JP2020020198A - Revolving construction machine - Google Patents

Abstract

To suppress occurrence of distortion in a periphery of an attaching portion of a revolving device by eliminating difference between rigidity at an inner surface side and an outer surface side of left and right vertical plates to a bottom plate.SOLUTION: A bottom plate 12 of a revolving frame 11 includes: a revolving device attaching portion 18 to which a revolving device 28 that becomes a driving source when revolving an upper structure 4 is attached; and a center joint attaching portion 14 to which a center joint 27 distributing a pressure oil between a lower structure 2 and the upper structure 4 is attached. A thickness dimension t3 in a plate thickness direction of the revolving device attaching portion 18 is formed to be larger than a thickness dimension t1 of the center joint attaching portion 14. In addition, a lower end face 19C of a left vertical plate 19 and a lower end face 21C of a right vertical plate 21 are joined to the bottom plate 12 including the revolving device attaching portion 18.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a swing type construction machine suitable for use in construction work such as a hydraulic shovel, a hydraulic crane, and the like.

  Generally, a construction machine such as a hydraulic shovel has a self-propelled lower traveling body, an upper revolving body mounted on the lower traveling body via a revolving wheel so as to be capable of turning, and a vertically movable upper revolving body. And a front device provided. Further, the upper revolving superstructure has a weight of a revolving frame rotatably supported on the lower traveling structure, a cab provided on the front side of the revolving frame, a motor mounted on the rear side of the revolving frame, and a front device. And a counterweight mounted on the rear end of the revolving frame and positioned on the rear side of the prime mover for balancing.

  A revolving frame serving as a base of the upper revolving structure is provided with a flat bottom plate and a front and rear direction extending on the bottom plate, and standing upright and leftward and rightward in a width direction orthogonal to the front and rear directions. It is configured to include a left vertical plate and a right vertical plate on which a front device is mounted on the front side.

  The bottom plate is provided with a turning device serving as a driving source when turning the upper turning body. When the swing device is driven, the upper swing body swings on the lower traveling body via the swing wheel. By operating the front device, excavation work of earth and sand can be performed.

  Here, when the excavation work is performed by the front device, the impact at the time of the excavation work becomes a reaction force, and a large load propagates on the left and right vertical plates of the turning frame to act on the bottom plate. For this reason, the bottom plate is formed to have a large thickness dimension in the plate thickness direction so as to withstand the load due to the excavation work.

  On the other hand, there is a hydraulic excavator called a small turning machine in which an upper turning body is made compact so that the turning operation can be performed while avoiding surrounding obstacles even in a narrow work site. In this small swing hydraulic excavator, the distance dimension from the swing center of the upper swing body to the rear surface of the counterweight is reduced. Accordingly, since various devices such as a prime mover are mounted on the rear side of the turning frame, there is currently no space for mounting the turning device on the rear side of the turning frame. In view of this, in the small turning hydraulic excavator, the turning device is mounted on the floor plate at a position forward of the turning center and between the left and right vertical plates.

  In this case, the turning device comes closer to the mounting portion of the front device located on the front side, so that the load due to the excavation work is easily transmitted around the mounting portion of the turning device.

  On the other hand, in the bottom plate, the reinforcing plate is provided between the left vertical plate and the right vertical plate to increase the thickness dimension so as not to cause distortion due to the excavation reaction force, around the mounting portion of the turning device. The swivel is attached to the thick swivel mount. Thereby, the periphery of the mounting portion of the turning device is reinforced (for example, see Patent Document 1).

JP 2014-43733 A

  In Patent Document 1, a reinforcing plate is provided between a left vertical plate and a right vertical plate. That is, the reinforcing plate is joined to the inner surface of each vertical plate on the side of the turning device and the upper surface of the bottom plate using welding means. In this case, each vertical plate has a high mounting strength (rigidity) to the bottom plate on the inner surface side joined to the reinforcing plate, and a low mounting strength (rigidity) to the bottom plate on the outer surface side joined only to the bottom plate. Therefore, in each vertical plate, there is a difference in rigidity in a joint portion between the inner surface side joined to the reinforcing plate and the outer surface side joined to the bottom plate. For this reason, when the load due to the excavation reaction force propagates to the left and right vertical plates, this load increases the load on the outer surface of the low-rigidity vertical plate and the bottom plate, and the load on the load increases. May occur.

