JP2011140854A - Revolving frame of construction machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress thermal strain of a bottom plate of a center frame and to enhance bonding strength of a beam to the center frame with simple constitution. <P>SOLUTION: A left front reinforcing plate 20 is disposed between a left edge part 13C of a bottom plate 13 and an intermediate part 19E of a left front beam 19. The left edge part 13C of the bottom plate 13 is welded to the left front reinforcing plate 20, and the intermediate part 19E of the left front beam 19 is welded to the left front reinforcing plate 20. The intermediate part 19E of the left front beam 19 is thereby supported by the left front reinforcing plate 20 to enhance bonding strength of the left front beam 19 and center frame 12. In this case, since the intermediate part 19E of the left front beam 19 is welded to the left front reinforcing plate 20 welded to the left edge part 13C of the bottom plate 13, heat transmitted to the bottom plate 13 when welding the left front beam 19 can be reduced to protect, from heat, a machined surface 13A1 or the like formed at a wide part 13A of the bottom plate 13. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a turning frame of a construction machine used for, for example, a hydraulic excavator, a hydraulic crane, or the like.

  In general, a hydraulic excavator as a construction machine includes a self-propelled lower traveling body, an upper revolving body that is rotatably mounted on the lower traveling body via a swirling wheel (bearing), and a front of the upper revolving body. It is roughly constituted by a working device provided on the part side. The upper swivel body has a swivel frame as a base, and a working device is provided on the front side of the swivel frame so as to be able to move up and down, and a weight balance with the work device is provided on the rear side of the swivel frame. A counterweight is provided. Further, a cab that defines a cab is provided on the left side of the front part of the swivel frame, and a building cover that accommodates a prime mover and the like is provided on the rear side of the cab.

  Here, the swivel frame of the construction machine is a center frame composed of a bottom plate and left and right vertical plates standing on the bottom plate, and is located on both the left and right sides of the center frame and extends in the front and rear directions. The left and right side frames are disposed between the center frame and the left and right side frames, and the left and right beams are joined to the center frame. It is configured. A flat machined surface with reduced surface roughness is usually formed on the lower surface side of the bottom plate constituting the center frame so that the outer ring of the large-diameter turning wheel comes into contact with the outer ring. A plurality of bolt holes (female screw holes) into which bolts for mounting are screwed are screwed.

  In this case, the swivel frame according to the prior art usually forms a machined surface by milling or the like on the lower surface side of the bottom plate after the left and right vertical plates are welded to the bottom plate serving as the base of the center frame. A center frame is formed by screwing a plurality of bolt holes along the processing surface.

  And after joining one end side of the left and right direction (length direction) of a plurality of beams provided between the center frame and the left side frame to the bottom plate and the left vertical plate of the center frame, respectively, A left side frame is joined to the other end of each beam in the left and right directions by welding, and the left and right ends of the plurality of beams provided between the center frame and the right side frame are connected to the center frame. After joining the bottom plate and the right vertical plate of each beam by welding, the right side frame is joined by welding to the other end in the left and right directions of each beam. As a result, a revolving frame that forms a strong support structure including the center frame, the left and right side frames, and the beams is manufactured.

  By the way, when manufacturing a swivel frame according to the prior art, normally, a flat machined surface and a plurality of bolt holes are formed on the lower surface side of the bottom plate of the center frame, and then the left and right vertical plates of the center frame are formed. A method of joining one end of each beam to the plate by welding is employed.

  For this reason, the heat generated when welding one end of each beam to the bottom plate of the center frame may cause thermal distortion (thermal deformation) on the machined surface and each bolt hole formed on the bottom plate. When the outer ring of the swivel ring is fastened to the bottom plate using bolts in a state where thermal strain is generated on the machined surface of the bottom plate and each bolt hole, the swivel ring is affected by the thermal strain generated on the bottom plate. Thus, there is a problem that the smooth turning operation of the upper turning body with respect to the lower traveling body is hindered.

  On the other hand, as a revolving frame of a construction machine according to the prior art, a box-shaped welding deformation prevention structure is joined to the upper surface side of a bottom plate (lower plate) constituting a center frame (center frame) by welding, and then the bottom plate There has been proposed a swivel frame having a configuration in which a machined surface is formed on the lower surface side (see, for example, Patent Document 1).

  And the turning frame by patent document 1 welds the one end side of a beam (horizontal frame) to the welding deformation prevention structure joined to the upper surface side of the bottom plate, and the heat at the time of this welding is directly transmitted to a bottom plate. Can be suppressed, and thermal deformation of the bottom plate can be prevented.

  In addition, as a revolving frame according to another conventional technique, a reinforcing material is welded to the lower surface of the side deck welded to the vertical plate of the center frame (center section), and the side deck is welded to the vertical plate and the end of the bottom plate is reinforced. A swivel frame configured to be welded to a material has been proposed (see, for example, Patent Document 2).

  And even if the end of the bottom plate is thermally deformed so that the end of the bottom plate is lifted upward when the standing plate is welded, the swing frame according to Patent Document 2 can join the side deck to the center frame in a horizontal state, and The load acting on the deck can be supported by the bottom plate via the reinforcing material.

JP 2007-32262 A JP-A-11-256614

  However, the swivel frame according to Patent Document 1 has a structure in which a welding deformation prevention structure having a box shape is joined to the upper surface side of the bottom plate by welding. There is a problem that the weight also increases. Further, since the bottom plate generates a large thermal strain due to heat generated when welding the weld deformation prevention structure, the machining range when forming a machined surface by milling on the lower surface side of the bottom plate is increased. There is a problem that the workability when forming the film is lowered.

  On the other hand, the swivel frame according to Patent Document 2 has a structure in which the abutting portion between the end portion of the bottom plate and the reinforcing material is joined by welding in a state where the reinforcing material is previously welded to the lower surface of the side deck. When the end of the bottom plate is thermally deformed by the heat when welding, the interval between the end of the bottom plate and the reinforcing material welded to the side deck changes according to the degree of this thermal deformation, It becomes difficult to reliably weld the two. As a result, there is a problem that a sufficient bonding strength of the beam to the center frame cannot be obtained.

  The present invention has been made in view of the above-described problems of the prior art, and can suppress the thermal distortion of the bottom plate of the center frame and can increase the bonding strength of the beam to the center frame with a simple configuration. The object is to provide a swivel frame of the machine.

  In order to solve the above-described problems, the present invention is mounted on a self-propelled traveling body, and includes a center frame including a bottom plate and left and right vertical plates erected on the bottom plate, and a left side of the center frame, Left and right side frames disposed on both right sides and extending in the front and rear directions, and provided between the center frame and the left and right side frames, respectively, with respect to the center frame. This is applied to a turning frame of a construction machine having left and right beams for joining the side frames.

