JP2007051413A - Turning frame of construction machinery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a turning frame of construction machinery capable of improving the rigidity of an area of a joint in a bracket without using any other member of a reinforcing plate or the like and improving joint efficiency by the welding etc. of a lower beam of a cab. <P>SOLUTION: A front side plane table of the lower beam 16 of the cab is used as a front side inclined plate 16a having an optional inclination, specially the inclination of the front side inclined plate 16a makes approximately the same as that of an inclined plate 9b of a front plate 9, and the font side inclined plate 16a of the lower beam 16 of the cab makes approximately the same plate face as that of the inclined plate 9b of the front plate 9, the lower beam 16 of the cab is constituted of at least the front side inclined plate 16a and an upper plate 16c, and one end of the lower beam 16 of the cab is connected to the other surface of one bracket 7a and the upper surface of the bottom plate 6 to connect the other end to one side frame so that a folding section intersecting the front side inclined plate 16a at the upper plate 16c can approximately coincide with the inclined plate 9b of the front plate 9 or a vertical plate 9a. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a swivel frame for a construction machine, and in particular, in a swivel frame for a construction machine such as a hydraulic excavator, without using other members such as a reinforcing plate, the bracket portion is joined to a front plate and a cab lower beam. The present invention relates to a swivel frame for a construction machine that can improve the durability by improving the rigidity of the partial region and can improve the joining property by welding or the like of the beam under the cab.

  In a hydraulic excavator as a construction machine, an upper swing body is rotatably mounted on a lower traveling body via a swing mechanism. A work machine including a boom or the like is attached to the front center portion of the swing frame in the upper swing body so as to be able to move up and down, a cab or the like is provided on one front side, and a tool or the like is stored on the other front side. A storage box or the like is provided.

  As a conventional turning frame in a hydraulic excavator as such a construction machine, for example, there are those shown in FIGS. As shown in FIGS. 4 and 5, the revolving frame 1 includes a center frame 2 and a tail frame 3 that are located in the center and extend in the front and rear directions, and side frames 4 and 5 that are located on both the left and right sides thereof. It is configured.

  In the revolving frame 1, the side on which the center frame 2 is positioned is the front side with respect to the tail frame 3 side. In the following description, when the left side and the right side are referred to, the side on which the center frame 2 is positioned is the front side. It points to the left side and the right side.

  Left and right vertical plates 8a and 8b are erected on the upper surface of the bottom plate 6 in the center frame 2 so as to extend forward and rearward and the front end side becomes left and right boom mounting brackets 7a and 7b. . Further, in order to increase the bending strength of the left and right boom mounting brackets 7a and 7b, the left and right end sides of the front plate 9 are joined to the inner sides facing the boom mounting brackets 7a and 7b, respectively, by welding. On the lower front end side of the left and right boom mounting brackets 7a and 7b, portions located on the front side of the front plate 9 are left and right cylinder mounting brackets 10a and 10b.

  As shown in FIG. 6, the front plate 9 is formed by bending a flat plate such as a steel plate into a substantially square shape, and the lower end side is joined to the bottom plate 6 by welding and extends upward substantially vertically. The vertical plate portion 9a is composed of a vertical plate portion 9a and an inclined plate portion 9b extending obliquely upward and rearwardly between the left and right boom mounting brackets 7a and 7b from the upper end side of the vertical plate portion 9a. The front plate 9 has a substantially square opening 9c.

  A cab lower beam 11 is provided between the center frame 2 and the left side frame 4. The lower end of the cab beam 11 is joined to the side frame 4 by welding, the right end is joined to the left boom mounting bracket 7a by welding, and the lower end is joined to the upper surface of the bottom plate 6 by welding. Has been.

  The cab lower beam 11 is made of a beam material having a U-shaped cross section with the lower side open, and an upper plate portion 11c connecting the front and rear side plate portions 11a and 11b and the front and rear side plate portions 11a and 11b. And is formed. As shown in FIG. 6, the cab lower beam 11 is disposed at an offset position in which the front side plate portion 11 a is displaced to the front side by a dimension a with respect to the vertical plate portion 9 a of the front plate 9. This dimension a is set to a different size depending on the type of hydraulic excavator.

