JP2008149945A - Truck frame for construction machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress mud soil or the like from being deposited on an upper surface of a leg part and to enhance joint strength of a leg part and a central frame. <P>SOLUTION: A left front leg part lower plate 13B is integrally formed with a bottom plate 13, a left front inclination plate part 19B is provided on an upper plate 19, and a left front leg part upper plate 21 is fixed to the left front inclination plate part 19B and a pair of left front leg part side plates 15 erected on the left front leg part lower plate 13B. Thereby, a left front leg part 25 with a strong box structure surrounded by the left front leg part lower plate 13B, the left front leg part side plates 15, the left front leg part upper plate 21, etc. can be formed, and the joint strength of the left front leg part 25 to the central frame 12 can be enhanced. Further, since the left front leg part upper plate 21 has a crest-like inclination surface 21A inclined in front/rear direction making a ridge line part 21B as an apex part, the mud soil or the like can be suppressed from being deposited on the left front leg part 25 and a left side frame 29 by dropping off the mud soil or the like along the inclination surface 21A in the front/rear direction. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a truck frame of a construction machine that is preferably used for a lower traveling body such as a hydraulic excavator or a hydraulic crane.

  In general, a hydraulic excavator, which is a typical example of a construction machine, includes a self-propelled crawler-type lower traveling body, an upper revolving body that is turnably mounted on the lower traveling body, and a front side of the upper revolving body. And a work device provided so as to be able to move up and down. The hydraulic excavator can stably travel on rough terrain such as mountainous land and muddy ground by a crawler (crawler belt) type lower traveling body.

  Here, this type of crawler type lower traveling body according to the prior art includes a center frame to which an upper turning body is attached, and left and right sides that are located on both the left and right sides of the center frame and extend in the front and rear directions. A track frame comprising a frame and leg portions before and after connecting the center frame and the side frames is provided (for example, Patent Document 1).

Japanese Patent No. 3247256

  The track frame according to the prior art of Patent Document 1 is formed so that a lower plate and an upper plate constituting a center frame are substantially X-shaped when viewed from above, and the left and right sides of the lower and upper plates of the center frame are formed. By using the part extending toward the frame as the lower leg plate and upper leg plate, and by providing the front and rear plates between the lower leg plate and the upper leg plate, the lower leg plate and the upper leg plate are provided. Four legs that form a box structure are constituted by the plate, the front side plate, and the rear side plate.

  However, in the track frame of Patent Document 1, the upper leg plate is integrally formed on the upper plate of the center frame, and the upper leg plate is slightly downward in the left and right directions from the center frame toward the side frame. Although it is inclined, it is hardly inclined in the forward and backward directions. For this reason, the mud that is splashed up when the excavator travels in a muddy ground or the like is likely to accumulate on the leg upper plate of each leg, and the mud is spread from the leg upper plate to the upper surface of the side frame. In the case of accumulation, there is a problem that the smooth crawling operation of the crawler is hindered.

  On the other hand, a track frame having a structure in which a plurality of cylindrical leg parts made of members different from the center frame and the side frame are formed and the center frame and the side frame are connected to each other through the leg parts. Has been proposed (for example, Patent Documents 2 and 3).

Japanese Utility Model Publication No. 62-59577 JP 2004-345422 A

  In the track frames according to the prior arts of Patent Documents 2 and 3, the upper surfaces of the leg portions connecting the center frame and the side frames are inclined surfaces with respect to the front and rear directions. It is easy for the mud that is splashed up when traveling on the ground or the like to fall along the inclined surfaces of the legs, and it is possible to suppress the accumulation of mud on each leg or side frame.

  However, the track frame according to Patent Documents 2 and 3 described above forms a cylindrical leg portion made of a member different from the center frame and the side frame, and one end of the leg portion is formed on a cylindrical body provided at the center portion of the center frame. The side is butt welded, and the other end side of the leg is butt welded to the side surface of the side frame.

  As a result, a large load is applied to the joint between the center frame cylinder and the leg when the hydraulic excavator is operated, and the center frame cylinder is subjected to an out-of-plane load via the leg. Comes to work.

  For this reason, in order to suppress stress concentration at the joint between the cylindrical body and the leg of the center frame, the weld leg length of the weld bead formed at the joint is increased, or the weld bead is attached with a grinder or the like. Therefore, it is necessary to perform a complicated operation such as forming into a smooth bead shape, and there is a problem that workability when manufacturing the track frame is lowered.

  In addition, in order to increase the rigidity of the cylindrical body of the center frame, the manufacturing cost of the track frame increases when the thickness of the cylindrical body is increased or a reinforcing plate is provided between the cylindrical body and the leg. There is a problem.

  The present invention has been made in view of the above-described problems of the prior art, so that mud etc. can be prevented from accumulating on the upper surface of the leg portion, and the bonding strength between the leg portion and the center frame can be increased. The purpose is to provide a truck frame for construction machinery.

  In order to solve the above-described problems, the present invention provides a center frame, left and right side frames located on both left and right sides of the center frame and extending in the front and rear directions, the center frame, and the side frames. It is applied to the track frame of construction machinery that consists of the leg part before and after connecting the two.

  The center frame is characterized in that the center frame includes a bottom plate comprising a lower central plate portion and a plurality of lower leg plate plates extending from the lower central plate portion and constituting the lower surfaces of the leg portions, A hollow cylinder projecting upward from the center plate part of the bottom plate and a pair of legs standing on the bottom plate of the bottom plate in front and rear directions, and a base end side fixed to the cylinder The upper part which consists of a pair of leg part side plate, the upper center board part fixed to the upper end side of the said cylinder, and the inclination board part each inclined and provided in the part corresponding to each leg part lower board of the said bottom plate It is constituted by a plate and a leg upper plate which has an inclined surface inclined in a mountain shape and is fixedly provided to the inclined plate portion and the pair of leg side plates.

  The invention of claim 2 is that the upper plate is configured such that the upper center plate portion and the inclined plate portion are integrally formed on a single plate material.

  According to a third aspect of the present invention, the upper plate is configured such that the upper central plate portion and the inclined plate portion are formed by separate members and are integrally joined.

  According to a fourth aspect of the present invention, the leg upper plate has a ridge line portion that becomes a top portion of the inclined surface inclined in the mountain shape, and the ridge line portion of the leg portion extends from the center frame to the side frame. The configuration is arranged parallel to the extending direction.

