JP5798097B2 - Swivel construction machine - Google Patents

Description

  The present invention relates to a swivel construction machine suitable for use in construction work such as a hydraulic excavator and a hydraulic crane.

  In general, a construction machine such as a hydraulic excavator is a self-propelled lower traveling body, an upper revolving body that is mounted on the lower traveling body through a swirling wheel so as to be capable of swiveling, and a front and rear of the upper revolving body. It is comprised by the working apparatus provided so that it was possible. The upper swing body includes a swing frame supported to be swingable on the lower traveling body, a cab provided on the front side of the swing frame, an engine mounted on the rear side of the swing frame, and the working device. In order to balance the weight of the engine, a counterweight or the like mounted on the rear end portion of the turning frame is provided on the rear side of the engine.

  In addition, the revolving frame that is the base of the upper revolving structure is a left-and-right vertical plate that has a flat bottom plate, and extends on the bottom plate in the front and rear directions, and is erected at intervals in the left and right directions. It is comprised including the board and the right vertical board.

  The bottom plate is provided with a turning device serving as a drive source for turning the upper turning body. By driving the turning device, the upper turning body turns on the lower traveling body via the turning wheel. It has a configuration (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 9-158252

  Here, when excavation work or the like is performed by the working device, a reaction force in the excavation work becomes a large load, propagates through the left vertical plate and the right vertical plate, and acts on the bottom plate. In addition, even when the work apparatus is lifted, a load acts so as to twist each vertical plate when the work apparatus shakes, and the load propagates to the bottom plate. Therefore, the bottom plate has a thickness (plate thickness) that can sufficiently withstand such excavation reaction force.

  Here, in a small swing type hydraulic excavator in which the distance from the swing center to the rear surface of the counterweight is reduced, various devices such as an engine and a hydraulic pump are mounted on the rear side of the swing frame, and on the rear side of the swing frame. There is not enough equipment storage space. For this reason, the swivel device is positioned on the front side of the center joint and is mounted on the bottom plate between the left vertical plate and the right vertical plate.

  By the way, in recent years, the engine tends to increase in size as a whole as a result of the addition of various devices to comply with exhaust gas regulations of engines mounted on hydraulic excavators. For this reason, it is necessary to move the mounting position of the swivel device to the front side of the bottom plate in a small swivel excavator that cannot secure a sufficient device accommodation space on the swivel frame.

  However, when the swivel device mounting portion to which the swivel device is mounted on the bottom plate is moved to the front side of the conventional art, the swivel device mounting portion is connected to the left and right vertical plates and the boom, and the left Since the right vertical plate and the boom cylinder are close to each other, the excavation reaction force when the working device performs excavation work is easily transmitted to the swivel mounting portion of the bottom plate through the left and right vertical plates. In addition, since the engine is enlarged and the excavation force is increased, the excavation reaction force transmitted to the swivel mounting portion of the bottom plate is also increased.

  As a result, during excavation work, a large excavation reaction force always acts on the swivel device mounting portion of the bottom plate, and the swivel device mounting portion is distorted, thereby impairing the stable operation of the swivel device. There is.

  The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to provide a swivel type that suppresses distortion of the swivel mounting portion of the bottom plate and can stably operate the swivel. To provide construction machinery.

  In order to solve the above-described problems, the present invention provides a lower traveling body, an upper revolving body that is mounted on the lower traveling body via a swirl wheel so as to be capable of swiveling, and is provided on the front side of the upper revolving body so as to move up and down. The upper revolving unit comprises a bottom plate and a left vertical plate and a right plate that extend forward and rearward on the bottom plate and are provided with a space in the left and right directions and to which the working device is attached on the front side. A swivel frame having a vertical plate, a center joint that is positioned on the swivel center of the swivel frame and is mounted on the bottom plate to allow pressure oil to flow between the lower traveling body and the upper swivel body, and the center joint A turning device that is located on the front side and is mounted on the bottom plate between the left vertical plate and the right vertical plate and serves as a drive source when the upper turning body is turned via the turning wheel. Applied to the swivel construction machine .

