Abstract: A method for manufacturing a welded structure and a welding apparatus capable of reducing formation of burrs are provided. The method for manufacturing the welded structure according to the present disclosure is the method for manufacturing the welded structure formed by spot-welding a laminate formed of three or more metal plates, at least one metal plate of the three or more metal plates being thinner than the other metal plates. This manufacturing method includes a step of energizing a welding point of the laminate while pressurizing it and causing a main current to flow through the welding point of the laminate and a step of continuously energizing the welding point of the laminate while pressurizing it and causing a large current that is larger than the main current to flow through the welding point of the laminate.

Abstract: An operation management system obviates such a situation that a power substation would trip and a supply of power to overhead wires would stop. The operation management system controls operation of electric drive vehicles, each of which is provided with a trolley mode, in which the electric drive vehicle runs by power supplied to the overhead wires, and a diesel mode, in which the electric drive vehicle runs by an output from an engine. A supply margin detection unit detects a current supply margin of power and a running position detecting unit detects a current running position of the electric drive vehicle. A running mode detection unit detects a current running mode of the electric drive vehicle and a running mode determination unit determines a next running mode based on the detection results of the supply margin detection unit, running position detecting unit, and running mode detection unit.

Abstract: A trolley-type truck is provided with a pantograph and travels in a trolley mode under electric power from an overhead wire and a non-trolley mode without obtaining electric power. The pantograph has a base frame, a bottom frame and a top frame rockably attached to the base frame, and a collector shoe supported by the top end portion of the top frame. A fixing member is disposed on the top end side of the top frame for fixing the pantograph, a hook device is disposed on the base frame, and a hook receiver is disposed on the base frame in order to receive the fixing member. When a frame assembly formed of the bottom frame and the top frame is folded, the fixing member becomes seated in the hook receiver and is pressed by means of the hook device, thereby securely fixing the frame assembly to the base frame.

Abstract: Provided is an electric drive vehicle which can control wheel speed so as to achieve an appropriate slip ratio of the wheels even when pitching vibration of the vehicle is large. This electric drive vehicle is provided with electric motors (1, 4), drive wheels (3, 6), driven wheels (7, 8), an electric motor controller (50) for controlling the electric motors, and speed detectors (9-12) for detecting the wheel speed of the drive wheels and the driven wheels.

Abstract: A mining vehicle is provided, which is capable of appropriately recognizing a condition of a traveling road in front of the vehicle, preventing an obstacle on a roadside from being erroneously detected by a distance detector, and controlling the speed of the vehicle in a stable manner even when the vehicle is approaching a curved portion of the road from a linear portion of the road.

Abstract: Disclosed is a body structure for a dump truck (1) having a body frame (3). The body structure is provided with hinge pins (5) to be located toward a rear of the body frame, a body (2A) to be tiltably disposed on the body frame via the hinge pins and to be adapted to load payload (9), and stiffening members arranged on outer surfaces of the body. The body is constructed at least of a floor board (62a), a front board (62b), side boards (62c), and a canopy (62d). The stiffening members include side-board stiffeners (61) 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 (9) in a longitudinal direction of the body.

Abstract: An operation management system obviates such a situation that a power substation would trip and a supply of power to overhead wires would stop. The operation management system controls operation of electric drive vehicles, each of which is provided with a trolley mode, in which the electric drive vehicle runs by power supplied to the overhead wires, and a diesel mode, in which the electric drive vehicle runs by an output from an engine. A supply margin detection unit detects a current supply margin of power and a running position detecting unit detects a current running position of the electric drive vehicle. A running mode detection unit detects a current running mode of the electric drive vehicle and a running mode determination unit determines a next running mode based on the detection results of the supply margin detection unit, running position detecting unit, and running mode detection unit.

Abstract: Disclosed is a driving force control device that includes a determination section (12), a driving force command value calculation section (13), and a command value output section (14). The determination section (12) determines whether each of a plurality of motors (106), which independently drive a plurality of wheels (107), can be operated within a desired operating range when driven by a target driving force calculated for each of the motors (106). The driving force command value calculation section (13) 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.

Abstract: Provided is an electric drive vehicle which can control wheel speed so as to achieve an appropriate slip ratio of the wheels even when pitching vibration of the vehicle is large. This electric drive vehicle is provided with electric motors (1, 4), drive wheels (3, 6), driven wheels (7, 8), an electric motor controller (50) for controlling the electric motors, and speed detectors (9-12) for detecting the wheel speed of the drive wheels and the driven wheels.

