Hitachi Construction Machinery Co., Ltd.

Atsushi Kitaguchi

Kazunori Ishihara

Yasuki Kita

Takayuki Satou

Yoshifumi Nabeshima

Tomohiko Yasuda

Takashi Sasaki

Takehito Ikema

Jun Ikeda

Hitomi Ooshima

Takeshi Iwaki

Naoki Fukuda

Mitsuhiro Kadota

Masatsugu Arai

Masanori Ichinose

Takayuki Sato

Takaaki Tanaka

Michio Fushiki

Shinji Akino

Yuuichi Kunitomo

Takeo Yamamoto

A dump truck reduces drive wheel braking torques to avoid locking drive wheels during slipping and generates braking torques for driven wheels to ensure an overall braking torque using a controller that outputs a regenerative torque command value, corresponding to a brake pedal operation amount, to an inverter that regeneratively controls electric motors. The controller reduces the regenerative torque command value and outputs a drive command value, corresponding to a regenerative torque command value reduction amount, to a solenoid proportional valve, when the controller determines that slip ratios of rear wheels equal or exceed a predetermined value. A hydraulic pressure generated by a hydraulic valve based on the brake pedal operation amount actuates rear wheel brakes. A hydraulic pressure selected by a higher-pressure selecting valve that selects the higher of the hydraulic pressure from the hydraulic valve and the hydraulic pressure from the solenoid proportional valve actuates front wheel brakes.

Dump truck

To provide an electric vehicle capable of reducing heat generation of the switching elements while achieving energy saving, the electric vehicle includes: an engine; a first generatordriven by the engine; a first rectifier circuitconnected to the output of the first generator; a first DC lineto receive the DC output of the first rectifier circuit; a driving motorconnected to the first DC line; a power converterconfigured to convert voltage of the first DC line; a second DC lineto receive the DC output subjected to voltage conversion by the power converter; an auxiliary deviceconnected to the second DC line; and a controllerconfigured to control the power converter. The controller is configured to, in response to the voltage Vof the first DC line becoming equal to or less than a first threshold V, control the output power Pof the power converter to a rated power P, and in response to the voltage becoming larger than the first threshold, control the output power Pto be smaller than the rated power.

Electric vehicle

When regeneration operation is being performed, electric power on a main-machine side is supplied to an auxiliary-machine side, a voltage on the auxiliary-machine side is controlled to become a first voltage value predetermined on the basis of operating voltage specifications of an auxiliary apparatus, a generator on the auxiliary-machine side is deactivated to stop supply of electric power to the auxiliary-machine side, and electric power on the auxiliary-machine side is supplied to a power storage apparatus. When the regeneration operation is ended, the supply of the electric power from the main-machine side to the auxiliary-machine side is stopped, the generator on the auxiliary-machine side is activated, the generator on the auxiliary-machine side is controlled such that a voltage on the auxiliary-machine side becomes the first voltage value, electric power of the power storage apparatus is supplied to the auxiliary-machine side, and the voltage on the auxiliary-machine side is controlled to become a second voltage value higher than the first voltage value. This enables reduction of fluctuations of a voltage supplied to auxiliary machines at a time of switching of regeneration operation by travel motors.

Regenerative braking system, and electrically driven work vehicle using the same

A dump truck pitching control system that can improve the ride quality of a vehicle body and the drive stability during traveling is provided. The present invention includes: a pitching state amount detection sectionthat detects a state amount of the pitching movement of the vehicle body; a spring characteristics calculation sectionthat calculates spring characteristics of suspension cylinders, based on detection results of stroke sensors, pressure sensors, and temperature sensors; a pitching target amount calculation sectionthat calculates a target amount of the pitching movement of the vehicle body, according to the spring characteristics calculated by the spring characteristics calculation section; and a torque correction value calculation sectionthat calculates a torque correction value required to correct the pitching amount, according to the spring characteristics calculated by the spring characteristics calculation section

Dump truck pitching control system

Stresses are decreased at joints of a support structure disposed on a body of a dump truck. The dump truck includes a body frame (), a body (), a support structure () disposed on the body and supported by the body frame, and load transmission structures configured to transmit a load from the support structure to the body frame and, to transmit a reaction force from the body frame to the support structure. The support structure has a plurality of vertical plates () and a bottom plate (). The vertical plates are arranged along a direction in which the reaction force is received from the body frame, and the bottom plate is maintained in upward contact with these vertical plates. The bottom plate is divided into first areas and a second area. The first areas include areas where the bottom plate is in contact with the vertical plates, and the second area is an area other than the first areas. The load transmission structures are configured to transmit the reaction force from the body frame such that a reaction force to be transmitted to each of the first areas becomes greater than a reaction force to be transmitted to the second area.