  The feature of the configuration adopted by the invention of claim 1 is that the turning device mounting portion to which the turning device is mounted in the bottom plate is more in the thickness direction than the center joint mounting portion to which the center joint is mounted in the bottom plate. The thick portion is configured as a thick portion, the left end portion of the thick portion is fixed to the left vertical plate, and the right end portion of the thick portion is fixed to the right vertical plate. It is in.

  On the other hand, the feature of the configuration adopted by the invention of claim 2 is that the reinforcing plate is located between the left vertical plate and the right vertical plate on the upper surface of the bottom plate where the turning device is attached. A left end portion of the reinforcing plate is fixed to the left vertical plate and a right end portion is fixed to the right vertical plate, and a thick portion formed in the plate thickness direction by the bottom plate and the reinforcing plate is provided. The swivel device mounting portion to which the swivel device is mounted is used.

  According to the first aspect of the present invention, the thickness dimension of the swivel device mounting portion to which the swivel device is mounted is formed thicker than other parts of the bottom plate of the swivel frame, and both left and right end sides are respectively formed. Since it is configured to connect to the left vertical plate and the right vertical plate, the swivel device mounting portion of the bottom plate can maintain rigidity enough to withstand the excavation reaction force. Therefore, even if a large excavation reaction force acts on the front side of the bottom plate, it is possible to prevent the turning device mounting portion from being distorted and to always operate the turning device stably. Reliability can be improved.

  In addition, by making the swivel attachment portion of the bottom plate a thick wall portion, only the portion of the bottom plate that needs reinforcement can be efficiently reinforced without greatly increasing the weight of the bottom plate.

  According to the invention of claim 2, the reinforcing plate is fixed to the upper surface of the bottom plate between the left vertical plate and the right vertical plate, the left end portion of the reinforcing plate is fixed to the left vertical plate, and the right end portion is fixed to the right vertical plate. By simply adhering to the plate, the swivel device mounting portion of the swivel frame (bottom plate) can be reinforced easily and efficiently.

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 turning frame and a lower traveling body. It is the elements on larger scale which show a baseplate, a reinforcement board, a turning apparatus attachment part, and a center joint attachment part in the state which removed the front board from the left and right vertical boards. FIG. 4 is a left side view of a bottom plate, left and right vertical plates, a front plate, a reinforcing plate, and the like when viewed from the direction of arrows IV-IV in FIG. 2. FIG. 5 is a cross-sectional view of a bottom plate, a reinforcing plate, a right vertical plate, a front plate, a turning device, a center joint, and the like when viewed from the direction of arrows V-V in FIG. 2. It is the expansion perspective view which looked at the baseplate, the reinforcement board, the right vertical board, the front board, the turning apparatus attachment part, the center joint attachment part, etc. from the diagonal rear side. FIG. 5 is a left side view similar to FIG. 4 showing a bottom plate, left and right vertical plates, a front plate and the like according to a second embodiment of the present invention. It is sectional drawing similar to FIG. 5 which shows a baseplate, a right vertical board, a front board, a turning apparatus, a center joint, etc. It is an expansion perspective view similar to FIG. 6 which looked at the bottom plate, the right vertical plate, and the front plate from the oblique rear side.

  Hereinafter, a case where the embodiment of the swivel construction machine according to the present invention is applied to a hydraulic excavator provided with a crawler type lower traveling body will be described in detail with reference to the accompanying drawings.

  1 to 6 show a first embodiment of the present invention, and 1 shows a hydraulic excavator as a typical example of a construction machine. The hydraulic excavator 1 includes a self-propelled crawler-type lower traveling body 2, an upper revolving body 4 that is mounted on the lower traveling body 2 via a revolving wheel 3 so as to be capable of swiveling, and the upper revolving body 4. A work apparatus 8 (described later) provided so as to be able to move up and down is provided on the front side. The work apparatus 8 is used for excavating earth and sand.