Abstract: Provided is an electrically driven vehicle that is capable of suppressing drive wheel slippage without increasing the pitching vibration of the vehicle. The electrically driven vehicle having electric motors (1, 4), drive wheels (3, 6) driven by the electric motors respectively, and, when at least one of the drive wheels slips, an electric motor control device (40) for reducing the torque of at least one of the electric motors that drives the at least one wheel slipped, and for restoring the torque of the at least one electric motor when the slippage is stopped includes a pitching detection device (26) for detecting the amplitude of pitching vibration to which the vehicle is subjected. The amount of torque of the at least one electric motor to be restored by the electric motor control device over a predetermined period of time after the slippage is stopped varies depending on whether or not the amplitude A detected by the pitching detection device is greater than an assessment value A1.

Abstract: A dump truck parking position/direction indication system and a hauling system are provided that allow the operator of a loading machine to determine a parking position and a parking direction of a dump truck. The dump truck parking position/direction indication system includes: a bucket position detection device which detects the position of a bucket of the loading machine; a locus calculation device which calculates a movement locus of the bucket based on the positions of the bucket detected by the bucket position detection device; a parking position/direction determination device which determines the parking position and the parking direction of the dump truck based on the movement locus calculated by the locus calculation device; and an output device which outputs the parking position and the parking direction of the dump truck determined by the parking position/direction determination device.

Abstract: A dump vehicle overturn preventing device includes: a loaded weight estimation unit which estimates loaded weight on the body; a vehicle rotation moment calculation unit which calculates a vehicle rotation moment Mb caused by movement of the dump vehicle's load upon discharging of the load; a reference moment calculation unit which determines a reference moment Ms not greater than an overturn threshold moment MI which is the minimum value of a rotation moment required to lift the front wheels off the ground; a judgment unit which judges whether or not the vehicle rotation moment Mb has exceeded the reference moment Ms; and a display device which notifies the driver that there is a probability of an overturn of the vehicle when the vehicle rotation moment Mb is judged to have exceeded the reference moment Ms.

Abstract: A trolley-type truck is provided with a pantograph and travels in a trolley mode under electric power from an overhead wire and a non-trolley mode without obtaining electric power. The pantograph has a base frame, a bottom frame and a top frame rockably attached to the base frame, and a collector shoe supported by the top end portion of the top frame. A fixing member is disposed on the top end side of the top frame for fixing the pantograph, a hook device is disposed on the base frame, and a hook receiver is disposed on the base frame in order to receive the fixing member. When a frame assembly formed of the bottom frame and the top frame is folded, the fixing member becomes seated in the hook receiver and is pressed by means of the hook device, thereby securely fixing the frame assembly to the base frame.

Abstract: A mining vehicle is provided, which is capable of appropriately recognizing a condition of a traveling road in front of the vehicle, preventing an obstacle on a roadside from being erroneously detected by a distance detector, and controlling the speed of the vehicle in a stable manner even when the vehicle is approaching a curved portion of the road from a linear portion of the road.

Abstract: 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.

Abstract: 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.

Abstract: An electrically driven vehicle equipped with electric motors (1, 4) for driving or braking drive wheels (3, 6), and an electric motor controller (33) for controlling the electric motors includes: wheel speed detectors (9 to 12) for detecting the wheel speed of the drive wheels and that of idler wheels (7, 8); computing means (22 to 28, 35 to 38) 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 (29) 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 Va2, Vb2, then the determiner (29) changes the slip ratio determination value to a value having as the same sign as, and a larger absolute value than, the values ?a2, ?b2 used when the wheel speed of the idler wheels is higher than the set speeds Va2, Vb2.

Abstract: 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.

Abstract: The present invention provides a dump truck parking position/direction indication system and a hauling system that allow the operator of a loading machine to determine a parking position and a parking direction of a dump truck that let the operator easily perform the loading operation and to make the dump truck stop and park at the parking position and in the parking direction.

Abstract: Disclosed is a body structure for a dump truck (1) having a body frame (3). The body structure is provided with hinge pins (5) to be located toward a rear of the body frame, a body (2A) to be tiltably disposed on the body frame via the hinge pins and to be adapted to load payload (9), and stiffening members arranged on outer surfaces of the body. The body is constructed at least of a floor board (62a), a front board (62b), side boards (62c), and a canopy (62d). The stiffening members include side-board stiffeners (61) 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 (9) in a longitudinal direction of the body.