JP4237682B2 - Work machine working arm - Google Patents

Description

  The present invention relates to a work arm equipped on a work machine such as a hydraulic excavator.

  For example, a hydraulic excavator, which is a typical example of a work machine, includes a work arm device in which a plurality of work arms are connected to an articulated structure by a shaft and a work tool such as a bucket is attached to a distal end portion.

  There is a known offset boom device as one form of this working arm device (see, for example, Patent Document 1). The offset boom device includes a base end boom that is swingably movable in the vertical direction on the airframe, an offset boom that is swingably movable in the left and right direction at the distal end of the base end boom, and an offset boom at the distal end of the offset boom. The arm is attached so as to be swingable in the vertical direction, and has an arm to which a work tool such as a bucket is attached. Then, by swinging the offset boom with respect to the base end boom, it is possible to shift (offset) the left-right machine body width direction position of the arm with respect to the base end boom. Therefore, with the offset boom device, for example, the side groove can be efficiently excavated by the bucket outside the width of the airframe while the airframe is faced to the front.

  In order to offset the offset boom, the offset operation cylinder attached to the proximal boom in parallel with the offset boom is expanded and contracted.

A typical example of the offset boom of the above-described offset boom device will be described with reference to FIG. 4 (a figure corresponding to FIG. 8 of Patent Document 1). The offset boom denoted by reference numeral 40 is formed in a box shape having a rectangular cross section by welding and joining a pair of upper and lower plates 42a, 42b and a pair of side plates 44a and 44b extending in the longitudinal direction (left and right direction in FIG. 4). Cylindrical connecting bosses 46 through which connecting shafts are inserted at both ends in the longitudinal direction penetrate the upper plate 42a and the lower plate 42b at both ends, and abut against the longitudinal ends of the side plates 44a and 44b. , Each is welded and attached.
JP 2002-47680 A

  However, the working arm such as the offset boom 40 as described above has the following problems to be solved.

  The offset boom 40 is used in a state where it is offset between the base end boom and the arm due to the mechanism of the offset boom device, and forces in various directions act on the connecting bosses 46, 46 at both ends. Works. Therefore, stress concentrated on the intersecting portion of the upper plate 42a and the lower plate 42b through which the connecting bosses 46, 46 pass is likely to occur. As a measure for reducing this stress, for example, as shown in FIG. 5, a reinforcing plate 48 is added to each of the joint portions of the connecting boss 46 and the upper plate 42a and the lower plate 42b, and the thicknesses of the upper plate, the lower plate, and the side plate are increased. Is done. However, these measures have problems such as the work arm becomes heavier and the operation is slowed down, the balance of the airframe becomes poor, the work arm device performance decreases, such as the force to lift the work arm decreases, and the cost increases. is there.

  The present invention has been made in view of the above facts, and its technical problem is that it is strong against an external force applied to the work arm, for example, “twist”, has a small number of parts, is light in weight, and is low in cost. It is possible to provide a working arm for a work machine.

  According to the present invention, as a work arm for solving the above technical problem, a work arm of a work machine provided with bearing holes through which shafts are inserted substantially parallel to each other at both longitudinal ends thereof, An extended substrate and a longitudinal end portion of one side surface of this substrate were bent into an L shape by a plate material, joined to one end on one side of the L shape, and attached to the other end toward the front end in the longitudinal direction. It is located between a pair of L-shaped members and a pair of L-shaped members on one side of the substrate, is formed into a cross-sectional groove shape by a plate material, extends in the longitudinal direction, and extends both ends of the pair of L-shaped members. Each of the groove-shaped members each having an opening having a groove-shaped cross section bonded and attached to the substrate and the other side of the pair of L-shaped members and one surface of the substrate are bonded to each other. A pair of bearing members, and through the bearing member, the L-shaped member, and the substrate Receiving hole is formed, it is provided working arm of a working machine, characterized in that.

  Preferably, the work arm is an offset boom interposed between a proximal boom attached to the fuselage and an arm attached to the work tool of an offset boom device mounted on a hydraulic excavator that is a work machine. is there.

  According to the working arm configured in accordance with the present invention, L-shaped members obtained by bending a plate material are used for bearing portions at both ends, and a pair of L-shaped members are joined to a groove-shaped member obtained by bending a substrate and a plate material into a cross-sectional groove shape. Therefore, the L-shaped bent portion can absorb the external force without concentrating it. Further, since the bearing member in which the bearing hole is formed is brought into contact with each other without being penetrated between the substrate and the L-shaped member, and can be joined to the entire circumference thereof, concentration of stress is avoided. Therefore, it is possible to provide a work arm that is unnecessary for adding a reinforcing plate, increasing the plate thickness, etc., is strong against external force, has a small number of parts, is light in weight, and can be increased in cost.

  Hereinafter, a working arm of a working machine configured according to the present invention will be described in more detail with reference to the accompanying drawings illustrating a preferred embodiment.

  A description will be given with reference to FIG. The work arm indicated as a whole by number 2 has a substrate 4 extending in a rectangular band shape in the longitudinal direction (left and right direction in FIG. 1A), and one side attached to both ends in the longitudinal direction of one side surface F of the substrate 4. A pair of L-shaped members 6, 6, a groove-shaped member 8 positioned between the surface F of the substrate 4 and the L-shaped members 6, 6, and the other sides of the L-shaped members 6, 6 and the surface F of the substrate 4 A pair of bearing members 10 and 10 are provided between them.