  A feature of the invention of claim 1 is that the beam is welded at one end side in the left and right directions to the vertical plate of the center frame and at the other end side in the left and right directions to the side frame. In addition, between the left and right edge portions of the bottom plate of the center frame and the left and right halfway portions of the beam, a reinforcing plate that supports the left and right halfway portions of the beam is disposed above, It is arranged to extend downward, and welds the edge portion of the bottom plate of the center frame and the reinforcing plate, and welds the reinforcing plate and the intermediate portion in the left and right directions of the beam. is there.

  According to a second aspect of the present invention, a plurality of the beams are provided between the center frame and the side frame so as to be separated from each other in the front and rear directions, and the reinforcing plate is provided between an intermediate portion of each beam and a bottom plate of the center frame. That is, it is composed of a plurality of reinforcing plates that are individually welded to the edge portion.

  According to a third aspect of the present invention, a plurality of the beams are provided between the center frame and the side frame so as to be separated from each other in the front and rear directions, and the reinforcing plate is provided at the left of two beams adjacent in the front and rear directions. , It is constituted by a single reinforcing plate welded to the middle part in the right direction and the edge of the bottom plate of the center frame.

  According to a fourth aspect of the present invention, the beam includes a horizontal beam portion extending in the left and right directions with one end facing the bottom plate in the upward and downward directions, and a vertical beam portion extending from the horizontal beam portion toward the bottom plate side. In the vertical beam portion of the beam, a through hole is provided between the vertical plate and the reinforcing plate and penetrates in the front and rear directions.

  The invention of claim 5 is mounted on a self-propelled traveling body and comprises a center frame comprising a bottom plate and left and right vertical plates standing on the bottom plate, and positions on both the left and right sides of the center frame. The left and right side frames are provided between the center frame and the left and right side frames, respectively. In a turning frame of a construction machine comprising left and right beams to be joined, the beams are welded at one end side in the left and right directions to the vertical plate of the center frame and at the other end side in the left and right directions. The side frame is welded, and a reinforcing plate that supports one end of the beam extends left and right between the vertical plate of the center frame and one end of the beam in the left and right directions. And place the center Is welded vertical plate arm and the said reinforcing plate, the left of the said reinforcing plate beam is characterized in that a configuration of welding the one end side of the right direction.

  According to the first aspect of the present invention, the left and right ends of the beam are welded to the vertical plate of the center frame, and the reinforcing plate welded to the edge of the bottom plate of the center frame and the left and right directions of the beam. By welding the intermediate portion, the intermediate portion in the left and right directions of the beam can be supported by the reinforcing plate, and the beam can be reliably bonded to the center frame. In this case, the reinforcing plate that supports the left and right part of the beam in the left and right direction is welded to the left and right edge portions of the bottom plate, so that the heat when welding this reinforcing plate is applied to the lower surface side of the bottom plate. It is possible to suppress transmission. Therefore, for example, even when the beam is welded to the center frame after forming the machined surface on the lower surface side of the bottom plate, the machined surface of the bottom plate can be reliably prevented from causing thermal distortion. Can be protected.

  Also, since the beam is welded to the vertical plate at one end in the left and right directions, and the intermediate portion in the left and right directions is welded to the reinforcing plate, it is possible to increase the bonding strength of the beam to the center frame. The strength of the entire turning frame including the frame, the left and right side frames, and each beam can be ensured. In addition, by supporting the left and right intermediate portions of the beam with the reinforcing plate welded to the edge of the bottom plate, it is possible to contribute to the simplification and weight reduction of the entire revolving frame.

  According to the invention of claim 2, a reinforcing plate is prepared for each of a plurality of beams provided between the center frame and the side frame, and the plurality of reinforcing plates are provided in the middle of the left and right directions of each beam. The welding strength of each beam with respect to the center frame can be increased by welding the part and the edge of the bottom plate individually.

  According to the third aspect of the present invention, one reinforcing plate welded to the edge of the bottom plate can be welded to the middle portions of the two beams adjacent in the front and rear directions. In this case, a rectangular frame-like body is formed by the bottom plate and the vertical plate of the center frame, the two beams adjacent in the front and rear directions, and the reinforcing plate, so that the bonding strength of each beam to the center frame is further increased. Can be increased. In addition, by using one reinforcing plate for two adjacent beams, the number of parts can be reduced and the configuration can be simplified.

  According to the invention of claim 4, by providing a through-hole penetrating in the front and rear directions in the vertical beam portion of the beam that joins between the center frame and the side frame, The connected hydraulic hose or the like can be routed in a state where it is extended forward and backward through the through hole. In this case, since the through hole is provided between the vertical plate and the reinforcing plate in the vertical beam portion, the strength of the beam having the through hole can be maintained.

  According to the invention of claim 5, one end of the beam is welded to the vertical plate of the center frame and welded to the reinforcing plate welded to the vertical plate of the center frame. The side can be supported by the reinforcing plate, and the beam can be reliably bonded to the center frame. In this case, by welding the reinforcing plate that supports one end of the beam to the vertical plate, it is possible to suppress the transfer of heat when welding the reinforcing plate to the lower surface side of the bottom plate. The formed machined surface can be protected.