  According to a fifth aspect of the present invention, a connecting flange projecting toward the center frame is provided on one end side of the side frame, and a motor bracket for mounting a traveling motor is provided on the connecting flange. The side has a configuration in which the ridge line portion is joined to the side frame and the connection flange in a state in which the ridge line portion is abutted to an intersection of the side frame and the connection flange.

  The invention of claim 6 is configured such that the leg upper plate is joined to the inclined plate portion in a state in which the ridge line portion is orthogonal to a boundary line between the upper central plate portion and the inclined plate portion of the upper plate. It is in.

  According to the first aspect of the present invention, the inclined plate portion provided on the upper plate corresponding to the lower leg plate of the bottom plate, and the pair of leg side plates provided upright on the lower leg plate of the bottom plate, By fixing the plate, a leg portion surrounded by the lower leg plate, the leg side plate, and the upper leg plate can be formed. In this case, since the leg upper plate has an inclined surface inclined in a mountain shape, it is possible to prevent the mud from being deposited on the leg by dropping the mud along the inclined surface.

  In addition, the lower leg plate is integrally provided on the bottom plate, the base side of the leg side plate is fixed to a cylinder provided on the bottom plate, and the upper leg plate is fixed to the inclined plate portion and the leg side plate of the upper plate. Has been. Therefore, for example, when a leg made of a member different from the center frame is abutted against and welded to the cylindrical body of the center frame, the load is concentrated below the joint where the center frame and the leg are joined. The load can be supported by the entire leg components such as the plate, the leg side plate, and the leg upper plate. As a result, the joint strength of the leg portion with respect to the center frame can be increased, and a reinforcing material or the like can be dispensed with. In addition, the work of forming a weld bead formed between a leg portion made of a separate member and the cylindrical body of the center frame using a grinder or the like can be eliminated, so that workability when manufacturing a track frame is improved. be able to.

  According to the invention of claim 2, since the upper central plate portion and the inclined plate portion of the upper plate can be integrally formed using a single plate material, the upper plate comprising the upper central plate portion and the inclined plate portion. The workability when forming the film can be improved, and the manufacturing cost can be reduced.

  According to the invention of claim 3, the upper central plate portion and the inclined plate portion are fixed by fixing the inclined plate portion made of a member different from the upper plate to a portion corresponding to each lower leg plate of the bottom plate of the upper plate. Since the upper board which consists of these can be formed, the freedom degree of the shape of this inclination board part can be raised.

  According to the invention of claim 4, the ridge line portion of the leg upper plate having a mountain-shaped inclined surface is arranged in parallel with the extending direction of the leg portion extending from the center frame to the side frame, thereby The transmission of the load to the side frame can be performed smoothly through each leg portion, and the rigidity of the entire track frame can be increased. Moreover, it can suppress that mud etc. accumulate on a side frame by dropping the mud etc. which fell on the leg part to the front and back along the mountain-shaped inclined surface of a leg upper board.

  According to invention of Claim 5, when joining the front end side of a leg upper board to a side frame and a connection flange, it butt | matches the ridgeline part of a leg upper board to the intersection of a side frame and a connection flange. The front end side of the leg portion can be joined to the side frame and the connection flange with a large area, and the joining strength between the leg portion and the side frame can be increased. Moreover, by colliding the ridge line portion of the leg upper plate with the intersection of the side frame and the connecting flange, it is possible to prevent mud etc. from being deposited in the vicinity of the motor bracket provided on the connecting flange. The attached traveling motor can be protected from mud and the like.

  According to invention of Claim 6, the leg upper board which has a mountain-shaped inclined surface by making the ridgeline part of a leg upper board orthogonal to the boundary line of the upper center board part of an upper board, and an inclined board part. The shape of the joint portion between the upper plate and the inclined plate portion of the upper plate can be simplified. As a result, when the upper plate of the leg portion and the inclined plate portion of the upper plate are joined by welding, they can be welded in a state where they are abutted without gaps, and the workability and reliability of this welding work can be improved. Can do.

  Hereinafter, the embodiment of the track frame of the construction machine according to the present invention will be described in detail with reference to FIGS. 1 to 13 by taking as an example the case of applying to a lower traveling body of a hydraulic excavator.

  First, FIGS. 1 to 10 show a first embodiment of the present invention. In the figure, reference numeral 1 denotes a hydraulic excavator which is a typical example of a construction machine. The hydraulic excavator 1 can turn on a self-propelled crawler type lower traveling body 2 and a swiveling wheel 3 on the lower traveling body 2. The upper swing body 4 mounted on the upper swing body 4 and a work device 5 provided on the front side of the upper swing body 4 so as to be able to move up and down and excavating mud or the like are roughly constituted.

  Here, the lower traveling body 2 includes a track frame 11 described later, drive wheels 6 and idle wheels 7 provided on left and right side frames 29 and 33 described later, and the drive wheels 6 and idle wheels 7. It is roughly constituted by a wound crawler belt 8. The lower traveling body 2 travels stably on rough terrain such as a mountainous area and a muddy area by driving the crawler belt 8 around by the drive wheels 6. Further, on the front side of the track frame 11, a soil discharge plate 9 for performing soil removal work such as mud and leveling work is provided so as to be rotatable upward and downward.

  Reference numeral 11 denotes a track frame serving as a base of the lower traveling body 2. The track frame 11 includes a center frame 12, a left front leg 25, and a left rear leg 26, which will be described later, as shown in FIGS. The right front leg 27, the right rear leg 28, the left side frame 29, the right side frame 33, and the like.

  Reference numeral 12 denotes a center frame, and the center frame 12 constitutes a central portion of the track frame 11. As shown in FIGS. 7 to 10 and the like, the center frame 12 includes a bottom plate 13, a cylindrical body 14, each leg side plate 15, 16, 17, 18, an upper plate 19, and each leg portion. The upper plates 21, 22, 23, and 24 are roughly configured.

  Reference numeral 13 denotes a bottom plate of the center frame 12, and the bottom plate 13 is formed in a substantially X shape as a whole by, for example, a thick single steel plate as shown in FIGS. Here, the bottom plate 13 includes a horizontal lower center plate portion 13A located at the center portion in the left and right directions, and a left front leg extending leftward while being inclined obliquely downward from the left front end side of the lower center plate portion 13A. The lower plate 13B, the left rear leg lower plate 13C extending obliquely downward from the left rear end side of the lower central plate portion 13A, and obliquely downward from the right front end side of the lower central plate portion 13A. The right front leg lower plate 13D that extends to the right side while inclining, and the right rear leg lower plate 13E that extends diagonally downward from the right rear end side of the lower center plate part 13A and that extends obliquely rearward to the right. The lower center plate 13A and the leg lower plates 13B, 13C, 13D, and 13E are integrally formed.