  Here, the revolving wheel is mounted on the lower surface side of the bottom plate using a plurality of bolts around the revolving center of the upper revolving unit. In this case, some of the bolts located on the front side are arranged in a region where distortion due to the above-described difference in rigidity occurs. There is a problem that a large bolt having high strength is required for the bolts arranged in this region because the load to be borne is larger than the bolts outside the region.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and an object of the present invention is to eliminate the difference between the rigidity of each vertical plate on the inner surface side and the rigidity on the outer surface side with respect to the bottom plate, thereby mounting the turning device. It is an object of the present invention to provide a turning type construction machine capable of suppressing the occurrence of distortion around a part and improving reliability.

  The present invention comprises a lower traveling body, an upper revolving body mounted on the lower traveling body via a revolving wheel so as to be pivotable, and a front device provided on a front side of the upper revolving body. The body has a bottom plate, a left vertical plate and a right vertical plate that extend forward and rearward on the bottom plate and are erected at intervals in the left and right directions, and the front device is mounted on the front side. A center joint that is mounted on the bottom plate at the center of rotation of the frame and allows pressure oil to flow between the lower traveling structure and the upper revolving structure, and the left vertical plate that is located forward of the center joint and A revolving construction machine comprising: a revolving device that is mounted on the bottom plate between the right vertical plate and the revolving unit as a drive source when revolving the upper revolving unit via the revolving wheel; The turning A pivot joint mounting portion to which the device is mounted, and a center joint mounting portion to which the center joint is mounted. The lower end surfaces of the left vertical plate and the right vertical plate are joined to the upper surface of the bottom plate including the turning device mounting portion.

  ADVANTAGE OF THE INVENTION According to this invention, generation | occurrence | production of the distortion around the mounting part of a turning device can be suppressed by eliminating the difference of the rigidity of the inner surface side of each vertical plate with respect to a bottom plate, and the rigidity of an outer surface side, and the reliability is improved. be able to.

1 is a front view showing a hydraulic excavator according to a first embodiment of the present invention. It is a top view which shows a lower traveling structure, a turning frame, a turning device, and a center joint. FIG. 4 is an enlarged plan view of a main part showing a bottom plate and left and right vertical plates with a front plate removed. FIG. 4 is a cross-sectional view of a turning wheel, a bottom plate, a right vertical plate, a front plate, a turning device, and a center joint as viewed from a direction indicated by arrows IV-IV in FIG. 2. It is the left view which looked at the bottom board, the left and right vertical boards, and the front board from the front side. It is the perspective view which looked at the bottom board, the left and right vertical boards, and the front board from diagonally the front side. FIG. 7 is an exploded perspective view of a state in which left and right vertical plates and a front plate are separated from a bottom plate as viewed from the same position as in FIG. 6. FIG. 7 is an exploded perspective view showing a state in which left and right vertical plates and a front plate are separated from a bottom plate and a reinforcing plate of the bottom plate is separated from the same position as in FIG. 6. It is sectional drawing which looked at the turning wheel by the 2nd Embodiment of this invention, a bottom plate, a right vertical plate, a front plate, a turning device, and a center joint from the same position as FIG. FIG. 8 is an exploded perspective view of a state in which left and right vertical plates and a front plate are separated from a bottom plate as viewed from the same position as in FIG. 7.

  Hereinafter, as a typical example of the swing-type construction machine according to the embodiment of the present invention, a rear-extra-small swing type hydraulic excavator will be described in detail with reference to the accompanying drawings. In this embodiment, the horizontal direction perpendicular to the front and rear directions of the upper revolving structure is defined as left and right directions, and the configuration and arrangement of each device and member will be described.

  1 to 8 show a first embodiment of the present invention. In FIG. 1, a hydraulic excavator 1 as a swing type construction machine includes a self-propelled crawler-type lower traveling body 2 and an upper swing body 4 that is swingably mounted on the lower traveling body 2 via a swing wheel 3. And a front device 8 described below, which is provided on the front side of the upper revolving unit 4 so as to be capable of raising and lowering. The front device 8 is used for excavating earth and sand.

