摘要:
Hydraulic excavators 1 working in fields each include a controller 2, and an operating time is measured for each of an engine 32, a front 15, a swing body 13 and a track body 12. The measured data is stored in a memory of the controller 2, transferred to a base station computer 3 through satellite communication, an FD, etc., and stored in a database 100 of the base station computer 3. In the base station computer 3, the data stored in the database 100 is read out for each of the hydraulic excavators to obtain a value of an index (e.g., a travel ratio) regarding the state of use of a particular one of the hydraulic excavators and a distribution of the number of operated hydraulic excavators of the same model as the particular hydraulic excavator with respect to the index. The index value and that distribution are compared with each other to determine whether the particular hydraulic excavator is an optimum model. It is therefore possible to make an evaluation after confirming how a customer employs a machine, and to give an advice about the optimum model depending on the state of use of the machines.
摘要:
A hydraulic control valve apparatus including a flow control valve having a pair of variable throttles, a feeder passage, a pair of load passages, directional control valve devices comprise a seat valve having a seat valve body movably disposed in a housing to form an auxiliary variable throttle in the feeder passage, and a control variable throttle (33) formed in the seat valve body for changing an opening area in accordance with an amount of movement of the seat valve body; (b) a pilot line (24, 29-31, 35-37) for communicating a portion (7C) of the feeder passage upstream of the auxiliary variable throttle with a downstream portion (7A, 7B) of the feeder passage through the control variable throttle to determine the amount of movement of the seat valve body in accordance with a flow rate of the hydraulic fluid passing through the pilot line; and (c) pilot flow control (400; 401; 403; 405; 406; 407; 408) having a pilot variable throttle (45) disposed in the pilot line and input (800; 52-59; 159, 54-59; 231A, 231B, 251, 252) for receiving a flow restricting signal whereby an opening area of the pilot variable throttle is changed in accordance with the received flow restricting signal to control a flow rate of the hydraulic fluid passing through the pilot line.
摘要:
A hydraulic circuit system comprising a hydraulic-fluid supply source, at least one hydraulic actuator operated by hydraulic fluid from the hydraulic-fluid supply source, a flow control valve for controlling the flow of the hydraulic fluid to be supplied to the actuator and a pressure control element for maintaining the differential pressure across the flow control valve at a predetermined value. The system according to the present invention comprises: first element for selectively creating, from the load pressure of the actuator and the supply pressure of the hydraulic-fluid supply source, either the pressure which is the same as the load pressure or the intermediate pressure which is higher than the load pressure but lower than the supply pressure and transmitting it as the control pressure; second element for operating said first element for instructing to select either the pressure which is the same as the load pressure or the intermediate pressure; and connection element for introducing the control pressure to the pressure control element. The pressure control element maintains the above-described differential pressure at the predetermined value when the level of the control pressure is the same as that of the load pressure, while it makes the level of the differential pressure lower than the predetermined value when the control pressure is the intermediate pressure.
摘要:
In a hydraulic machine such as, for example, a hydraulic excavator equipped with hydraulic actuators, a hydraulic driving method and a hydraulic driving apparatus enable all the hydraulic actuators to be operated according to normal operational-speed characteristics (first mode). The method and the apparatus alter the operational-speed characteristics of at least one of the hydraulic actuators, according to other characteristics (second mode), in accordance with working contents. The actuators altered in this manner can be operated according to the operational-speed characteristics of the second mode, without exerting an influence upon the operational-speed characteristics of the remaining hydraulic actuators.
摘要:
A hydraulic circuit for a construction machine which operates an actuator for working machine simultaneously with an actuator for working element without degrading the operation of the actuator for working machine. The hydraulic circuit comprises a first hydraulic pump, a first directional control valve connected to the first hydraulic pump and controlling an operation of the working machine actuator, a third directional control valve controlling an operation of the working element actuator, a second directional control valve connected to a second hydraulic pump, a first pilot operating device for controlling an operation of the first directional control valve and a second pilot operating device for controlling an operation of the third directional control valve. The hydraulic circuit further comprises a first hydraulic fluid joining device for providing hydraulic fluid of the second hydraulic pump to the input side of third directional control valve, a second hydraulic fluid joining device for supplying the hydraulic fluid of the second hydraulic pump to the input side of the first directional control valve, and a priority switching device for preventing, in response to a signal of the first pilot operating device, the signal of the second pilot operating device from being applied to the second directional control valve.
