摘要:
The object is to make it possible to efficiently utilize rated output torque of the prime mover by performing total torque control with high precision through precise detection of absorption torque of the other hydraulic pump by use of a purely hydraulic structure and feedback of the absorption torque to one hydraulic pump's side. For this purpose, the hydraulic drive system is equipped with: a torque feedback circuit 112v which is supplied with delivery pressure of a main pump 202 and load sensing drive pressure, modifies the delivery pressure of the main pump 202 to achieve a characteristic simulating the absorption torque of the main pump 202, and outputs the modified pressure; and a torque feedback piston 112f which is supplied with an output pressure of the torque feedback circuit and controls displacement of a main pump 102 so as to decrease the displacement of the main pump 102 and thereby decrease maximum torque T12max as the output pressure increases.
摘要:
An assembly of valve sections 10 includes an inlet section 12, an outlet section 14, a working section 16, and a working section 18. The working section 16 is a conventional pressure compensated working section. The working section 18 includes a directional control valve 21, a pressure compensator valve 50, and a pressure limiter valve 52. The valves 50 and 52 can be of integral construction, such that each is an essential part to complete the other. The pressure compensator valve 50 includes a pressure compensator spool 60 movable between an opened position (Figures 2 and 5) and a closed position (Figures and 6) in response to a pressure differential across the spool. The pressure limiter valve 52 includes a pressure limiter spool 76 that moves to an open position to change the pressure differential and close the pressure compensator valve when a selected limit pressure is reached.
摘要:
An assembly of valve sections 10 includes an inlet section 12, an outlet section 14, a working section 16, and a working section 18. The working section 16 is a conventional pressure compensated working section. The working section 18 includes a directional control valve 21, a pressure compensator valve 50, and a pressure limiter valve 52. The valves 50 and 52 are of integral construction, such that each is an essential part to complete the other. The pressure compensator valve 50 includes a pressure compensator spool 60 movable between an opened position (Figures 2 and 5) and a closed position (Figures 4 and 6) in response to a pressure differential across the spool. The pressure limiter valve 52 includes a pressure limiter spool 76 that moves to an open position to change the pressure differential and close the pressure compensator valve when a selected limit pressure is reached.
摘要:
In einer hydraulischen Steuervorrichtung (H) mit einer abschaltbaren Druckquelle (P), einem Reservoir (R) und einer in einem Abströmweg (13) von der Ventilanordnung (V) zum Reservoir (R) angeordneten Druckweiche (W), die entweder die Ventilanordnung (V) mit dem Reservoir (R) verbindet oder gegenüber dem Reservoir (R) absperrt, und ein verstellbares Steuerglied (16) enthält, das in einer ersten Verstellrichtung durch eine Feder (17) und einen aus dem von der Ventilanordnung (V) anstehenden Druck (P1) abgeleiteten Steuerdruck und in einer zweiten Stellrichtung zu einer den Abströmweg (13) absperrenden Steuerstellung durch einen aus dem Versorgungsdruck abgeleiteten Steuerdruck beaufschlagbar ist, ist die Druckweiche (W) ein 2/2-Wegesitzventil (16) mit leckagefreier Absperrstellung und mit einem das Steuerglied (16) bildenden Ventilkegel (24) und einem im Abströmweg (13) angeordneten Ventilsitz (25), sind die Druckquelle (P) und die Ventilanordnung (V) permanent über vom Hauptkanal (10, 11, 12) eine Drossel (D) enthaltenden Hauptkanal (10, 11, 12) verbunden, zweigt der Abströmweg (13) zwischen der Ventilanordnung (V) und der Drossel (D) ab, und wird der den Ventilkegel (24) in der zweiten Stellrichtung zum Ventilsitz (25) beaufschlagende Steuerdruck zwischen der Druckquelle (P) und der Drossel (D) aus dem Versorgungsdruck abgeleitet.
摘要:
Methods of controlling an actuator 101 during operation using a hydraulic circuit, and related apparatus, are described. The circuit can comprise a first path section along which fluid is supplied to a first chamber of the actuator using a first valve 110 and a second path section along which fluid is extracted from a second chamber of the actuator using a second valve 111. In various embodiments, pressure data associated with a pressure of the fluid supplied to the first side of the actuator are obtained, a pilot pressure pPilot is produced based on the data and the first and second valves are configured based on the pilot pressure pPilot.