  The left front leg lower plate 13B and the left rear leg lower plate 13C of the bottom plate 13 are arranged at intervals in the front and rear directions, and the left front leg lower plate 13B constitutes the lower surface of the left front leg 25 described later, The lower leg plate 13C constitutes the lower surface of the left rear leg portion 26 described later. Further, the right front leg lower plate 13D and the right rear leg lower plate 13E of the bottom plate 13 are arranged with a space in the front and rear directions, and the right front leg lower plate 13D constitutes the lower surface of the right front leg 27 described later, and the right rear leg The leg lower plate 13E constitutes the lower surface of the right rear leg 28 described later. Further, a central hole 13F for performing assembly work and inspection work is formed at the center of the lower central plate part 13A.

  Reference numeral 14 denotes a cylindrical body as a hollow cylinder provided on the upper surface side of the bottom plate 13. The cylindrical body 14 connects between the bottom plate 13 and an upper plate 19 described later, and each leg side plate 15 described later. 16, 16, 17, 18 are fixed to the base end side. Here, as shown in FIGS. 8 and 9, the cylindrical body 14 has a cylindrical shape having an outer diameter larger than the center hole 13 </ b> F of the bottom plate 13, and a lower end portion of the cylindrical body 14 forms a lower center plate portion 13 </ b> A of the bottom plate 13. By being welded over the entire circumference, it protrudes upward from the upper surface side of the lower central plate portion 13A.

  Reference numeral 15 denotes a left front leg side plate standing on the left front leg lower plate 13B of the bottom plate 13. As shown in FIGS. 8 and 9, the left front leg side plate 15 is a cylinder while facing the front and rear directions with a space therebetween. It is constituted by a pair of front plate 15A and rear plate 15B extending from the body 14 to the left side. The lower ends of the front plate 15A and the rear plate 15B constituting the left front leg side plate 15 are fixed to the upper surfaces of the lower center plate portion 13A and the left front leg lower plate 13B of the bottom plate 13 by welding, respectively. Further, the base end portion 15A1 of the front plate 15A and the base end portion 15B1 of the rear plate 15B are welded to the outer peripheral surface of the cylindrical body 14, respectively.

  Reference numeral 16 denotes a left hind leg side plate standing on the left hind leg lower plate 13C of the bottom plate 13. The left hind leg side plate 16 is diagonally left rearward from the cylindrical body 14 while facing each other in the front and rear directions. It is comprised by a pair of front board 16A and rear board 16B which extend to. The lower end of the front plate 16A and the rear plate 16B of the left rear leg side plate 16 is welded to the upper surface of the lower center plate portion 13A of the bottom plate 13 and the lower left leg portion lower plate 13C. Further, the base end portion 16A1 of the front plate 16A and the base end portion 16B1 of the rear plate 16B are welded to the outer peripheral surface of the cylindrical body 14, respectively.

  Reference numeral 17 denotes a right front leg side plate that is erected on the right front leg lower plate 13D of the bottom plate 13, and the right front leg side plate 17 extends from the cylindrical body 14 to the right side while facing each other with a gap in the front and rear directions. The front plate 17A and the rear plate 17B. The lower end of the front plate 17A and the rear plate 17B of the right front leg side plate 17 is welded to the upper surface of the lower center plate portion 13A of the bottom plate 13 and the right front leg portion lower plate 13D, and the base end portion 17A1 of the front plate 17A. The base end portion 17B1 of the rear plate 17B is welded to the outer peripheral surface of the cylindrical body 14, respectively.

  Reference numeral 18 denotes a right rear leg side plate that is erected on the right rear leg lower plate 13E of the bottom plate 13. The right rear leg side plate 18 is diagonally right rearward from the cylindrical body 14 while facing each other in the front and rear directions. It is comprised by a pair of front board 18A and rear board 18B which extend to. The lower end of the front plate 18A and the rear plate 18B of the right rear leg side plate 18 is welded to the upper surface of the lower center plate portion 13A of the bottom plate 13 and the lower rear plate 13E of the right rear leg, and the base end portion of the front plate 18A. The base end portion 18B1 of 18A1 and the rear plate 18B are welded to the outer peripheral surface of the cylindrical body 14, respectively.

  Reference numeral 19 denotes an upper plate provided on the upper end side of the cylindrical body 14, and the upper plate 19 is arranged to face the bottom plate 13 in the upper and lower directions. Here, as shown in FIGS. 8 and 10, the upper plate 19 is formed using, for example, a thick single steel plate material, and is fixed to the upper end side of the cylindrical body 14. And inclined plate portions 19B, 19C, 19D, and 19E, which will be described later, that are inclined downward from the upper central plate portion 19A and face the lower leg plates 13B, 13C, 13D, and 13E of the bottom plate 13, respectively. The upper central plate portion 19A and the inclined plate portions 19B, 19C, 19D, 19E are integrally formed. A center hole 19F for arranging a center joint (not shown) and the like is formed at the center of the upper center plate portion 19A of the upper plate 19 corresponding to the center hole 13F of the bottom plate 13.

  The upper plate 19 faces the bottom plate 13 in the upward and downward directions with the cylindrical body 14 interposed therebetween by welding the lower surface of the upper central plate portion 19A to the upper end portion of the cylindrical body 14 over the entire circumference. Yes. Further, an annular round cylinder 20 is fixed to the upper surface side of the upper central plate portion 19A of the upper plate 19 by means of welding or the like, and the swiveling wheel 3 shown in FIG. It has a configuration.

  19B is a left front inclined plate portion integrally provided on the left front side of the upper center plate portion 19A. The left front inclined plate portion 19B is bent downward by bending a portion corresponding to the left front leg lower plate 13B of the bottom plate 13 downward. It is integrally formed with the upper central plate portion 19A. Here, the left front inclined plate portion 19B protrudes leftward from the upper central plate portion 19A while being inclined obliquely downward with an inclination angle θ with respect to the vertical direction (see FIG. 4). The lower surface of the left front inclined plate portion 19B is welded to the upper end portions of the front plate 15A and the rear plate 15B constituting the left front leg portion side plate 15. In addition, a left front leg upper plate 21 described later is welded to the upper surface of the left front inclined plate portion 19B.

