JP4763631B2 - Construction machine truck frame - Google Patents

Description

  The present invention relates to a truck frame of a construction machine that constitutes a lower traveling body such as a hydraulic excavator.

  In general, a hydraulic excavator used for excavation work such as earth and sand is provided with a crawler type lower traveling body in order to stably travel on rough terrain such as a mountainous area and a muddy area. The track frame constituting the crawler type lower traveling body is usually composed of a center frame and left and right side frames extending on the left and right sides of the center frame and extending in the front and rear directions. Yes. A drive wheel is attached to one end of each side frame via a traveling hydraulic motor, and an idler wheel is attached to the other end, and a crawler belt (crawler) is wound around the drive wheel and the idler wheel. Has been.

  Here, the center frame of the track frame is provided between an upper plate extending left and right, a lower plate provided facing the lower side of the upper plate, and the upper plate and the lower plate. Further, it is formed in a box shape by a plurality of vertical plates. Each side frame is formed in an inverted U shape by an upper surface plate, an inner surface plate extending downward from the inner side of the upper surface plate, and an outer surface plate extending downward from the outer side of the upper surface plate. It is fixed to the left and right sides of the frame using welding means.

  Also, the track frame has a front end of the center frame that extends almost straight in the left and right directions, and the front end is used as it is with each side frame and welding means in order to mount the earth removing plate device for leveling. Are joined. In this case, stress acting from, for example, the earth removing plate device, the working device (front device), or the like tends to concentrate on the joint portion between the center frame and the side frame. In view of this, a reinforcing plate is attached to the joint between the front end of the center frame and the side frame to disperse the stress and increase the mounting strength of the side frame with respect to the center frame (see, for example, Patent Document 1). The reinforcing plate is made of a substantially triangular steel plate and is welded to the upper surface of the upper plate constituting the center frame and the upper surface plate of the U-shaped side frame.

JP-A-9-202261

  By the way, the track frame according to Patent Document 1 described above has the center part disposed at a high position with the left and right sides of the center frame inclined downward so that the lower side does not contact an obstacle such as a rock during traveling. Yes. In addition, the upper side plate of the side frame is directed to the outside in the left and right directions by the mounting structure of the upper roller that supports the crawler belt from the bottom, the structure for improving mud removal and preventing sedimentation, etc. And tilted downward.

  Here, when the inclination angle of the center frame and the inclination angle of the upper surface plate of the side frame become closer, the reinforcing plate may be welded to the upper surface plate of the side frame having low strength. In this case, in order to increase the strength of the welded portion between the reinforcing plate and the upper surface plate of the side frame, the reinforcing plate must be enlarged or bent, resulting in poor productivity and manufacturing costs. Will also be bulky. In addition, the large reinforcing plate has a problem that earth and sand are easily accumulated, and it takes time and effort for cleaning work.

  In addition, since both the left and right sides of the center frame and the upper surface plate of the side frame are inclined downward toward the outside, the reinforcing plate is attached to the upper and side plates of the center frame in the work of attaching the reinforcing plate. The range in which the frame can be in close contact with both the upper surface plates of the frame is narrow, and if it is outside this attachment range, the reinforcing plate may be twisted and the welding strength may be reduced. For this reason, there is a problem that the reinforcing plate must be processed with high accuracy and an accurate positioning operation must be performed, and a great deal of labor is required for the processing operation and the mounting operation.

  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 a construction machine in which a reinforcing plate can be easily made small and sufficient strength can be obtained by a simple mounting operation. Is to provide a track frame.

  The track frame of the construction machine according to the present invention includes an upper plate extending in the left and right directions, a lower plate provided facing the lower side of the upper plate, and a plurality of plates provided between the upper plate and the lower plate. Formed in an inverted U shape by a center frame formed in a box shape by a single vertical plate, an upper surface plate, an inner side surface plate extending downward from the inner side of the upper surface plate, and an outer side surface plate extending downward from the outer side of the upper surface plate The left and right side frames fixed to the left and right sides of the center frame by welding means so as to extend in the front and rear directions, the left and right front ends of the center frame, and the left In order to reinforce the joint portion with the right side frame, a reinforcing plate fixed to the joint portion using welding means is provided.

In order to solve the above-mentioned problem, the feature of the configuration adopted by the invention of claim 1 is that the reinforcing plate has an upper surface abutting against a lower surface of the upper plate of the center frame , and a front side of the upper plate. with fixed by performing welding along the edge, the outer edge is located in the side frame side angular corner is abutted against the corner portion between the upper plate and the inner surface plate of the side frames It is in the structure which adheres by performing welding along .