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

  Reference numeral 3 denotes a turning wheel provided between the lower traveling body 2 and an upper turning body 4 described later. The turning wheel 3 includes an inner ring 3A fixed on a support cylinder 2B of the lower traveling body 2, and an after-mentioned rotating wheel 3A. The outer ring 3B is fixed to the lower surface side of the turning frame 11, and a number of steel balls 3C (only one is shown) provided between the inner ring 3A and the outer ring 3B. Further, an inner tooth 3D is formed over the entire circumference on the inner circumference side of the inner ring 3A. Then, the turning device 28 described later is operated and the outer ring 3B fixed to the turning frame 11 rotates around the inner wheel 3A, so that the upper turning body 4 performs a turning operation on the lower traveling body 2. Yes.

  On the other hand, as shown in FIGS. 1 and 2, the upper swing body 4 includes a later-described swing frame 11 serving as a base, a swing device 28 described later provided on the front side of the swing frame 11, and a swing of the swing frame 11. The weight of the working device 8 is provided at the center joint 27, which will be described later, provided on the left side of the front part of the revolving frame 11 and attached to the rear end of the revolving frame 11 and the cab 5 that defines the cab. The counter weight 6 for balancing and a building cover 7 that is disposed on the front side of the counter weight 6 and accommodates equipment (not shown) such as an engine, a hydraulic pump, and a heat exchange device inside. Has been.

  Reference numeral 8 denotes a work device provided on the front side of the upper swing body 4 so as to be able to move up and down. The work device 8 includes a boom 8A rotatably attached to a swing frame 11 described later, and a tip portion of the boom 8A. An arm 8B rotatably attached to the arm 8B, a bucket 8C rotatably attached to the tip of the arm 8B, two boom cylinders 8D for driving the boom 8A, and an arm cylinder for driving the arm 8B 8E and a bucket cylinder 8F that drives the bucket 8C.

  Here, the foot portion (base end portion) of the boom 8A includes a boom mounting portion 14C of the left vertical plate 14 to be described later, a boom mounting portion 15C of the right vertical plate 15, and left and right boom mounting brackets of the front plate 16. 17 is supported by a left vertical plate 14, a right vertical plate 15 and a front plate 16 that constitute the revolving frame 11.

  Next, 11 shows a turning frame of the excavator 1 according to the present embodiment. As shown in FIGS. 2 and 3, the revolving frame 11 is positioned at the center of the left and right directions and extends in the front and rear directions, and will be described later. The left side frame 23 (described later) extending in the direction and the right side frame 25 (described later) disposed on the right side of the center frame 12 and extending in the front and rear directions are roughly configured to form a strong support structure.

  Reference numeral 12 denotes a center frame that constitutes the central portion of the revolving frame 11. The center frame 12 extends in the front and rear directions, and extends on the bottom plate 13 in the front and rear directions and is fixed in the left and right directions. A left vertical plate 14 and a right vertical plate 15 erected at intervals, a front plate 16 positioned on the front side of the bottom plate 13 and connecting the left vertical plate 14 and the right vertical plate 15, and a reinforcing plate 21 described later. And is roughly composed.

  Reference numeral 13 denotes a bottom plate serving as a base of the center frame 12. The bottom plate 13 is a thick steel plate having a thickness dimension (plate thickness) A in a direction (plate thickness direction) orthogonal to the upper surface 13A and the lower surface 13B. Is formed into a flat plate shape. The bottom plate 13 is provided with a center joint attachment portion 13C for attaching a center joint 27 described later on the turning center O of the turning frame 11, and penetrates the center joint attachment portion 13C upward and downward. A mounting hole 13D is provided. Further, a reinforcing plate 21 described later is provided between the left vertical plate 14 and the right vertical plate 15 on the front side of the center joint mounting portion 13C.