  19C is a left rear inclined plate portion integrally provided on the left rear side of the upper center plate portion 19A, and the left rear inclined plate portion 19C folds a portion corresponding to the left rear leg lower plate 13C of the bottom plate 13 downward. By bending, the upper central plate portion 19A protrudes diagonally to the left and rearward while being inclined at the same inclination angle θ as the left front inclined plate portion 19B. And the lower surface of the left rear inclined plate portion 19C is welded to the upper end portion of the left rear leg portion side plate 16, and the left rear leg upper plate 22 described later is welded to the upper surface of the left rear inclined plate portion 19C. It has become.

  19D is a right front inclined plate portion integrally provided on the right front side of the upper center plate portion 19A, and the right front inclined plate portion 19D is bent downward by bending a portion corresponding to the right front leg lower plate 13D of the bottom plate 13 downward. While tilting at an inclination angle θ similar to that of the left front inclined plate portion 19B, it protrudes rightward from the upper central plate portion 19A. And the lower surface of right front inclination board part 19D is welded to the upper end part of right front leg part side plate 17, and the below-mentioned right front leg part upper board 23 is welded to the upper surface of right front inclination board part 19D. .

  19E is a right rear inclined plate portion integrally provided on the right rear side of the upper central plate portion 19A. The right rear inclined plate portion 19E folds a portion corresponding to the right rear leg lower plate 13E of the bottom plate 13 downward. By bending, the upper central plate portion 19A protrudes obliquely rearward to the right while tilting at the same inclination angle θ as the left front inclined plate portion 19B. A lower surface of the right rear inclined plate portion 19E is welded to the upper end portion of the right rear leg portion side plate 18, and a right rear leg upper plate 24 described later is welded to the upper surface of the right rear inclined plate portion 19E. It has become.

  Reference numeral 21 denotes a left front leg upper plate provided facing the left front leg lower plate 13B of the bottom plate 13 in the upward and downward directions. The left front leg upper plate 21 bends, for example, one flat plate into a mountain shape. It is formed by. Here, as shown in FIGS. 8 and 10, the left front leg upper plate 21 has two inclined surfaces 21A inclined in a mountain shape in the front and rear directions, and the top of each inclined surface 21A is linear. The ridge line portion 21B.

  As shown in FIGS. 4 and 5, the lower surface of the left front leg upper plate 21 includes the upper surface of the left front inclined plate portion 19 </ b> B of the upper plate 19, and the front plate 15 </ b> A and the rear plate constituting the left front leg side plate 15. It is welded to the upper end of 15B. As a result, a left front leg portion 25 described later having a strong box structure surrounded by the left front leg lower plate 13B of the bottom plate 13, the front plates 15A and rear plates 15B of the left front leg side plate 15, and the left front leg upper plate 21 is formed. Has been.

  Here, as shown in FIG. 2, if the boundary line between the upper center plate portion 19A of the upper plate 19 and the left front inclined plate portion 19B is A1, the ridge line portion 21B of the left front leg upper plate 21 is the boundary line A1. Is welded to the left front inclined plate portion 19B. This simplifies the shape of the joint portion between the left front leg upper plate 21 having the mountain-shaped inclined surface 21A and the left front inclined plate portion 19B of the upper plate 19, and can be welded in a state where they are abutted without gaps. It can be configured.

  Reference numeral 22 denotes a left rear leg upper plate provided facing the lower left leg lower plate 13C of the bottom plate 13 in the upward and downward directions. The left rear leg upper plate 22 bends, for example, one flat plate. And has two inclined surfaces 22A inclined in a mountain shape in the front and rear directions, and the top of each inclined surface 22A is a ridge line portion 22B.

  The lower surface of the left rear leg upper plate 22 is welded to the upper surface of the left rear inclined plate portion 19C of the upper plate 19 and the upper end portion of the left rear leg side plate 16, whereby the left rear leg of the bottom plate 13 is welded. A left rear leg portion 26, which will be described later, has a strong box structure surrounded by the lower plate 13C, the front plate 16A and the rear plate 16B of the left rear leg side plate 16, and the left rear leg upper plate 22. In this case, assuming that the boundary line between the upper center plate portion 19A of the upper plate 19 and the left rear inclined plate portion 19C is A2, the left rear leg portion upper plate 22 is in a state where the ridge line portion 22B is orthogonal to the boundary line A2. The left rear inclined plate portion 19C is welded (see FIG. 2). Thereby, it becomes the structure which can simplify the shape of the junction part of the left rear leg part upper board 22 and the left rear inclination board part 19C of the upper board 19.

  23 is a right front leg upper plate provided facing the right front leg lower plate 13D of the bottom plate 13 in the upward and downward directions, and the right front leg upper plate 23 is the front, It has two inclined surfaces 23A inclined in a mountain shape in the rear direction, and the top of each inclined surface 23A is a ridge line portion 23B.

  The lower surface of the right front leg upper plate 23 is welded to the upper surface of the right front inclined plate portion 19D of the upper plate 19 and the upper end portion of the right front leg side plate 17, whereby the right front leg lower plate 13D of the bottom plate 13 is A right front leg portion 27 (to be described later) having a strong box structure surrounded by the front plate 17A and the rear plate 17B of the right front leg portion side plate 17 and the right front leg upper plate 23 is formed. In this case, assuming that the boundary line between the upper center plate portion 19A of the upper plate 19 and the right front inclined plate portion 19D is A3, the right front leg upper plate 23 has the ridge line portion 23B orthogonal to the boundary line A3. It is welded to the inclined plate portion 19D (see FIG. 2).

  Reference numeral 24 denotes a right rear leg upper plate provided facing the right rear leg lower plate 13E of the bottom plate 13 in the upward and downward directions. The right rear leg upper plate 24 is the same as the left rear leg upper plate 22. In addition, there are two inclined surfaces 24A inclined in a mountain shape in the front and rear directions, and the top of each inclined surface 24A is a ridge line portion 24B.

