Abstract:
A hydraulic circuit for a construction machine is disclosed, which can prevent a loss of pressure during a combined work. The hydraulic circuit includes a variable displacement hydraulic pump, at least two hydraulic actuators driven by hydraulic fluid that is supplied from the hydraulic pump, control valves installed in a center bypass path of the hydraulic pump and shifted to control a start, a stop, and a direction change of the hydraulic actuators, parallel flow paths having inlets branched and connected to predetermined positions on an uppermost stream side of the center bypass path and outlets connected to inlet ports of the control valves, bleed-off paths formed on the control valves other than the lowermost downstream side control valve among the control valves to selectively communicate with the center bypass path, the bleed-off paths communicating with the center bypass path when the plurality of control valves are shifted for a combined work, and a switching valve installed on a lowermost downstream side of the center bypass path to intercept the center bypass path when pilot signal pressure is applied.
Abstract:
Disclosed is a hydraulic circuit for construction equipment for controlling to selectively supply a hydraulic oil from a hydraulic pump to a hydraulic cylinder for driving a boom. The hydraulic circuit for construction equipment, according to the present invention, comprises: a hydraulic cylinder driven by a hydraulic oil of a hydraulic pump; a direction control valve installed on the oil passage between the hydraulic pump and the hydraulic cylinder; an operating device installed on the oil passage between a pilot pump and the direction control valve; a center by-pass switching valve installed at the most downstream side of a center by-pass passage of the hydraulic pump; a pressure detection sensor that detects the pressure of a hydraulic oil at the large chamber side of the hydraulic cylinder; a jack-up switching valve installed on the oil passage between the operating device and the center by-pass switching valve; and a flow control valve installed in the spool of the direction control valve.
Abstract:
Die Erfindung stellt ein Hubmodul (H), insbesondere für Flurförderfahrzeuge wie Gabelstapler, Hubgerüste, Mobilhydraulikgeräte, Arbeitsfahrzeuge oder dergleichen, mit einem Hebestrang (5) und einem Senkstrang (9) bereit, an die ein Hydroverbraucher, insbesondere ein Hydraulikzylinder anschließbar ist. Der Hebestrang (5) ist durch eine vom einen Motor (M) angetriebene Pumpe (6) mit einem unter Lastdruck stehenden Druckmittel beaufschlagbar. Im Senkstrang (9) ist ein Senkventil (17) angeordnet, um beispielsweise eine Senkgeschwindigkeit einzustellen. Im Senkstrang (9) ist stromab des Senkventils (17) eine Verzweigung (18) angeordnet, an der sich der Senkstrang (9) in einen Rückführungsstrang (13') und eine Ablassleitung (13) verzweigt. Über den Rückführungsstrang (13') ist damit ein im Senkstrang (9) geführtes Druckmittel zur Energierückgewinnung der Pumpe (6) zuführbar, so dass die Pumpe (6) zur Energierückgewinnung über das im Rückführungsstrang (13') geführte Druckmittel motorisch betrieben werden kann. Ferner weist das Hubmodul (H) stromab der Verzweigung (18) ein in der Ablassleitung (13) angeordnetes 2/2-Wegeventil mit einer Absperrstellung auf, in der eine Fluidverbindung zwischen dem Senkstrang (9) und der Ablassleitung (13) abgesperrt ist, und einer Durchlassstellung auf, in der das im Senkstrang (9) geführte Druckmittel über die Ablassleitung (13) zu einem Tank (T) abfließen kann.
Abstract:
To provide construction machinery capable of more efficiently utilizing the energy of return hydraulic oil from a hydraulic actuator. The present invention is provided with: an engine 11; a hydraulic pump 12 that is driven by the engine 11; a hydraulic actuator 17 that is driven by fluid discharged from the hydraulic pump 13; a discharge pressure sensor 12d that detects the discharge pressure from the hydraulic pump 13; a hydraulic regenerative motor 18 that is driven by the return hydraulic oil from the hydraulic actuator 17; a flow meter 18e that detects the flow rate of the return hydraulic oil; a flow dividing valve 50 that controls the rate of inflow to the hydraulic regenerative motor 18; a controller 15 that controls the flow dividing valve 50 according to the discharge pressure detected by the discharge pressure sensor 12d and the flow rate detected by the flow meter 18e; a regenerative generator 19 that generates electric power by being driven by the power of the hydraulic regenerative motor 18; and a motor generator 13 that assists drive of the engine 11 by the electric power supplied from the regenerative generator 19.