  Reference numeral 14 denotes a left vertical plate positioned on the left end side of the bottom plate 13, and the left vertical plate 14 is formed in a flat plate shape that extends forward and backward using, for example, a steel plate or the like, and is substantially perpendicular to the upper surface 13A of the bottom plate 13. It is erected. The left vertical plate 14 has a mountain shape in which the front and rear center portions protrude upward, and the upper side of the left vertical plate 14 is directed from the inner side surface 14A of the left vertical plate 14 to the outer side surface 14B. There is provided a boom attachment portion 14C that has a through hole that penetrates and to which the foot portion of the boom 8A is attached. Further, a through-hole penetrating from the inner side surface 14A to the outer side surface 14B of the left vertical plate 14 is provided on the front end side of the left vertical plate 14 which is located below the boom mounting portion 14C and protrudes forward. A boom cylinder attachment portion 14D to which one end side (bottom side) of the boom cylinder 8D is attached is provided.

  On the other hand, reference numeral 15 denotes a right vertical plate facing the left vertical plate 14 with a certain distance left and right, and the right vertical plate 15 is also made of, for example, a steel plate like the left vertical plate 14. It is formed in a flat plate shape extending in the front and rear directions, and is erected substantially vertically on the upper surface 13A of the bottom plate 13 located on the right end side of the bottom plate 13. The right vertical plate 15 has a mountain shape in which the front and rear central portions protrude upward, and the upper side of the right vertical plate 15 is directed from the inner surface 15A to the outer surface 15B of the right vertical plate 15. There is provided a boom attachment portion 15C having a through hole that penetrates and to which the foot portion of the boom 8A is attached. Further, a through-hole penetrating from the inner side surface 15A to the outer side surface 15B of the right vertical plate 15 is provided on the front end side of the right vertical plate 15 positioned below the boom mounting portion 15C and protruding forward. A boom cylinder attachment portion 15D to which one end side (bottom side) of the boom cylinder 8D is attached is provided. A counterweight 6 is attached to the rear end side of the left vertical plate 14 and the right vertical plate 15, and an engine and a hydraulic pump (both not shown) are mounted on the front side of the counterweight 6. It is the composition which becomes.

  Reference numeral 16 denotes a front plate that is located on the front side of the bottom plate 13 and connects the left vertical plate 14 and the right vertical plate 15, and the front plate 16 is formed as a strength member using, for example, a steel plate or the like. The working device 8 is supported together with the plate 14 and the right vertical plate 15. Here, the front plate 16 is formed as a polygonal polyhedral plate bent at a plurality of locations in the front and rear directions, for example, by bending a steel plate material, and is a reinforcing plate 21 fixed on a bottom plate 13 described later. A front surface portion 16A extending obliquely upward from the rear and a rear surface portion 16B extending obliquely downward from the top (upper end portion) of the front surface portion 16A are formed in a mountain shape as a whole.

  In this case, the front surface portion 16A of the front plate 16 is located on the rear side of the boom cylinder mounting portion 14D provided on the left vertical plate 14 and the boom cylinder mounting portion 15D provided on the right vertical plate 15, and will be described later. A short rising portion 16A1 rising in a vertical direction from the upper surface 21A of the upper portion 21; a lower inclined portion 16A2 extending obliquely upward while being inclined rearward from the upper end of the rising portion 16A1; and the lower inclined portion 16A2 And an upper inclined portion 16A3 extending obliquely upward while being inclined further rearward from the upper end. On the other hand, the rear surface portion 16B of the front plate 16 extends obliquely downward from the top of the front surface portion 16A (upper inclined portion 16A3) toward the rear.

  The front plate 16 is secured to the upper surface 21A of the reinforcing plate 21 described later by means of welding or the like at the lower end edge of the front surface portion 16A (rising portion 16A1), and the left edge of the front surface portion 16A and the rear surface portion 16B. The portion is fixed to the inner side surface 14A of the left vertical plate 14 using welding means, and the right edge of the front surface portion 16A and the rear surface portion 16B is fixed to the inner side surface 15A of the right vertical plate 15 using welding means. Thus, the reinforcing plate 21 is joined to the left vertical plate 14 and the right vertical plate 15 which will be described later.