It is a front view which shows the hydraulic shovel provided with the turning frame by the 1st Embodiment of this invention. It is a perspective view which shows the turning frame by 1st Embodiment. FIG. 3 is a plan view of an enlarged main part when a bottom plate, a left vertical plate, a left front beam, a left rear beam, a left front reinforcing plate, a left rear reinforcing plate and the like in FIG. 2 are viewed from above. FIG. 4 is a cross-sectional view of a bottom plate, a left vertical plate, a left front beam, a left rear beam, a left front reinforcing plate, and a left rear reinforcing plate viewed from the direction of arrows IV-IV in FIG. 3. It is sectional drawing which looked at the bottom board, the left vertical board, the left front beam, and the left front reinforcement board from the arrow VV direction in FIG. It is sectional drawing which looked at the bottom board, the left vertical board, the left back beam, and the left back reinforcing board from the arrow VI-VI direction in FIG. It is a perspective view which shows a left front reinforcement board alone. It is a perspective view which shows a left back reinforcement board alone. It is a perspective view which shows the turning frame by 2nd Embodiment. It is sectional drawing which looked at the bottom plate, the left vertical plate, the left front beam, the left rear beam, and the left reinforcing plate from the direction of arrows XX in FIG. It is sectional drawing which looked at the bottom board, the left vertical board, the left front beam, and the left reinforcement board from the arrow XI-XI direction in FIG. It is a perspective view which shows the turning frame by 3rd Embodiment. It is sectional drawing similar to FIG. 5 which looked at the bottom board, the left vertical board, the left front beam, the left front reinforcement board, etc. from the arrow XIII-XIII direction in FIG. It is sectional drawing similar to FIG. 6 which looked at the bottom board, the left vertical board, the left rear beam, the left rear reinforcement board, etc. from the arrow XIV-XIV direction in FIG. It is a perspective view which shows the turning frame by 4th Embodiment. It is sectional drawing which looked at the bottom plate, the left vertical plate, the left front beam, the left rear beam, the left front reinforcing plate, and the left rear reinforcing plate from the arrow XVI-XVI direction in FIG. It is sectional drawing which looked at the bottom board, the left vertical board, the left front beam, and the left front reinforcement board from the arrow XVII-XVII direction in FIG. It is sectional drawing which looked at the bottom board, the left vertical board, the left front beam, and the left rear reinforcement board from the arrow XVIII-XVIII direction in FIG. It is a perspective view which shows a left front reinforcement board alone. It is sectional drawing similar to FIG. 5 which shows the welding part of the left front reinforcement board and bottom board by a 1st modification. It is sectional drawing similar to FIG. 5 which shows the welding part of the left front reinforcement board and bottom board by a 2nd modification.

  Hereinafter, an embodiment of a turning frame for a construction machine according to the present invention will be described in detail with reference to the accompanying drawings, taking as an example a case where it is applied to a hydraulic excavator.

  1 to 8 show a first embodiment of the present invention. In the figure, reference numeral 1 denotes a hydraulic excavator, which is a typical example of a construction machine. The hydraulic excavator 1 turns on a self-propelled crawler-type lower traveling body 2 and a swiveling wheel 3 on the lower traveling body 2. The upper revolving body 4 that can be mounted is generally configured. And the working device 5 which performs excavation work, such as earth and sand, is provided in the front part side of the upper revolving body 4 so that a vertical movement is possible.

  Here, the upper swing body 4 is disposed on a swing frame 11 (to be described later), a counterweight 6 provided on the rear end side of the swing frame 11 to balance the weight of the working device 5, and a front side of the counterweight 6. The building cover 7 accommodates an engine, a hydraulic pump, etc. (none of which are shown), and a cab 8 that is disposed on the left side of the front portion of the swivel frame 11 and defines a driver's cab.

  In addition, the working device 5 includes a boom 5A whose base end is rotatably attached to a turning frame 11 described later, an arm 5B rotatably attached to the distal end of the boom 5A, and a tip of the arm 5B. The bucket 5C is pivotally attached to the side, a boom cylinder 5D composed of a hydraulic cylinder, an arm cylinder 5E, and a bucket cylinder 5F.

  Reference numeral 11 denotes a turning frame as a vehicle body frame. The turning frame 11 is a base of the upper turning body 4. 2 to 4, the revolving frame 11 includes a center frame 12, a left side frame 17, a left front beam 19, a left front reinforcing plate 20, a left rear beam 24, a left rear reinforcing plate 25, a right side, which will be described later. The frame 29, each right beam 30 and the like constitute a strong support structure.

  Reference numeral 12 denotes a center frame that constitutes a central portion of the revolving frame 11. The center frame 12 is formed in a flat plate shape using a thick steel plate or the like, and extends in the front and rear directions, and an upper surface of the bottom plate 13. The left vertical plate 14 and the right vertical plate 15 which are provided upright by means of welding or the like and extend forward and backward while maintaining a constant interval in the left and right directions. Further, the front plate side of the left vertical plate 14 (boom bracket portion 14A side) and the front side of the right vertical plate 15 (boom bracket portion 15A side) are reinforced by a vertical plate reinforcing plate 16 joined to both. Has been.

  Here, the front side of the bottom plate 13 is a wide portion 13A which is wider in the left and right directions than the rear side, and the outer ring of the swivel wheel 3 shown in FIG. Is fixed using a large number of bolts. For this reason, the lower surface side of the wide portion 13A of the bottom plate 13 is a flat machined surface 13A1 in which the surface roughness is suppressed by milling or the like and the outer ring of the swivel wheel 3 abuts. Further, the wide portion 13A of the bottom plate 13 has a large number of bolt holes (internal screw holes) 13B into which bolts for fixing the outer ring of the swivel ring 3 are screwed. It is formed in an annular shape penetrating in the direction. Further, a left front reinforcing plate 20 and a left rear reinforcing plate 25, which will be described later, are fixed to a left end edge portion 13C facing the left side frame 17 described later in the wide portion 13A by welding.

  On the other hand, the front side of the left vertical plate 14 and the right vertical plate 15 are boom bracket portions 14A and 15A raised in a mountain shape, respectively, and the left and right boom bracket portions 14A and 15A have the work shown in FIG. The base end side of the boom 5A of the device 5 is configured to be pin-coupled so as to be rotatable. The rear side of the left and right vertical plates 14 and 15 has an I-shaped cross section and extends rearward from the boom bracket portions 14A and 15A. The rear end sides of the left and right vertical plates 14 and 15 are These are weight attaching portions 14B and 15B to which the counterweight 6 shown in FIG. 1 is attached. Further, the outer side surface of the left vertical plate 14 facing the left side frame 17 is a beam joining surface 14C to which a left front beam 19, a left rear beam 24 and the like which will be described later are joined.

  Here, the center frame 12 is formed by welding the left and right vertical plates 14 and 15 to the upper surface side of the bottom plate 13 by welding, and the left and right vertical plates 14 and 15 are usually welded to the bottom plate 13. Later, a plurality of bolt holes 13 </ b> B are formed in the wide portion 13 </ b> A of the bottom plate 13. Thereby, it becomes the structure which can suppress that the machining surface 13A1 and the bolt hole 13B which are the lower surfaces of 13 A of wide parts generate | occur | produce a thermal strain by the heat | fever at the time of welding operation.

  Reference numeral 17 denotes a left side frame arranged on one side (left side) in the left and right directions with the center frame 12 interposed therebetween. Here, the left side frame 17 and a right side frame 29 to be described later are formed using, for example, a D-shaped frame made of a cylindrical body having a D-shaped cross section, and extend forward and rearward along the center frame 12. . The left side frame 17 is attached to the left side of the center frame 12 via a cab support frame 18, a left front beam 19, a left rear beam 24 and the like which will be described later.