According to a second aspect of the present invention, a notch portion is provided at a position located on the upper side of the reinforcing plate at a front end portion of the upper plate of the center frame, and welding is performed along the notch portion to thereby reinforce the reinforcing plate. The plate is fixed to the lower surface of the upper plate.

  According to the first aspect of the present invention, the reinforcing plate is fixed to the lower surface of the upper plate constituting the center frame, thereby being influenced by the inclination angles of the left and right sides of the center frame and the inclination angle of the upper surface plate of the side frame. It can adhere to the corner part between the upper surface board of a side frame, and an inner surface part, without it. In this case, the corner portion between the upper surface plate and the inner side surface portion of the side frame has high strength due to the three-dimensional structure. Therefore, the reinforcing plate can be attached to the center frame and the side frame with high attachment strength.

  As a result, the reinforcing plate does not need to be enlarged or bent to increase the strength, so that the reinforcing plate can be easily manufactured as a small and simple flat plate. In addition, the small reinforcing plate can suppress sedimentation and can save time and effort for cleaning. Further, the weight can be reduced by downsizing the reinforcing plate. Furthermore, since the reinforcing plate can be easily butted against the side frame, high dimensional accuracy and accurate positioning work are not required, and workability of processing work and mounting work can be improved.

  According to the second aspect of the present invention, the upper plate of the center frame is provided with a notch at a portion located above the reinforcing plate, and welding is performed along the notch. The welding length can be increased by the curved line. Thereby, the attachment strength of the reinforcing plate and the upper plate of the center frame can be increased.

  Hereinafter, a case where the track frame of the construction machine according to the embodiment of the present invention is applied to a lower traveling body of a hydraulic excavator will be described as an example and described in detail with reference to FIGS.

  In FIG. 1, reference numeral 1 denotes a hydraulic excavator as a construction machine used for excavation work such as earth and sand. The hydraulic excavator 1 includes a crawler type lower traveling body 2 provided with a track frame 11 described later according to the present embodiment. The upper turning body 4 is mounted on the lower traveling body 2 via the turning device 3 so as to be turnable, and the working device 27 described later is provided on the front side of the upper turning body 4.

  Here, on the front side of the lower traveling body 2, the earth removing plate device 5 is provided so as to be rotatable upward and downward. The earth removing plate device 5 includes a blade 5A extending in the left and right directions, a support arm 5B having the blade 5A attached to the front end, and the blade 5A in the upward and downward directions via the support arm 5B. This is generally constituted by a rotating discharge cylinder (not shown). Further, the support arm 5B is pivotally attached to an arm bracket 19 of a center frame 12 constituting a track frame 11 described later at a base end side branched into two branches. The earth removal cylinder has a proximal end rotatably attached to the cylinder bracket 18 of the center frame 12 and a distal end rotatably attached to the distal end of the support arm 5B.

  On the other hand, the lower traveling body 2 includes a track frame 11, which will be described later, and left and right drive wheels 6 provided at front and rear ends of the left and right side frames 20 and 21 constituting the track frame 11, Left and right idler wheels 7 provided at the other front and rear ends of the left and right side frames 20 and 21, and left and right crawler belts wound around the drive wheels 6 and idler wheels 7. 8 (both shown only on the left side). A plurality of lower rollers 9 and one upper roller 10 for guiding the crawler belt 8 in the circumferential direction are provided below and above the side frames 20 and 21.

  Reference numeral 11 denotes a track frame of the excavator 1 according to this embodiment. As shown in FIGS. 2 to 6, the track frame 11 is roughly composed of a center frame 12 to be described later and left and right side frames 20 and 21 located on both the left and right sides of the center frame 12. Yes.

  A center frame 12 is located at the center of the track frame 11. As shown in FIG. 3, the center frame 12 includes a center frame portion 12A located at the center, a left front leg portion 12B and a right front leg portion 12C that are located on the front side of the center frame portion 12A and extend leftward and rightward. And a left rear leg portion 12D and a right rear leg portion 12E which are located behind the central frame portion 12A and extend obliquely. Here, the left and right front legs 12B and 12C extend in a straight line in the left and right directions, for example, in order to have a structure in which the earth removing plate device 5 is provided on the front side. As a result, the center frame 12 is substantially K-shaped as a whole, and the side frames 20 and 21 are attached to the left front leg portion 12B and the right front leg portion 12C at substantially right angles.