  A cab support frame 12 is formed between the cab lower beam 11 and the front portion of the side frame 4. The cab support frame 12 is positioned in front of the cab lower beam 11 and extends in parallel with the cab lower beam 11, and a horizontal beam portion 13 having a left end joined to the front end of the side frame 4 and a front end side of the horizontal beam portion. 13, extending in parallel with the left boom mounting bracket 7 a, and the rear end side is formed by the cab lower beam 11 and the vertical beam portion 14 joined to the bottom plate 6 by welding.

  A cab mounting beam 15 is provided at a position appropriately spaced behind the cab lower beam 11. The left end of the cab mounting beam 15 is joined to the side frame 4 by welding, and the right end is joined to the upper surfaces of the left vertical plate 8a and the bottom plate 6 by welding.

  Further, for example, the following is known as a conventional technique related to a turning frame of a construction machine. In this prior art, the following reinforcing plate is provided at the end of the lower beam of the cab located at the gap between the vertical beam portion of the cab support frame and the left boom mounting bracket. It is set as the structure which raises the joint strength of a mounting bracket and a cab lower beam.

  The reinforcing plate includes a front plate portion that rises so as to be substantially perpendicular to the bottom plate, and an upper plate portion that is bent rearward from the upper end of the front plate portion in an L shape and extends substantially parallel to the bottom plate. The width dimension corresponds to the gap length between the vertical beam portion and the left boom mounting bracket.

  The lower end side of the front plate portion is joined to the upper surface of the bottom plate by welding, and the rear end of the upper plate portion is on the corner portion side located between the side plate portion and the upper plate portion in the cab lower beam. The left and right sides are joined to each other by welding and joined to the outer surface of the left boom mounting bracket and the vertical beam.

As a result, the left boom mounting bracket is sandwiched between the reinforcing plate and the front plate so as to be sandwiched from both the left and right sides, and the left boom mounting bracket is bent and deformed in the left and right directions by a lateral load from the outside. Is suppressed. In addition to the L shape, the reinforcing plate may have a U shape or a shape in which the upper side of the front plate portion is greatly curved (see, for example, Patent Document 1).
Japanese Patent No. 3634723 (pages 7-8, FIGS. 1-8).

  In the prior art shown in FIGS. 4 to 6, the front side plate portion of the lower cab beam is offset to the front side by a dimension a with respect to the vertical plate portion of the front plate and provided between the left side frame and the center frame. The end portion of the cab lower beam is joined to the other surface of the left boom mounting bracket and the bottom plate by welding.

  By the way, a lateral bending stress is generated in the left and right boom mounting brackets in the center frame due to a lateral load applied to the work machine from the outside. This bending stress is caused by the fact that the inclined plate portion of the front plate is joined to one surface of the left boom mounting bracket by welding and the other surface of the left boom mounting bracket. It tends to occur in a concentrated manner between the welded portion of the lower beam of the cab that is welded while being displaced from the vertical plate portion by a dimension a to the front side. For this reason, it is difficult to increase the durability of the welded portion.

  In contrast, it is conceivable that a rib is additionally provided between the end of the cab lower beam and the left boom mounting bracket, and the welded portion between the cab lower beam and the left boom mounting bracket is reinforced by this rib. ing.

  However, because it is arranged in a gap with a small size, it is difficult to sufficiently reinforce the welded part between the end of the cab lower beam and the left boom mounting bracket, which is effective for reducing stress concentration. It is not a countermeasure.

  Moreover, in the prior art described in patent document 1, it is set as the structure which raises the joint strength of the left boom attachment bracket and a cab lower beam with the following reinforcement boards. The reinforcing plate is joined to the upper surface of the bottom plate by welding at the lower end side of the front plate portion, and the rear end of the upper plate portion is welded to the corner portion located between the side plate portion and the upper plate portion of the cab lower beam. The left and right side portions are joined to the outer surface of the left boom mounting bracket and the longitudinal beam portion of the cab support frame.