  The lower surface of the right rear leg portion upper plate 24 is welded to the upper surface of the right rear inclined plate portion 19E of the upper plate 19 and the upper end portion of the right rear leg portion side plate 18, whereby the right rear leg of the bottom plate 13 is welded. A right rear leg portion 28, which will be described later, has a strong box structure surrounded by the lower plate 13E, the front and rear plates 18A and 18B of the right rear leg portion side plate 18, and the right rear leg upper plate 24. In this case, if the boundary line between the upper center plate portion 19A of the upper plate 19 and the right rear inclined plate portion 19E is A4, the right rear leg portion upper plate 24 is in a state where the ridge line portion 24B is orthogonal to the boundary line A4. The right rear inclined plate portion 19E is welded (see FIG. 2).

  Accordingly, as shown in FIGS. 6 and 7, the left front side of the center frame 12 is surrounded by the left front leg lower plate 13 </ b> B of the bottom plate 13, the left front leg side plate 15, and the left front leg upper plate 21. A left front leg portion 25 having a box structure is formed (see FIG. 5). Further, on the left rear side of the center frame 12, a left rear leg having a box structure surrounded by a left rear leg lower plate 13C of the bottom plate 13, a left rear leg side plate 16, and a left rear leg upper plate 22 is provided. A portion 26 is formed. A left side frame 29 (to be described later) is attached to the front end sides of the left front leg portion 25 and the left rear leg portion 26.

  On the other hand, on the right front side of the center frame 12, a right front leg portion 27 having a box structure surrounded by a right front leg lower plate 13D of the bottom plate 13, a right front leg side plate 17, and a right front leg upper plate 23 is formed. ing. Further, on the right rear side of the center frame 12, a right rear leg having a box structure surrounded by a right rear leg lower plate 13E of the bottom plate 13, a right rear leg side plate 18, and a right rear leg upper plate 24 is provided. A portion 28 is formed. A right side frame 33 (to be described later) is attached to the distal ends of the right front leg portion 27 and the right rear leg portion 28.

  Reference numeral 29 denotes a left side frame located on the left side of the center frame 12 and extending in the front and rear directions. As shown in FIGS. 2 and 6, the left side frame 29 has an inverted U-shaped cross-sectional shape in the front and rear directions. A connecting flange 30 described later is provided on the rear end side (one end side). The front end side of the left side frame 29 is an idler wheel support portion 29A that supports the idler wheel 7 shown in FIG. 1 so as to be movable in the front and rear directions, and a side surface 29B of the left side frame 29 that faces the center frame 12. The front left side of the left front leg 25 and the left rear leg 26 are joined together.

  A connection flange 30 is provided on the rear end side of the left side frame 29, and the connection flange 30 is formed in a substantially rectangular flat plate shape using a steel plate or the like. The connection flange 30 includes a frame side flange surface 30A welded to the rear end portion of the left side frame 29, and a leg side flange surface 30B projecting from the frame side flange surface 30A to the center frame 12 side. The front end side of the left rear leg portion 26 is welded to the leg side flange surface 30B. A motor bracket 31 for attaching a travel motor (not shown) of the drive wheel 6 shown in FIG. 1 to the surface (rear surface) opposite to the surface to which the left side frame 29 is joined of the connection flange 30. Is fixed.

  And the front end side of the left front leg part 25 which consists of the left front leg part lower board 13B, the left front leg part side board 15, the left front leg part upper board 21 grade | etc., Of the bottom board 13 is the intermediate part of the length direction of the left side frame 29 (side surface 29B). A substantially triangular reinforcing plate 32 is fixed between the inclined surface 21A of the left front leg upper plate 21 and the side surface 29B of the left side frame 29.

  In this case, when the extension direction of the left front leg part 25 is expressed as an extension direction line B1-B1 indicated by a one-dot chain line in FIG. 6, the ridge line part 21B of the left front leg part upper plate 21 is the extension direction line B1-B1. They are arranged in parallel. Thereby, the transmission of the load from the center frame 12 to the left side frame 29 can be smoothly performed through the left front leg portion 25, and mud or the like that has fallen on the left front leg portion 25 is inclined to the left front leg portion upper plate 21. It is configured to fall along the surface 21A.

  On the other hand, the front end side of the left rear leg portion 26 including the left rear leg lower plate 13C, the left rear leg side plate 16, the left rear leg upper plate 22 and the like of the bottom plate 13 is the rear end of the left side frame 29 (side surface 29B). Side and the leg side flange surface 30B of the connection flange 30 are joined by welding.

  In this case, when the extension direction of the left rear leg portion 26 is expressed as an extension direction line B2-B2 indicated by a one-dot chain line in FIG. 6, the ridge line portion 22B of the left rear leg portion upper plate 22 has an extension direction line B2-B2. It arrange | positions so that it may become parallel to B2. Thereby, the transmission of the load from the center frame 12 to the left side frame 29 can be smoothly performed through the left rear leg portion 26, and the mud or the like that has fallen on the left rear leg portion 26 is left on the left rear leg portion upper plate. It is configured to fall along 22 inclined surfaces 22A.

  Furthermore, as shown in FIG. 2, when the intersection of the side surface 29B of the left side frame 29 and the connection flange 30 is P1, the tip side of the left rear leg upper plate 22 has the ridge line portion 22B butted against the intersection P1. In the state, it is welded to the side surface 29B of the left side frame 29 and the leg side flange surface 30B of the connection flange 30. Thereby, the front end side of the left rear leg portion 26 can be welded to the left side frame 29 and the connection flange 30 with a large area, and the joining strength between the left rear leg portion 26 and the left side frame 29 can be increased. It has a configuration.

  Reference numeral 33 denotes a right side frame located on the right side of the center frame 12 and extending in the front and rear directions. The right side frame 33 has a reverse U-shaped cross-sectional shape and extends in the front and rear directions. A connecting flange 34 is provided. Similarly to the left side frame 29, the front end side of the right side frame 33 is an idler wheel support portion 33A, and a right front leg portion 27 and a right rear leg are formed on the side surface 33B of the right side frame 33 facing the center frame 12. The front end side of the portion 28 is joined.

  Reference numeral 34 denotes a connection flange provided on the rear end side of the right side frame 33. The connection flange 34 is formed in a substantially rectangular flat plate shape using a steel plate or the like. The connection flange 34 includes a frame side flange surface 34A welded to the rear end portion of the right side frame 33, and a leg side flange surface 34B projecting from the frame side flange surface 34A to the center frame 12 side. The front end side of the right rear leg portion 28 is welded to the leg side flange surface 34B. A motor bracket 35 is fixed to a surface (rear surface) of the connection flange 34 opposite to the surface to which the right side frame 33 is joined.