  Reference numeral 18 denotes a cab support frame that connects the front end side of the left side frame 17 and the center frame 12, and the cab support frame 18 supports the cab 8 shown in FIG. Is. Here, the cab support frame 18 includes a rectangular tube-shaped vertical frame member 18A extending in the front and rear directions along the left vertical plate 14, a front end portion of the vertical frame member 18A, and a front end portion of the left side frame 17. It is formed in a substantially L shape by a horizontal frame member 18B joined by welding and extending in the left and right directions. The rear end portion of the vertical frame member 18A is joined to the left front beam 19 described later by welding, and the left end portion of the horizontal frame member 18B is joined to the front end side of the left side frame 17 by welding.

  Reference numeral 19 denotes a left front beam located between the center frame 12 and the left side frame 17 at the rear side of the cab support frame 18, and the left front beam 19 together with a left rear beam 24 described later and the like. On the other hand, the left side frame 17 is joined.

  Here, the left front beam 19 is formed as a plate-like body extending in the left and right directions with an L-shaped cross-sectional shape, for example, by bending a steel plate material, and one end side is in the upward and downward direction with the bottom plate 13. It is comprised by the horizontal beam part 19A extended in the left and right direction in the facing state, and the vertical beam part 19B bent toward the bottom board 13 from the front-end side of this horizontal beam part 19A (refer FIG. 4).

  Then, one end side 19C in the left and right direction (length direction) of the left front beam 19 is welded to the beam joining surface 14C of the left vertical plate 14, and the other end side 19D in the left and right direction of the left front beam 19 is left. It is welded to the side frame 17. Further, a middle portion 19E in the left and right directions of the left front beam 19 is welded to a left front reinforcing plate 20 described later.

  Reference numeral 20 denotes a left front reinforcing plate provided between the left end edge portion 13C of the wide width portion 13A constituting the bottom plate 13 and the left and right intermediate portions 19E of the left front beam 19. The middle part 19E of the left front beam 19 refers to a part (intermediate part) between the one end side 19C and the other end side 19D. The left front reinforcing plate 20 supports the left and right halfway portions 19E of the left front beam 19, and is welded to the left end edge 13C of the bottom plate 13, and the left front beam 19 halfway portions in the left and right directions. It is welded to 19E.

  Here, as shown in FIGS. 4, 5, and 7, the left front reinforcing plate 20 is a sheet having an upper edge portion 20 </ b> A, a lower edge portion 20 </ b> B, a front edge portion 20 </ b> C, and a rear edge portion 20 </ b> D using a steel plate or the like. It is formed in a rectangular flat plate shape. The left front reinforcing plate 20 is in contact with the left end edge portion 13C of the left vertical plate 14 with the inner side surface 20E facing the beam joining surface 14C contacting the left end edge portion 13C of the bottom plate 13 (wide portion 13A). Welded.

  As a result, a lower weld portion 21 extending in the front and rear directions along the lower edge portion 20B is formed between the left end edge portion 13C of the bottom plate 13 and the lower edge portion 20B of the left front reinforcing plate 20, and this lower weld The left front reinforcing plate 20 joined to the left end edge 13C of the bottom plate 13 by the portion 21 extends upward and downward from the bottom plate 13 upward. Thus, since the left front reinforcing plate 20 is welded to the left end edge portion 13C of the bottom plate 13, the range in which heat at the time of welding is transmitted to the bottom plate 13 can be reduced, and the machining surface 13A1 formed on the bottom plate 13 can be reduced. In addition, the heat distortion of the bolt holes 13B and the like can be suppressed.

  On the other hand, the lower surface of the lateral beam portion 19A constituting the left front beam 19 is welded to the upper edge portion 20A of the left front reinforcing plate 20 rising upward from the bottom plate 13, and the left front beam is connected to the front edge portion 20C of the left front reinforcing plate 20. The rear surface of the vertical beam portion 19B constituting 19 is welded. Thereby, between the horizontal beam portion 19A of the left front beam 19 and the upper edge portion 20A of the left front reinforcing plate 20, the upper welded portion 22 extending in the front and rear directions along the upper edge portion 20A is attached to the left front reinforcing plate 20. It is formed on both the left and right sides. Further, between the vertical beam portion 19B of the left front beam 19 and the front edge portion 20C of the left front reinforcing plate 20, a vertical welded portion 23 extending upward and downward along the front edge portion 20C is attached to the left front reinforcing plate 20. It is formed on both the left and right sides.

  Reference numeral 24 denotes a left rear beam that is located between the center frame 12 and the left side frame 17 and is located behind the left front beam 19. The left rear beam 24 is connected to the center frame 12 together with the left front beam 19 and the like. The left side frame 17 is joined.

  Here, similarly to the left front beam 19, the left rear beam 24 is also formed as a plate-like body extending in the left and right directions with an L-shaped cross-sectional shape by the horizontal beam portion 24A and the vertical beam portion 24B. Then, one end side 24C in the left and right direction (length direction) of the left rear beam 24 is welded to the beam joining surface 14C of the left vertical plate 14, and the other end side 24D in the left and right direction of the left rear beam 24 is The left side frame 17 is welded. Further, a middle portion 24E in the left and right directions of the left rear beam 24 is welded to a left rear reinforcing plate 25 described later.

  Reference numeral 25 denotes a left rear reinforcing plate which is located on the rear side of the left front reinforcing plate 20 and is provided between the left end edge portion 13C of the bottom plate 13 (wide portion 13A) and the left and right intermediate portions 24E of the left rear beam 24. Is shown. The middle part 24E of the left rear beam 24 refers to a part (intermediate part) between the one end side 24C and the other end side 24D. The left rear reinforcing plate 25 supports the left and right intermediate portions 24E of the left rear beam 24, and is welded to the left end edge portion 13C of the bottom plate 13, and the left rear beam 24 has left and right directions. It is welded to the middle part 24E.

  Here, the left rear reinforcing plate 25 has an upper edge portion 25A, a lower edge portion 25B, a front edge portion 25C, and a rear edge portion 25D, as shown in FIGS. 4, 6, and 8. It is formed into a single rectangular flat plate with a small length in the front and rear directions. The left rear reinforcing plate 25 is welded to the left end edge portion 13C with the inner side surface 25E facing the beam joining surface 14C of the left vertical plate 14 in contact with the left end edge portion 13C of the bottom plate 13. .

  Thereby, a lower welded portion 26 extending in the front and rear directions along the lower edge portion 25B is formed between the left end edge portion 13C of the bottom plate 13 and the lower edge portion 25B of the left rear reinforcing plate 25. The left rear reinforcing plate 25 joined to the left end edge portion 13C of the bottom plate 13 by the welded portion 26 extends upward and downward from the bottom plate 13 upward. In this way, the left rear reinforcing plate 25 is also welded to the left end edge portion 13C of the bottom plate 13 to suppress heat from being transmitted to the bottom plate 13 when the left rear reinforcing plate 25 is welded. The configuration is such that thermal distortion of the machined surface 13A1 or the like can be suppressed.