  Further, the center frame 12 is provided with each leg portion 12B to 12B of each center frame 12 as shown in FIGS. 12E is inclined downward, and the central frame portion 12A is arranged at a high position. The center frame 12 is formed in a box shape by an upper plate 13, a lower plate 14, a vertical plate 15 and the like which will be described later.

  Reference numeral 13 denotes an upper plate that forms an upper portion of the center frame 12, and the upper plate 13 is formed in a substantially K shape using a steel plate or the like. That is, the upper plate 13 is located at the center and has a flat center plate 13A, a left front plate 13B that extends straight from the left front side to the left side of the center plate 13A, and a right front side to the right side of the center plate 13A. An extended right front plate 13C, a left rear plate 13D extending from the left rear side of the center plate 13A to the left diagonal rear side, and a right rear plate 13E extending from the right rear side of the central plate 13A to the right diagonal rear side It is made up of.

  Here, the front end edge 13F of the upper plate 13 is formed in a substantially linear shape in a plan view shown in FIG. 3, and a notch portion 16 described later is formed on both the left and right sides thereof. A reinforcing plate 26, which will be described later, is fixed on the lower side. Further, the left front plate 13B and the left rear plate 13D of the upper plate 13 are inclined such that the front end side which is the outside in the left and right directions is inclined downward, and the end portion uses welding means for the frame body 22 of the left side frame 20 described later. Are joined. On the other hand, the right front plate 13C and the right rear plate 13E are tilted downward at the front end side which is the outside in the left and right directions, and are joined to the frame body 22 of the right side frame 21 described later using welding means.

  Reference numeral 14 denotes a lower plate of the center frame 12 which is disposed on the lower side of the upper plate 13 so as to face each other at a desired interval. The lower plate 14 is formed in a substantially K shape by a central plate 14A, a left front plate 14B, a right front plate 14C, a left rear plate 14D, and a right rear plate 14E using a steel plate or the like in substantially the same manner as the upper plate 13. . Each of the plates 14B to 14E is inclined downward at an angle substantially equal to that of the upper plate 13, and ends of the left front plate 14B and the left rear plate 14D are below the frame body 22 of the left side frame 20 described later. It is fixed to the site. On the other hand, end portions of the right front plate 14C and the right rear plate 14E are fixed to a lower portion of the frame body 22 of the right side frame 21.

  Reference numeral 15 denotes a plurality of vertical plates provided between the upper plate 13 and the lower plate 14, and each vertical plate 15 includes, for example, a front vertical plate 15A, intermediate vertical plates 15B and 15C, and a rear vertical plate 15D. Has been. The vertical plate 15 forms side portions of the leg portions 12B to 12E of the center frame 12. The vertical plates 15A, 15B, 15C, and 15D have upper and lower end portions fixed to the upper plate 13 and the lower plate 14 using welding means. The box structure is formed by closing. Further, the left and right front vertical plates 15A located on the front side of the vertical plate 15 are equivalent to the mounting margin of the reinforcing plate 26 described later from the front end edge 13F of the upper plate 13 (larger than the notch portion 16 described later). It is disposed at the retracted position.

  Reference numeral 16 denotes a notch provided at the front end of the left and right front plates 13B and 13C of the upper plate 13, respectively. The left and right cutout portions 16 are formed by cutting out the straight front end edge 13F into a gentle arc shape. Each notch 16 is located above a later-described reinforcing plate 26 and is a part where a weld bead is formed when the reinforcing plate 26 is welded. Here, each notch part 16 lengthens welding length (length dimension of a weld bead) by bending in circular arc shape, and raises the attachment strength of the upper board 13 and the reinforcement plate 26 by welding. Further, since the notch portion 16 is formed in an arc shape, concentration of stress can be avoided and durability can be improved.

  Reference numeral 17 denotes a round cylinder provided in the center frame portion 12 </ b> A of the center frame 12. Reference numeral 18 denotes a cylinder bracket provided at the center of the front portion of the center frame 12, and 19 denotes two arm brackets provided on the left and right sides of the cylinder bracket 18 and provided at the front portion of the center frame 12. Show. Further, a support arm 5B of the earth discharging plate device 5 is attached to each arm bracket 19 so as to be able to rotate upward and downward, and to the cylinder bracket 18, the earth discharging cylinder of the earth discharging plate device 5 is upper and lower. It is mounted so as to be rotatable in the direction.

