JP4403854B2 - Revolving frame structure of upper revolving structure - Google Patents

Description

  The present invention relates to an upper swing body that is rotatably mounted on a lower traveling body, and more particularly to a swing frame structure that supports the upper swing body.

  In general, a hydraulic excavator includes a lower traveling body having crawlers on the left and right sides, and an upper revolving body that is rotatably mounted on the lower traveling body. FIG. 8 shows a base portion of the upper revolving body. The swivel frame is shown.

  The swivel frame mainly includes a center frame 50 disposed in the center, a right deck frame 51 disposed on the right side of the center frame 50, and a left deck frame 52 disposed on the left side.

  For example, an engine, a counterweight, a front attachment, and the like are attached to the center frame 50, an electrical component such as a battery, a tank, and the like are disposed on the right deck frame 51, and a cab, a cooling device, and the like are disposed on the left deck frame 52. Is done.

  The center frame 50 is provided with a pair of left and right center beams 53, 54, and an engine (not shown) is installed near the rear of each center beam 53, 54. It is a counterweight support portion 55 for supporting (not shown).

Since the center beams 53 and 54 of the center frame 50 support the counterweight, which is the largest heavy object, the cross section often adopts an I-shaped cross-sectional structure with high rigidity (see, for example, Patent Document 1).
JP 2003-27522 A

  However, the conventional center beam 53 is configured by combining the back plate 56, the vertical plate 57, and the bottom plate 58 to form an I-shaped cross section. However, the process of joining the back plate 56 and the vertical plate 57 takes time. There is.

  The vertical plate 57 has a slope that decreases in height while drawing a curve so as to smoothly connect from the attachment mounting portion 59 formed in a raised state to the front portion to the counterweight support portion 55 at the rear end portion. It has a different shape.

  Therefore, it is necessary to bend the back plate 56 along the curve of the upper edge of the vertical plate 57, and further, the bent curve of the back plate 56 and the curve of the vertical plate 57 must be matched. I must.

  However, since there are a plurality of curved portions on the upper edge of the vertical plate 57, it is difficult to make the vertical plate 57 and the back plate 56 correspond to each other so that the plurality of curved portions are completely matched. If there is a portion not to be welded, a gap is formed at the joint between both plates, resulting in poor welding.

Although it is conceivable to increase the rigidity of the center beam 53 by omitting the back plate 56 and increasing the thickness of the vertical plate 57, the weight of the swing frame becomes heavy and the load of the swing motor increases. Not only will the equipment be affected, but the swivel frame may need to be redesigned.

  The present invention has been made in consideration of the problems in the conventional swivel frame structure as described above, and provides a swivel frame structure that can easily reinforce the center beam without causing poor welding.

The inventions of claim 1, is arranged a pair of center beam in the central portion of the bottom plate, each center beam, attachment mounting unit to the front, formed counterweight support portion after portion, respectively Rutotomoni, the attachment in the vertical plate in communication with the mounting portion and the counterweight support portions are provided swivel frame structure includes a reinforcing member for reinforcing the vertical plate, the reinforcement
(A) It is formed in accordance with the upper edge line of the vertical plate, and the end on the attachment mounting portion side is formed in a wedge shape when seen from the plane so as to be joined to the side surface of the vertical plate without a step,
(B) Between the attachment attachment part and the counterweight support part, it is welded to at least one side surface of the vertical plate along the upper edge of the vertical plate.

According to a second aspect of the present invention, in the configuration of the first aspect, the reinforcing member is made of a strip steel that is arranged in parallel with the vertical plate and is formed in accordance with an upper edge line of the vertical plate.

  According to a third aspect of the present invention, in the configuration of the first aspect, the reinforcing member is a rod-shaped member that is bent in accordance with the upper edge line of the vertical plate.

  According to the present invention, in reinforcing the center beam, the back plate is not welded to the upper edge of the vertical plate, and the reinforcing material formed in accordance with the upper edge line of the vertical plate is joined to the side surface of the vertical plate. This eliminates the need for the conventional complicated joining in which the curve of the reinforcing material coincides with the curve of the upper edge line of the vertical plate, and makes it possible to manufacture a center beam without defective welding extremely easily.

In this case, the reinforcing material can be bonded to the vertical plate between the attachment mounting portion and the counterweight support portion. Thereby, the range in which stress is generated in the center beam can be effectively reinforced.

In addition, by forming the end of the reinforcing member on the attachment mounting portion side in a wedge shape when seen from the plane, the end of the reinforcing member can be joined to the vertical plate without a step, thereby suppressing local stress. Can contribute.

Further, in the invention of claim 3, wherein the reinforcing member is formed by a rod-shaped member bent to match the upper edge line of the vertical plate, when a round bar is used as the rod-shaped member, the reinforcing material is reinforced when it comes into contact with the vertical plate. Since a gap corresponding to a groove is formed on both upper and lower sides of the material, the reinforcing material can be joined to the vertical plate using the gap.

  Hereinafter, the present invention will be described in detail based on the embodiments shown in the drawings.