  Then, the lower surface of the transverse beam portion 24A of the left rear beam 24 is welded to the upper edge portion 25A of the left rear reinforcing plate 25 rising upward from the bottom plate 13, and the left edge of the left rear reinforcing plate 25 is The rear surface of the vertical beam portion 24B of the rear beam 24 is welded. As a result, an upper welded portion 27 extending in the front and rear directions along the upper edge portion 25A is provided between the horizontal beam portion 24A of the left rear beam 24 and the upper edge portion 25A of the left rear reinforcing plate 25. It is formed on both the left and right sides of the plate 25. Further, a vertical welded portion 28 extending upward and downward along the front edge portion 25C is provided between the vertical beam portion 24B of the left rear beam 24 and the front edge portion 25C of the left rear reinforcing plate 25. It is formed on both the left and right sides of the plate 25.

  Reference numeral 29 denotes a right side frame disposed on the other side (right side) in the left and right directions with the center frame 12 interposed therebetween. The right side frame 29 uses, for example, a D-shaped frame made of a cylindrical body having a D-shaped cross section. And extends forward and rearward along the center frame 12. The right side frame 29 is attached to the right side of the center frame 12 via respective right beams 30, 31, 32 and the like which will be described later.

  Reference numerals 30, 31, and 32 indicate a right front beam, a right intermediate beam, and a right rear beam provided between the right vertical plate 15 and the right side frame 29 of the center frame 12. Each of these beams 30, 31, and 32 is disposed at an appropriate interval in the front and rear directions, and joins the right side frame 29 to the center frame 12. Here, the right front beam 30, the right intermediate beam 31, and the right rear beam 32 are formed, for example, by bending a steel plate material, and one end side (left end side) in the left and right directions is the right vertical direction of the center frame 12. While being welded to the plate 15 respectively, the other end side (right end side) in the left and right directions is welded to the right side frame 29, respectively.

  The left front and right intermediate beams 31, and the right rear beam 32 are formed in substantially the same plate as the left front reinforcing plate 20 between the left and right intermediate portions and the right edge of the bottom plate 13. Three right reinforcing plates (not shown) are respectively disposed, and these right reinforcing plates are welded to the left and right intermediate portions of the beams 30, 31, 32 and the right edge of the bottom plate 13, respectively. As a result, the intermediate portions of these beams 30, 31, 32 are supported.

  The revolving frame 11 according to the present embodiment has the above-described configuration. According to this revolving frame 11, the left front reinforcing plate 20 is disposed between the left end edge portion 13C of the bottom plate 13 and the middle portion 19E of the left front beam 19. The left end edge portion 13C of the bottom plate 13 and the left front reinforcing plate 20 are welded, and the middle portion 19E of the left front beam 19 and the left front reinforcing plate 20 are welded. As a result, an intermediate portion 19E of the left front beam 19 whose one end side 19C in the left and right directions is welded to the left vertical plate 14 of the center frame 12 can be supported by the left front reinforcing plate 20, and the left front beam 19 and the center frame can be supported. The bonding strength with 12 can be increased.

  Further, the left rear reinforcing plate 25 is disposed between the left end edge portion 13C of the bottom plate 13 and the middle portion 24E of the left rear beam 24, and the left end edge portion 13C of the bottom plate 13 and the left rear reinforcing plate 25 are welded, The middle part 24E of the left rear beam 24 and the left rear reinforcing plate 25 are welded. Accordingly, the left rear reinforcing plate 25 can support the middle portion 24E of the left rear beam 24 whose one end side 24C in the left and right directions is welded to the left vertical plate 14 of the center frame 12, and the left rear beam 24 can be supported. And the center frame 12 can be increased in bonding strength.

  In this case, the middle portion 19E of the left front beam 19 is not directly welded to the bottom plate 13 of the center frame 12, but is welded to the left front reinforcing plate 20 welded to the left end edge portion 13C of the bottom plate 13. Further, the middle portion 24E of the left rear beam 24 is also not directly welded to the bottom plate 13 of the center frame 12, but is welded to the left rear reinforcing plate 25 welded to the left end edge portion 13C of the bottom plate 13. For this reason, heat transmitted to the bottom plate 13 when the left front beam 19 and the left rear beam 24 are welded to the center frame 12 can be reduced. As a result, when the left front beam 19 and the left rear beam 24 are welded to the machined surface 13A1, the bolt hole 13B, etc. formed in the wide portion 13A of the bottom plate 13 before the left front beam 19 and the left rear beam 24 are welded. It is possible to reliably prevent thermal distortion from being caused by the heat, and the swivel wheel 3 attached to the machined surface 13A1 of the bottom plate 13 can be smoothly rotated.

  Moreover, the left front reinforcing plate 20 that supports the middle portion 19E of the left front beam 19 and the left rear reinforcing plate 25 that supports the middle portion 24E of the left rear beam 24 are welded to the left end edge 13C of the bottom plate 13, respectively. Since it consists of a sheet | seat body, it can contribute also to simplification of the structure of the whole turning frame 11, and weight reduction.

  Next, FIGS. 9 to 11 show a second embodiment of the present invention. The feature of the present embodiment is that the left and right intermediate portions and the bottom plate of two beams adjacent in the front and rear directions are shown. In other words, one reinforcing plate is provided between the end edge portions of the two. In the present embodiment, the same components as those in the first embodiment described above are denoted by the same reference numerals, and the description thereof is omitted.

  In the figure, reference numeral 41 denotes a revolving frame according to the second embodiment. The revolving frame 41 is substantially the same as the revolving frame 11 according to the first embodiment, and the center frame 12, the left side frame 17, and the left front beam 19. The left rear beam 24, the right side frame 29, each right beam 30 and the like, but the first left beam reinforcing plate 42 described later is provided between the left front beam 19 and the left rear beam 24. This is different from the turning frame 11 according to the embodiment.

  Reference numeral 42 denotes a left beam reinforcing plate disposed between the left front beam 19 and the left rear beam 24 adjacent in the front and rear directions. The left beam reinforcing plate 42 supports the left and right intermediate portions 19E of the left front beam 19 and the left and right intermediate portions 24E of the left rear beam 24, and is welded to the left end edge 13C of the bottom plate 13. At the same time, it is welded to the middle part 19E of the left front beam 19 and the middle part 24E of the left rear beam 24.