摘要:
The invention relates to a first valve component (10), in particular a pressure compensator-type component, comprising a valve slide (16) that can be guided in a valve housing (12) in a longitudinal direction, said valve slide having a control part (34) for controlling a fluid-conducting connection (28) between at least two fluid connection points (30, 32) accommodated in the valve housing (12). Said control part has at least one pocket-like recess (38), at least part of which is bordered by a fluid-guiding surface (40) running at least between two vertices of the recess and running with increasing inclination from one vertex to another vertex. The first valve component is characterised in that, starting from a predeterminable distance before the other vertex, the fluid-guiding surface (40) runs from its point of greatest inclination with decreasing inclination in the direction of said other vertex. The invention also relates to two further valve components.
摘要:
An object of the invention is to achieve a travel speed known in the art during travelling operation, improve energy efficiency by reducing energy loss, and obtain favorable travel operability less susceptible to effects from variations in a travel load and changes in a pump delivery pressure when travelling operation is performed through operation of a travel lever over a half stroke range or less. A variable restrictor valve 80 is disposed in parallel with a flow sensing valve 50 of an engine speed sensing valve unit 13. A travel pilot pressure is adapted to act in an opening direction of the variable restrictor valve 80. The variable restrictor valve 80 is set to have a continuously increasing opening area from a full closure to a maximum with an increasing travel pilot pressure. Travel flow control valves 6d and 6e have an opening area that allows a predetermined flow rate QT required for traveling to be obtained even when a target LS differential pressure is decreased to a second specified value Pa3 when the travel lever is fully operated. In a first half of a spool stroke, the travel flow control valves 6d and 6e have an opening area approximate to an opening area of comparative example 1.
摘要:
L'invention a pour objet une vanne (V1, V2) d'équilibrage entre des pressions de fluides (F1, F2) admis dans la vanne (V1, V2) par des deuxièmes conduits (17, 17') respectifs. La vanne (V1, V2) comprend une chambre (14) de guidage en translation d'un piston (15) et des chemins fluidiques comprenant chacun un dit deuxième conduit (17, 17') et un premier conduit (16, 16') d'admission d'un fluide (F1, F2) provenant d'une même source de fluide (S1, S2) que le fluide (F1, F2) circulant dans le deuxième conduit (17, 17'). Les premiers conduits (16, 16') sont munis chacun d'un obturateur (20, 20') coopérant avec une rampe (21, 21') ménagé sur le piston (15). Un déplacement en translation du piston (15) en cas de différence de pression entre les fluides (F1, F2) respectivement admis dans les deuxièmes conduits (17, 17') provoque un glissement d'un obturateur (20, 20') le long de la rampe (21, 21') et par suite fournit un apport de fluide (F1, F2) depuis un premier conduit (16, 16') vers le deuxième conduit (17, 17') d'un même chemin fluidique.
摘要:
Disclosed are a flow control device and a flow control method for a construction machine for preventing the loss of fluid exhausted from a hydraulic pump when a boom and an arm of an excavator are operated in combination. The flow control device for a construction machine according to the present invention includes: an engine; a variable capacity hydraulic pump connected to the engine; a first hydraulic cylinder and a second hydraulic cylinder connected to the hydraulic pump; a first control valve disposed in a center bypass channel of the hydraulic pump, the first control valve, in neutral, returning the fluid exhausted from the hydraulic pump to a hydraulic tank and, when switched, controlling the driving, stopping, and direction change of the first hydraulic cylinder; a second control valve disposed downstream of the center bypass channel of the hydraulic pump, the second control valve, in neutral, returning the fluid exhausted from the hydraulic pump to the hydraulic tank and, when switched, controlling the driving, stopping, and direction change of the second hydraulic cylinder; a regeneration fluid channel for supplementing and reusing fluid returned to the hydraulic tank during a compression stroke of the first hydraulic cylinder, and a regeneration valve disposed in the regeneration fluid channel; and a pressure-compensated flow control valve which is disposed in a meter-in fluid channel of a spool of the first control valve and limits the quantity of working fluid supplied from the hydraulic pump to the first hydraulic cylinder when the first hydraulic cylinder and the second hydraulic cylinder are operated in combination.