Abstract: A cooling device includes: a cooling fan; a shroud provided at an outer circumferential side of the cooling fan; an inner circumferential wall provided on the shroud and adjacent to the outer circumference of the cooling fan; and an outer circumferential wall provided to surround the inner circumferential wall. An air-flow-direction downstream side end of an outer circumferential edge of the cooling fan is positioned at a further downstream position in an air flow direction than an air-flow-direction downstream side end of the inner circumferential wall. An angle between: an line connecting the air-flow-direction downstream side end of the inner circumferential wall to the air-flow-direction downstream side end of the outer circumferential wall in cross section along the air flow direction of the inner circumferential wall and the outer circumferential wall; and a line orthogonal to the air flow direction, is 9 degrees or more and 45 degrees or less.

Abstract: A cooling device includes: a cooling fan; a shroud provided at an outer circumferential side of the cooling fan; and a ring having an inner circumferential wall and an outer circumferential wall. The inner circumferential wall is provided on the shroud and adjacent to an outer circumference of the cooling fan. The outer circumferential wall surrounds the inner circumferential wall, and an air-flow-direction downstream side end of the outer circumferential wall is positioned at a further downstream position in an air flow direction than an air-flow-direction downstream side end of the inner circumferential wall. An air-flow-direction downstream side end of an outer circumferential edge of the cooling fan is positioned at a further downstream position in the air flow direction than the air-flow-direction downstream side end of the inner circumferential wall.

Abstract: A cooling device includes: a cooling fan; a shroud provided at an outer circumferential side of the cooling fan; an inner circumferential wall provided on the shroud and adjacent to the outer circumference of the cooling fan; and an outer circumferential wall provided to surround the inner circumferential wall. An air-flow-direction downstream side end of the outer circumferential wall is positioned at a further downstream position in an air flow direction than an air-flow-direction downstream side end of the inner circumferential wall. An air-flow-direction downstream side end of the cooling fan is positioned at a further downstream position than the air-flow-direction downstream side end of the inner circumferential wall. A ratio between a length of the outer circumferential wall and a length of the inner circumferential wall in the air flow direction is 1.07 or more and 1.81 or less, and a width between the outer circumferential wall and the inner circumferential wall is 15 mm or more and 55 mm or less.

Abstract: A cooling device includes: a cooling fan; a shroud provided at an outer circumferential side of the cooling fan; an inner circumferential wall provided on the shroud and adjacent to the outer circumference of the cooling fan so as to surround the cooling fan; an outer circumferential wall provided to surround the inner circumferential wall. An air-flow-direction downstream side end of the outer circumferential wall is positioned at a further downstream position in an air flow direction than an air-flow-direction downstream side end of the inner circumferential wall. The cooling fan is rotatable within a space provided on a radially inner side of the inner circumferential wall. The air-flow-direction downstream side end of the outer circumferential wall is provided at a further upstream position in the air flow direction than an air-flow-direction downstream side end of the cooling fan.

Abstract: A cooling device includes: a cooling fan; a shroud provided at an outer circumferential side of the cooling fan; an inner circumferential wall provided on the shroud and adjacent to the outer circumference of the cooling fan; and an outer circumferential wall provided to surround the inner circumferential wall. An air-flow-direction downstream side end of an outer circumferential edge of the cooling fan is positioned at a further downstream position in an air flow direction than an air-flow-direction downstream side end of the inner circumferential wall. An angle between: an line connecting the air-flow-direction downstream side end of the inner circumferential wall to the air-flow-direction downstream side end of the outer circumferential wall in cross section along the air flow direction of the inner circumferential wall and the outer circumferential wall; and a line orthogonal to the air flow direction, is 9 degrees or more and 45 degrees or less.

Abstract: A cooling device includes: a cooling fan; a shroud provided at an outer circumferential side of the cooling fan; an inner circumferential wall provided on the shroud and adjacent to the outer circumference of the cooling fan so as to surround the cooling fan; an outer circumferential wall provided to surround the inner circumferential wall. An air-flow-direction downstream side end of the outer circumferential wall is positioned at a further downstream position in an air flow direction than an air-flow-direction downstream side end of the inner circumferential wall. The cooling fan is rotatable within a space provided on a radially inner side of the inner circumferential wall. The air-flow-direction downstream side end of the outer circumferential wall is provided at a further upstream position in the air flow direction than an air-flow-direction downstream side end of the cooling fan.

Abstract: A cooling device includes: a cooling fan; a shroud provided at an outer circumferential side of the cooling fan; an inner circumferential wall provided on the shroud and adjacent to the outer circumference of the cooling fan; and an outer circumferential wall provided to surround the inner circumferential wall. An air-flow-direction downstream side end of the outer circumferential wall is positioned at a further downstream position in an air flow direction than an air-flow-direction downstream side end of the inner circumferential wall. An air-flow-direction downstream side end of the cooling fan is positioned at a further downstream position than the air-flow-direction downstream side end of the inner circumferential wall. A ratio between a length of the outer circumferential wall and a length of the inner circumferential wall in the air flow direction is 1.07 or more and 1.81 or less, and a width between the outer circumferential wall and the inner circumferential wall is 15 mm or more and 55 mm or less.

Abstract: A cooling device includes: a cooling fan; a shroud provided at an outer circumferential side of the cooling fan; and a ring having an inner circumferential wall and an outer circumferential wall. The inner circumferential wall is provided on the shroud and adjacent to an outer circumference of the cooling fan. The outer circumferential wall surrounds the inner circumferential wall, and an air-flow-direction downstream side end of the outer circumferential wall is positioned at a further downstream position in an air flow direction than an air-flow-direction downstream side end of the inner circumferential wall. An air-flow-direction downstream side end of an outer circumferential edge of the cooling fan is positioned at a further downstream position in the air flow direction than the air-flow-direction downstream side end of the inner circumferential wall.

