) at said first check system (30) reaches a first predetermined value; said second supply conduit (21) comprises a primary branch (21) along which said first check system (30) is positioned, and a secondary branch (22) parallel to said primary branch (21) and along which a second check system (40, 50) is positioned, wherein said second check system (40, 50) is configured to allow to open a passage for a fluid coming from said distribution valve (100) and directed towards said second chamber (12) along said secondary branch (22) if the pressure difference between the pressure of said fluid coming from said distribution valve (100) and the pressure in said second chamber (12) exceeds a second predetermined value, wherein said first and said second check systems (30, 40, 50) are dimensioned in such a way that a maximum fluid flow which can pass through said second check system (40, 50) is at least twice as large as a maximum fluid flow which can pass through said first check system (30).
Abstract:
A switching valve (22) of a fluid pressure control device (100) includes a pilot chamber (22a) to which pilot pressure is leaded via the pilot valve (10), a spool (36) configured to move in a valve-opening direction in accordance with the pilot pressure in the pilot chamber (22a), a biasing member (41) configured to bias the spool (36) in a valve-closing direction, and a conduction path (46) configured to lead one part of a pilot pressure fluid leaded to the pilot chamber (22a) to a drain passage (40). The conduction path (46) is configured to communicate with the drain passage (40), when the switching valve (22) moves by a predetermined stroke amount or more in the valve-opening direction.
Abstract:
In some applications, a piston of a hydraulic actuator may move at high speeds, and large undesired forces may be generated if the piston reaches an end-stop of the hydraulic actuator at a high speed. The undesired forces may, for example, cause mechanical damage in the hydraulic actuator. A controller may receive information indicative of the piston reaching a first position at a first threshold distance from the end-stop, and, in response, may modify a signal to a valve assembly controlling flow of hydraulic fluid to and from the hydraulic actuator. Further, the controller may receive information indicative of the piston reaching a second position at a second threshold distance closer to the end-stop of the hydraulic actuator, and, in response, the controller may further modify the signal to the valve assembly so as to apply a force on the piston in a away from the end-stop.
Abstract:
An electro-hydrostatic actuator system (1) for raising/lowering a landing gear (11) of an aircraft includes: at least one hydraulic actuator (21, 22) configured to retract and extend the landing gear (11); a hydraulic circuit (33); a hydraulic pump (32); an electric motor (31); a controller (4) configured to control the operation of the electric motor at receiving a command to retract or extend the landing gear; and a sensor (34) detecting the discharge pressure of the hydraulic pump. The controller, when receiving the command, feeds back the discharge pressure detected by the sensor, and controls the operation of the electric motor such that the discharge pressure of the hydraulic pump reaches a target discharge pressure.
Abstract:
A rotary valve that controls a flow rate at which working oil is supplied to and discharged from a hydraulic cylinder (20) that causes a wing (2, 3) to rotate about a rotary shaft (5) includes a rotor (60) that rotates as the wing (2, 3) rotates about the rotary shaft (5), and a first control flow passage (61) and a second control flow passage (65) formed in the rotor (60) to control the flow rate at which the working fluid is supplied to and discharged from the hydraulic cylinder (20), wherein the first control flow passage (61) and the second control flow passage (65) respectively vary a resistance exerted on a flow of the working fluid passing therethrough as the rotor (60) rotates.
Abstract:
Bei einem pneumatischen Volumenstromverstärker (1) zum Verstärken eines pneumatischen Stelldruckausgangssignals eines Stellungsreglers, der einen pneumatischen Antrieb, wie einen pneumatischen Stellantrieb (73), zum Betätigen einer Stellarmatur, wie eines Stellventils, einer prozesstechnischen Anlage, wie einer petrochemischen Anlage, einer Lebensmittelverarbeitungsanlage, wie eine Brauerei, oder dergleichen, belüftet und/oder entlüftet, ist vorgesehen: einen pneumatischen Steuerausgang (23) zum Anschluss an eine pneumatische Arbeitskammer des pneumatischen Antriebs, einen ersten pneumatischen Belüftungseingang (15) insbesondere zum Empfangen eines pneumatischen Stelldruckausgangssignals eines Stellungsreglers, wenigstens einen pneumatischen Verstärkungseingang (17), insbesondere zum Empfangen eines insbesondere konstanten pneumatischen Luftverstärkungssignals, wie eines Boostersignals, eine pneumatische Entlüftungsverbindung von dem Steuerausgangs zu einer Drucksenke zum Entlüften des Stellantriebs, ein die pneumatische Entlüftungsverbindung trennendes und/oder öffnendes Entlüftungssitzventil (3), eine pneumatische Belüftungsverbindung zwischen dem ersten Belüftungseingang und dem Steuerausgang; ein die pneumatische Belüftungsverbindung trennendes und/oder öffnendes Belüftungssitzventil (5), eine pneumatische Verstärkungsverbindung zwischen dem Verstärkungseingang und dem Steuerausgang; ein die pneumatische Verstärkungsverbindung trennendes und/oder öffnendes Verstärkungssitzventil (7); und eine mechanische Sitzventil-Betätigung zum gemeinsamen Betätigen des Entlüftungssitzventils, des ersten Belüftungssitzventils und des Verstärkungssitzventils.
Abstract:
Die Erfindung betrifft ein Antriebsaggregat für eine Hebebühne, insbesondere eine Scherenhebebühne, das einen Hydraulikkreis mit mindestens einer Hydraulikpumpe, die mindestens einen Arbeitszylinder mit Hydraulikfluid beaufschlagt, und einen Elektromotor zum Antrieb der mindestens einen Hydraulikpumpe, einen Frequenzumrichter zum Ansteuern des Elektromotors, und eine Steuereinrichtung zum Steuern des Frequenzumrichters und daher der Drehzahl des Elektromotors, damit dieser in einem ersten Bereich mit einer niedrigeren Drehzahl derart angesteuert ist, dass die mindestens eine Hydraulikpumpe den mindestens einen Arbeitszylinder mit niedrigerer Geschwindigkeit ausfährt, und in einem zweiten Bereich mit einer höheren Drehzahl derart angesteuert ist, dass die mindestens eine Hydraulikpumpe den mindestens einen Arbeitszylinder schneller ausfährt, umfasst. Die Erfindung betrifft auch eine Scherenhebebühne, die ein solches Antriebsaggregat umfasst, sowie ein Verfahren zum Betreiben eines Antriebs für eine Scherenhebebühne.