  Here, the upper swing body 4 of the hydraulic excavator 1 of the ultra-small rear swing type is configured to swing within a predetermined range with respect to the width dimension (full width) of the lower traveling body 2 in the left and right directions. ing. Specifically, the predetermined range with respect to the entire width of the lower traveling body 2 indicates a range within 130% of the entire width of the lower traveling body 2. The upper revolving superstructure 4 of the ultra-small back swing hydraulic excavator 1 is set so that an arc-shaped trajectory drawn by a rear surface of a counterweight 6 described later falls within a range of 130% or less of the entire width described above.

  The lower traveling body 2 has a track frame 2A as a base, and a cylindrical support cylinder 2B is provided on an upper end side of the track frame 2A. An inner ring 3A of a turning wheel 3 described later is attached to the support cylinder 2B of the lower traveling body 2.

  The revolving wheel 3 is provided between the lower traveling structure 2 and the upper revolving structure 4. As shown in FIG. 4, the turning wheel 3 includes an inner ring 3A fixed on a support cylinder 2B of the lower traveling body 2, an outer ring 3B fixed to a lower surface side of a turning frame 11, which will be described later, an inner ring 3A, and an outer ring. 3B and a large number of steel balls 3C (only one is shown). On the inner peripheral side of the inner ring 3A, internal teeth 3D are formed over the entire circumference. The upper revolving unit 4 can perform a revolving operation on the lower traveling unit 2 by the operation of the later-described revolving device 28 and the rotation of the outer wheel 3B fixed to the revolving frame 11 around the inner wheel 3A. .

  On the other hand, as shown in FIGS. 1 and 2, the upper revolving unit 4 is provided with a revolving frame 11 which will be described later as a base, a revolving device 28 provided on the front side of the revolving frame 11, and a revolving center of the revolving frame 11. A cab 5 which is provided at the front left side of the turning frame 11 and forms a driver's cab, and a counter which is attached to the rear end of the turning frame 11 and balances the weight with the front device 8. The weight includes a weight 6 and an outer cover 7 which is disposed in front of the counterweight 6 and houses therein internal equipment such as an engine, a hydraulic pump, and a heat exchange device (all not shown).

  The front device 8 is provided on the front side of the upper swing body 4 so as to be able to perform an elevating operation. The front device 8 includes a boom 8A rotatably attached to a later-described swivel frame 11, an arm 8B rotatably attached to a distal end of the boom 8A, and a rotatable attachment to a distal end of the arm 8B. A bucket 8C, a boom cylinder 8D for driving the boom 8A, an arm cylinder 8E for driving the arm 8B, and a bucket cylinder 8F for driving the bucket 8C.

  Here, the foot portion (base end portion) of the boom 8A is rotatably mounted on a boom mounting portion 19A of a left vertical plate 19 and a boom mounting portion 19A of a right vertical plate 21, which will be described later. 11 are supported by a left vertical plate 19 and a right vertical plate 21.

  Next, the configuration of the revolving frame 11 including the bottom plate 12 which is a characteristic part of the present embodiment will be described in detail.

  The revolving frame 11 forms a support structure for the upper revolving unit 4. As shown in FIG. 2, the turning frame 11 includes a bottom plate 12, a left vertical plate 19, a right vertical plate 21, a front plate 22, a left side frame 23, a left overhanging beam 24, a right side frame 25, and a right overhanging beam 26 which will be described later. It consists of.

  The bottom plate 12 serves as a base of the revolving frame 11. As shown in FIG. 3, the upper revolving unit 4 is formed in a flat plate shape using a steel plate or the like extending in the front and rear directions and in the left and right directions. Specifically, the bottom plate 12 is composed of an entire plate 13 that forms the entire area of the bottom plate 12 in a plan view, and a reinforcing plate 16 provided on the upper side of the full plate 13.

  The full surface plate 13 is formed from one steel plate formed in a rectangular shape. That is, the entire surface plate 13 is formed of a plate material having a uniform thickness t1 in the thickness direction throughout the entire plate. As a result, a center joint mounting portion 14 and a reinforcing plate mounting portion 13F described later have the same thickness.