  However, the gap between the outer surface of the left boom mounting bracket and the longitudinal beam portion in the cab support frame is quite narrow. For this reason, there exists a possibility that the weldability of the reinforcement board with respect to such a narrow location may deteriorate.

  Therefore, without using other members such as a reinforcing plate, it is necessary to solve the problem in order to improve the durability by increasing the rigidity of the joint region in the bracket portion, and to improve the joint property by welding the beam under the cab. A technical problem arises, and the present invention aims to solve this problem.

  The present invention has been proposed in order to achieve the above object, and the invention according to claim 1 is characterized in that a pair of vertical plates constituting a pair of bracket portions to which the work implement is attached are arranged on the bottom plate at a required interval. A center frame which is provided with an inclined plate portion between the pair of bracket portions and the front plate for reinforcing each bracket portion is joined by welding; and side frames respectively provided on both sides of the center frame; In a turning frame of a construction machine having a cab lower beam having one end part welded to the other surface part of the one bracket part and the upper surface of the bottom plate and the other end part joined to the one side frame by welding, A turning frame for a construction machine is provided in which a front side plate portion of the cab lower beam is a front side inclined plate portion having an arbitrary inclination.

  According to this structure, the joining length of the front inclined plate portion of the cab lower beam to be joined to the bracket portion can be increased, the region where the inclined plate portion of the front plate is joined to one surface of the bracket portion, the bracket The rigidity of the area where the end of the cab lower beam is joined to the other surface of the part can be increased, and the bending stress generated in the area due to the lateral load applied from the outside to the work machine attached to the bracket part can be reduced. Thus, bending deformation and the like of the bracket portion can be suppressed.

  The invention according to claim 2 is the invention according to claim 1, wherein the inclination of the front inclined plate portion of the cab lower beam is made substantially the same as the inclination of the inclined plate portion of the front plate, and the front inclined plate portion of the cab lower beam A turning frame for a construction machine is provided which has a plate surface substantially the same as the inclined plate portion of the front plate.

  According to this configuration, the rigidity of the region can be increased, and the lateral load applied from the outside to the work machine can be distributed to both the cab lower beam and the front plate to reduce stress concentration. By making the longitudinal direction of the joint region on the one surface side of the bracket portion substantially coincide with the longitudinal direction of the joint region on the other surface side of the bracket portion, the bending stress generated in the region is further reduced. Bending deformation of the part can be suppressed.

  The invention according to claim 3 is the invention according to claim 1 or 2, wherein the cab lower beam is composed of at least a front inclined plate portion and an upper plate portion, and a bent portion where the front inclined plate portion and the upper plate portion intersect is provided. Provided is a swing frame for a construction machine configured to substantially coincide with the inclined plate portion or the vertical plate portion of the front plate in a side view.

  According to this configuration, the rigidity of the region can be increased, and in particular, the bent portion where the front inclined plate portion and the upper plate portion intersect with the inclined plate portion or the vertical plate portion of the front plate substantially coincide. This reduces the stress concentration by dispersing the lateral load applied to the work machine from the outside to both the cab lower beam and the front plate, reducing the bending stress generated in the region, and bending deformation of the bracket part. Etc. can be suppressed.

  The invention according to any one of claims 1 to 3 is a region in which the inclined plate portion of the front plate is joined to one surface of the bracket portion as compared with the conventional cab lower beam in which the front side plate portion of the cab lower beam is a vertical plate portion. In addition, the rigidity of the area where the end of the cab lower beam is joined to the other surface of the bracket part can be increased, and the lateral load applied from the outside to the work machine is distributed to both the cab lower beam and the front plate. Thus, there is an advantage that the stress concentration can be relaxed and the joining property when the cab lower beam is welded to the other surface portion of one bracket portion and the upper surface of the bottom plate can be improved.