摘要:
To keep one of three hydraulic pumps unaffected by variations in torque of the remaining hydraulic pumps when the three hydraulic pumps are used, displacements of the first and second hydraulic pumps are controlled based on their own delivery pressures P1,P2 and a pressure P3′ obtained by reducing through a reducing valve 14 a delivery pressure P3 from the third hydraulic pump, while a displacement of the third hydraulic pump 3 is controlled only by its own delivery pressure P3. The pressure oil delivered from the third hydraulic pump 3, therefore, remains unaffected by variations in delivery flow rates from the first and second hydraulic pumps 1,2, in other words, by variations in their torque consumptions, so that the third hydraulic pump is assured to provide a stable flow rate.
摘要:
A hydraulic drive system includes a hose rupture control valve unit 200 having a poppet valve member 5 serving as a main valve for opening and closing communication between a cylinder connection chamber 8 and a hose connection chamber 9, a spool valve member 6 disposed in pilot passages 15a, 15b connecting a back pressure chamber 10 and the hose connection chamber 9 of the poppet valve member 5. The spool valve member is operated by a pilot pressure supplied as an external signal and operates the poppet valve member 5, and a small relief valve 7 having the function of an overload relief valve. A check valve 39 is disposed in the pilot passage 15b for cutting off a flow of the hydraulic fluid from the hose connection chamber 9 to the back pressure chamber 10. A hose rupture control valve unit 200 comprises a poppet valve member 5 serving as a main valve for opening and closing communication between a cylinder connection chamber 8 and a hose connection chamber 9, a spool valve member 6 disposed in pilot passages 15a, 15b connecting a back pressure chamber 10 and the hose connection chamber 9 of the poppet valve member 5, the spool valve member being operated by a pilot pressure supplied as an external signal and operating the poppet valve member 5, and a small relief valve 7 having the function of an overload relief valve. The valve unit further comprises a check valve 39 disposed in the pilot passage 15b for cutting off a flow of the hydraulic fluid from the hose connection chamber 9 to the back pressure chamber 10.
摘要:
To keep one of three hydraulic pumps unaffected by variations in torque of the remaining hydraulic pumps when the three hydraulic pumps are used, displacements of the first and second hydraulic pumps are controlled based on their own delivery pressures P1,P2 and a pressure P3′ obtained by reducing through a reducing valve 14 a delivery pressure P3 from the third hydraulic pump, while a displacement of the third hydraulic pump 3 is controlled only by its own delivery pressure P3. The pressure oil delivered from the third hydraulic pump 3, therefore, remains unaffected by variations in delivery flow rates from the first and second hydraulic pumps 1,2, in other words, by variations in their torque consumptions, so that the third hydraulic pump is assured to provide a stable flow rate.
摘要:
To keep one of three hydraulic pumps unaffected by variations in torque of the remaining hydraulic pumps when the three hydraulic pumps are used, displacements of the first and second hydraulic pumps are controlled based on their own delivery pressures P1, P2 and a pressure P3′ obtained by reducing through a reducing valve 14 a delivery pressure P3 from the third hydraulic pump, while a displacement of the third hydraulic pump 3 is controlled only by its own delivery pressure P3. The pressure oil delivered from the third hydraulic pump 3, therefore, remains unaffected by variations in delivery flow rates from the first and second hydraulic pumps 1,2, in other words, by variations in their torque consumptions, so that the third hydraulic pump is assured to provide a stable flow rate.
摘要:
A hose rupture control valve unit includes a housing provided with two input/output ports. One input/output port is directly attached to a bottom port of a hydraulic cylinder, and the other input/output port is connected to one of actuator ports of a control valve via an actuator line. Within the housing, there are provided a poppet valve body serving as a main valve, a spool valve body serving as a pilot valve which is operated with a pilot pressure supplied as an external signal from a manual pilot valve, thereby operating the poppet valve body, and a small spool having the function of an overload relief valve. The above construction reduces the number of components arranged in a flow passage through which a hydraulic fluid passes at a large flow rate, and hence a pressure loss. A further reduction in overall size and production cost of the valve unit is achieved.