  Here, the cylinder brackets 18 and the arm brackets 19 can be mounted at accurate positions by a simple mounting operation by forming the front portion of the center frame 12 in a straight line in the left and right directions. Further, it is possible to easily handle a hydraulic hose (not shown) and to secure a space for maintenance work in the surroundings.

  Reference numeral 20 denotes a left side frame fixed to the left side of the center frame 12 using welding means, and 21 denotes a right side frame fixed to the right side of the center frame 12 using welding means. Further, the left side frame 20 extends in the front and rear directions while being attached to the front end portions of the left front leg portion 12B and the left rear leg portion 12D of the center frame 12. On the other hand, the right side frame 21 extends in the front and rear directions while being attached to the front end portions of the right front leg portion 12C and the right rear leg portion 12E of the center frame 12.

  The left side frame 20 is provided on the front side of the frame main body 22 extending in the front and rear directions, and the idler wheel 7 can be moved in the front and rear directions via a yoke (not shown). And two guide plates 23 supported on the frame body, and a drive wheel bracket 24 provided on the rear side of the frame body 22 to which the drive wheels 6 are attached via a hydraulic motor (not shown).

  Moreover, the frame main body 22 which comprises the main-body part of the left side frame 20 is formed by bending, for example, one steel plate as shown in FIG. That is, the frame body 22 includes an upper surface plate 22A, an inner side surface plate 22B extending downward from the inner side (center frame 12 side) of the upper surface plate 22A, and an outer side surface plate 22C extending downward from the outer side of the upper surface plate 22A. It is formed in an inverted U shape. Further, the upper surface plate 22A is inclined downward from the inside toward the outside so that earth and sand and the like riding on the upper side fall to the outside.

  Here, since the frame body 22 is provided with the inner side plate 22B by bending the inner side portion of the upper surface plate 22A downward, the upper corner plate 22A and the inner side plate 22B are bent to form the corners 22D. It has become. Further, since the corner portion 22D has a three-dimensional structure, it has higher strength than a flat plate. Thereby, when fixing the below-mentioned reinforcement plate 26 to the frame main body 22, it can attach with high attachment strength by welding to the corner part 22D.

  When the left side frame 20 is attached to the center frame 12, welding means are used for the front end of the left front plate 13 </ b> B and the left rear plate 13 </ b> D of the upper plate 13 constituting the center frame 12 on the upper corner corner 22 </ b> D of the frame body 22. It is stuck. Further, the inner side surface plate 22B of the frame body 22 is fixed to the front end of the left front plate 14B, the left rear plate 14D of the lower plate 14, and the front end of the corresponding vertical plate 15 using welding means.

  The left side frame 20 and the right side frame 21 have the same configuration and mounting structure except that the left side frame 20 and the right side frame 21 are symmetrical on the left and right. The same reference numerals are given to the same components as those in FIG.

  As described above, when the left and right side frames 20 and 21 are fixed to the center frame 12, the front ends of the front legs 12B and 12C of the center frame 12 extending linearly in the left and right directions are The side frames 20 and 21 extending rearward are fixed. For this reason, the joint portion between the left and right front ends of the center frame 12 and the side frames 20 and 21 is a cross joint portion 25 that intersects (collides) in a T shape. There is a possibility that stress acting from, for example, the earth discharging plate device 5 and the work device 27 may be concentrated on the cross joint portion 25. As a means for avoiding this stress concentration, the cross joint portion 25 is located at the cross joint portion 25 and the side of the center frame 12 and each side. A reinforcing plate 26 described later is attached between the frames 20 and 21.

  Reference numeral 26 denotes a left and right reinforcing plate provided between the center frame 12 and the left and right side frames 20 and 21. The left and right reinforcing plates 26 reinforce a substantially right-angled cross joint portion 25 formed on the front side when the left and right side frames 20 and 21 are fixed to the center frame 12 in a T shape. To do. Since the left and right reinforcing plates 26 have the same configuration, the left reinforcing plate 26 will be described, and the description of the right reinforcing plate 26 will be omitted.

  The left reinforcing plate 26 is formed using, for example, a high-strength steel plate. That is, as shown in FIG. 7, the reinforcing plate 26 has a linear rear end edge 26A located on the center frame 12 side and a linear shape that is located on the left side frame 20 side and is substantially perpendicular to the rear end edge 26A. An outer edge 26B, a concave arc-shaped edge 26C extending from the front end of the outer edge 26B toward the tip of the rear edge 26A, and the space between the arc-shaped edge 26C and the rear edge 26A It is formed in a trapezoidal shape or a substantially triangular shape composed of an inner end edge 26D formed in the shape. Further, since the reinforcing plate 26 can be fixed with high welding strength to the center frame 12 and the left side frame 20 by a welding structure described later, it can be formed small and lightweight.