  Without using other members such as a reinforcing plate, a pair to which the work machine is attached has the purpose of improving durability by improving the rigidity of the joint region in the bracket portion and improving the weldability of the beam under the cab. A pair of vertical plates constituting the bracket portion are erected on the bottom plate at a required interval, an inclined plate portion is provided between the pair of bracket portions, and the front plate for reinforcing each bracket portion is joined by welding. A center frame, side frames respectively provided on both sides of the center frame, one end of which is joined to the other surface of the bracket portion and the upper surface of the bottom plate by welding, and the other end is the side frame. In a swivel frame of a construction machine having a cab lower beam joined to a cab by welding, the front side plate portion of the cab lower beam is a front side inclined plate portion having an arbitrary inclination. The inclination of the front inclined plate portion of the cab lower beam is substantially the same as the inclination of the inclined plate portion of the front plate, and the front inclined plate portion of the cab lower beam is substantially the same plate surface as the inclined plate portion of the front plate. In addition, the cab lower beam is composed of at least a front inclined plate portion and an upper plate portion, and a bent portion where the front inclined plate portion and the upper plate portion intersect with each other is an inclined plate portion or a vertical plate of the front plate in a side view. Realized by making it almost coincide with the plate part.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The present embodiment is applied to a hydraulic excavator as a construction machine. 1 is a plan view of the main part, FIG. 2 is a diagram showing an example of a cross section taken along line AA in FIG. 1, and FIG. 3 is a diagram showing another example of the cross section taken along line AA in FIG. 1 to 3, the same or equivalent components as those in FIGS. 4 to 6 are denoted by the same reference numerals as those described above, and redundant description is omitted.

  First, the structure of the turning frame of the construction machine according to the present embodiment will be described. As shown in FIGS. 1 to 3, in this embodiment, the front side plate portion of the cab lower beam 16 is formed of a front inclined plate portion 16a having an arbitrary inclination. The cab lower beam 16 includes a front inclined plate portion 16a and a rear side plate portion 16b, and an upper plate portion 16c connecting the front inclined plate portion 16a and the rear side plate portion 16b.

  The cab lower beam 16 shown in FIG. 2 or FIG. 3 has the front inclined plate portion 16a joined by welding to the opposite position of the front plate 9 across the vertical plate 8a constituting the left boom mounting bracket 7a. The inclination of the front inclined plate portion 16a of the lower beam 16 is made substantially the same as the inclination of the inclined plate portion 9b of the front plate 9, and the cab lower beam 16 is constituted by at least the front inclined plate portion 16a and the upper plate portion 16c, One end of the bent boom bracket on the left side is such that a bent portion where the front inclined plate portion 16a and the upper plate portion 16c intersect each other substantially coincides with the inclined plate portion 9b or the vertical plate portion 9a of the front plate 9 in a side view. The other surface of 7a and the upper surface of the bottom plate 6 are joined by welding, and the other end is joined to the left side frame 4 by welding.

  The configuration shown in FIG. 2 is such that the inclination of the front inclined plate portion 16a of the cab lower beam 16 is substantially the same as the inclination of the inclined plate portion 9b of the front plate 9, and the front inclined plate portion 16a of the cab lower beam 16 is the front plate. The inclined plate portion of the front plate 9 is joined in such a manner that the inclined plate portion 9b is substantially the same plate surface, and the bent portion where the front inclined plate portion 16a and the upper plate portion 16c of the cab lower beam 16 intersect each other is seen in side view. 9b or the configuration substantially coincident with the vertical plate portion 9a is satisfied. Although not shown in the drawings, the above-described constituent elements can be made independent and the inclination of the front inclined plate portion 16a of the cab lower beam 16 can be arbitrarily set.

  Further, as shown in FIG. 3, the inclination of the front inclined plate portion 16a of the cab lower beam 16 is made substantially the same as the inclination of the inclined plate portion 9b of the front plate 9, and the front inclined plate portion 16a of the cab lower beam 16 and The bent portion where the upper plate portion 16c intersects may be configured so as to substantially coincide with the vertical plate portion 9a of the front plate 9 in a side view and to deviate vertically from the inclined plate portion 9b of the front plate 9. it can.

  Next, the operation of the cab support structure for a construction machine configured as described above will be described. One end of the cab lower beam 16 is joined to the other surface of the left boom mounting bracket 7a by welding.