  As shown in FIG. 8, a plurality of screw holes 13A are provided in the entire surface plate 13 so as to extend in the plate thickness direction. These screw holes 13 </ b> A are arranged along a circle having a large pitch circle diameter corresponding to the turning wheel 3. Further, a joint insertion hole 13B is provided in the entire surface plate 13 so as to be located at the center of the above-described circle, that is, at the turning center O (shown in FIG. 2) in the plate thickness direction. The center joint 27 is inserted into the joint insertion hole 13B. A swivel insertion hole 13C is provided in the entire surface plate 13 at a position forward of the joint insertion hole 13B and penetrates in the plate thickness direction. The turning device 28 is inserted into the turning device insertion hole 13C.

  In the entire surface plate 13, a range in which the joint insertion hole 13 </ b> B and the periphery of the joint insertion hole 13 </ b> B are combined is a center joint mounting portion 14. The center joint 27 is attached to the center joint attachment portion 14. Here, an upper side of the center joint 27 is fixedly attached to the center joint attachment portion 14. In this configuration, the center joint 27 is attached to the lower traveling body 2 only in a rotational direction so that the lower side thereof rotates together with the lower traveling body 2.

  In the configuration in which the upper side of the center joint 27 is attached to the center joint mounting portion 14 only in a state of being engaged in the rotation direction, the lower side of the center joint 27 is fixedly attached to the lower traveling body 2. Have been.

  A reinforcing plate 16, a lower end surface 19C of a left vertical plate 19, and a lower end surface 21C of a right vertical plate 21, which will be described later, are joined to the upper surface 13D of the entire surface plate 13 constituting the bottom plate 12 by welding means. On the other hand, as shown in FIG. 4, a plurality of bolts 15 (only one is shown) inserted from below into an outer ring 3B constituting the turning wheel 3 is provided on a lower surface 13E of the entire plate 13 with each screw hole 13A. The outer ring 3B is attached by screwing to the outer ring 3B.

  Further, a reinforcing plate mounting portion 13 </ b> F is provided on the entire surface plate 13 in front of the center joint mounting portion 14. The reinforcing plate mounting portion 13F is for mounting a reinforcing plate 16 described later. As shown by a two-dot chain line in FIG. 8, the reinforcing plate mounting portion 13F is set in a rectangular area that is long in the left and right directions in accordance with the shape of the reinforcing plate 16. As shown in FIG. 4, the thickness of the reinforcing plate mounting portion 13F is the same as the thickness t1 of the center joint mounting portion 14.

  The reinforcing plate 16 forms a part of the bottom plate 12. The reinforcing plate 16 is overlapped with and joined to the upper side of the reinforcing plate mounting portion 13F of the entire surface plate 13 to form a later-described turning device mounting portion 18 in cooperation with the entire surface plate 13. The reinforcing plate 16 is formed as a rectangular plate that is elongated in the left and right directions and has a thickness t2 in the plate thickness direction. The lower surface 19C of the left vertical plate 19 and the lower surface 21C of the right vertical plate 21 are joined to the upper surface 16A of the reinforcing plate 16.

  As shown in FIG. 5, the length dimension (width dimension) W1 of the reinforcement plate 16 in the left and right directions is the length dimension W2 of the left and right directions between the left vertical plate 19 and the right vertical plate 21 described later. It is formed with a larger value. When the reinforcing plate 16 is joined to the reinforcing plate mounting portion 13F, a turning device insertion hole 16B is formed at a position corresponding to the turning device insertion hole 13C of the entire surface plate 13.

  As shown in FIG. 7, the reinforcing plate 16 is disposed so as to overlap the reinforcing plate mounting portion 13 </ b> F of the entire surface plate 13. In this state, a welding bead 17 is formed on the entire periphery of the reinforcing plate 16 by welding means. Thereby, it is joined on the reinforcing plate mounting portion 13F. As a result, the reinforcing plate mounting portion 13F of the entire surface plate 13 and the reinforcing plate 16 overlap each other in the upward and downward directions, so that the later-described turning device mounting portion 18 is thicker than the thickness dimension t1 of the center joint mounting portion 14. Can be formed.

  The turning device mounting portion 18 forms a part of the bottom plate 12. The turning device mounting portion 18 is to which the turning device 28 is mounted. The turning device mounting portion 18 is formed by overlapping and joining the reinforcing plate 16 above the reinforcing plate mounting portion 13F of the entire surface plate 13. Thus, the thickness W3 of the turning device mounting portion 18 can be formed to be larger than the thickness t1 of the center joint mounting portion 14 by the thickness t2 of the reinforcing plate 16.