  Here, the left beam reinforcing plate 42 is formed into a single rectangular flat plate extending in the front and rear directions using a steel plate or the like, and includes an upper edge portion 42A, a lower edge portion 42B, a front edge portion 42C, and a rear edge portion. 42D. The left beam reinforcing plate 42 is in a state where the inner side surface 42E facing the beam joining surface 14C of the left vertical plate 14 is in contact with the left end edge portion 13C of the bottom plate 13 (wide portion 13A). It is welded to.

  As a result, a lower weld 43 is formed between the left end edge 13C of the bottom plate 13 and the lower edge 42B of the left beam reinforcing plate 42 so as to extend forward and rearward along the lower edge 42B. The left beam reinforcing plate 42 joined to the left end edge portion 13 </ b> C of the bottom plate 13 by the welded portion 43 rises upward from the bottom plate 13.

  Then, the lower surface of the lateral beam portion 19A constituting the left front beam 19 is welded to the upper edge portion 42A of the left beam reinforcing plate 42 rising upward from the bottom plate 13, and the left front portion is connected to the front edge portion 42C of the left beam reinforcing plate 42. The rear surface of the vertical beam portion 19B constituting the beam 19 is welded, and the front surface of the vertical beam portion 24B constituting the left rear beam 24 is welded to the rear edge portion 42D of the left beam reinforcing plate 42.

  As a result, an upper welded portion 44 extending forward and rearward along the upper edge portion 42A is provided between the horizontal beam portion 19A of the left front beam 19 and the upper edge portion 42A of the left beam reinforcing plate 42. 42 on both left and right sides. Further, a front vertical welded portion 45 extending upward and downward along the front edge portion 42C is provided between the vertical beam portion 19B of the left front beam 19 and the front edge portion 42C of the left beam reinforcing plate 42. The plate 42 is formed on both the left and right sides. Further, a rear vertical welded portion 46 extending upward and downward along the rear edge portion 42D is provided between the vertical beam portion 24B of the left rear beam 24 and the rear edge portion 42D of the left beam reinforcing plate 42. It is formed on both the left and right sides with the beam reinforcing plate 42 in between.

  As described above, the left beam reinforcing plate 42 according to the present embodiment configures the center frame 12 with the left and right intermediate portions 19E of the left front beam 19 and the left and right intermediate portions 24E of the left rear beam 24. By being welded to the left end edge portion 13C of the bottom plate 13, the middle portion 19E of the left front beam 19 and the middle portion 24E of the left rear beam 24 that are adjacent in the front and rear directions are supported simultaneously. Yes. In this case, since the left beam reinforcing plate 42 is welded to the left end edge portion 13C of the bottom plate 13, the thermal distortion of the machined surface 13A1 and the bolt hole 13B formed on the bottom plate 13 can be suppressed. .

  The turning frame 41 according to the second embodiment has the left beam reinforcing plate 42 as described above, and the basic operation thereof is not particularly different from that of the above-described first embodiment.

  However, according to the second embodiment, the left and right end portions 19C are welded to the left vertical plate 14, the middle portion 19E of the left front beam 19, and the left and right end portions 24C are the left vertical plate. 14, one left beam reinforcing plate 42 is welded to the middle portion 24 </ b> E of the left rear beam 24 welded to 14 and the left end edge 13 </ b> C of the bottom plate 13. Thus, a rectangular frame-like body welded to each other can be formed by the bottom plate 13 and the left vertical plate 14 of the center frame 12, the left front beam 19, the left rear beam 24, and the left beam reinforcing plate 42. Therefore, the joint strength of the left front beam 19 and the left rear beam 24 with respect to the center frame 12 can be further increased.

  Further, a single left beam reinforcing plate 42 is welded to the middle portion 19E of the left front beam 19, the middle portion 24E of the left rear beam 24, and the left end edge portion 13C of the bottom plate 13, so that the middle of the left front beam 19 is reached. Since the part 19E and the middle part 24E of the left rear beam 24 can be supported at the same time, the number of parts of the turning frame 41 can be reduced, and the configuration can be simplified.

  Next, FIG. 12 to FIG. 14 show a third embodiment of the present invention, and the feature of this embodiment is that a through-hole penetrating in the front and rear directions is provided in the vertical beam portion of the beam. It is in. In the present embodiment, the same components as those in the first embodiment described above are denoted by the same reference numerals, and the description thereof is omitted.

  In the figure, reference numeral 51 denotes a turning frame according to the third embodiment. The turning frame 51 is substantially the same as the turning frame 11 according to the first embodiment. Although the beam 52, the left front reinforcing plate 20, the left rear beam 53, which will be described later, the left rear reinforcing plate 25, the right side frame 29, the right beams 30, and the like, the shapes of the left front beam 52 and the left rear beam 53 are The left front beam 19 and the left rear beam 24 according to the first embodiment are different.

  Reference numeral 52 denotes a left front beam positioned between the center frame 12 and the left side frame 17 and located on the rear side of the cab support frame 18. The left front beam 52 is replaced with the left front beam 19 according to the first embodiment. Used in the third embodiment.

  Here, like the left front beam 19 according to the first embodiment, the left front beam 52 is formed as a plate-like body extending in the left and right directions with an L-shaped cross-sectional shape, and one end side is above and below the bottom plate 13. The horizontal beam portion 52A extends in the left and right directions while facing each other, and the vertical beam portion 52B is bent toward the bottom plate 13 from the front end side of the horizontal beam portion 52A. The left and right one end sides 52C of the left front beam 52 are welded to the beam joining surface 14C of the left vertical plate 14, and the left and right other end sides 52D of the left front beam 52 are welded to the left side frame 17. An intermediate portion 52E in the left and right direction of the left front beam 52 is welded to the left front reinforcing plate 20.

  Further, in the vertical beam portion 52B of the left front beam 52, a rectangular square hole extending in the left and right directions is formed between the left vertical plate 14 and the left front reinforcing plate 20, and penetrates in the front and rear directions. A hole 52F is formed.

  A left rear beam 53 is located between the center frame 12 and the left side frame 17 and is located behind the left front beam 52. The left rear beam 53 is the left rear beam 24 according to the first embodiment. Instead of this, it is used in the third embodiment.

  Here, the left rear beam 53 is formed as a plate-like body having an L-shaped cross section having a horizontal beam portion 53A and a vertical beam portion 53B, like the left rear beam 24 according to the first embodiment. Extending in the direction. The left and right one end sides 53C of the left rear beam 53 are welded to the beam joining surface 14C of the left vertical plate 14, and the left and right other end sides 53D of the left rear beam 53 are welded to the left side frame 17. Then, the left and right intermediate portions 53E of the left rear beam 53 are welded to the left rear reinforcing plate 25.