  And the front end side of the right front leg part 27 consisting of the right front leg part lower plate 13D, the right front leg part side plate 17, the right front leg part upper plate 23, etc. of the bottom plate 13 is an intermediate part in the length direction of the right side frame 33 (side surface 33B). A substantially triangular reinforcing plate 36 is fixed between the inclined surface 23A of the right front leg upper plate 23 and the side surface 33B of the right side frame 33.

  In this case, when the extension direction of the right front leg portion 27 is expressed as an extension direction line B3-B3 indicated by a one-dot chain line in FIG. 6, the ridgeline portion 23B of the right front leg portion upper plate 23 is the extension direction line B3-B3. They are arranged in parallel. As a result, transmission of the load from the center frame 12 to the right side frame 33 can be smoothly performed through the right front leg portion 27, and mud or the like that has fallen on the right front leg portion 27 is inclined to the right front leg portion upper plate 23. It is configured to fall along the surface 23A.

  On the other hand, the front end side of the right rear leg portion 28 including the right rear leg lower plate 13E, the right rear leg side plate 18, the right rear leg upper plate 24, etc. of the bottom plate 13 is the rear end of the right side frame 33 (side surface 33B). Side and the leg side flange surface 34B of the connection flange 34 are joined by welding.

  In this case, when the extension direction of the right rear leg portion 28 is expressed as an extension direction line B4-B4 indicated by a one-dot chain line in FIG. 6, the ridge line portion 24B of the right rear leg portion upper plate 24 has an extension direction line B4-. It arrange | positions so that it may become parallel to B4. As a result, the transmission of the load from the center frame 12 to the right side frame 33 can be smoothly performed through the right rear leg portion 28, and the mud or the like that has fallen on the right rear leg portion 28 is removed from the right rear leg portion upper plate. It is configured to fall along 24 inclined surfaces 24A.

  Further, as shown in FIG. 2, when the intersection of the side surface 33B of the right side frame 33 and the connection flange 34 is P2, the tip side of the right rear leg upper plate 24 has the ridge line portion 24B butted against the intersection P2. In the state, it is welded to the side surface 33B of the right side frame 33 and the leg side flange surface 34B of the connection flange 34. Thereby, the front end side of the right rear leg portion 28 can be welded to the right side frame 33 and the connection flange 34 with a large area, and the bonding strength between the right rear leg portion 28 and the right side frame 33 can be increased. It has a configuration.

  Reference numeral 37 denotes a cylinder bracket that is located at the center of the center frame 12 in the left and right directions and is fixed to the cylindrical body 14 and the like. As shown in FIGS. Protruding. The cylinder bracket 37 is attached with a hydraulic cylinder (not shown) for raising and lowering the earth discharging plate 9 shown in FIG.

  A pair of earthing plate brackets 38 and 38 are arranged on the left and right sides of the cylinder bracket 37. The earthing plate bracket 38 can turn the earthing plate 9 shown in FIG. 1 upward and downward. To support.

  The track frame 11 of the hydraulic excavator 1 according to the present embodiment has the above-described configuration. Next, the function and effect will be described.

  First, regarding the left front leg portion 25 connecting the center frame 12 and the left side frame 29, the lower plate 13B of the left front leg portion is integrally formed on the bottom plate 13, and the upper plate facing the bottom plate 13 with the cylindrical body 14 interposed therebetween. 19 is provided with a left front inclined plate portion 19B, and by attaching a left front leg upper plate 21 to the left front inclined plate portion 19B and a pair of left front leg side plates 15 erected on the left front leg lower plate 13B. The left front leg portion 25 having a strong box structure surrounded by the left front leg portion lower plate 13B, the left front leg portion side plate 15, and the left front leg portion upper plate 21 can be formed.

  In this case, the left front leg upper plate 21 has a mountain-shaped inclined surface 21A inclined frontward and rearward with the ridge line portion 21B as the top, so that the mud and the like are front and rear along the inclined surface 21A. By dropping in the direction, it is possible to suppress mud and the like from accumulating on the left front leg portion 25 and the left side frame 29.

  In addition, the left front leg lower plate 13B is provided integrally with the bottom plate 13, the base end side of the left front leg side plate 15 is fixed to the cylindrical body 14 provided on the bottom plate 13, and the left front leg upper plate 21 is fixed to the upper plate 19. Since the left front inclined plate portion 19B and the left front leg portion side plate 15 are fixed, the load can be supported by the entire components of the left front leg portion 25. Therefore, for example, when the left front leg made of a member different from the center frame is butted against the cylinder of the center frame and welded, the center of the center frame and the leg is compared with the case where the load is concentrated. The joint strength of the left front leg 25 with respect to the frame 12 can be increased. In addition, for example, when the left front leg portion and the center frame made of different members are joined by welding, a complicated work such as forming a weld bead portion formed between the two using a grinder or the like can be eliminated. The workability when manufacturing the frame 11 can be improved.

  Further, when the extension direction of the left front leg portion 25 is represented as an extension direction line B1-B1 indicated by a one-dot chain line in FIG. 6, the ridge line portion 21B of the left front leg upper plate 21 is parallel to the extension direction line B1-B1. It is set as the structure arrange | positioned so that it may become. Thereby, the transmission of the load from the center frame 12 to the left side frame 29 can be smoothly performed through the left front leg portion 25, and the rigidity of the entire track frame 11 can be increased. Further, since mud or the like dropped on the left front leg portion 25 can be dropped forward and backward along the inclined surface 21A of the left front leg portion upper plate 21, mud mud is left on the left front leg portion 25 and the left side frame 29. It is possible to reliably suppress the accumulation of the crawler belt 8 and to smoothly circulate the crawler belt 8 at all times.

  Further, as shown in FIG. 2, when the boundary line between the upper center plate portion 19A of the upper plate 19 and the left front inclined plate portion 19B is A1, the ridge line portion 21B of the left front leg upper plate 21 is separated from the boundary line A1. It is set as the structure welded to the left front inclination board part 19B in the state orthogonally crossed. This simplifies the shape of the joint portion between the left front leg upper plate 21 having the mountain-shaped inclined surface 21A and the left front inclined plate portion 19B of the upper plate 19, and can be welded in a state where they are abutted without gaps. Therefore, workability and reliability when welding the left front leg upper plate 21 and the left front inclined plate portion 19B can be enhanced.