  Reference numeral 17 denotes left and right boom mounting brackets provided on the front surface portion 16A of the front plate 16. Each boom mounting bracket 17 is fixed to the upper inclined portion 16A3 of the front surface portion 16A by means of welding or the like. . The left boom mounting bracket 17 is disposed adjacent to the boom mounting portion 14C provided on the left vertical plate 14, and the right boom mounting bracket 17 is disposed on the boom mounting portion 15C provided on the right vertical plate 15. Adjacent to each other. Thus, the boom mounting portions 14C and 15C of the left and right vertical plates 14 and 15 and the left and right boom mounting brackets 17 provided on the front plate 16 support the boom 8A of the work device 8. ing.

  Reference numeral 18 denotes left and right cylinder mounting brackets provided on the front plate 16 below the boom mounting bracket 17. Here, the left cylinder mounting bracket 18 faces a boom cylinder mounting portion 14D provided on the left vertical plate 14 with a certain distance, and a rising portion 16A1 and a lower inclined portion 16A2 of the front surface portion 16A, and will be described later. The reinforcing plate 21 is welded to the upper surface 21A. On the other hand, the cylinder mounting bracket 18 on the right side faces a boom cylinder mounting portion 15D provided on the right vertical plate 15 at a certain interval, and rises 16A1 and the lower inclined portion 16A2 of the front surface portion 16A, and will be described later. The reinforcing plate 21 is welded to the upper surface 21A. The boom cylinder 8D of the work device 8 is connected to the boom cylinder mounting portions 14D and 15D provided on the left and right vertical plates 14 and 15 and the left and right cylinder mounting brackets 18 provided on the front plate 16, respectively. It becomes the structure which supports.

  Reference numeral 19 denotes a device insertion hole provided in the front surface portion 16A of the front plate 16. The device insertion hole 19 is a range extending from the front surface portion 16A of the front plate 16 to the lower inclined portion 16A2 and the upper inclined portion 16A3. Is provided. A swiveling device 28 to be described later is arranged below the device insertion hole 19, so that the swiveling device 28 can be attached to and removed from the bottom plate 13 through the device insertion hole 19. In addition, the device insertion hole 19 can secure a work space when performing maintenance work on the swivel device 28.

  Reference numeral 20 denotes an opening provided on the front surface portion 16A of the front plate 16 that is positioned below the device insertion hole 19, and the opening portion 20 is connected to the rising portion 16A1 of the front surface portion 16A of the front plate 16. It is provided in a range extending to the lower inclined portion 16A2. A plurality of hydraulic hoses (not shown) that supply pressure oil to the boom cylinder 8D, the arm cylinder 8E, the bucket cylinder 8F, and the like constituting the work device 8 are inserted into the opening 20.

  Next, 21 indicates a reinforcing plate located on the bottom plate 13 between the left vertical plate 14 and the right vertical plate 15. The reinforcing plate 21 is formed as a rectangular flat plate using a steel plate or the like. That is, the reinforcing plate 21 has a thickness dimension (plate thickness) B in a direction (plate thickness direction) orthogonal to the upper surface 21A and the lower surface 21B, and has a front end portion 21C, a rear end portion 21D, a left end portion 21E, and a right end portion. It is formed in a flat plate shape having 21F. The front end portion 21C of the reinforcing plate 21 is fixed to the bottom plate 13 by a front end welding portion 21G welded from the inner side surface 14A of the left vertical plate 14 to the inner side surface 15A of the right vertical plate 15 on the front end side of the bottom plate 13. The rear end portion 21D is welded to the bottom plate 13 by the rear end weld portion 21H welded from the inner side surface 14A of the left vertical plate 14 to the inner side surface 15A of the right vertical plate 15 on the front side of the center joint mounting portion 13C of the bottom plate 13. It is fixed. On the other hand, the left end 21E of the reinforcing plate 21 is fixed to the left vertical plate 14 by a left end welded portion 21J welded to the inner side surface 14A of the left vertical plate 14 in the front and rear directions, and the right end 21F is The right vertical plate 15 is fixed to the right vertical plate 15 by a right end welded portion 21K welded to the inner side surface 15A of the right vertical plate 15 in the front and rear directions. That is, as shown in FIG. 3, the four sides of the reinforcing plate 21 are welded to the bottom plate 13 or the left and right vertical plates 14 and 15 with no gaps in plan view.

