Class / Patent application number | Description | Number of patent applications / Date published |
060418000 | Control by sensor of accumulator condition | 10 |
20080216471 | Hydraulic system - A hydraulic system comprising a pump for feeding hydraulic fluid from an inlet side to an outlet side, wherein a pressure accumulator is disposed at the outlet side, wherein between the pump and the pressure accumulator a hydraulic control valve is disposed, which has at least two valve positions, wherein the outlet side of the pump is connected to the pressure accumulator in a first valve position, and separated from the pressure accumulator in a second valve position, wherein the outlet side of the pump is connected to the inlet side through the control valve in the second valve position. | 09-11-2008 |
20080276607 | HYDRAULIC DRIVE SYSTEM WITH PRECHARGE LOGIC - A hydraulic drive system for storing and releasing hydraulic fluid includes a high pressure storage device, a low pressure storage device and a pump-motor operating at a range of pump-motor speeds for converting between hydraulic energy and mechanical energy. The pump-motor is disposed between the high pressure device and the low pressure device. In normal operation, the hydraulic drive system enters a motoring mode where hydraulic energy is released from the high pressure storage device and converted to mechanical energy using the pump-motor. It also enters a pumping mode where mechanical energy is converted into hydraulic energy. A neutral state exists where hydraulic energy is neither stored nor released from the high pressure storage device. An approach for facilitating the precharging of the high pressure storage device to a minimum threshold pressure promotes efficiency within the hydraulic drive system. | 11-13-2008 |
20090139223 | FUEL EFFICIENT HYDRAULIC POWER STEERING - A hydraulic power steering system that maintains proportional pressure control between an input side of a gear and assist pressures internal to the steering gear by relying upon a control valve. A pressure differential is maintained between the input side of a gear and assist pressures internal to the steering gear throughout certain events. Those events include running the pump to fully charge the accumulator, idling the pump after fully charging the accumulator, discharging pressure from the fully charged accumulator at an onset of a steering event having a demand for steering load, recovering the discharged pressure of the accumulator by running the pump after turning on the pump at the onset of the steering event, and opening the relief valve in the valve manifold during the steering event. | 06-04-2009 |
20100257854 | FUEL EFFICIENT HYDRAULIC POWER STEERING - A hydraulic power steering system that maintains proportional pressure control between an input side of a gear and assist pressures internal to the steering gear by relying upon a control valve. A pressure differential is maintained between the input side of a gear and assist pressures internal to the steering gear throughout certain events. Those events include running the pump to fully charge the accumulator, idling the pump after fully charging the accumulator, discharging pressure from the fully charged accumulator at an onset of a steering event having a demand for steering load, recovering the discharged pressure of the accumulator by running the pump after turning on the pump at the onset of the steering event, and opening the relief valve in the valve manifold during the steering event. | 10-14-2010 |
20100257855 | FUEL EFFICIENT HYDRAULIC POWER STEERING - A hydraulic power steering system that maintains proportional pressure control between an input side of a gear and assist pressures internal to the steering gear by relying upon a control valve. A pressure differential is maintained between the input side of a gear and assist pressures internal to the steering gear throughout certain events. Those events include running the pump to fully charge the accumulator, idling the pump after fully charging the accumulator, discharging pressure from the fully charged accumulator at an onset of a steering event having a demand for steering load, recovering the discharged pressure of the accumulator by running the pump after turning on the pump at the onset of the steering event, and opening the relief valve in the valve manifold during the steering event. | 10-14-2010 |
20100319336 | Leakage Detection System in a Wind Turbine - In one aspect, a hydraulic system including a reservoir, a hydraulic device, a first sensor, a second sensor and a controller is described. The reservoir is connected to the hydraulic device for supplying hydraulic fluid to and from the hydraulic device. The first sensor is adapted for measuring a first volume of the hydraulic fluid in the reservoir. The second sensor is connected to the hydraulic device such that at least one parameter being indicative for a second volume of the hydraulic fluid in the hydraulic device is measurable. The controller is adapted for calculating the second volume of the hydraulic fluid based on the at least one parameter. The controller is adapted for determining a leakage of hydraulic fluid in the hydraulic system based on the first volume and the second volume. | 12-23-2010 |
20140345265 | HYDRAULIC DRIVE SYSTEM - An operating state determining unit determines whether a hydraulic cylinder is in operation or not in operation. A discharge pressure reducing unit reduces the discharge pressure of a charge pump. A discharge pressure control unit controls the discharge pressure reducing unit when the hydraulic cylinder in not in operation to reduce the discharge pressure of the charge pump to a low pressure lower than a normal pressure. The normal pressure is the discharge pressure of the charge pump when the hydraulic cylinder is in operation. An accumulator is connected to a charge flowpath. A one-way valve is disposed between the accumulator and the charge pump. The one-way valve allows the flow of hydraulic fluid from the charge pump to the accumulator and prohibits the flow of hydraulic fluid from the accumulator to the charge pump. | 11-27-2014 |
20150059327 | DUAL CHANNEL PULSED VARIABLE PRESSURE HYDRAULIC TEST APPARATUS - A fast and flexible pressure testing apparatus includes two parallel pressure channels having independent pumps and pressure regulators. Pressure pulse cycle times are minimized by using large diameter hydraulic lines. A fluid accumulator in each channel stores pre-pressurized fluid to avoid pressure delivery delays due to limited pump output. In embodiments, the outputs of the two delivery channels can be combined to deliver pressure pulses to the part under test (PUT) from either channel in any desired sequence, or one channel can be used to return the PUT to its initial status. Embodiments gate the pressure pulses using servo valves, which can have pressure outputs that are proportional to their control signals, thereby enabling shaped output pressure profiles according to shaping of the control signals. The pressure channels can be further split into first and second branches which set the ranges over which the channel output can be varied. | 03-05-2015 |
20160003266 | WORK MACHINE - A work machine is adapted for reduced fuel consumption in regions where swinging by a hydraulic motor is prone to deterioration in efficiency, such as when the operating stroke of the swinging is small. The work machine includes an engine, a hydraulic pump, a swing structure, an electric motor for driving the swing structure, and a hydraulic motor for driving the swing structure, the hydraulic motor being driven by the hydraulic pump, and includes a swing control lever device that commands the swing structure to be driven. A control device operates in either an electric swing mode in which the swing structure is driven mainly by torque of the electric motor or a hydraulic swing mode in which the swing structure is driven mainly by torque of the hydraulic motor, depending on an operating stroke of the control lever device and/or a swing speed of the swing structure. | 01-07-2016 |
20160090997 | HYDRAULIC SYSTEM - A hydraulic system is provided, the hydraulic system including a hydraulic load defining a first chamber and a second chamber. Additionally, the hydraulic system includes a pressure source, a fluid storage vessel, a load sense line, and a spool valve. The spool valve fluidly connects the fluid storage vessel to one of the first or second chambers and fluidly connects the pressure source to the other of the first or second chambers. A bypass line is also provided defining a flow path between the hydraulic load and the fluid storage vessel that bypasses the spool valve. Fluid flow may encounter less resistance through the bypass line, such that the hydraulic system may run more efficiently and with a reduced risk for cavitation in the hydraulic load. | 03-31-2016 |