  FIG. 1 shows an embodiment of a turning frame structure according to the present invention.

  In the figure, a center frame 1 serving as the center of a revolving frame that supports the upper revolving structure has a pair of center beams 2 and 3 disposed in the center in the front-rear direction. The right side deck mounting portion 4 extends horizontally, and the left side deck mounting portion 5 extends horizontally on the left side of the center beam 3.

  The center frame 1 is equipped with a turning device for turning the upper turning body, an engine, a hydraulic pump, and the like.

  Attachment mounting portions 6 and 7 that protrude in a convex shape are formed at the front portions of the center beams 2 and 3, and a boom for connecting the boom base end portion of the work attachment to the attachment mounting portions 6 and 7. Mounting brackets 8 and 9 are fixed. In addition, 8a and 9a are brackets for inserting boom foot pins for connecting the boom cylinders, and 10 is a connection plate for connecting the left and right attachment mounting portions 6 and 7.

  Counterweight support portions 11 and 12 for mounting a counterweight (not shown) are provided at the rear ends of the center beams 2 and 3.

  Next, the configuration of the center beam 3 will be described as a representative.

  In the center beam 3, the vertical plate 13 that connects the attachment mounting portion 7 and the counterweight support portion 12 is inclined downward from the attachment mounting portion 7 toward the rear, and the first plate is closer to the attachment mounting portion 7. The second round portion B is formed near the round portion A and the counterweight support portion 12.

  Two rounded portions A and B are formed, and a reinforcing material 14 is provided along the upper edge line 13a of the vertical plate 13 inclined rearward.

  The reinforcing member 14 is made of a flat bar (band steel plate) having substantially the same thickness as the vertical plate 13, and is parallel to the vertical plate 13 along the upper edge of the vertical plate 13 (viewed from the front-rear direction). It arrange | positions and is joined to the outer side surface of the vertical board 13. As shown in FIG.

  Further, the reinforcement member 14 is attached between the attachment attachment portion 7 and the counterweight support portion 12, and the same round portions 14 a and 14 b as the round portions A and B along the upper edge line 13 a of the vertical plate 13. Is formed.

  The rounded portions 14a and 14b can be formed by bending the reinforcing plate 14 in the width direction.

  Further, the end of the reinforcing member 14 on the attachment mounting portion 7 side is formed in a wedge shape when seen from the plane, and is joined to the vertical plate 13 without having a step.

  FIG. 2 shows a joined state of the vertical plate 13 and the reinforcing material 14.

  When the vertical plate 13 and the upper surface of the reinforcing material 14 are joined at the same height, the upper joint surfaces of the plates 13 and 14 are grooved to form a V-shaped groove 15 and welded to the V-shaped groove 15. Metal 16 is buried and bonded. In addition, about the lower part of the reinforcing material 14, the fillet is welded using the level | step difference of the vertical board 13 and the reinforcing material 14. FIG.

  Further, the upper surface of the reinforcing member 14 is not necessarily required to coincide with the upper surface of the vertical plate 13, and if it is provided along the upper edge 13a of the vertical plate 13, as shown in FIG. You may join in the state shifted.

  If the vertical plate 13 and the reinforcing material 14 are arranged so as to be shifted in this way, a step corresponding to the thickness of the reinforcing material 14 is formed with respect to the vertical plate 13. Therefore, the reinforcing material 14 is attached to the vertical plate 13 using this step. Can be joined by fillet welding. In this case, there is an advantage that it is not necessary to provide a groove on both plates 13 and 14, and the assembly process of the center beam 3 can be shortened.

  FIG. 4 shows a comparison of stress distribution between the center frame of the conventional configuration and the center frame according to the present embodiment.

  FIG. 5A illustrates the distance from the measurement center to the center C of the center frame, and the center frame shown in the side view has a conventional configuration.

  FIG. 4B is a graph showing the stress generated according to the distance from the machine center C. The horizontal axis shows the distance from the machine center C, and the vertical axis shows the tensile stress generated on the center frame. ing. A load corresponding to the weight of the counterweight is applied to the rear ends of the center beams 2 and 3.

  In the graph, the characteristic L1 indicates the stress distribution in the conventional center frame, and the characteristic L2 indicates the stress distribution by the center frame of the present embodiment.

  As indicated by the characteristic L1, in the conventional center frame, local stresses are generated at a distance l1 and a distance l2 from the machine center C, respectively. In the following description, what occurs at a distance l1 from the machine center C is referred to as a first local stress P1, and what occurs at a distance l2 is referred to as a second local stress P2.

  In the characteristic L1, the first local stress P1 is generated at the front end 13c of the back plate 13b welded to the upper edge of the vertical plate 13. This seems to be due to the fact that a step corresponding to the thickness of the back plate is generated between the front end 13c and the upper edge of the vertical plate 13. Also, stress concentration is likely to occur when there is a difference in thickness between the back plate 13b and the vertical plate 13 to be joined.

  On the other hand, the second local stress P2 is a stress inevitably generated in the center beam 3 by mounting the counterweight.