  Further, in the vertical beam portion 53B of the left rear beam 53, a rectangular square hole extending in the left and right directions is formed between the left vertical plate 14 and the left rear reinforcing plate 25 and penetrates in the front and rear directions. A through-hole 53F is formed.

  As a result, a hydraulic hose (both not shown) for supplying and discharging pressure oil to and from the hydraulic actuator mounted on the turning frame 51 is provided in the through hole 52F provided in the left front beam 52 and the through hole provided in the left rear beam 53. It is the structure which can be extended and extended through the hole 53F to the front and back.

  The turning frame 51 according to the third embodiment has the left front beam 52 and the left rear beam 53 as described above, and the basic operation thereof is not particularly different from that of the first embodiment.

  However, according to the third embodiment, the through hole 52F is provided in the vertical beam portion 52B of the left front beam 52, and the through hole 53F is provided in the vertical beam portion 53B of the left rear beam 53. A hydraulic hose (both not shown) for supplying and discharging pressure oil to and from the hydraulic actuator mounted on the front 51 through the through hole 52F provided in the left front beam 52 and the through hole 53F provided in the left rear beam 53, It is possible to perform the routing by extending in the rear direction, and the routing work of the hydraulic hose can be easily performed.

  In this case, since the through hole 52F of the left front beam 52 is provided between the left vertical plate 14 and the left front reinforcing plate 20 in the vertical beam portion 52B, the strength of the left front beam 52 having the through hole 52F can be maintained. it can. Further, since the through hole 53F of the left rear beam 53 is provided between the left vertical plate 14 and the left rear reinforcing plate 25 in the vertical beam portion 53B, the strength of the left rear beam 53 having the through hole 53F is maintained. be able to.

  Next, FIGS. 15 to 19 show a fourth embodiment of the present invention. The feature of the present embodiment is that the center frame has a vertical plate and one end side in the left and right directions of the beam. The reinforcing plate for supporting the one end side of the beam is provided. In the present embodiment, the same components as those in the first embodiment described above are denoted by the same reference numerals, and the description thereof is omitted.

  In the figure, reference numeral 61 denotes a revolving frame according to the fourth embodiment. The revolving frame 61 is substantially the same as the revolving frame 11 according to the first embodiment, and the center frame 12, the left side frame 17, and the left front beam 19. The left rear beam 24, the right side frame 29, each right beam 30 and the like, but the left front reinforcing plate 62, which will be described later, is disposed between the left vertical plate 14 constituting the center frame 12 and one end side 19C of the left front beam 19. And a left rear reinforcing plate 65 described later is provided between the left vertical plate 14 and one end side 24C of the left rear beam 24, which is different from the revolving frame 11 according to the first embodiment.

  Reference numeral 62 denotes a left front reinforcing plate provided between the left vertical plate 14 of the center frame 12 and one end side 19C in the left and right directions of the left front beam 19. The left front reinforcing plate 62 is provided on the left and right sides of the left front beam 19. One end side 19C of the direction is supported and welded to the beam joining surface 14C of the left vertical plate 14 and welded to one end side 19C of the left front beam 19.

  Here, the left front reinforcing plate 62 is formed in a single triangular flat plate shape having an upper edge portion 62A, a lower edge portion 62B, and a right end edge portion 62C using a steel plate or the like, and extends in the left and right directions. The left front reinforcing plate 62 is welded to the beam joining surface 14C of the left vertical plate 14 at the right end edge 62C facing the left vertical plate 14, and extends left and right from the beam joining surface 14C. . Thereby, between the right end edge 62C of the left front reinforcing plate 62 and the beam joining surface 14C of the left vertical plate 14, a vertical welded portion 63 extending upward and downward along the right end edge 62C is provided. It is formed on both the front and rear sides across 62.

  Then, the lower surface of the left beam 19 A of the left front beam 19 is welded to the upper edge 62 A of the left front reinforcing plate 62 that protrudes left and right from the beam joining surface 14 C of the left vertical plate 14. Thereby, between the horizontal beam portion 19A of the left front beam 19 and the upper edge portion 62A of the left front reinforcing plate 62, the upper welded portion 64 extending in the left and right directions along the upper edge portion 62A is connected to the left front reinforcing plate 62. It is formed on both front and rear sides.

  Reference numeral 65 denotes a left rear reinforcing plate provided between the left vertical plate 14 of the center frame 12 and one left end 24C of the left rear beam 24. The left rear reinforcing plate 65 is provided with the left rear beam 24. Are supported on one end side 24C of the left rear plate 24 and welded to one end side 24C of the left rear beam 24.

  Here, similarly to the left front reinforcing plate 62, the left rear reinforcing plate 65 is formed in a single triangular flat plate shape having an upper edge portion 65A, a lower edge portion 65B, and a right end edge portion 65C. It extends. The left rear reinforcing plate 65 extends leftward and rightward from the beam joining surface 14C by welding the right end edge portion 65C facing the left longitudinal plate 14 to the beam joining surface 14C of the left longitudinal plate 14. Yes. Thus, a vertical welded portion 66 extending upward and downward along the right end edge portion 65C is formed between the right end edge portion 65C of the left rear reinforcing plate 65 and the beam joining surface 14C of the left vertical plate 14. The reinforcing plate 65 is formed on both the front and rear sides.

  Further, the lower surface of the left beam 24A of the left rear beam 24 is welded to the upper edge portion 65A of the left rear reinforcing plate 65 projecting left and right from the beam joining surface 14C of the left vertical plate 14. Thus, an upper welded portion 67 extending in the left and right directions along the upper edge portion 65A is provided between the horizontal beam portion 24A of the left rear beam 24 and the upper edge portion 65A of the left rear reinforcing plate 65. It is formed on both the front and rear sides of the plate 65.

  In this way, the left front plate 14 and the left front reinforcing plate 62 of the center frame 12 are welded, and the left front reinforcing plate 62 and the one end side 19C of the left front beam 19 are welded, whereby the left front reinforcing plate 62 causes the left front beam 19 to be welded. 19C can be supported, and the left vertical plate 14 and the left rear reinforcing plate 65 of the center frame 12 are welded, and the left rear reinforcing plate 65 and the one end side 24C of the left rear beam 24 are welded. Thus, the left rear reinforcing plate 65 can support the one end side 24C of the left rear beam 24.

  The revolving frame 61 according to the fourth embodiment includes the left front reinforcing plate 62 and the left rear reinforcing plate 65 as described above, and there is no particular difference in basic operation from the above-described first embodiment.