Abstract:
A hydraulic circuit for a construction machine including a direction control valve group having multiple direction control valves that are provided in tandem to a center bypass passage of the construction machine, a bleed-off valve provided to the center bypass passage downstream of the direction control valve group, and a control valve that controls an amount of pressure oil to be supplied to the direction control valve. The direction control valve includes a first internal passage that flows out the pressure oil supplied to the direction control valve to the center bypass passage, and a second internal passage that supplies the pressure oil to a hydraulic actuator of the construction machine. The first internal passage causes pressure oil discharged from the hydraulic pump to flow out to the center bypass passage downstream of the direction control valve, so that the center bypass passage and the first internal passage form a parallel passage. The bleed-off valve performs bleed-off control on pressure oil supplied by way of the parallel passage by changing an opening area of the bleed-off valve. The control valve controls the amount of the pressure oil to be supplied to the second internal passage by changing an opening degree of the control valve.
Abstract:
Die Erfindung betrifft eine mobile Arbeitsmaschine (10) mit mehreren ersten hydraulischen Verbrauchern (11; 13) und einem zweiten hydraulischen Verbraucher (41), wobei die ersten Verbraucher (11; 13) einen Fahrantrieb und/oder einen Arbeitsantrieb der mobilen Arbeitsmaschine (10) umfassen, wobei eine erste Pumpe (30) mit verstellbarem Verdrängungsvolumen Hydraulikfluid aus einem Tank (16) zu den ersten Verbrauchern (11; 13) fördern kann, wobei eine zweite Pumpe (32) Hydraulikfluid aus dem Tank (16) zu dem zweiten Verbraucher (41) fördern kann, wobei ein Verbrennungsmotor (40) vorgesehen ist, der mit der ersten und der zweiten Pumpe (30; 32) in Drehantriebsverbindung steht, wobei der zweite Verbraucher (41) ein drehbares Lüfterrad (42) zur Kühlung des Verbrennungsmotors (40) antreibt. Erfindungsgemäß ist ein Druckspeicher (50) zum Speichern von unter Druck stehendem Hydraulikfluid vorgesehen, wobei der Druckspeicher (50) derart in Fluidverbindung mit den ersten Verbrauchern (11; 13) steht, dass Hydraulikfluid, welches von wenigstens einem ersten Verbraucher (13) zurückfließt, in den Druckspeicher (50) fließen kann, nicht aber umgekehrt, wobei der Druckspeicher (50) derart in Fluidverbindung mit dem zweiten Verbraucher (41) steht, dass Hydraulikfluid von dem Druckspeicher (50) zum zweiten Verbraucher fließen kann.
Abstract:
The invention relates to systems and methods for rapidly and isothermally expanding and compressing gas in energy storage and recovery systems (300) that use open-air hydraulic-pneumatic cylinder assemblies, such as an accumulator (316, 317) and an intensifier (318, 319) in communication with a high-pressure gas storage reservoir on a gas-side of the circuits and a combination fluid motor/pump (330), coupled to a combination electric generator/motor (332) on the fluid side of the circuits. The systems use heat transfer subsystems in communication with at least one of the cylinder assemblies or reservoir to thermally condition the gas being expanded or compressed.
Abstract:
A plurality of hydraulic actuators are connected between a supply line (14) and a tank return line (18). A separate desired velocity is requested for each hydraulic actuator. In response to a respective metering mode and the desired velocity for each hydraulic actuator, the flow requirements that each hydraulic actuator has from the supply and return lines are derived. A determination is made as to what fractions of the required flows can be provided by the flow levels that are available from the supply and return lines. Those fractions are used to convert the desired velocity for the given hydraulic actuator into a velocity command which indicates the velocity of the given hydraulic actuator that can be achieved with the available fluid flows. The respective velocity command is used to control the flow of fluid to each hydraulic actuator.
Abstract:
The invention relates to a device for attaching adhesive labels to packaged goods by means of a cylinder. A piston (2) is displaced within said cylinder by introducing pressurized air with a negative or positive pressure into the cylinder at the upper and lower side of the piston via inlets (3, 4). Said cylinder is closed off at the inlet side by a pneumatic damper unit (14). The movement of the piston (2) is transmitted to a plunger (6) which attaches the adhesive labels to the packaged goods. The aim of the invention is to improve the dynamic properties of such a device. To this end, the first inlet (3) is mounted on the cylinder (1) in such a position that it can be closed by the wall of the piston (2) in such a manner that the build-up of the negative pressure above the piston is disrupted shortly before or when the piston is in the first dead center position.