  As a result, the portion of the bottom plate 13 to which the reinforcing plate 21 is fixed is the sum of the thickness A of the bottom plate 13 above and below and the thickness B of the reinforcing plate 21 above and below. It becomes a thick portion having (plate thickness), and is formed as a turning device attachment portion 22 to which a turning device 28 described later is attached. Here, a through hole 22 </ b> A that penetrates the bottom plate 13 and the reinforcing plate 21 in the upward and downward directions is provided in the central portion of the turning device attachment portion 22. A turning device 28 (described later) is attached to the upper surface side of the through hole 22A, and an output shaft 28A of the turning device 28 protrudes toward the turning wheel 3 through the through hole 22A. That is, the reinforcing plate 21 is positioned on the front side of the center joint mounting portion 13C on the bottom plate 13 and is fixed between the left and right vertical plates 14 and 15, so that a turning device 28 to be described later is attached. A mounting portion 22 is configured.

  Thus, by fixing the reinforcing plate 21 to the bottom plate 13, the turning device mounting portion 22 provided on the front end side of the bottom plate 13 is formed as a thick portion, and the left end portion 21 </ b> E of the reinforcing plate 21 is the left vertical plate 14. Even if a large excavation reaction force acts on the front side of the bottom plate 13 during excavation work using the work device 8 by adhering the right end portion 21F of the reinforcing plate 21 to the right vertical plate 15, the swivel device is attached. The portion 22 is configured to suppress the occurrence of distortion.

  Reference numeral 23 denotes a left side frame disposed on the left side of the center frame 12, and the left side frame 23 is formed using, for example, a D-shaped frame having a D-shaped cross section, and forward and rearward along the center frame 12. It extends to. The left side frame 23 is fixed to the center frame 12 by being joined to a plurality of left extending beams 24 extending left and right from the bottom plate 13 and the left vertical plate 14.

  Reference numeral 25 denotes a right side frame disposed on the right side of the center frame 12, and the right side frame 25 is formed using a D-type frame similar to the left side frame 23, and forward and backward along the center frame 12. It extends to. The right side frame 25 is fixed to the center frame 12 by being joined to a plurality of right extending beams 26 extending leftward and rightward from the bottom plate 13 and the right vertical plate 15.

  Reference numeral 27 denotes a center joint provided on the turning center O of the turning frame 11, and the center joint 27 circulates pressure oil between the lower traveling body 2 and the upper turning body 4. The center joint 27 is disposed in a mounting hole 13D of a center joint mounting portion 13C provided in the bottom plate 13, and is mounted on the bottom plate 13 using bolts or the like. Further, a hydraulic hose or the like (not shown) for supplying and discharging pressure oil to and from a running motor (not shown) provided on the lower running body 2 is connected to the lower running body 2 side of the center joint 27. 27 is connected to a hydraulic power source (not shown) via a hydraulic hose (not shown) on the upper swing body 4 side.

  Reference numeral 28 denotes a swivel device located between the left vertical plate 14 and the right vertical plate 15 located in front of the center joint 27, and the swivel device 28 is disposed on the swivel device mounting portion 22 of the bottom plate 13. This is a drive source for turning the upper turning body 4. The turning device 28 is attached to the upper surface 21 </ b> A of the reinforcing plate 21 by a plurality of bolts 29, and the output shaft 28 </ b> A of the turning device 28 protrudes toward the turning wheel 3 through the through hole 22 </ b> A of the turning device attachment portion 22. Further, the pinion 30 provided on the lower end side of the output shaft 28 </ b> A meshes with the internal teeth 3 </ b> D of the turning wheel 3.

  The hydraulic excavator 1 according to the present embodiment has the revolving frame 11 as described above, and the hydraulic excavator 1 self-travels to a desired work place by the lower traveling body 2. Then, the excavator 1 performs soil excavation work and the like by moving the working device 8 up and down while turning the upper turning body 4 on the lower traveling body 2.