  On the other hand, regarding the left rear leg portion 26 that connects between the center frame 12 and the left side frame 29, the left rear leg portion 26 also includes the left rear leg lower plate 13C, the left rear leg side plate 16, A strong box structure surrounded by the left rear leg upper plate 22 is formed, and the left rear leg upper plate 22 is fixed to the left rear inclined plate portion 19 </ b> C of the upper plate 19 and the left rear leg side plate 16. Thereby, a load can be supported by the whole component of the left hind leg part 26, and the joining strength of the left hind leg part 26 with respect to the center frame 12 can be raised. Further, since the left rear leg upper plate 22 has a mountain-shaped inclined surface 22A, it is possible to prevent mud and the like from accumulating on the left rear leg 26 and the left side frame 29.

  Further, when the extension direction of the left rear leg portion 26 is an extension direction line B2-B2 indicated by a one-dot chain line in FIG. 6, the ridge line portion 22B of the left rear leg portion upper plate 22 is set to the extension direction line B2-B2. , The load from the center frame 12 to the left side frame 29 can be smoothly transmitted through the left rear leg portion 26.

  As shown in FIG. 2, when the boundary line between the upper center plate portion 19A of the upper plate 19 and the left rear inclined plate portion 19C is A2, the ridge line portion 22B of the left rear leg portion upper plate 22 is defined as the boundary line A2. By making them orthogonal, the left rear leg part upper plate 22 and the left rear inclined plate part 19C of the upper plate 19 can be welded in a state of abutting each other without any gap, so that workability and reliability can be improved. it can.

  Furthermore, as shown in FIG. 2, when the intersection of the side surface 29B of the left side frame 29 and the connection flange 30 is P1, the front end side of the left rear leg upper plate 22 is abutted against the intersection P1 of the ridge 22B. In this state, the side side 29B of the left side frame 29 and the leg side flange surface 30B of the connection flange 30 are welded. Thereby, the front end side of the left rear leg portion 26 can be welded to the left side frame 29 and the connection flange 30 with a large area, and the joining strength between the left rear leg portion 26 and the left side frame 29 can be increased. . Also, the ridge line portion 22B of the left rear leg upper plate 22 is mud in the vicinity of the motor bracket 31 provided on the connection flange 30 by abutting the intersection of the side surface 29B of the left side frame 29 and the connection flange 30 with P1. It is possible to prevent the traveling motor attached to the motor bracket 31 from being mud and the like.

  The effects of the left front leg 25 and the left rear leg 26 described above are the same for the right front leg 27 and the right rear leg 28 connecting the center frame 12 and the right side frame 33.

  Next, FIGS. 11 to 13 show a second embodiment of the present invention. The feature of this embodiment is that the upper center plate portion and the inclined plate portion constituting the upper plate are formed by separate members. Thus, it is configured to be integrally joined. In the present embodiment, the same components as those in the first embodiment described above are denoted by the same reference numerals, and the description thereof is omitted.

  In the figure, reference numeral 41 denotes a center frame according to the present embodiment. The center frame 41 is similar to the center frame 12 according to the first embodiment, and includes a bottom plate 13, a cylindrical body 14, and leg side plates 15 and 16. , 17, 18, an upper plate 42 described later, and leg upper plates 21, 22, 23, 24. However, the configuration of the upper plate 42 is different from that of the upper plate 19 according to the first embodiment.

  Reference numeral 42 denotes an upper plate provided on the upper end side of the cylindrical body 14, and the upper plate 42 is arranged to face the bottom plate 13 in the upper and lower directions. The upper plate 42 has a central hole 43A and is formed of a single horizontal plate fixed to the upper end side of the cylindrical body 14, and the upper central plate portion 43 is a separate member. The left front inclined plate portion 44, the left rear inclined plate portion 45, the right front inclined plate portion 46, and the right rear inclined plate portion 47 are formed, and each of the inclined plate portions 44, 45, 46, 47 is integrally joined.

  Here, the left front inclined plate portion 44 is formed of a single plate having a horizontal surface 44A that contacts the lower surface of the upper central plate portion 43 and an inclined surface 44B inclined downward from the horizontal surface 44A. Then, by welding the horizontal surface 44A of the left front inclined plate portion 44 to the lower surface on the front left end side of the upper central plate portion 43, the inclined surface 44B of the left front inclined plate portion 44 has an inclination angle θ with respect to the vertical direction. It protrudes to the left side from the upper center board part 43, inclining diagonally downward (refer FIG. 13). Further, the lower surface of the left front inclined plate portion 44 is welded to the upper end portion of the left front leg portion side plate 15, and the left front leg upper plate 21 is welded to the upper surface of the inclined surface 44 </ b> B of the left front inclined plate portion 44.

  On the other hand, the left rear inclined plate portion 45 is composed of a single plate having a horizontal surface 45A and an inclined surface 45B. Then, by welding the horizontal surface 45A of the left rear inclined plate portion 45 to the lower surface on the rear left end side of the upper central plate portion 43, the inclined surface 45B has the same inclination angle θ as the inclined surface 44B of the left front inclined plate portion 44. It protrudes from the upper center board part 43 diagonally to the left diagonally. Further, the lower surface of the left rear inclined plate portion 45 is welded to the upper end portion of the left rear leg portion side plate 16, and the left rear leg upper plate 22 is welded to the upper surface of the inclined surface 45B of the left rear inclined plate portion 45. ing.

  Similarly, the right front inclined plate portion 46 has a horizontal plane 46A welded to the lower surface on the front right end side of the upper central plate portion 43 and a right side from the upper central plate portion 43 while being inclined downward from the horizontal plane 46A. It consists of the inclined surface 46B which protrudes. The lower surface of the right front inclined plate portion 46 is welded to the upper end portion of the right front leg portion side plate 17, and the right front leg upper plate 23 is welded to the upper surface of the inclined surface 46 </ b> B of the right front inclined plate portion 46.

  Further, the right rear inclined plate portion 47 protrudes from the upper central plate portion 43 diagonally to the right rear side while being inclined downward from the horizontal surface 47A and the horizontal surface 47A welded to the lower surface of the upper right central plate portion 43 on the rear right end side. It consists of an inclined surface 47B. The lower surface of the right rear inclined plate portion 47 is welded to the upper end portion of the right rear leg side plate 18, and the upper right rear leg portion plate 24 is welded to the upper surface of the inclined surface 47B of the right rear inclined plate portion 47. ing.