Dump truck and load transmission structure for same

Disclosed is a body structure for a dump truck () having a body frame (). The body structure is provided with hinge pins () to be located toward a rear of the body frame, a body (A) to be tiltably disposed on the body frame via the hinge pins and to be adapted to load payload (), and stiffening members arranged on outer surfaces of the body. The body is constructed at least of a floor board (), a front board (), side boards (), and a canopy (). The stiffening members include side-board stiffeners () connecting upper portions of elongated joints between the side boards and the front board to portions of elongated joints between the side boards and the floor board. The latter portions are located rearward of positions laterally corresponding to a barycentric position (G) of the payload () in a longitudinal direction of the body.

Body structure for dump truck

A dump truck is provided with a frame, hinge pins and a body (). The body is provided on a lower surface of a floor board () thereof with a rail () along a longitudinal direction of the frame. The rail is a hollow structure member comprised of two side rail plates () and a bottom rail plate (). The two side rail plates () extend downwardly from the lower surface of the floor board () of the body and oppose each other with an interval therebetween in a lateral direction of the frame, and the bottom rail plate () is arranged in contact with respective lower end surfaces (-) of these two side rail plates (). The dump truck () satisfies a relationship of Ts&#x3c;Tb&#x3c;Tf, where Ts is a thickness of the side rail plates, Tb is a thickness of the bottom rail plate, and Tf is a thickness of a top frame plate (-) of the frame.

A body for a dump truck includes a body frame, a bottom wall, front wall, and left and right side walls arranged on the body frame. The body also includes an earth/sand anti-sticking device and a steel member arranged outside and opposite the earth/sand anti-sticking device such that a space is formed between the steel member and the earth/sand anti-sticking device. The body is provided with at least one steel rib arranged in the space, fixedly secured to the steel member to reinforce the steel member, and arranged extending upright toward the earth/sand anti-sticking device. The steel member is any one of the bottom wall, front wall, and left and right walls, and the steel rib is shaped to divide the space.

Body for dump truck

A body for a dump truck includes a body frame, a bottom wall, front wall and left and right side walls arranged on the body frame. The bottom wall, front wall and left and right side walls define a payload section for loading a payload, an earth/sand anti-sticking device is arranged in a corner part of the payload section to prevent earth or sand from sticking in the corner part. A steel member is arranged outside and opposite to the earth/sand anti-sticking device such that a space is formed between the steel member and the earth/sand anti-sticking device. The body includes at least one steel rib having a ridge extending out from a surface of a plate that forms the earth/sand anti-sticking device, the ridge is fixedly secured by welding to the plate that forms the earth/sand anti-sticking device.

Rear wheel tires of a vehicle body are spaced apart from each other in the vehicle width direction. A foreign object removing device is provided between an outer tire and an inner tire of the rear wheels on one side of the vehicle for removing foreign objects between the tires. The foreign object removing device includes a bar-shaped member inserted in a suspended state between the tires, and a shoe provided in a lower end side of the bar-shaped member to collide with foreign objects such as earth and sand, and stones getting in between the tires for flicking out the foreign objects from between the tires. The shoe is replaceably attached to the lower end side of the bar-shaped member by using a bolt. In a case where the shoe wears down, only the shoe is replaced.

Transporter vehicle

A crusher is provided that can quickly return to the operating state from a shutdown state which occurs due to the incorporation of a foreign object. Provided are a crushing rotor, a housingand an anvilsupported by the housing to face a crushing chamber. A leveris disposed on the side opposite the crushing rotorwith respect to the housing, pivotably installed with respect to side frames, and provided with a holding portion for holding the housingto keep a posture where the anvilfaces the crushing chamber. An elastic memberis for biasing the leverat a set biasing force. When the biasing force is exceeded, the leverturns to permit the anvilto turn and retreat from the crushing chamber

Crusher

A crusher comprises a crushing rotor being rotatable and having a crushing bit to crush target materials to be crushed, a feed conveyor for conveying the target materials toward the crushing rotor, and a pressing feeder unit including a pressing roller disposed above the feed conveyor and introducing the target materials on the feed conveyor toward the crushing rotor while pressing the target materials from above, and an anvil disposed at a position which is closer to the crushing rotor than a point where the pressing roller presses the target materials and which is outward of the crushing rotor in the radial direction. The fixed bit has a bumping surface, against which the target materials bump, disposed in an opposed relation to the rotating direction of the crushing bit, thereby crushing the target materials introduced toward the crushing rotor.

A crusher comprises a crushing apparatus including a crushing rotor provided with a crushing bit for crushing target materials, a feed conveyor for conveying the target materials to the crushing apparatus, a pressing roller for pressing the target materials conveyed on the feed conveyor and introducing the target materials to the crushing apparatus in cooperation with the feed conveyor, and hydraulic cylinders for changing a relative positional relationship between the crushing apparatus and the feed conveyor, to thereby change a crushing angle formed between a feed direction of the target materials when the target materials are introduced to the crushing apparatus and a line tangential to the crushing rotor at a position where the crushing bit hits against the target materials. Since an angle at which the crushing bit cuts into the target materials is adjustable, crushed chips can be produced in a way flexibly adapted for various needs caused in sites by using a single crusher.

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Tsuchiura, Japan

Atsushi Kitaguchi