  Here, when soil excavation work or the like is performed using the work device 8, the left vertical plate 14 and the right vertical plate 15 that support the work device 8 in the revolving frame 11 are provided on the front side of the bottom plate 13 provided. On the other hand, a large load is applied by the excavation reaction force.

  On the other hand, the hydraulic excavator 1 according to the present embodiment fixes the bottom plate 13 by fixing the reinforcing plate 21 between the left vertical plate 14 and the right vertical plate 15 on the front end side of the bottom plate 13 constituting the revolving frame 11. The swivel device mounting portion 22 is formed of a thick portion in which the plate thickness A and the plate thickness B of the reinforcing plate 21 are superimposed, and the left end portion 21E of the reinforcing plate 21 is fixed to the inner side surface 14A of the left vertical plate 14. At the same time, the right end portion 21F of the reinforcing plate 21 is fixed to the inner side surface 15A of the right vertical plate 15. Thereby, in addition to the increase in the plate thickness on the front end side of the bottom plate 13, the bonding strength between the bottom plate 13 and the left vertical plate 14 and the bonding strength between the bottom plate 13 and the right vertical plate 15 can be increased. As a result, even when a large excavation reaction force acts on the front side of the bottom plate 13, it is possible to prevent distortion from occurring in the swivel device attachment portion 22 and the vicinity thereof. Therefore, the operation of the swivel device 28 attached to the swivel device mounting portion 22 can be stabilized over a long period of time, and the reliability of the hydraulic excavator 1 can be improved.

  Moreover, since only the swivel device mounting portion 22 to which the reinforcing plate 21 is fixed is made thick in the bottom plate 13, the weight of the bottom plate 13 does not increase greatly, and the strength of the swivel device mounting portion 22 that needs reinforcement is increased. Can be effectively increased.

  Next, FIG. 7 to FIG. 9 show a second embodiment of the present invention. The feature of this embodiment is that the thick wall portion is not a double structure composed of a bottom plate and a reinforcing plate, and the bottom plate is a thin wall portion. And the thick part. 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.

  Reference numeral 31 denotes a bottom plate serving as a base of the center frame 12, and the bottom plate 31 is used in the present embodiment in place of the bottom plate 13 according to the first embodiment described above. Here, the bottom plate 31 is formed in a step shape by a thin portion 32 and a turning device mounting portion 33 which will be described later, and has a plate-like shape having a thickness equal to the thickness dimension C in the upper and lower directions of the turning device mounting portion 33. It is formed by subjecting a steel plate material to milling or the like.

  32 indicates a thin portion constituting the bottom plate 31, and the thin portion 32 is formed by shaving a portion of the bottom plate 31 excluding a later-described turning device mounting portion 33 using means such as milling. It is formed as a thin portion having a downward thickness dimension D. Here, a center joint mounting portion 32A is provided on the rear end side of the thin portion 32, and a mounting hole 32B for mounting the center joint 27 is drilled upward and downward in the center joint mounting portion 32A. ing. A left vertical plate 14 is provided upright on the left end side of the thin portion 32 so as to extend in the front and rear directions, and a right vertical plate facing the left vertical plate 14 at a predetermined interval on the right end side. 15 is erected so as to extend in the front and rear directions.

  Reference numeral 33 denotes a swivel device mounting portion located between the left vertical plate 14 and the right vertical plate 15 located in front of the center joint mounting portion 32 </ b> A. It is formed as a thick-walled portion that is not subjected to cutting by machining or the like. Accordingly, the thickness dimension C in the upper and lower direction of the turning device mounting portion 33 is larger than the thickness dimension D in the upper and lower direction of the thin portion 32.

  A through hole 33 </ b> A through which the output shaft 28 </ b> A of the turning device 28 is inserted is formed at the center of the turning device mounting portion 33. Further, the left end portion 33B of the swivel device mounting portion 33 is fixed to the left vertical plate 14 by the left end welded portion 33C welded in the front and rear directions on the inner side surface 14A of the left vertical plate 14, and the swivel device mounting portion 33. The right end portion 33D of the right vertical plate 15 is fixed to the right vertical plate 15 by a right end welding portion 33E welded in the front and rear directions on the inner surface 15A of the right vertical plate 15.