  Therefore, a case where the reinforcing plate 26 is fixed to the center frame 12 and the left side frame 20 using welding means will be described. In this case, as shown in FIG. 7, the reinforcing plate 26 has the outer edge 26 </ b> B on the left side frame in a state where it is in contact with the lower surface of the left front plate 13 </ b> B of the upper plate 13 so as to be below the notch 16. 20 is brought into contact with the corner portion 22D of the frame main body 22 constituting 20. At this time, the outer edge 26B of the reinforcing plate 26 can be easily connected to the corner 22D of the frame body 22 regardless of the inclination angle of the left front plate 13B of the upper plate 13 and the inclination angle of the upper surface plate 22A of the frame body 22. It is possible to make an exact match, and the positioning operation can be easily performed.

  When the reinforcing plate 26 is positioned at the welding position, as shown in FIGS. 5 and 6, the outer end edge 26 </ b> B is welded to the corner 22 </ b> D of the frame body 22, and the inner end edge 26 </ b> D is the left front plate of the upper plate 13. Weld to the lower surface of 13B. Further, the left front plate 13 </ b> B of the upper plate 13 and the upper surface 26 </ b> E of the reinforcing plate 26 are welded along the curve of the notch 16.

  In this welded structure, the reinforcing plate 26 is attached to the reinforcing plate 26 and the left side frame 20 at a high level by welding the outer end edge 26B thereof to the high-strength corners 22D with the frame body 22 of the left side frame 20. Can be fixed with strength. Further, the reinforcing plate 26 has an inner edge 26D welded to the lower surface of the left front plate 13B of the upper plate 13, and an upper surface 26E welded to the left front plate 13B. In addition, since the weld length (the length dimension of the weld bead) with respect to the upper surface 26E of the reinforcing plate 26 can be extended by welding along the bent notch 16, the reinforcing plate 26 and the center frame 12 can be attached to each other with high attachment. Can be fixed with strength.

  Reference numeral 27 denotes a working device provided at the front of the upper swing body 4. The working device 27 performs excavation work of earth and sand by moving up and down.

  The hydraulic excavator 1 according to the present embodiment has the above-described configuration, and the operation thereof will be described next.

  First, the operator can move the hydraulic excavator 1 forward or backward by the lower traveling body 2 by getting on the cab of the upper swing body 4 and operating the operating lever for traveling. Further, by operating an operation lever (not shown) for working, the working device 27 can be moved up and down to perform excavation work of earth and sand.

  As described above, according to the present embodiment, the reinforcing plate 26 fixed to the cross joint portion 25 when the left and right side frames 20 and 21 are fixed to the center frame 12 using the welding means is provided in the center frame 12. The frame 12 is fixed to the lower surfaces of the front plates 13B and 13C of the upper plate 13 and is fixed to the corners 22D of the frame main body 22 to the side frames 20 and 21.

  Therefore, the reinforcing plate 26 is not affected by the inclination angle of the front plates 13B and 13C of the upper plate 13 and the inclination angle of the upper surface plate 22A of each frame main body 22, and the outer edge 26B of the reinforcing plate 26 is the angle of the frame main body 22. The corner 22D can be easily and accurately abutted. Further, the reinforcing plate 26 can be fixed to the corner portions 22D of the frame body 22 having high strength at the portions constituting the side frames 20, 21. As a result, the reinforcing plate 26 can be easily positioned, and can be attached to the center frame 12 and the side frames 20 and 21 with high attachment strength.

  As a result, the reinforcing plate 26 can obtain sufficient structural strength and mounting strength as a reinforcing member even in a small and flat shape. Thereby, the reinforcing plate 26 can be easily manufactured as a small and simple flat plate.

  In addition, since the small reinforcing plate 26 is difficult for sediment to accumulate, the cleaning work can be simplified. Further, the weight can be reduced by downsizing the reinforcing plate 26. Furthermore, since the reinforcing plate 26 can be easily abutted against the side frames 20 and 21, high dimensional accuracy and accurate positioning work are not required, and workability of processing work and mounting work can be improved. it can.