  The turning device mounting portion 18 is set to have a length in the left and right directions at which the lower end surface 19C of the left vertical plate 19 and the lower end surface 21C of the right vertical plate 21 can be joined. As shown in FIG. 5, specifically, the left and right lengths of the turning device mounting portion 18 are the left and right lengths W2 between the left vertical plate 19 and the right vertical plate 21. It is formed larger than. That is, the left and right lengths of the turning device mounting portion 18 are the same as the left and right lengths W1 of the reinforcing plate 16.

  Here, when the welded portion of the reinforcing plate 16 to the entire surface plate 13 and the welded portion of the left and right vertical plates 19 and 21 to the reinforcing plate 16 are close to each other, heat due to welding is concentrated and distortion is likely to occur. Therefore, the length of the left and right directions of the turning device mounting portion 18 is sufficient for the welding portion of the reinforcing plate 16 to the entire surface plate 13 and the welding portion of the left and right vertical plates 19 and 21 to the reinforcing plate 16. It is set to a value that leaves.

  The left vertical plate 19 is arranged on the left side of the bottom plate 12. Specifically, the left vertical plate 19 is disposed between the turning device insertion hole 13 </ b> C of the entire surface plate 13 and the turning device insertion hole 16 </ b> B of the reinforcing plate 16 and the left end of the reinforcing plate 16. The left vertical plate 19 is formed in a flat plate shape extending in the front and rear directions using, for example, a steel plate or the like, and stands substantially vertically on the bottom plate 12.

  The left vertical plate 19 has a mountain shape in which an intermediate portion in the front and rear directions protrudes upward, and an upper position of the left vertical plate 19 is a boom mounting portion 19A to which a foot portion of the boom 8A is mounted. A cylinder mounting portion 19B to which one end (bottom side) of the boom cylinder 8D is mounted is provided at a front position of the left vertical plate 19 which is located below the boom mounting portion 19A and protrudes forward. I have.

  The left vertical plate 19 has a lower end surface 19C joined to the upper surface of the bottom plate 12. Specifically, a front portion of the lower end surface 19C of the left vertical plate 19, which is on the side of the turning device mounting portion 18, is an upper surface of the turning device mounting portion 18, that is, a front lower end surface 19C1 joined to the upper surface 16A of the reinforcing plate 16. It has become. On the other hand, a rear portion on the side of the center joint mounting portion 14 is a rear lower end surface 19C2 which is lower by one step than the front lower end surface 19C1 and is joined to the upper surface 13D of the entire plate 13.

  The left vertical plate 19 has the front lower end surface 19C1 abutted on the upper surface 16A of the reinforcing plate 16, and the rear lower end surface 19C2 abuts on the upper surface 13D of the entire plate 13. In this state, a welding bead 20 is formed between the outer surface 19D of the left vertical plate 19, the upper surface 16A of the reinforcing plate 16 and the upper surface 13D of the entire plate 13 by welding means. Further, a welding bead 20 is formed between the inner side surface 19E of the left vertical plate 19, the upper surface 16A of the reinforcing plate 16 and the upper surface 13D of the entire plate 13 by welding means. Thus, the left vertical plate 19 is integrally joined to the bottom plate 12.

  Here, the left vertical plate 19 is disposed above the turning device mounting portion 18. Therefore, the weld beads 20 formed on the outer surface 19D side and the inner surface 19E side with the left vertical plate 19 interposed therebetween can be formed symmetrically left and right with the left vertical plate 19 interposed therebetween. Thereby, the rigidity regarding the attachment of the left vertical plate 19 to the turning device mounting portion 18 can be made equal between the outside and the inside of the left vertical plate 19 in the left and right directions.

  Next, the right vertical plate 21 is disposed closer to the right side of the bottom plate 12 so as to be spaced from the left vertical plate 19 in the left and right directions. Specifically, the left and right lengths between the left vertical plate 19 and the right vertical plate 21 are longer than the left and right lengths W1 of the reinforcing plate 16 (the swivel mounting portion 18). It is formed with a large dimension W2. The right vertical plate 21 is disposed between the turning device insertion hole 13 </ b> C of the entire plate 13 and the turning device insertion hole 16 </ b> B of the reinforcing plate 16 and the right end of the reinforcing plate 16.

