Hitachi Construction Machinery Co., Ltd.

Yukihiro Tatsuno

Kazuhiro Ichimura

Hidetoshi Satake

Hidefumi Hiramatsu

Tsuyoshi Ueki

Kazuhiko Hiraoka

Hiroshi Tsukui

Katsuaki Kodaka

Tsuyoshi Takayama

Hideki Haramoto

A working mechanism () takes a traveling stance by a way that left and right boom cylinders () are expanded to rotate a tip end of a first boom () to the rear side and a positioning cylinder () is compressed to rotate a tip end of a second boom () to the lower side. In the traveling stance of the working mechanism (), a front surface plate (A) of a right front housing cover () is inclined along a tilting angle (&#x3b1;) of the left and right boom cylinders (), and the front surface plate (A) of the right front housing cover () is arranged in a position of lining with front ends (AA) of tubes (A,A) in the left-right direction forming the respective boom cylinders ().

Construction machine

A hydraulic control device for work machine includes: a driving device that generates a driving force for traveling of the work machine; a park braking device that parks the work machine; an operating unit that is provided in a cab of the work machine and operated by an operator for driving a work device; a hydraulic brake device that generates a braking force according to operation of a brake pedal; a hydraulic lock unit that hydraulically locks the hydraulic brake device to cause the hydraulic brake device to be continuously operated; a work device drivable state judging unit that judges whether or not the work device is in a work device drivable state in which the work device can be driven; and a park brake control unit that brings the park braking device into operation when the hydraulic lock unit hydraulically locks the hydraulic brake device and the work device drivable state judging unit judges that the work device drivable state has not been established.

Hydraulic control device for work machine

Cover for construction machine

Hydraulic excavator

A prime mover control device of a construction machine includes a hydraulic pump () driven by a prime mover (), an actuator () driven with pressure oil discharged from the hydraulic pump (), and a control valve () that controls a flow of the pressure oil from the hydraulic pump () to the actuator () in response to an operation of a first operating member (). The prime mover control device includes a first set means () that sets a first set rotation speed Nt of the prime mover () according to the operation of the first operating member (), a second set means () that sets a second set rotation speed Nx of the prime mover () according to an operation of a second operating member (), a selection member () that selects one of a first mode and a second mode, and a rotation speed control means () that controls a prime mover rotation speed to match with a maximum value of the first set rotation speed Nt and the second set rotation speed Nx when the selection member () selects the first mode, and controls the prime mover rotation speed to match with the second set rotation speed Nx when the selection member () selects the second mode.

Prime mover control device of construction machine

The present invention includes: a hydraulic pumpthat is driven by a driving motor; a travel motion motorthat is driven with pressure oil supplied from the hydraulic pump; a travel motion control valvethat controls a flow rate of the pressure oil supplied from the hydraulic pumpto the travel motion motor; a means for operationwith which the travel motion control valveis operated; a means for rotation rate detectionthat detects a rotation rate N of the travel motion motor; and a means for motor over rotation preventionthat reduces the rotation rate of the travel motion motorif the means for rotation rate detectiondetects a rotation rate equal to or higher than a predetermined rotation rate upper limit Nmax.

Travel motion control apparatus for hydraulically driven vehicle, hydraulically driven vehicle and wheel hydraulic excavator

A construction machine according to the present invention includes a variable displacement hydraulic pump () driven by a prime mover (), a single traveling actuator () driven with pressure oil discharged from the hydraulic pump (), a plurality of work actuators (to) driven with the pressure oil discharged from the hydraulic pump (), a plurality of control valves (to) that control flows of the pressure oil from the hydraulic pump () to each of the traveling actuator () and the plurality of work actuators (to), a detection means () for detecting a drive command for the traveling actuator (), and a flow rate control means () for increasing a maximum flow rate of the hydraulic pump () when the drive command for the traveling actuator () is detected with the detection means ().