  However, according to the fourth embodiment, the left front reinforcing plate 62 welded to the left vertical plate 14 and the left front beam 19 of the center frame 12 supports the one end side 19 </ b> C of the left front beam 19 and the center frame 12. One end side 24 </ b> C of the left rear beam 24 is supported by a left rear reinforcing plate 65 welded to the left vertical plate 14 and the left rear beam 24.

  For this reason, it is possible to reliably suppress the heat transmitted when the left front reinforcing plate 62 and the left rear reinforcing plate 65 are welded to the left vertical plate 14 of the center frame 12 to the lower surface side of the bottom plate 13. As a result, the machined surface 13A1 and the like formed on the bottom plate 13 before the left front beam 19 and the left rear beam 24 are welded can be protected from heat during welding work.

  In the first embodiment described above, when the left front reinforcing plate 20 is welded to the left end edge portion 13C of the bottom plate 13, the space between the lower edge portion 20B of the left front reinforcing plate 20 and the left end edge portion 13C of the bottom plate 13 is determined. The case where the lower welding part 21 is formed in is illustrated (refer FIG. 5). However, the present invention is not limited to this. For example, as in the first modification shown in FIG. 20, the lower welded portion 68 is provided between the inner side surface 20E of the left front reinforcing plate 20 and the left end edge portion 13C of the bottom plate 13. It is good also as a structure which forms. The same applies to the welded portion between the left rear reinforcing plate 25 and the left end edge portion 13C of the bottom plate 13.

  Further, for example, as in the second modification shown in FIG. 21, a lower welded portion 21 is formed between the lower edge portion 20B of the left front reinforcing plate 20 and the left end edge portion 13C of the bottom plate 13, and the left front reinforcing plate 20 The lower welded portion 68 may be formed between the inner side surface 20E of the base plate 13 and the left end edge portion 13C of the bottom plate 13. The same applies to the welded portion between the left rear reinforcing plate 25 and the left end edge portion 13C of the bottom plate 13.

  In the first embodiment described above, the left front reinforcing plate 20 is provided between the middle portion 19E of the left front beam 19 and the bottom plate 13, and the left rear portion is disposed between the middle portion 24E of the left rear beam 24 and the bottom plate 13. The case where the reinforcing plate 25 is provided and the reinforcing plate (not shown) is provided between the middle portions of the plurality of right beams 30, 31, 32 and the bottom plate 13 is illustrated. However, the present invention is not limited to this. For example, a configuration in which a reinforcing plate is provided between any one of the beam provided on the left side and the beam provided on the right side across the center frame 12 and the bottom plate 13 is provided. Also good.

  Furthermore, in each of the above-described embodiments, the swivel frame applied to the hydraulic excavator has been described as an example. However, the present invention is not limited to this and is widely applied to other construction machines such as a hydraulic crane. It is something that can be done.

1 Excavator (construction machine)
2 Lower traveling body (running body)
11, 41, 51, 61 Rotating frame 12 Center frame 13 Bottom plate 13C Left edge (edge)
14 Left vertical plate 15 Right vertical plate 17 Left side frame 19,52 Front left beam (beam)
19A, 24A, 52A, 53A Horizontal beam portion 19B, 24B, 52B, 53B Vertical beam portion 19C, 24C, 52C, 53C One end side 19D, 24D, 52D, 53D The other end side 19E, 24E, 52E, 53E Intermediate portion 20, 62 Front left reinforcing plate (reinforcing plate)
21, 26, 43, 68 Lower welded portion 22, 27, 44, 64, 67 Upper welded portion 23, 28, 63, 66 Vertical welded portion 24, 53 Left rear beam (beam)
25,65 Left rear reinforcing plate (reinforcing plate)
29 Right side frame 30 Right front beam
31 Right middle beam
32 Right rear beam (beam)
42 Left beam reinforcement plate (reinforcement plate)
45 Front vertical welded portion 46 Rear vertical welded portion 52F, 53F Through hole

Claims (5)

A center frame that is mounted on a self-propelled traveling body and consists of a bottom plate and left and right vertical plates standing on the bottom plate, and is located on both the left and right sides of the center frame and extends in the front and rear directions. Left and right side frames and left and right beams which are provided between the center frame and the left and right side frames and which join the left and right side frames to the center frame. In a turning frame of a construction machine comprising
The beam is configured to weld one end side in the left and right directions to the vertical plate of the center frame and weld the other end side in the left and right directions to the side frame,
Between the left and right edge portions of the bottom plate of the center frame and the left and right intermediate portions of the beam, reinforcing plates that support the left and right intermediate portions of the beam are located above and below. Extending in the direction,
A swivel frame for a construction machine, characterized in that the edge of the bottom plate of the center frame and the reinforcing plate are welded, and the reinforcing plate is welded to an intermediate portion in the left and right directions of the beam. . A plurality of the beams are provided between the center frame and the side frame so as to be separated in the front and rear directions,
The revolving frame for a construction machine according to claim 1, wherein the reinforcing plate is constituted by a plurality of reinforcing plates that are individually welded to an intermediate portion of each beam and an end edge portion of a bottom plate of the center frame. . A plurality of the beams are provided between the center frame and the side frame so as to be separated in the front and rear directions,
The reinforcing plate is composed of one reinforcing plate that is welded to an intermediate portion in the left and right directions of two beams adjacent in the front and rear directions and an edge of the bottom plate of the center frame. The turning frame of the construction machine according to claim 1.   The beam is composed of a horizontal beam portion extending in the left and right directions with one end facing the bottom plate in the upward and downward directions, and a vertical beam portion extending from the horizontal beam portion toward the bottom plate side. The revolving frame for a construction machine according to claim 1, 2 or 3, wherein the vertical beam portion is provided with a through hole that is located between the vertical plate and the reinforcing plate and penetrates in the front and rear directions. A center frame that is mounted on a self-propelled traveling body and consists of a bottom plate and left and right vertical plates standing on the bottom plate, and is located on both the left and right sides of the center frame and extends in the front and rear directions. Left and right side frames and left and right beams which are provided between the center frame and the left and right side frames and which join the left and right side frames to the center frame. In a turning frame of a construction machine comprising
The beam is configured to weld one end side in the left and right directions to the vertical plate of the center frame and weld the other end side in the left and right directions to the side frame,
Between the vertical plate of the center frame and one end side in the left and right directions of the beam, a reinforcing plate that supports one end side of the beam is arranged extending in the left and right directions,
A turning frame for a construction machine, wherein the vertical plate of the center frame and the reinforcing plate are welded, and the reinforcing plate and one end side in the left and right directions of the beam are welded.

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