  The right vertical plate 21, like the left vertical plate 19, is formed in a flat plate shape extending forward and backward using, for example, a steel plate or the like, and stands substantially vertically on the bottom plate 12. The right vertical plate 21 is the same as the left vertical plate 19 in shape, mounting structure for the bottom plate 12, and the like. The right vertical plate 21 has a boom mounting portion 21A, a cylinder mounting portion 21B, a lower end surface 21C, an outer surface 21D, and an inner surface 21E. The lower end surface 21C includes a front lower end surface 21C1 and a rear lower end surface 21C2.

  That is, similarly to the left vertical plate 19, the right vertical plate 21 is joined to the bottom plate 12 by the welding beads 20 formed symmetrically on the left and right sides of the right vertical plate 21. Thereby, the rigidity regarding the attachment of the right vertical plate 21 to the turning device mounting portion 18 can be made equal between the outside and the inside of the right vertical plate 21 in the left and right directions.

  The front plate 22 is located on the front side of the bottom plate 12 and connects between the left vertical plate 19 and the right vertical plate 21. The front plate 22 is formed as a strength member using, for example, a steel plate or the like. Here, the front plate 22 is formed, for example, by bending a plate material into an inverted J-shape. The front plate 22 has a front lower end edge joined to the upper surface 16A of the reinforcing plate 16 using welding means, and a left edge in the left and right directions joined to an inner surface 19E of the left vertical plate 19 using welding means. The right edges in the left and right directions are joined to the inner side surface 21E of the right vertical plate 21 by using welding means.

  As shown in FIG. 2, the left side frame 23 is formed on the left side of the bottom plate 12 and extends forward and backward. The left side frame 23 is attached to the distal ends of a plurality of left overhanging beams 24 projecting leftward from the bottom plate 12 and the left vertical plate 19. On the other hand, the right side frame 25 is formed on the right side of the bottom plate 12 and extends forward and backward. The right side frame 25 is attached to the distal ends of a plurality of right overhanging beams 26 projecting rightward from the bottom plate 12 and the right vertical plate 21.

  Next, the configurations of the center joint 27 and the turning device 28 provided on the turning frame 11 will be described.

  The center joint 27 is provided on the turning center O of the turning frame 11. The center joint 27 allows pressure oil to flow between the lower traveling structure 2 and the upper revolving structure 4. The center joint 27 is inserted through the joint insertion hole 13 </ b> B of the entire surface plate 13, and the upper side is fixedly attached to the center joint attachment portion 14. On the other hand, the lower side of the center joint 27, which is rotatable relative to the upper side, is attached to the lower traveling body 2 only in the rotational direction so as to rotate together with the lower traveling body 2. Have been.

  A hydraulic hose (not shown) for supplying and discharging pressure oil to a traveling motor (not shown) provided on the lower traveling body 2 is connected to the lower traveling body 2 side of the center joint 27. The upper revolving unit 4 side of the center joint 27 is connected to a hydraulic pressure source (not shown) via a hydraulic hose (not shown).

  The turning device 28 is mounted on the bottom plate 12 between the left vertical plate 19 and the right vertical plate 21 at a position forward of the center joint 27. The revolving device 28 is disposed on the revolving device mounting portion 18 of the bottom plate 12 and serves as a drive source when revolving the upper revolving unit 4. The turning device 28 is attached to the turning device mounting portion 18 (the reinforcing plate 16) by a plurality of bolts. The output shaft 28A of the turning device 28 protrudes toward the turning wheel 3 through the turning device insertion hole 13C of the entire surface plate 13 and the turning device insertion hole 16B of the reinforcing plate 16, which constitute the turning device mounting portion 18. A pinion 28B provided at a lower position of the output shaft 28A meshes with the internal teeth 3D of the turning wheel 3.

  The hydraulic excavator 1 according to the present embodiment has the turning frame 11 as described above. Next, the operation thereof will be described.