Abstract: The present invention provides for a control system 20 of a hydraulic construction machine for enhancing a responsibility and stability of a work implement movement. The control system 20 comprises a variable displacement type hydraulic pump 2, a hydraulic actuator 7 driven by hydraulic fluid delivered from the pump 2, a flow control valve 5 for controlling the flow rate of the hydraulic fluid to the hydraulic actuator 7 in response to a travel amount of an operating lever 8, the variable bleed valve 14 disposed in the bleed-off hydraulic circuit 13 through which exhausts the hydraulic fluid supplied to the hydraulic actuator 7 and a controller 15 for controlling the flow rate through the variable bleed valve 14.

Abstract: A travel motor hydraulic control system for a construction machine having a plurality of hydraulic pumps which supply individually pressurized fluid for a plurality of hydraulic travel motors and a plurality of flow control valves which control the flow rate of the pressurized fluid to be supplied to the motor during an ordinary work. A controller receives a control signal representative of a travel control lever stroke sensed by a position sensor and a control signal detected by a pressure sensor, determines if the vehicle is traveling up a slope, and transmits a command signal to a solenoid operated valve to move a pilot operated shut off valve toward a valve-closing position, thereby the travel hydraulic motors are individually supplied the pressurized fluid from the hydraulic pumps.

Abstract: A travel motor hydraulic control system for a construction machine having a plurality of hydraulic pumps which supply individually pressurized fluid for a plurality of hydraulic travel motors and a plurality of flow control valves which control the flow rate of the pressurized fluid to be supplied to the motor during an ordinary work. A controller receives a control signal representative of a travel control lever stroke sensed by a position sensor and a control signal detected by a pressure sensor, determines if the vehicle is traveling up a slope, and transmits a command signal to a solenoid operated valve to move a pilot operated shut off valve toward a valve-closing position, thereby the travel hydraulic motors are individually supplied the pressurized fluid from the hydraulic pumps.

Abstract: The present invention provides for a control system 20 of a hydraulic construction machine for enhancing a responsibility and stability of a work implement movement The control system 20 comprises a variable displacement type hydraulic pump 2, a hydraulic actuator 7 driven by hydraulic fluid delivered from the pump 2, a flow control valve 5 for controlling the flow rate of the hydraulic fluid to the hydraulic actuator 7 in response to a an amount of an operating lever 8, the variable bleed valve 14 disposed in the bleed-off hydraulic circuit 13 through which exhausts the hydraulic fluid supplied to the hydraulic actuator 7 and a controller 15 for controlling the flow rate through the variable bleed valve 14.

Abstract: A hydraulic excavating mobile machine comprises a working implement at least two parts of which is operated by respective hydraulic actuators (hydraulic cylinders 2 and 3), pressure control valves 6 and 7 provided in pressurized fluid supply lines 4 and 5 to the actuators and connected to operating levers 11 and 12, respectively, pressure compensating valves 10 and 10a provided between the pressure control valve 6 and the one hydraulic actuator (the hydraulic cylinder 2) and between the pressure control valve 7 and the other actuator (the hydraulic cylinder 3), respectively, an operation mode selecting unit (a monitor 18) provided in a cab of the mobile machine, a controller 14 providing a control signal, and a variable pressure compensating value function storing unit provided in the controller 14.

Abstract: The invention provides a controller of an engine and a variable capacity pump which can perform a speedy work even under a heavy load and a strong work at the critical moment. Accordingly, there is provided control means (30) which outputs commands to a fuel injection pump (2), relief control means (19, 21) and variable capacity pump output control means (27, 29) so that when a signal for an on operation of an active mode switch (7) is inputted, the product of a pump discharge pressure P by a pump discharge amount Q is expressed by a P-Q constant horsepower curve Ha in an active mode in which the product of P and Q is higher than a predetermined value in the normal operation, and when a signal for an on operation of a power mode switch (9) is inputted, the product of the pump discharge pressure P by the pump discharge amount Q is expressed by a P-Q constant horsepower curve Hap in a power active mode in which the product of P and Q is higher than that in the active mode by one stage.

Abstract: A controller, for a variable capacity pump, prevents engine stalls due to rapid changes in operating load by increasing the pump absorption torque when the engine speed is high so as to increase the work amount and by reducing the pump absorption torque when the engine speed is low. The controller receives a signal from an engine speed sensor for detecting engine speed. A pump absorption torque curve is pre-set so as to be consecutively stepped with respect to engine speed so as to intersect at an engine rated point. The pump absorption torque is then calculated in accordance with increases or decreases in engine speed. The pump absorption torque is then set to prescribe values based on the results of these calculations and an instruction is outputted to a control valve in such a manner as to regulate a regulator of the variable capacity pump.

Abstract: A control circuit for a piece of heavy machinery reduces a speed of one actuator, having a lower load, when that actuator and another actuator, having a higher load, are operated simultaneously. The control circuit includes a first control valve for supplying a first actuator with pressurized oil, discharged from a hydraulic pump; a second control valve for supplying a second actuator with pressurized oil, discharged from the hydraulic pump; operating units for actuating the first control valve and the second control valve; and a mode selector for providing a command to the second control valve in order to increase a speed of the first actuator compared with that of the second actuator when the first and second actuators are operated simultaneously. A variable adjustor can be provided to control the open area of a valve for enabling the stroke of the spool of the second control valve to regulated.