  Thus, in the case where the bottom plate 31 is integrally formed by the thin portion 32 and the turning device mounting portion 33, as in the first embodiment, in addition to the increase in the plate thickness on the front end side of the bottom plate 31, The joining strength between the bottom plate 31 and the left vertical plate 14 and the joining strength between the bottom plate 31 and the right vertical plate 15 can be increased. As a result, even when a large excavation reaction force acts on the front side of the bottom plate 31, it is possible to prevent distortion from occurring in the swivel device mounting portion 33 and the vicinity thereof. Therefore, the operation of the turning device 28 attached to the turning device attaching portion 33 can be stabilized over a long period of time, and the reliability of the hydraulic excavator 1 can be improved.

  In the above-described embodiment, the crawler type hydraulic excavator has been described as an example of the construction machine. However, the present invention is not limited to this, and can be widely applied to a turning frame of another construction machine including an upper turning body such as a wheel-type hydraulic excavator or a hydraulic crane.

1 Excavator (construction machine)
2 Lower traveling body 3 Swivel wheel 4 Upper revolving body 8 Working device 11 Swivel frame 13, 31 Bottom plate 13A Top surface 13C, 32A Center joint mounting portion 14 Left vertical plate 15 Right vertical plate 21 Reinforcement plate 21E Left end portion 21F Right end portion 22, 33 Swivel device mounting portion 33B Left end portion 33D Right end portion 27 Center joint 28 Swivel device O Center of rotation

Claims (2)

A lower traveling body, an upper revolving body mounted on the lower traveling body via a swirling wheel so as to be able to swivel, and a work device provided on the front side of the upper revolving body so as to be able to move up and down,
The upper swing body includes a bottom frame and a swing frame that extends in the front and rear directions on the bottom plate and has a left vertical plate and a right vertical plate that are erected at intervals in the left and right directions and to which the working device is attached on the front side. A center joint which is mounted on the bottom plate and located on the bottom plate of the swivel frame and allows pressure oil to flow between the lower traveling body and the upper swivel body, and is located on the front side of the center joint and the left In a swivel construction machine comprising a turning device that is mounted on the bottom plate between a vertical plate and the right vertical plate and serves as a drive source for turning the upper turning body via the turning wheel,
Of the bottom plate, the turning device mounting portion to which the turning device is attached is configured as a thick portion having a thickness dimension larger in the plate thickness direction than the center joint attaching portion to which the center joint is attached, of the bottom plate,
A swivel construction machine characterized in that a left end portion of the thick portion is fixed to the left vertical plate, and a right end portion of the thick portion is fixed to the right vertical plate. A lower traveling body, an upper revolving body mounted on the lower traveling body via a swirling wheel so as to be able to swivel, and a work device provided on the front side of the upper revolving body so as to be able to move up and down,
The upper swing body includes a bottom frame and a swing frame that extends in the front and rear directions on the bottom plate and has a left vertical plate and a right vertical plate that are erected at intervals in the left and right directions and to which the working device is attached on the front side. A center joint which is mounted on the bottom plate and located on the bottom plate of the swivel frame and allows pressure oil to flow between the lower traveling body and the upper swivel body, and is located on the front side of the center joint and the left In a swivel construction machine comprising a turning device that is mounted on the bottom plate between a vertical plate and the right vertical plate and serves as a drive source for turning the upper turning body via the turning wheel,
A reinforcing plate is provided between the left vertical plate and the right vertical plate on the upper surface of the bottom plate to which the turning device is attached, and the left end of the reinforcing plate is used as the left vertical plate. The right end is fixed to the right vertical plate while being fixed,
A turning construction machine characterized in that a thick part formed in the plate thickness direction by the bottom plate and the reinforcing plate is used as a turning device mounting portion to which the turning device is attached.

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