Abstract: A hydraulic system includes a hydraulic pump, a first hydraulic actuator, a second hydraulic actuator, a first control valve to control the first hydraulic actuator, a second control valve to control the second hydraulic actuator, a return fluid tube in which a return fluid discharged from the first hydraulic actuator flows, the return fluid tube connecting the first control valve and the first hydraulic actuator, a first inner fluid tube provided in the first control valve and connected to the return fluid tube, an outer fluid tube connected to the first inner fluid tube, the outer fluid tube connecting the first control valve and the second control valve, a return-discharge fluid tube to discharge the return fluid, the discharge fluid tube being branched from the outer fluid tube, and a throttle provided in the return-discharge fluid tube.

Abstract: A hydraulic system of a work machine includes a first oil path which is connected to a hydraulic pump and though which hydraulic oil is to flow from the hydraulic pump. An operation valve is connected to the first oil path. An operation lever is to control the operation valve to control pressure of the hydraulic oil in accordance with an operation of the operation member. A hydraulic instrument is to be actuated by the hydraulic oil output from the operation valve. A second oil path connects the operation valve and the hydraulic instrument. The hydraulic oil in the second oil path is discharged through a discharge oil path. An actuation valve is provided in the discharge oil path. An actuation valve controller is to control the actuation valve to be opened and closed according to a temperature of hydraulic oil detected by a first sensor.

Abstract: A hydraulic system for a working machine includes a first hydraulic apparatus to be activated by the operation fluid, a second hydraulic apparatus being configured to be activated by the operation fluid, a first operation valve to control the operation fluid to be supplied to the first hydraulic apparatus, a second operation valve to control the operation fluid to be supplied to the second hydraulic apparatus, a first fluid tube connecting the first operation valve to the first hydraulic apparatus, a second fluid tube connecting the first operation valve to the second hydraulic apparatus, a third fluid tube connecting the first fluid tube to the second fluid tube, and an outputting fluid tube connected to any one of the first operation valve and the second operation valve and configured to output the operation fluid supplied from any one of the first fluid tube and the second fluid tube.

Abstract: A hydraulic system for a working machine includes a hydraulic pump, a first hydraulic actuator, a second hydraulic actuator, a first control valve to control the first hydraulic actuator, a second control valve to control the second hydraulic actuator, and a discharge fluid tube in which the operation fluid flows. The discharge fluid tube is connected to the first control valve. The hydraulic system includes a first fluid tube in which a return fluid flows toward the second control valve. The first fluid tube couples the first control valve to the second control valve. The hydraulic system includes a second fluid tube coupling the first fluid tube and the discharge fluid tube, a first throttle disposed on the first fluid tube, and a second throttle disposed on the second fluid tube, the second throttle having an opening area smaller than an opening area of the first throttle.

Abstract: A hydraulic system includes a hydraulic pump, a first hydraulic actuator, a second hydraulic actuator, a first control valve to control the first hydraulic actuator, a second control valve to control the second hydraulic actuator, the second control valve being arranged on a downstream side of the first control valve, and a discharge fluid tube in which the operation fluid flows. The hydraulic system further includes a first fluid tube in which a return fluid flows toward the second control valve. The hydraulic system further includes a second fluid tube in which a supply fluid flows toward the first hydraulic actuator, a third fluid tube coupling the first fluid tube to the discharge fluid tube, and a fourth fluid tube in which the return fluid flows toward the second fluid tube, the fourth fluid tube being connected to the first fluid tube.

Abstract: A hydraulic system includes a hydraulic pump, a first hydraulic actuator, a second hydraulic actuator, a first control valve to control the first hydraulic actuator, and a second control valve to control the second hydraulic actuator, the second control valve being arranged on a downstream side of the first control valve. The hydraulic system includes a first fluid tube in which a return fluid flows toward the second control valve. The first fluid tube couples the first control valve to the second control valve. The hydraulic system includes a second fluid tube in which a supply fluid flows toward to the first hydraulic actuator. The second fluid tube being connected to the first hydraulic actuator. The hydraulic system further a third fluid tube in which the return fluid in the first fluid tube flows toward the second fluid tube.

