The number of steps required for a welding operation of a work implement of a hydraulic excavator is reduced while the welding quality is improved. A boom includes a top plate, a left side plate joined to the top plate, and a boom foot bracket. The boom foot bracket includes an extending portion. The extending portion includes a portion that faces a side surface of the top plate.

A work machine includes a machine body, an engine, a rotary electrical device, and an electric power controller. The engine is provided on the machine body to move the machine body. The rotary electrical device is provided on the machine body to move the machine body. The electric power controller is disposed above the rotary electrical device in a height direction along a height of the work machine to control the rotary electrical device.

A revolving frame includes a center frame and a plurality of beams welded to a side surface of the center frame and extending away from the center frame along a transverse direction. The plurality of beams includes a skirt beam that includes a pair of beam side plates having a first end that is welded to the side surface of the center frame. An upper surface of each beam side plate has a notch surface that extends from the first end to a notch edge. The notch surface defines a notch groove, such that the notch edge of each beam side plate is separated from the center frame along the transverse direction by a gap across the notch groove. The skirt beam further includes a beam upper plate integrally fixed to the pair of beam side plates, and a notch connection plate welded to each beam side plate.

To provide a frame of construction machines that can enhance the rigidity of support members. The frame comprises a bottom plate, a pair of vertical plates being disposed spacedly in a width direction on a top surface of the bottom plate and extending longitudinally and vertically, and multiple support members extending toward outside in a width direction from breadthwise outer surface of the pair of vertical plates. At least one of the multiple support members comprises a vertical wall perpendicular to the bottom plate. A breadthwise inner end part of vertical wall is welded on breadthwise outer surface of one of pair of vertical plates. A lower end of the pair of vertical plates is welded intermittently on a top surface of the bottom plate, and there exists a non-welded part where the lower end of the vertical plates is not welded on the top surface of the bottom plate under breadthwise inner end part of the vertical wall.

Problem to Be Solved: To provide a frame of a construction machine that can prevent a crack caused by a torsion load. Solution: The frame comprises the center member including the bottom plate and a pair of left and right vertical plates disposed on a top surface of the bottom plate, a pair of left and right skirt members horizontally disposed on both left and right sides of the center member, and a plurality of beam members disposed between the center member and right skirt member and between the center member and left skirt member, respectively. The plurality of beam members include the plate beam member disposed in a perpendicularly erected manner against the bottom plate. The first and second bent parts are formed on the plate beam member. The plate beam member has the first part extending outward in a horizontal direction from the center member to the first bent part, the second part extending from the first bent part to second bent part, and the third part extending outward in a horizontal direction from the second bent part to the skirt member.

A welded structure makes a relationship between one intermittent weld which fixes a long member to a base material and the other intermittent weld which fixes a plate-shaped member to the long member appropriately respond to a type of a load which dominantly acts on the long member. A lower long side edge of a beam member which serves as the long member is fixed onto a machine body frame which serves as the base material by intermittent welds. A top plate which serves as the plate-shaped member is fixed onto an upper long side edge of the beam member by the other intermittent welds. In a region where a load which twists the top plate dominantly acts on the beam member, a parallel weld portion in which the intermittent welds and the intermittent welds are welded in a parallel weld form is employed, and in a region where a bending load from the top plate dominantly acts on the beam member, the zigzag weld portion in which the intermittent weld and the intermittent weld are welded in a zigzag weld form is employed.

This invention relates to a cab support structure for construction machine. The cab support structure has a rear beam and a front beam, which support front and rear part of cab, and a center beam located and welded between inner and outer frames of the machine. A stopper located at the corner of center beam side of the junction of rear beam and outer frame is formed box shape. The stopper has an L-shaped plate welded to the rear beam and the outer frame, and a doubling L-shaped plate welded to the L-shaped plate, rear beam, and outer frame.

A frame assembly for a machine includes a main frame and a crossmember. The main frame includes first pair of rails and a second pair of rails laterally spaced from the first pair of rails. Each of the first pair of rails and the second pair of rails includes a first rail and a second rail vertically spaced from the first rail. The crossmember includes a first flange connected to both the first rail and second rail of the first pair of rails. The crossmember further includes a second flange connected to both the first rail and the second rail of the second pair of rails.

The hydraulic excavator capable of accurately positioning an engine and an exhaust gas treatment unit is provided. The hydraulic excavator includes a engine, an exhaust gas treatment unit, a front left pillar portion, a rear left pillar portion, a plurality of support portions, and a center frame. The exhaust gas treatment unit treats an exhaust gas from the engine. The plurality of support portions support the exhaust gas treatment unit. The center frame carries the engine. The center frame has a vertical plate. Two support portions are fixed to the vertical plate.

A post-treatment device mounting frame on which an exhaust gas post-treatment device is mounted is constituted by a front mounting leg, a rear mounting leg, and a deck connecting the front and rear mounting legs to each other. A vertical leg part of the front mounting leg is mounted on a front vertical leg part mounting plate of a right front extension beam. A lateral leg part of the front mounting leg is mounted on a front lateral leg part mounting plate of a right front engine support bracket. A vertical leg part of the rear mounting leg is mounted on a rear vertical leg part mounting plate of a right rear extension beam. A lateral leg part of the rear mounting leg is mounted on a rear lateral leg part mounting plate of a right rear engine support bracket. Therefore, the post-treatment device mounting frame is firmly mounted in a state of four-point support on a revolving frame.