  The hydraulic excavator 1 can travel to a desired work place by the lower traveling body 2 by itself. The hydraulic excavator 1 that has moved to the work place can perform excavation work and the like by operating the front device 8 while rotating the upper swing body 4 on the lower traveling body 2.

  Here, when excavation work or the like is performed using the front device 8, a large load is applied to the left vertical plate 19 and the right vertical plate 21 supporting the front device 8 by the excavation reaction force from the front device 8. Works.

  In this case, in Patent Literature 1, the mounting strength (rigidity) of the vertical plate to the inner bottom plate is high, and the mounting strength (rigidity) of the vertical plate to the outer bottom plate is low. As described above, when there is a difference in rigidity in mounting between the inner surface side and the outer surface side of the vertical plate, when a load due to the excavation reaction force is applied, the mounting portion between the outer surface of the lower rigidity vertical plate and the bottom plate is reduced. There is a possibility that the load on the strength increases and distortion occurs.

  However, according to the present embodiment, the bottom plate 12 has the turning device mounting portion 18 to which the turning device 28 is mounted, and the center joint mounting portion 14 to which the center joint 27 is mounted. The thickness t3 of the turning device mounting portion 18 in the plate thickness direction is formed to be larger than the thickness t1 of the center joint mounting portion 14. On this, the lower end surface 19C of the left vertical plate 19 and the lower end surface 21C of the right vertical plate 21 are joined to the upper surface of the bottom plate 12, that is, the upper surface 13D of the entire plate 13, including the turning device mounting portion 18.

  Therefore, in the configuration in which the left vertical plate 19 is disposed above the turning device mounting portion 18, the welding beads 20 formed on the outer side surface 19 </ b> D side and the inner side surface 19 </ b> E side with the left vertical plate 19 interposed therebetween. It is formed symmetrically left and right across 19. Thereby, the rigidity regarding the attachment of the left vertical plate 19 to the turning device mounting portion 18 can be made equal between the outside and the inside of the left vertical plate 19 in the left and right directions. Similarly, the rigidity relating to the attachment of the right vertical plate 21 to the turning device mounting portion 18 can be made equal between the outside and the inside of the right vertical plate 21 in the left and right directions.

  As a result, the difference between the rigidity on the inner surface side and the rigidity on the outer surface side of the left and right vertical plates 19 and 21 with respect to the bottom plate 12 can be eliminated. ) Can be suppressed, and the reliability of the excavator 1 can be improved.

  In addition, when the generation of distortion around the mounting portion of the turning device 28 (the turning device mounting portion 18) is suppressed, the strength of the bolt 15 for mounting the turning wheel 3 to the bottom plate 12 can be reduced, and the manufacturing cost can be reduced. Can be reduced.

  The left and right lengths W1 of the turning device mounting portion 18 are formed to be larger than the left and right lengths W2 between the left vertical plate 19 and the right vertical plate 21. Therefore, the welding portion of the reinforcing plate 16 to the entire surface plate 13 and the welding portion of the left and right vertical plates 19 and 21 to the reinforcing plate 16 can be arranged separately. Thus, it is possible to prevent distortion due to concentration of heat due to welding, and it is possible to improve assemblability of the turning frame 11.

  Furthermore, the bottom plate 12 has a reinforcing plate mounting portion 13F of the entire surface plate 13 located on the front side of the center joint mounting portion 14, and a flat reinforcing plate 16 facing the reinforcing plate mounting portion 13F from above. . The turning device mounting portion 18 can be formed by overlapping and joining the reinforcing plate 16 on the upper side of the reinforcing plate mounting portion 13F. Thereby, the bottom plate 12 can be easily formed by stacking two plate members.

  Next, FIGS. 9 and 10 show a second embodiment of the present invention. A feature of the present embodiment is that the bottom plate is formed as a single member by a thin portion and a thick portion, instead of having a double-layer structure of the entire plate and the reinforcing plate in the turning device mounting portion of the bottom plate. Note that, in the present embodiment, the same components as those in the above-described first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

  The bottom plate 31 according to the second embodiment is formed as a single plate having a thin portion 32 and a turning device mounting portion 33, which will be described later, having different thicknesses in a plate thickness direction. The bottom plate 31 is formed, for example, by performing milling or the like on a flat steel plate having a thickness dimension equal to or greater than the thickness dimension t5 of the turning device mounting portion 33 described later.

