Hitachi Construction Machinery Co., Ltd.

Takayuki Satou

Tomohiko Yasuda

Atsushi Kitaguchi

Kazunori Ishihara

Yasuki Kita

Takashi Sasaki

Masanori Ichinose

Yoshifumi Nabeshima

Takehito Ikema

Hitomi Ooshima

Hidefumi Ishimoto

Jun Ikeda

Takeshi Iwaki

Yasutaka Tsuruga

Hiroyuki Kobayashi

Masatsugu Arai

Kichio Nakajima

Akira Kikuchi

Mikio Bando

Takuya Naka

Masaki Kanai

Naoki Fukuda

Takanobu Ikari

Takaaki Tanaka

Yukihiko Ono

Mitsuhiro Kadota

Ishimoto Hidefumi

A power regeneration devicethat converts the power of a main engine DC lineconnected to a main engine power generatorthrough a rectification circuitto supply the converted power to an accessory DC lineconnected to an accessory power generatorthrough a rectification circuitincludes a plurality of power conversion modulestoN configured such that input sectionstoNa are connected in series. The main engine power generatorand a power consumption deviceare controlled such that a voltage input to the power regeneration devicedoes not exceed a voltage upper limit value Vm and a portion between a positive electrode terminal (+) and a negative electrode terminal (&#x2212;) of each of the input sections of the power conversion modules to be stopped is short-circuited by a bypass device and the voltage upper limit value Vm is decreased when some of the plurality of power conversion modulestoN are stopped. With this configuration, operational continuity can be improved while a device size increase is prevented.

Regenerative braking system and electrically-driven work vehicle using regenerative braking system

A hydraulic oil resupply device () is provided between first accumulators (F,R) in a manual braking operation circuit () and a second accumulator () in an automatic brake circuit (). The hydraulic oil resupply device () resupplies hydraulic oil accumulated in the second accumulator () to the first accumulators (F,R) at the operating of a manual braking operation by an operator. This configuration can suppress a rising speed of a brake pressure at the manual operation braking from being slow. Accordingly, in a vehicular brake system, it is possible to enhance a braking capability by the manual braking operation and improve the reliability.

Vehicular brake system

A device of estimating a slip angle of vehicle wheel has an attitude-toward-road surface estimation section that uses a series of distances to measurement points on a road surface to estimate vehicle-body-road-surface coordinate conversion information (VCCI) for conversion from a vehicle-body coordinate system to a road-surface coordinate system, an on-road-surface inertia quantity calculation section that removes a gravity acceleration component from the vehicle-body inertia quantity to obtain inertia quantity caused by motion of a vehicle body and uses the VCCI to convert from the inertia quantity caused by the motion of the vehicle body to the road-surface coordinate system, and a wheel slip angle estimation section that estimates a sideslip angle of the vehicle wheel on the basis of a difference between a wheel acceleration vector and the acceleration vector converted to the road-surface coordinate system.

Device and method for estimating slip angle of vehicle wheel

When large vehicles and small vehicles travel together in a mine, they are distinguishably detected. On a haulage vehicle for a mine, a first obstacle detection device and a second obstacle detection device are disposed. The obstacle detection devices are disposed so that they have detection directions oriented in a same direction in horizontal planes, respectively. The first obstacle detection deviceis disposed at a height where it can detect each small vehicle, while the second obstacle detection deviceis disposed at a height where it can detect each large vehicle without detection of any small vehicle. On the basis of detection results of the first obstacle detection deviceand second obstacle detection device, a detection processing devicedetermines whether an object is a small vehicle or a large vehicle.

Obstacle detection system and transportation vehicle

On a basis of a relative position of an obstacle, a size of the obstacle in an own vehiclewidth direction and a width of the own vehicle, a maximum amount Dof movement of the own vehiclein the vehicle width direction as required to avoid the obstacleis calculated. A point displaced over the maximum amount of movement toward a side of the adjacent lane from the relative position of the obstacleis determined as an avoiding point. If a distance d between the avoiding pointand the adjacent lane is greater than the width Wm of the own vehicle, an avoiding path is generated for allowing the own vehicleto pass the avoiding point

Obstacle avoidance 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.

Dump truck

Disclosed is a driving force control device that includes a determination section (), a driving force command value calculation section (), and a command value output section (). The determination section () determines whether each of a plurality of motors (), which independently drive a plurality of wheels (), can be operated within a desired operating range when driven by a target driving force calculated for each of the motors (). The driving force command value calculation section () adjusts the distribution of driving force for each of the motors in accordance with the target driving force for each of the motors and with the operating status of each of the motors and calculates an actual driving force command value for each of the motors for the purpose of operating each of the motors within the desired operating range if the determination means determines that each of the motors cannot be operated within the desired operating range. The command value output section () outputs the driving force command value to each of a plurality of inverters (). Therefore, a target vehicle motion can be maximally realized while appropriately maintaining the drive status of each of the motors.

Driving force control device for electric vehicle

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.

An electrically driven vehicle equipped with electric motors () for driving or braking drive wheels (), and an electric motor controller () for controlling the electric motors includes: wheel speed detectors (to) for detecting the wheel speed of the drive wheels and that of idler wheels (); computing means (toto) for computing the slip ratio of the drive wheels based on the wheel speed of the drive wheels and that of the idler wheels; and a determiner () for determining that the drive wheels are slipping if the slip ratio exceeds a slip ratio determination value. If the wheel speed of the idler wheels is lower than set speeds Va, Vb, then the determiner () changes the slip ratio determination value to a value having as the same sign as, and a larger absolute value than, the values &#x3bb;a, &#x3bb;bused when the wheel speed of the idler wheels is higher than the set speeds Va, Vb. This structure shortens acceleration time during acceleration traveling and reduces braking distance during deceleration traveling while inhibiting vibrations of the electrically driven vehicle.

Electrically driven vehicle

To suppress a change in a vehicle's attitude due to a pitch motion during vehicle braking, a pitch control device for an electric vehicle can prevent discontinuous negative acceleration from occurring at a moment of the vehicle stopping by appropriately controlling a braking force of the vehicle, thereby effectively controlling the pitch motion of the vehicle, and can enhance steering stability while ensuring riding comfort for passengers, even when traveling resistance significantly changes according to road surface gradient and when the vehicle weight significantly changes with increases/decreases in the number of drivers and in the quantity of goods loaded. This pitch control device for an electric vehicle, configured to conduct pitch control for suppressing the change in the attitude of the vehicle due to the pitch motion of the electric vehicle, controls the vehicle so that a braking/driving torque command value that is output to a motor for driving the vehicle when the vehicle stops will be a traveling resistance equivalent torque that is a value obtained by converting a force needed to stop the vehicle on a sloped road surface and maintain the vehicle in a stopped condition, into a torque of the driving motor.

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Tsuchiura, Japan

Takayuki Satou