Abstract:
A hydraulic control system (48) is disclosed. The hydraulic control system may have a pump (52), a plurality of actuators (20, 26), and a plurality of valve arrangements (54, 56) configured to meter pressurized. The hydraulic control system may also have at least one operator input device (98) configured to generate signals indicative of desired velocities of the plurality of actuators, and a controller (58). The controller may be configured to receive a pump torque limit, determine a maximum pump flow capacity, and determine desired flow rates for each of the plurality of valve arrangements based on the signals. The controller may also be configured to make a first reduction of the desired flow rates based on the maximum pump flow capacity, to make a second reduction of the desired flow rates based on the pump torque limit, and to command the plurality of valve arrangements to meter the desired flow rates after the second reduction.
Abstract:
A hydraulic system includes a first pump and a plurality of valves that control fluid flow from the first pump to several actuators. Variable source orifices in the control valves are connected in parallel between the first pump and a node, and variable bypass orifices in the control valves are connected in series between the node and a tank. Pressure at the node controls displacement of the first pump. Each control valve also has a metering orifice for varying fluid flow between the node and one of the actuators. A hydrostatic pump-motor, coupled between two ports of a given actuator, is driven in a motoring mode by fluid exiting one of those ports. In a pumping mode, the hydrostatic pump-motor forces lower pressure fluid exhausting from one port into the other port of the given actuator.
Abstract:
Electro-hydraulic systems (10, 110, 210, 310, 410, 510, 610 and 710) control multiple hydraulic motors without objectionable erratic or jerky motion. The system (10) includes a variable displacement pump (20), an electronic controller (30), a direction control valve (40), first and second pump outlet valves (60) and (70), and a fluid reservoir (80). The pump (20) does not require or use a load feedback signal to control pump output. The controller (30) provides electric control signals to a pump control (21) and to individual hydraulic motors (51). A load sense circuit (46) resolves a highest load sense pressure Ps, which is communicated to the first and second pump outlet valves (60) and (70). The first pump outlet valve (60) limits the maximum load sense pressure. The second pump outlet valve (70) limits the maximum pressure differential between the pump outlet and the load sense pressure.
Abstract:
The invention relates to a method for controlling a hydraulic system (10) of a working machine (1). The hydraulic system comprises a hydraulic machine (13) for providing hydraulic fluid to one or more actuators (11, 12) of the working machine. The method comprises the steps of receiving a signal requesting a pump pressure from the hydraulic machine (13) based on the load pressure of a first actuator (11) of said one or more actuators which first actuator has the highest load pressure of said one or more actuators, discriminating the pressure request from the first actuator (11 ) provided that the first actuator is stalled due to overload or geometrical limitations, and controlling the hydraulic machine (13) to provide a pump pressure based on the load pressure of a second actuator (12) of said one or more actuators which second actuator is in operation and has the second highest load pressure of said one or more actuators, or, if no actuator in addition to the first actuator is present and in operation, controlling the hydraulic machine to provide a predetermined idle pump pressure.
Abstract:
게시된 발명은 엔진; 붐이나 아암 및 버켓을 포함하는 복수의 작업장치용 액츄에이터 및 선회모터; 상기 엔진에 연결되며, 상기 작업장치용 액츄에이터 및 선회모터에 유압을 제공하는 복수의 가변 용량형 유압펌프; 조작레버 또는 조이스틱을 포함하며, 상기 복수의 액츄에이터의 움직임을 지시하는 조작부; 상기 조작부에 의해 상기 유압펌프의 유량을 상기 액츄에이터 및 선회모터로 각각 공급하는 컨트롤 밸브; 상기 액츄에이터의 일측에 설치되며, 상기 액츄에이터의 상대위치를 감지하는 작업장치 위치검출수단; 상기 조작부 일측에 설치되며, 조작레버 또는 조이스틱의 조작량을 감지하는 조작량 감지수단; 및 유량설정부와 작업장치 위치검출수단 및 엔진의 스피드 센서로부터 신호를 입력받아 선회요구유량을 보상하기 위해 유량의 증가율을 산출하는 유량제한부와 사판제어장치에 제어신호를 제공하는 출력수단을 구비하며, 상기 조작량 감지수단(9)으로 부터 감지된 신호를 입력받아 상기 유압펌프의 토출유량을 제어하는 유량제어 컨트롤러;을 포함하여 구성되는 건설기계용 선회유량제어 시스템에 관한 것이다.
Abstract:
Offenbart ist ein Druck- Förderstromregler (3) mit einem Druckregelventil (17) und mit einem Förderstromregelventil (19) und mit einem ersten Steueranschluss (A) zu Einstellung einer Verstellpumpe (5), wobei vom Förderstromregelventil über eine in einer Ruhestellung eines Ventilkolbens des Druckregelventils offene Steuerkante des Druckregelventils der Steueranschluss zu einem Tank (T) entlastbar ist.
Abstract:
A method and a device for controlling a load sensing hydraulic system, having a bypass valve (F), which is controlled by a pump pressure (P) and which when the hydraulic system is in operation diverts a pump flow of hydraulic fluid to a tank (E). The bypass valve (F) is pre-stressed towards a closed position and is put on load by the pump pressure (P) towards an open position against the action of the pre-stress. When the hydraulic system operates in a idling operation a first pre-stress element (I) limits the pre-stress to a first pressure and upon activation of the hydraulic system, a pressure regulator ( 10) increases the pre-stress to a second, substantially higher pressure by applying a hydraulic, constant second pre-stress force, that is added to the first pre-stress force and is substantially greater than this.
Abstract:
The present disclosure is directed toward a hydraulic control system. The system may have a pump and a tool actuator configured to move a tool with a flow of pressurized fluid provided by the pump. The system may further have a tool control valve configured to control the flow of pressurized fluid to the tool actuator. The system may also have a controller operably connected with the tool control valve and the pump. The controller may be configured to receive a tool movement request. The controller may further be configured to estimate a change in a flow demand across the tool control valve associated with the tool movement request. The controller may also be configured to command adjustment of a discharge flow rate of the pump based on the estimated change in flow demand to satisfy the tool movement request.
Abstract:
A hydraulic two-circuit system (2, 4) for activating consumers (A1, B1; A2, B2; A3, B3) of a mobile unit, for example a track-laying unit, and an interconnecting valve arrangement (38), which is suitable for a two-circuit system (2, 4) of this type and via which the two circuits (2, 4) can be interconnected so as to add them together, are disclosed. According to the invention, the interconnecting valve arrangement has an interconnecting valve with two pressure connections (P1, P2), two LS input connections (LS1, LS2) and two LS output connections, wherein a valve body of the interconnecting valve is designed with four control surfaces, of which two control surfaces which act in one direction are acted upon by the highest load pressure (LS1) in the first circuit and by the pumping pressure (P2) in the second circuit, and the control surfaces acting in the other direction are acted upon by the highest load pressure (LS2) in the second circuit and by the pumping pressure (P1) in the first circuit.