Abstract: A hydraulic system includes a hydraulic pump, a first hydraulic actuator, a second hydraulic actuator, a first control valve to control the first hydraulic actuator, and a second control valve to control the second hydraulic actuator, the second control valve being arranged on a downstream side of the first control valve. The hydraulic system includes a discharge fluid tube in which the operation fluid flows. The discharge fluid tube is connected to the first control valve. The hydraulic system includes a first fluid tube in which a return fluid flows toward the second control valve. The first fluid tube couples the first control valve to the second control valve. The hydraulic system includes a second fluid tube in which the return fluid flows toward the discharge fluid tube, and a third fluid tube in which a supply fluid flows toward the first fluid tube.

Abstract: A hydraulic system for a work machine includes a first control cylinder to move a boom and a second control cylinder to move a bucket. A body of the first control cylinder has a first fluid chamber and a second fluid chamber. A first control valve is connected to the first fluid chamber via a first fluid path and connected to the second fluid chamber via a second fluid path to control the first hydraulic cylinder. A bucket positioning valve is connected to the second fluid path and a third fluid path to control a second hydraulic cylinder so as to rotate the bucket. A discharge fluid path is connected to the second fluid path between the bucket positioning valve and the first control valve. A discharge control valve is provided in the discharge fluid path to be opened and closed.

Abstract: An elastic wave device includes a mount board, a transmit filter, a receive filter, and a sealing resin layer. The transmit filter includes a first piezoelectric substrate, and is joined to the mount board by first bumps. The receive filter includes a second piezoelectric substrate, and is joined to the mount board by second bumps. The sealing resin layer is provided on the mount board. The height of each first bump is H1; the joint area, on the first piezoelectric substrate side, of each first bump is A1; and the joint area, on the mount board side, of each first bump is B1; the height of each second bump is H2; the joint area, on the second piezoelectric substrate side, of each second bump is A2; and the joint area, on the mount board side, of each second bump is B2. The first bumps and the second bumps satisfy at least one of: A1>A2 and B1>B2; and H1<H2.

Abstract: A work machine includes a prime mover, a hydraulic pump to be operated by the prime mover to output an operation fluid, a hydraulic device to be operated by the operation fluid, a measurement sensor to measure a first temperature and a second temperature, the first temperature being a temperature of the operation fluid at starting of the prime mover, the second temperature being a temperature of the operation fluid after the starting of the prime mover, and a controller including a determiner to determine an upper limit revolution speed based on the first temperature, the upper limit revolution speed being an upper limit of a revolution speed of the prime mover, and a changer to change the upper limit revolution speed based on the second temperature.

Abstract: A hydraulic system of a work machine includes a first hydraulic actuator, a first control valve, a first oil passage, a second hydraulic actuator, a second control valve, a second oil passage, and a bypass oil passage. The first control valve is connected to the first hydraulic actuator to control the first hydraulic actuator. The first oil passage is connected to the first control valve to supply hydraulic oil to the first control valve. The second control valve connected to the second hydraulic actuator to control the second hydraulic actuator. The second oil passage connects the second control valve and the first hydraulic actuator via the first control valve. Hydraulic oil returning from the first hydraulic actuator to the first control valve is to be supplied to the second control valve through the second oil passage. The bypass oil passage connects the first oil passage and the second oil passage.

Abstract: A work machine includes an engine, a pilot pump to be driven by the engine to supply a pilot fluid, an operation pump to receive a first pilot fluid to change an output power in accordance with the first pilot fluid, a pilot fluid tube provided between the pilot pump and the operation pump, an operation valve connected to the pilot fluid tube to output the first pilot fluid, the first pilot fluid being a part of the pilot fluid supplied from the pilot fluid, a temperature sensor to measure a temperature of at least one of an operation fluid including the pilot fluid, a cooling water, an engine oil, and an outside air, and a pressure controller to control a first pilot pressure of the pilot fluid outputted from the operation valve when a temperature measured by the temperature sensor is equal to or higher than a first temperature.

Abstract: A hydraulic system for a work machine includes an operation member, a prime mover, a hydraulic pump driven by the prime mover, the hydraulic pump configured to output an operation fluid, a first temperature sensor to measure a temperature of the operation fluid, a first fluid tube connected to the hydraulic pump, an operation valve connected to the first fluid tube, the operation valve configured to control, in accordance with an operation extent of the operation member, a pressure of the outputted operation fluid, a hydraulic apparatus driven by the operation fluid outputted from the operation valve, a second hydraulic tube connecting the operation valve to the hydraulic apparatus, a discharge fluid tube to discharge the operation fluid included in the second fluid tube; and an actuation valve disposed on the discharge fluid tube, the actuation valve configured to control an aperture of the actuation valve based on the temperature.