  The front plates 13B and 13C of the upper plate 13 constituting the center frame 12 are each provided with a notch 16 at the end of the front edge 13F located above the reinforcing plate 26. Therefore, when the upper surface 26 </ b> E of the reinforcing plate 26 is fixed to the upper plate 13, the weld length can be increased by the notch 16 by performing welding along the curve of the notch 16. As a result, the reinforcing plate 26 can be fixed to the upper plate 13 of the center frame 12 with high mounting strength, and durability, reliability, and the like can be improved.

  In addition, the reinforcing plate 26 has an inclined portion that is continuous with the front plates 13B and 13C of the upper plate 13 and the corner portion 22D of the frame body 22 as an arc-shaped edge 26C that is curved into a concave arc shape. Can be dispersed in the periphery, and durability and the like can also be improved in this respect.

  Further, since the reinforcing plate 26 is disposed on the lower surface side of the upper plate 13, many welding parts can be disposed at positions where welding can be performed from the upper side in a normal working posture. Thereby, workability | operativity at the time of welding operation, the quality of welding, etc. can be improved.

  In the embodiment, the case where the four leg portions 12B to 12E are provided on the center frame 12 of the track frame 11 has been described as an example. However, the present invention is not limited to this, and may be applied to a track frame including a rectangular center frame extending in the left and right directions as in Patent Document 1 described in the related art.

  In the embodiment, the frame main body 22 constituting the left and right side frames 20 and 21 is formed in an inverted U shape comprising an upper surface plate 22A, an inner side surface plate 22B, and an outer side surface plate 22C by bending one plate material. The case where it was formed was described as an example. However, the present invention is not limited to this, and for example, a top plate, an inner side plate, and an outer side plate are provided as separate members, and the inner side plate and the outer side plate are fixed using welding means or the like so as to extend downward from the top plate. It is good. Moreover, it is good also as a structure which provides only any one of an inner surface board and an outer surface board separately, and welds it later.

  Furthermore, in the embodiment, the track frame 11 constituting the lower traveling body 2 of the excavator 1 is described as an example as the track frame of the construction machine. However, the present invention is not limited to this, and can be widely applied to a track frame of a lower traveling body of another construction machine such as a hydraulic crane.

It is a front view which shows the hydraulic shovel provided with the track frame by embodiment of this invention. It is an enlarged front view which shows the track frame in FIG. 1 alone. It is an enlarged plan view showing a track frame alone. It is an expansion perspective view which shows a track frame alone. It is the expanded sectional view which looked at the attachment relationship of a center frame, a left side frame, and a reinforcement plate from the arrow VV direction in FIG. It is a perspective view of the principal part expansion which shows the attachment relationship of a center frame, a left side frame, and a reinforcement plate. It is a disassembled perspective view of the principal part expansion which shows the state which attaches a reinforcement plate with respect to a center frame and a left side frame.

Explanation of symbols

1 Excavator (construction machine)
DESCRIPTION OF SYMBOLS 2 Lower traveling body 5 Earth removal board device 6 Drive wheel 7 Idle wheel 8 Crawler belt 11 Track frame 12 Center frame 13 Upper board 14 Lower board 15 Vertical board 16 Notch part 20 Left side frame 21 Right side frame 22 Frame main body 22A Upper surface board 22B Inner side plate 22C Outer side plate 22D Corner corner 25 Cross joint 26 Reinforcement plate 26A Rear edge 26B Outer edge 26C Arc-shaped edge 26D Inner edge

Claims (2)

It is formed in a box shape by an upper plate extending in the left and right direction, a lower plate provided facing the lower side of the upper plate, and a plurality of vertical plates provided between the upper plate and the lower plate. Center frame,
It is formed in an inverted U shape by an upper surface plate, an inner surface plate extending downward from the inner side of the upper surface plate, and an outer surface plate extending downward from the outer side of the upper surface plate, and forward and rearward on the left and right sides of the center frame. Left and right side frames fixed using welding means to extend to,
A construction machine comprising a left and right front end of the center frame and a reinforcing plate secured to the joint using welding means to reinforce the joint between the left and right side frames. In the track frame of
The reinforcing plate is fixed by abutting its upper surface against the lower surface of the upper plate of the center frame and welding along the front end of the upper plate, and an outer edge located on the side frame side. construction machine of the track frame, characterized in that a structure for fixing the corner portions by performing welding along the angular corner portion abutted between the top plate and the inner surface plate of the side frame. At the front end of the upper plate of the center frame, a notch is provided in a portion located on the upper side of the reinforcing plate, and welding is performed along the notch to thereby attach the reinforcing plate to the lower surface of the upper plate. The track frame of the construction machine according to claim 1, wherein the track frame is configured to be fixed to the vehicle.

Images