  The track frame according to the present embodiment includes the center frame 41 as described above, and the basic operation and effects thereof are not particularly different from those according to the first embodiment.

  However, according to the present embodiment, the upper central plate portion 43 and the inclined plate portions 44, 45, 46, 47 constituting the upper plate 42 are formed by separate members and are integrally joined. . Accordingly, the left front inclined plate portion 44, the left rear inclined plate portion 45, the right front inclined plate portion 46, and the right rear inclined plate portion 47 can be formed as separate members from the upper central plate portion 43, respectively. The degree of freedom of the shape of the inclined plate portions 44, 45, 46, 47 can be increased.

  In each of the above-described embodiments, the bottom plate 13 constituting the center frame 12 is made of the lower center plate portion 13A, the left front leg portion lower plate 13B, the left rear leg portion lower plate 13C, and the right front leg portion using a single steel plate material. The case where board 13D and the right back leg lower board 13E are integrally formed is illustrated. However, the present invention is not limited to this. For example, a member provided with a left front leg lower plate 13B and a left rear leg lower plate 13C on the left half of the lower central plate portion 13A, and a right side on the right half of the lower central plate portion 13A. Two members, the member provided with the front leg lower plate 13D and the right rear leg lower plate 13E, may be formed separately, and these two members may be joined together by means such as welding.

  Moreover, in each embodiment mentioned above, the case where the cylindrical body 14 is used as a cylinder provided on 13 A of lower center board parts of the baseplate 13 is illustrated. However, the present invention is not limited to this, and for example, a configuration using a rectangular tubular body may be used.

  Moreover, in each embodiment mentioned above, the track frame 11 which comprises the lower traveling body 2 of the hydraulic shovel 1 is illustrated as a track frame of a construction machine. However, the present invention is not limited to this, and can be widely applied to truck frames of other construction machines such as a hydraulic crane.

1 is a front view showing a hydraulic excavator provided with a track frame according to a first embodiment of the present invention. It is a top view which shows a track frame. It is the left view which looked at the track frame from the arrow III-III direction in FIG. FIG. 4 is an enlarged view of a main part showing an enlarged left front leg part in FIG. 3. It is sectional drawing which looked at the left front leg lower board, the left front leg side plate, and the left front leg upper board from the arrow V-V direction in FIG. It is a perspective view which shows a track frame. It is a perspective view which shows a center frame and a leg part. It is a disassembled perspective view which shows a center frame and a leg part. It is a disassembled plan view shown in the state which decomposed | disassembled the baseplate, the cylindrical body, and the leg part side plate. It is a disassembled plan view which shows the state which decomposed | disassembled the upper board and the leg part upper board. It is a perspective view similar to FIG. 7 which shows the center frame and leg part by 2nd Embodiment. It is a disassembled perspective view shown in the state which decomposed | disassembled the upper center board part and each inclination board part which comprise an upper board. It is a principal part enlarged view similar to FIG. 4 which expands and shows the left front leg part by 2nd Embodiment.

Explanation of symbols

1 Excavator (construction machine)
11 Track frame 12, 41 Center frame 13 Bottom plate 13A Lower center plate portion 13B Left front leg lower plate (lower leg plate)
13C Left lower leg lower plate (leg lower plate)
13D Right front leg lower plate (leg lower plate)
13E Lower right leg lower plate (lower leg plate)
14 Cylindrical body (tubular body)
15 Left front leg side plate (Leg side plate)
16 Left rear leg side plate (Leg side plate)
17 Right front leg side plate (Leg side plate)
18 Right rear leg side plate (Leg side plate)
19, 42 Upper plate 19A, 43 Upper central plate portion 19B, 44 Left front inclined plate portion (inclined plate portion)
19C, 45 Left rear inclined plate (inclined plate)
19D, 46 Right front inclined plate (inclined plate)
19E, 47 Right rear inclined plate (inclined plate)
21 Left front leg upper plate (leg upper plate)
21A, 22A, 23A, 24A Inclined surface 21B, 22B, 23B, 24B Ridge part 22 Left rear leg upper plate (leg upper plate)
23 Right front leg upper plate (leg upper plate)
24 Right rear leg upper plate (leg upper plate)
25 Left front leg part 26 Left rear leg part 27 Right front leg part 28 Right rear leg part 29 Left side frame 30, 34 Connection flange 31, 35 Motor bracket 33 Right side frame

Claims (6)

A center frame, left and right side frames located on both left and right sides of the center frame and extending in the front and rear directions, and front and rear legs connecting the center frame and the side frames. In a construction machine truck frame consisting of
The center frame is provided with a bottom plate including a lower central plate portion and a plurality of lower leg plate plates that extend from the lower central plate portion and constitute a lower surface of each leg portion, and protrudes upward from the central plate portion of the bottom plate. A hollow cylindrical body, a pair of leg side plates standing in pairs in the front and rear directions on the lower leg plates of the bottom plate and having proximal ends fixed to the cylindrical body, and An upper plate composed of an upper central plate portion fixed to the upper end side and an inclined plate portion provided at a position corresponding to each lower leg plate of the bottom plate, and an inclined surface inclined in a mountain shape A track frame for a construction machine, comprising: an inclined plate portion; and an upper leg portion plate fixed to the pair of leg side plates.   The track frame of a construction machine according to claim 1, wherein the upper plate is configured such that the upper central plate portion and the inclined plate portion are integrally formed on a single plate material.   The track frame of the construction machine according to claim 1, wherein the upper plate is configured such that the upper central plate portion and the inclined plate portion are formed by separate members and are integrally joined.   The leg upper plate has a ridge line part that becomes a top part of the inclined surface inclined in the mountain shape, and the ridge line part is arranged in parallel with an extending direction of the leg part extending from the center frame to the side frame. The track frame of the construction machine according to claim 1, 2 or 3 configured. A connection flange that protrudes toward the center frame is provided on one end of the side frame, and a motor bracket for mounting a travel motor is provided on the connection flange.
5. The front end side of the leg upper plate is configured to be joined to the side frame and the connection flange in a state where the ridge line portion is abutted with an intersection of the side frame and the connection flange. Construction machinery truck frame.   The said leg part upper board is comprised as a structure joined to the said inclination board part in the state in which the ridgeline part orthogonally crosses the boundary line of the upper center board part of the said upper board, and an inclination board part. Truck frame for construction machinery.

Images