Hitachi Construction Machinery Co., Ltd.

Takashi Sasaki

Takayuki Satou

Atsushi Kitaguchi

Kazunori Ishihara

Yasuki Kita

Yoshifumi Nabeshima

Tomohiko Yasuda

Takehito Ikema

Hitomi Ooshima

Yasutaka Tsuruga

Takanobu Ikari

Takaaki Tanaka

Takayuki Sato

Takashi Yagyu

Toshikazu Minoshima

Jun Ikeda

Takeshi Iwaki

An automatic brake subsystem () includes second accumulators (F,R), a front second line () and a rear second line (), second brake valves (F,R), a first solenoid switching valve (), first shuttle valves (F,R), and a controller. A second solenoid switching valve (F) and a pressure sensor (F) are provided in the front second line (), and a second solenoid switching valve (R) and a pressure sensor (R) are provided in the rear second line (). In a case where it is determined that each of the second brake valve (F,R) is not performing normally based upon a pressure of a hydraulic fluid detected by each of the pressure sensors (F,R) and an operating signal supplied to the first solenoid switching valve () or each of the second brake valves (F,R), a controllerperforms control to switch each of the second solenoid switching valves (F,R).

Brake 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

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 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.

Detection signals from lever sensor (), sit-down sensor () and vehicle speed sensor () are read into a controller (). A control signal is produced by the controller () to switch a directional control valve () of a control valve unit () instantly from a floating position (c) to a neutral position (a) and to switch another directional control valve () from a neutral position (a) to a lowering position (d) when a dump truck () is in travel with the directional control valve () of the control valve unit () is switched in the floating position (c). Whereupon, a hoist cylinder () is contracted by a hydraulic pressure force to hold a vessel () in a sit-down position on a vehicle body (), thereby preventing the vessel () from shaking movements like floating up while the dump truck () is in travel.

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Tsuchiura, Japan

Takashi Sasaki