  On the other hand, in the characteristic L2 by the center frame of the present embodiment, the local stress P3 appears at the same site as the second local stress P1, but the stress value is clearly low at the site where the first local stress P1 is generated (graph). In the middle, see P4), it was confirmed that local stress was not generated at the portion near the attachment mounting portion 7.

  In the conventional center frame structure, in order to suppress the first local stress P1, the vertical plate 13 is provided with a notch corresponding to the thickness of the back plate 13b, and the back plate 13b is joined without a step, in this case, In addition to the difficulty of joining the back plate 13b and the vertical plate 13 by matching the curves, the vertical plate 13 must be provided with a notch, which increases the number of processes.

  In the center frame structure of the present embodiment, the back plate 13b is not attached to the upper edge of the vertical plate 13, but instead the reinforcing member 14 (see FIG. 1) formed along the upper edge shape of the vertical plate 13 is It joins in the state parallel to the side surface of the board 13. Thereby, generation | occurrence | production of a local stress can be suppressed, without performing the above-mentioned complicated notch process and complicated joining.

  FIG. 5 shows a modification of the reinforcing member 14.

  When it is necessary to further increase the rigidity of the center beams 2 and 3, the reinforcing members 14 can be joined to both side surfaces of the vertical plate 13.

  In this case, as shown in FIG. 2, the reinforcing member 14 'joined to the inside of the vertical plate 13 is also subjected to groove processing on the upper joint surfaces of both plates 13, 14' to form a V-shaped groove 15 '. Then, the weld metal 16 is buried in the V-shaped groove 15 and joined. Note that, as shown in FIG. 3, the reinforcing member 14 ′ can be joined to the vertical plate 13 while being slightly shifted downward.

  6 and 7 show still another modified example of the reinforcing member 14.

  In the center frame structure shown in FIG. 6, the reinforcing member 20 made of a solid round bar is joined along the upper edge of the vertical plate 13.

  The reinforcing member 20 is bent along the upper edge line 13 a of the vertical plate 13, and the weld metal 16 is formed in a gap generated between the vertical plate 13 and the reinforcing member 20 in contact with the side surface of the vertical plate 13. Fill and join. Therefore, in this configuration, it is not necessary to provide a groove for both the vertical plate 13 and the reinforcing member 20.

  In the center frame structure shown in FIG. 7, a reinforcing member 21 made of a square pipe is joined along the upper edge of the vertical plate 13.

  The reinforcing member 21 is bent in the vertical direction along the upper edge line 13 a of the vertical plate 13, and is formed in a gap generated between the vertical plate 13 and the reinforcing member 21 in contact with the side surface of the vertical plate 13. The weld metal 16 is buried and bonded. Therefore, it is not necessary to provide a groove for both the vertical plate 13 and the reinforcing member 21 in this configuration.

It is a perspective view which shows the turning frame structure which concerns on this invention. It is explanatory drawing which shows the joining state of the reinforcement member of this invention. It is explanatory drawing which shows another joining state of the reinforcement member of this invention. (a) is explanatory drawing which shows the measurement distance from a machine center, (b) is the graph which compared the stress distribution by the conventional center frame structure, and the stress distribution by the center frame structure of this invention. It is explanatory drawing which shows the modification of the reinforcement member of this invention. It is explanatory drawing which shows another modification of the reinforcement member of this invention. It is explanatory drawing which shows another modification of the reinforcement member of this invention. It is a perspective view which shows the conventional turning frame structure.

DESCRIPTION OF SYMBOLS 1 Center frame 2,3 Center beam 4 Right side deck attaching part 5 Left side deck attaching part 6,7 Attachment attaching part 8,9 Boom attaching bracket 10 Connection board 11,12 Counterweight support part 13 Vertical board 13a Upper edge line 13b Back plate 13c End portion 14 Reinforcing material 15 V-shaped groove 16 Weld metal 20 Reinforcing member 21 Reinforcing member

Claims (3)

A pair of center beam is arranged at the center of the bottom plate, each center beam, attachment mounting unit to the front, the counterweight support portion after the portion is formed respectively Rutotomoni, the attachment mounting portion and the counterweight support portion in communication with swivel frame structure vertical plates is provided and the door, comprising a reinforcing member for reinforcing the vertical plate, the reinforcement
(A) It is formed in accordance with the upper edge line of the vertical plate, and the end on the attachment mounting portion side is formed in a wedge shape when seen from the plane so as to be joined to the side surface of the vertical plate without a step,
(B) A revolving frame structure characterized in that it is welded between at least one side surface of the vertical plate between the attachment mounting portion and the counterweight support portion along the upper edge of the vertical plate. The reinforcing material, turning the frame structure of claim 1 placing wherein the ing from the vertical plate parallel to arranged strip steel which is formed to fit the upper edge line of the vertical plate. The reinforcing material, revolving frame structure according to claim 1 Symbol mounting characterized by comprising the processed bar-like member bent to fit the upper edge line of the vertical plate.

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