  The L-shaped member 6 is formed by bending a plate material into an L shape by bending R, and is attached with the end of one side 6a of the L shape joined to the surface F and the other side 6b facing the distal end side in the longitudinal direction of the work arm 2. ing.

  The groove-shaped member 8 is formed by bending a plate material into a rectangular groove shape in cross section. Both ends in the longitudinal direction of the work arm 2 are formed on one side 6a of each of the L-shaped members 6 and 6, and the opening of the groove section is formed on the surface of the substrate 4. Each is joined and attached to F.

  The bearing member 10 is formed in a columnar shape, is passed between the other side 6b of the L-shaped member 6 and the surface F of the substrate 4 and joined to each other, and through the bearing member 10 and the L-shaped member 6 and the substrate 4, Bearing holes 10a and 10a through which shafts (not shown) are inserted are substantially parallel to each other at both ends of the work arm 2.

  The working arm 2 described above is formed by integrally joining the substrate 4, the L-shaped member 6, the groove-shaped member 8, and the bearing member 10 formed of a steel member such as a steel plate by welding.

  With reference to FIG.2 and FIG.3, the offset boom apparatus 12 with which the above-mentioned working arm 2 incorporated in the hydraulic shovel which is a typical example of a working machine was integrated as an offset boom is demonstrated. The offset boom device 12 includes a proximal boom 14 that is swingably mounted in a vertical direction (a direction indicated by an arrow 12a in FIG. 2) on a hydraulic excavator body (not shown), and a proximal boom 14 at the distal end. The offset boom 2 is mounted so as to be swingable in the left-right direction (the direction indicated by the arrow 12b in FIG. 3) via the shaft 16a, and the shaft 16b is mounted on the tip of the offset boom 2 in parallel with the shaft 16a. An arm 20 is attached to the bracket 18 so as to be swingable in a vertical direction (a direction indicated by an arrow 12c in FIG. 2), and a bucket 22 is attached to the tip of the arm 20.

  A boom operating cylinder 24 is provided between the airframe and the proximal boom 14, an offset boom operating cylinder 26 is provided between the proximal boom 14 and the bracket 18, and an arm operating cylinder 28 is provided between the bracket 18 and the arm 20. Between the bucket 20 and the bucket 22, bucket operating cylinders 30 are respectively attached.

  Thus, when the offset boom operating cylinder 26 is expanded and contracted to swing the offset boom 2 about the shaft 16a with respect to the proximal boom 14, the arm 20 moves in the left-right direction with respect to the center X of the machine body to which the proximal boom 14 is attached. Offset to an arbitrary position between the widths W.

  Therefore, the offset boom device 12 is used in a state in which the offset boom 2 is offset in the positions of the shafts 16a and 16b at both ends with respect to the center X of the fuselage. "Twisting force" acts on

  The operation of the offset boom 2 which is the working arm as described above will be described mainly with reference to FIG.

  An L-shaped member 6 obtained by bending a plate material is used for a portion to which the bearing members 10 at both ends of the offset boom 2 as a work arm are attached, and the pair of L-shaped members 6 and 6 are bent into a substrate 4 and a plate material in a cross-sectional groove shape. Since the groove member 8 is joined, the offset boom 2 can be absorbed by the bending R portion of the L-shaped member 6 without concentrating stress against the “twisting force”. Further, since the bearing member 10 in which the bearing hole is formed is brought into contact with the substrate 4 and the L-shaped member 6 without penetrating each other, and the entire circumference thereof can be joined, concentration of stress is avoided. .

  Therefore, it is not necessary to add a reinforcing plate to the “torsional force” or increase the plate thickness as in the past, which is strong against external force, has a small number of parts by plate bending, has a low mass, and has a high cost. A working arm that can hold down the object is provided.

1A is a side view of a work arm of a work machine configured according to the present invention, FIG. 1B is a cross-sectional view as viewed in the direction of the arrow in FIG. 1A, and FIG. 2C is a perspective view of an L-shaped member. The side view of the offset boom apparatus with which the working arm shown in FIG. 1 was integrated. The top view seen in the AA arrow direction of FIG. The side view and sectional drawing of the conventional working arm. The side view of the conventional reinforced working arm.

Explanation of symbols

2: Offset boom (working arm)
4: substrate 6: L-shaped member 8: groove-shaped member 10: bearing member 10a: bearing hole 40: offset boom (working arm)

Claims (2)

A working arm of a working machine having bearing holes into which shafts are inserted substantially parallel to each other at both ends in the longitudinal direction, the board extending in the longitudinal direction, and a plate material at both longitudinal ends of one side of the board A pair of L-shaped members that are bent into an L-shape and joined at one end of the L-shape with the other side facing the longitudinal tip; and a pair of L-shaped members on one side of the substrate Is formed in a cross-sectional groove shape by a plate material and extends in the longitudinal direction, and both extended ends are attached to each of the pair of L-shaped members and the opening of the groove-shaped cross section is attached to the substrate. A groove-shaped member, and a pair of bearing members that are passed between the other side of the pair of L-shaped members and one surface of the substrate and joined to each other, and the bearing member, the L-shaped member, The working machine is characterized in that the bearing hole is formed through the substrate. Working arm. The working arm is an offset boom interposed between a proximal boom attached to a fuselage and an arm attached to a work tool of an offset boom device mounted on a hydraulic excavator that is a working machine. The working arm of the working machine according to 1.

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