  The thin portion 32 constitutes the bottom plate 31, and has a thickness t4 in the plate thickness direction by cutting a portion of the bottom plate 31 other than the turning device attachment portion 33 using a means such as milling. It is formed as a thin part. Here, a joint insertion hole 32A is provided at a center position of the thin portion 32, and the joint insertion hole 32A and the periphery thereof form a center joint mounting portion 32B.

  The turning device mounting portion 33 is provided on the bottom plate 31 between the left vertical plate 19 and the right vertical plate 21 at a position forward of the center joint mounting portion 32B. The turning device attachment portion 33 is formed as a thick portion of the bottom plate 31 that is not cut by milling or the like. Accordingly, the thickness t5 of the turning device mounting portion 33 in the plate thickness direction is larger than the thickness t4 of the thin portion 32 in the plate thickness direction. A turning device insertion hole 33 </ b> A into which the output shaft 28 </ b> A of the turning device 28 is inserted is formed in the center of the turning device mounting portion 33.

  The turning device mounting portion 33 is, like the turning device mounting portion 18 according to the first embodiment, a dimension W1 larger than a length dimension W2 in the left and right directions between the left vertical plate 19 and the right vertical plate 21. Is formed.

  Thus, in the second embodiment configured as described above, similarly to the above-described first embodiment, while increasing the strength of the front portion of the bottom plate 31, the occurrence of distortion in the turning device mounting portion 33 is reduced. Can be suppressed.

  In each of the embodiments, the crawler type hydraulic excavator 1 has been described as an example of the swing type construction machine. However, the present invention is not limited to this, and can be widely applied to other revolving construction machines having an upper revolving body such as a wheel type hydraulic excavator or a hydraulic crane.

1 Hydraulic excavator (swivel type construction machine)
2 Lower traveling body 3 Revolving wheel 4 Upper revolving body 8 Front device 11 Revolving frame 12, 31 Bottom plate 13 Full plate 13D Upper surface 13F Reinforcement plate mounting portion 14, 32B Center joint mounting portion 16 Reinforcement plate 18, 33 Revolving device mounting portion 19 Left Vertical plate 19C, 21C Lower end surface 27 Center joint 28 Rotating device O Rotating center t1 to t5 Thickness in the thickness direction W1 Length of reinforcement plate in left and right directions W2 Between left vertical plate and right vertical plate Left and right length

Claims (4)

A lower traveling structure, an upper revolving structure mounted on the lower traveling structure via a revolving wheel so as to be pivotable, and a front device provided on a front side of the upper revolving structure,
A revolving frame having a bottom plate, a left vertical plate and a right vertical plate extending frontward and rearward on the bottom plate, standing upright and spaced apart in the left and right directions, and having the front device mounted on the front side; A center joint that is mounted on the bottom plate at the center of rotation of the revolving frame and allows pressure oil to flow between the lower traveling unit and the upper revolving unit; A swivel-type construction machine, comprising: a swivel device that is mounted on the bottom plate between the vertical plate and the right vertical plate and that serves as a drive source when the upper revolving unit is swiveled through the swivel wheel;
The bottom plate has a turning device mounting portion to which the turning device is mounted, and a center joint mounting portion to which the center joint is mounted,
The thickness of the turning device mounting portion in the plate thickness direction is formed to be larger than the thickness of the center joint mounting portion,
The turning type construction machine according to claim 1, wherein lower end surfaces of the left vertical plate and the right vertical plate are joined to an upper surface of the bottom plate including the turning device mounting portion.   The left and right lengths of the turning device mounting portion are formed to be larger than the left and right lengths between the left vertical plate and the right vertical plate. Item 4. A swiveling construction machine according to item 1. The bottom plate has a reinforcing plate mounting portion located on the front side of the center joint mounting portion, and a flat reinforcing plate facing the reinforcing plate mounting portion from above,
The turning type construction machine according to claim 1, wherein the turning device mounting portion is formed by overlapping and joining the reinforcing plate above the reinforcing plate mounting portion.   4. The swiveling construction machine according to claim 3, wherein the bottom plate is formed of a plate having the same thickness as the center joint mounting portion and the reinforcing plate mounting portion. 5.

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