Abstract: A hydraulic system for a work machine includes a hydraulic pump to supply a pilot fluid, and a hydraulic switch valve to be switched to a plurality of switching positions based on a pilot pressure. The pilot pressure is a pressure of the pilot fluid supplied from the hydraulic pump. The hydraulic system includes a direction switch valve to apply a first pilot pressure to the hydraulic switch valve to switch the hydraulic switch valve into one of the plurality of switching positions. The hydraulic system includes a pressure applying device to apply a second pilot pressure to the hydraulic switch valve. The second pilot pressure is lower than the first pilot pressure.

Abstract: A hydraulic system for a work machine includes a first control valve to control a first hydraulic actuator, a second control valve to control a second hydraulic actuator, a first fluid tube connecting the first hydraulic actuator to the first control valve, and a second fluid tube connecting the second hydraulic actuator to the second control valve. A level control valve apparatus is connected to the first fluid tube and the second fluid tube. The level control valve apparatus is configured to control a leveling operation for the second hydraulic actuator. An accumulator apparatus is connected to the first hydraulic actuator. The accumulator apparatus communicates with the first fluid tube between the level control valve apparatus and the first control valve. Circuitry is configured to control the level control valve apparatus to stop the leveling operation when the accumulator apparatus is in operation.

Abstract: A hydraulic system includes a hydraulic pump to discharge an operation fluid, a hydraulic device to be operated by the operation fluid, a plurality of hydraulic pressure controllers each to change an operation state of the hydraulic pressure controller based on a pressure of the operation fluid so as to control the hydraulic device, and a proportional valve connected to the plurality of hydraulic pressure controllers. The proportional valve is configured to set a pressure of the operation fluid supplied to the hydraulic pressure controllers.

Abstract: A hydraulic system for a work machine includes an operation member, a prime mover, a hydraulic pump driven by the prime mover, the hydraulic pump configured to output an operation fluid, a first temperature sensor to measure a temperature of the operation fluid, a first fluid tube connected to the hydraulic pump, an operation valve connected to the first fluid tube, the operation valve configured to control, in accordance with an operation extent of the operation member, a pressure of the outputted operation fluid, a hydraulic apparatus driven by the operation fluid outputted from the operation valve, a second hydraulic tube connecting the operation valve to the hydraulic apparatus, a discharge fluid tube to discharge the operation fluid included in the second fluid tube; and an actuation valve disposed on the discharge fluid tube, the actuation valve configured to control an aperture of the actuation valve based on the temperature.

Abstract: A hydraulic system includes a first hydraulic device, a second hydraulic device, a first control valve to control the first hydraulic device, a second control valve disposed on a downstream side of the first control valve and configured to control the second hydraulic device, a communication tube connecting the first hydraulic device to the first control valve, a supply fluid tube connecting the first control valve to the second control valve, a connection fluid tube disposed on the first control valve, the connection fluid tube connecting the communication tube to the supply fluid tube, a discharge fluid tube connected to the first control valve, a setting portion disposed on the discharge fluid tube and configured to increase a pressure in the discharge fluid tube, a branching fluid tube branched from the connection fluid tube and connected to the discharge fluid tube, and a throttle disposed on the branching fluid tube.

Abstract: A hydraulic system for a working machine, includes a first hydraulic pump to output an operation fluid, a hydraulic device to be operated by the operation fluid, an operation member to be operated, a control valve to control the hydraulic device based on an operation extent of the operation member, a holding member to set a held operation extent that is the operation extent held in the operation of the operation member, and a pedal to be operated to change the held operation extent set by the holding member.

Abstract: A hydraulic system in of a work machine includes a hydraulic pump to supply pilot hydraulic oil in a hydraulic oil reservoir. A travel pump is to drive a travel motor according to a pilot pressure of the pilot hydraulic oil. A target pilot pressure of the pilot hydraulic oil is input through a travel operation device to control, according to the target pilot pressure, the pilot pressure supplied from the hydraulic pump to the travel pump. A pilot oil path connects the travel operation device and the travel pump to supply the pilot pressure to the travel pump. A drain oil path is divided from the pilot oil path. A pressure adjustment valve is provided in the drain oil path to adjust the pilot pressure to be less than the target pilot pressure when a condition is satisfied.