A control apparatus of a construction machine includes a hydraulic pump driven by a prime mover, a hydraulic actuator, and a rotation speed detection device for detecting an actual rotation speed of the prime mover. The control apparatus includes a prime mover control device for controlling a rotation speed of the prime mover, and an input torque control device for adjusting an input torque for the hydraulic pump based on a deviation between the actual rotation speed detected by the rotation speed detection device and a control rotation speed set through an operation of the operating device, and the input torque control device executes control to decrease the input torque if the control rotation speed is greater than the actual rotation speed and the deviation calculated by subtracting the control rotation speed from the actual rotation speed is smaller than a predetermined negative value.

Control apparatus of construction machine and method for calculating input torque

The present invention includes a hydraulic pump (), a variable displacement hydraulic motor () for traveling driven by pressure oil from the hydraulic pump (), a motor displacement control means () for adjusting a displacement of the hydraulic motor () in correspondence to a drive pressure at the hydraulic motor (), an operating member () through which a forward travel command and a backward travel command for the vehicle are issued, a control means () to be driven in response to an operation of the operating member (), for controlling a flow of pressure oil from the hydraulic pump () to the hydraulic motor (), a reverse operation detection means (A,B) for detecting a reverse operation of the operating member () performed to a reverse side opposite from a direction along which the vehicle is advancing, and a cavitation preventing means (A,B) engaged in operation so as to prevent occurrence of cavitation at the hydraulic motor () when the reverse operation at the operating member () is detected by the reverse operation detection means (A,B).

Hydraulically driven vehicle

The present invention includes a hydraulic pumpdriven by a prime mover, a traveling motordriven with pressure oil delivered from the hydraulic pump, a control valvefor traveling that controls a flow rate of the pressure oil delivered from the hydraulic pumpto the traveling motor, a counterbalance valveswitched in response to a motor load pressure supplied via the control valve, that generates a braking pressure at a conduit LA or LB disposed on a return side of the traveling motoras the load pressure becomes lower, an overspeed detection meansfor detecting an overspeed state in the traveling motor, and a motor overspeed inhibiting meansfor inhibiting rotation of the traveling motorif the overspeed detection meansdetects an overspeed state in the traveling motoruntil a braking pressure is generated through a switchover at the counterbalance valveand the traveling motoris no longer in the overspeed state.

Travel control device for hydraulically driven vehicle and hydraulically driven vehicle

A prime mover control device of a construction machine according to the present invention includes a hydraulic pump () driven by a prime mover (), a hydraulic traveling motor () driven with pressure oil output from the hydraulic pump (), and a control valve () that controls a flow of the pressure oil from the hydraulic pump () to the hydraulic motor () in response to an operation of an operating member (). The prime mover control device further includes a deceleration detection means () that detects a deceleration operation at the operating member (), a rotation speed detection means () that detects a rotation speed Nm of the hydraulic motor (), and a prime mover rotation speed control means () that executes speed reduction control of the rotation speed of the prime mover () based upon detection results provided by the rotation speed detection means () if the deceleration operation is detected by the deceleration detection means () and controls the rotation speed of the prime mover () in correspondence to an operation of the operating member () which is detected to be other than the deceleration operation.

The wheeled work vehicle according to the present invention has a link that links at least either one of the axles and provided at the front and the rear of the vehicle to a body, suspension hydraulic cylinders provided at the left side and the right side of the chassis to link the axle to the body in conjunction with the link and an accumulator that is made to communicate with oil chambers and of the hydraulic cylinders via restrictors.

Wheeled type working vehicle

The wheeled work vehicle according to the present invention comprises a link that links at least either one of axles and &prime; provided at the front and the rear of the vehicle to a body , suspension hydraulic cylinders provided at the left side and the right side of the chassis to link the axle to the body in conjunction with the link and an accumulator that is made to communicate with oil chambers and of the hydraulic cylinders via restrictors and

Growing community of inventors

Tsukuba, Japan

Yukihiro Tatsuno