  For this reason, the bending stress generated by a lateral load or the like applied from the outside to the work machine attached to the left and right boom mounting brackets 7a and 7b is caused by the inclined plate portion of the front plate 9 on one surface of the left boom mounting bracket 7a. It tends to concentrate between the region where 9b is joined and the region where one end of the cab lower beam 16 is joined to the other surface of the left boom mounting bracket 7a by welding.

  On the other hand, the front inclined plate portion 16a in the cab lower beam 16 has an arbitrary inclination, and the bent portion where the front inclined plate portion 16a and the upper plate portion 16c intersect is an inclined plate of the front plate 9 in a side view. By attaching one end of the cab lower beam 16 to the other surface of the left boom mounting bracket 7a so as to substantially coincide with the portion 9b or the vertical plate portion 9a, The cab lower beam 16 can be attached across the bracket 7a.

  In addition, the inclination of the front inclined plate portion of the cab lower beam is substantially the same as the inclination of the inclined plate portion of the front plate, and the front inclined plate portion of the cab lower beam is substantially the same plate surface as the inclined plate portion of the front plate. By doing so, the longitudinal direction of the joint region on the one surface side of the left boom mounting bracket 7a and the longitudinal direction of the joint region on the other surface side of the left boom mounting bracket 7a substantially coincide.

  As a result, the bending stress that easily occurs between the joint region on the one surface side of the left boom mounting bracket 7a and the joint region on the other surface side of the left boom mounting bracket 7a is suppressed to be extremely low, The rigidity of the joint area in the left boom mounting bracket 7a is increased, and bending deformation of the boom mounting brackets 7a and 7b due to the bending stress is suppressed.

  As described above, in the construction machine according to the present embodiment, the rigidity of the joint area in the left boom mounting bracket 7a can be increased, and the durability of the joint area can be improved.

  The cab lower beam 16 can significantly improve the weldability to the other surface of the left boom mounting bracket 7a and the upper surface of the bottom plate 6 by using the front side plate portion as the front inclined plate portion 16a.

  The present invention can be variously modified without departing from the spirit of the present invention, and the present invention naturally extends to the modified ones.

The principal part top view of the turning frame of the construction machine which concerns on the Example of this invention. The figure which shows an example of the cross section which follows the AA line of FIG. The figure which shows another example of the cross section which follows the AA line of FIG. The top view of the turning frame of the conventional construction machine. The perspective view of FIG. Sectional drawing of the part which follows the BB line of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Revolving frame 2 Center frame 4,5 Side frame 6 Bottom plate 7a, 7b Boom mounting bracket (bracket part)
8a, 8b Vertical plate 9 Front plate 9b Inclined plate portion 16 Cab lower beam 16a Front inclined plate portion

Claims (3)

A pair of vertical plates constituting a pair of brackets to which the work machine is attached are erected on the bottom plate at a required interval, and an inclined plate portion is provided between the pair of bracket portions, and the front plate for reinforcing each bracket unit. A center frame joined by welding, side frames provided on both sides of the center frame, and one end of the other end portion joined to the other surface portion of the one bracket portion and the upper surface of the bottom plate by welding. In a swivel frame of a construction machine having a cab lower beam joined to one of the side frames by welding,
A swing frame for a construction machine, wherein the front side plate portion of the cab lower beam is a front inclined plate portion having an arbitrary inclination.   The inclination of the front inclined plate portion of the cab lower beam is substantially the same as the inclination of the inclined plate portion of the front plate, and the front inclined plate portion of the cab lower beam is substantially the same plate surface as the inclined plate portion of the front plate. The turning frame for a construction machine according to claim 1, wherein:   The lower beam of the cab is composed of at least a front inclined plate portion and an upper plate portion, and a bent portion where the front inclined plate portion and the upper plate portion intersect each other substantially coincides with the inclined plate portion or the vertical plate portion of the front plate in a side view. The swing frame of the construction machine according to claim 1, wherein the swing frame is constructed as described above.

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