JP2016141372A - Dump truck - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the deformation of a vehicle body frame.SOLUTION: A front cross member 39 and a rear cross member 40 are arranged in positions corresponding to a connection region 26A of an upper slope 26 and a connection region 27A of a lower slope 27, left end edges 39A, 40A of the cross members 39, 40 are joined to a left inner plate 22A of a left fame 22, and right end edges 39B, 40B are joined to a right inner plate 23A of a right frame 23. Then, upper end edges 39C, 40C of the cross members 39, 40 are joined to a connecting plate 26A4 of the upper plate 26, and lower end edges 39D, 40D are joined to a connecting plate 27A4 of a lower plate 27. By this constitution, a box structure 41 whose inside is a closed cross section space is formed in an intermediate part of the fore-and-aft direction of the vehicle body frame 21, the left frame 22 and the right frame 23 are connected to each other via the box structure 41, the rigidity of the vehicle body frame 21 is enhanced as a whole, and the deformation of the frame can be suppressed.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a dump truck that is preferably used to transport a transport object such as a crushed stone mined in a mine.

  This type of conventional dump truck has a vehicle body frame that forms a support structure, a cargo bed that is tiltably mounted with a rear position of the vehicle body frame as a fulcrum for loading an object to be transported, and a front side of the cargo bed. The engine includes an engine mounted on the body frame and a cab mounted on the body frame above the engine (see, for example, Patent Document 1).

  Here, the body frame of the dump truck according to the prior art is arranged on the left side in the left and right directions and extends in the front and rear directions, and on the right side in the left and right directions, and the right frame extends in the front and rear directions. A front cross member joined to the front end side of the left and right frames and connecting the frames; a rear cross member joined to the rear end side of the left and right frames and connecting the frames; left and right And an intermediate cross member that is joined to intermediate portions in the front and rear directions of the frame and connects the frames.

Japanese Utility Model Publication No. 2-83169

  By the way, in the state where the object to be transported is loaded on the loading platform, the vehicle body frame receives all the loads acting on the loading platform. The body frame has a structure that is long in the front and rear directions in order to support a large-capacity loading platform. For this reason, the left and right frames of the vehicle body frame have a box structure using a relatively thin plate material, thereby ensuring rigidity while reducing the weight of the vehicle body frame.

  However, the body frame is deformed by the load on the loading platform including the load and the traveling load received during traveling of the dump truck. For this reason, stress concentration due to deformation of the body frame occurs with respect to the joint portion by welding of each member constituting the body frame, and this state is repeated over a long period of time, so that the joint portion of each member of the body frame is There is a possibility that fatigue accumulates and damages.

  On the other hand, an upper plate is joined to the upper ends of the left and right frames, and a lower plate is joined to the lower ends of the left and right frames, and a mount for mounting a traveling drive device for driving wheels on the lower surface side of the lower plates. A vehicle body frame provided with a member is known.

  In such a vehicle body frame in which the upper plate is joined to the upper ends of the left and right frames and the lower plate is joined to the lower ends of the left and right frames, the load of the loading platform and the traveling load act on the vehicle body frames. It is known that the amount of deformation of the upper plate and the lower plate is large. In particular, a mounting member for mounting the traveling drive device is provided on the lower surface side of the lower plate constituting the vehicle body frame, and this mounting member is larger than the lower plate by being formed using a solid structure. It has rigidity. For this reason, for example, when the load of the loading platform is transmitted from the vehicle body frame to the wheels via the mount member and the travel drive device, there is a problem that the deformation amount of the lower plate having a lower rigidity than the mount member becomes large. .

  Furthermore, the left and right width dimensions of the body frame are generally set larger on the front side than on the rear side. For this reason, a torsion occurs when the vehicle body frame is displaced in the upward and downward directions, and the amount of displacement in the upward and downward directions on the front side of the vehicle body frame is larger than the amount of displacement in the upward and downward directions on the rear side. As a result, there is a tendency that the stress at the joint between the left and right frames and the upper plate on the front side of the vehicle body frame and at the joint between the left and right frames and the upper plate tends to increase.

  The present invention has been made in view of the above-described problems of the prior art, and an object thereof is to provide a dump truck capable of suppressing deformation of a vehicle body frame without significantly increasing the weight of the vehicle body frame. Yes.

  In order to solve the above-described problems, the present invention provides a support structure, a vehicle body frame to which a front wheel and a rear wheel are attached, and a rear end position of the vehicle body frame that can be tilted about a transportation object. The vehicle body frame is disposed on the left side in the left and right directions and extends to the front and the rear, and the right frame is disposed on the right side in the left and right directions and extends to the front and the rear. A front frame connecting the front end of the left frame and the front end of the right frame and extending left and right, and a rear frame connecting the rear end of the left frame and the rear end of the right frame and extending left and right The left frame includes a left inner plate and a left outer plate extending in the front and rear directions at intervals in the left and right directions, an upper plate that closes an upper end of the left inner plate and the left outer plate, and The left inner plate and the lower end of the left outer plate The right frame closes the right inner plate and the right outer plate extending in the front and rear directions with a space in the left and right directions, and the upper ends of the right inner plate and the right outer plate. The upper plate and the lower plate closing the lower end of the right inner plate and the right outer plate, the upper plate and the lower plate, the rear portion of the left frame and the right frame The present invention is applied to a dump truck that is formed as a branching portion that is a connecting portion that connects between the two, and a front portion of the connecting portion is bifurcated.

  The feature of the configuration adopted by the present invention is that the upper plate and the lower plate are arranged between the upper plate and the lower plate at positions corresponding to the connection sites in the front and rear directions with a gap therebetween. At least two cross members each having a left end joined to the left inner plate of the left frame, a right end joined to the right inner plate of the right frame, and an upper end of the upper plate. The lower end is bonded to the connecting portion of the lower plate and fixed to each other, and the cross member, the left inner plate, the right inner plate, the upper plate and the lower plate form a closed cross-sectional space. The box structure is formed.

  According to the present invention, the left end of each cross member is joined to the left inner plate of the left frame, the right end is joined to the right inner plate of the right frame, the upper end is joined to the connection portion of the upper plate, and the lower end is joined to the lower plate. By joining the connecting portions, the left and right frames can be connected at the front and rear intermediate portions of the body frame. In this case, each cross member, the left and right inner plates, the upper plate, and the lower plate form a strong box structure with a closed cross-sectional space inside, so the rigidity of the body frame can be increased, Deformation of the body frame can be suppressed.

  Thereby, it can suppress that a vehicle body frame deform | transforms with the load of a loading platform, or the driving | running | working load of a dump truck. For this reason, the left inner plate and the left outer plate and the upper plate of the left frame, the left inner plate and the left outer plate and the lower plate of the left frame, the right inner plate and the right outer plate of the right frame It is possible to suppress the stress concentration at the joint portion with the upper plate, the right inner plate of the right frame, and the joint portion between the right outer plate and the lower plate, and to increase the rigidity and durability of the vehicle body frame. Moreover, it is possible to form a strong box structure in the front and rear intermediate portions of the vehicle body frame by simply installing at least two cross members, without significantly increasing the weight of the vehicle body frame, The rigidity of the body frame can be increased.

1 is a front view showing a dump truck according to a first embodiment of the present invention. It is a perspective view which shows the vehicle body frame of a dump truck. It is a front view of a vehicle body frame. It is the top view which looked at the vehicle body frame from the arrow IV-IV direction in FIG. It is the bottom view which looked at the body frame from the arrow VV direction lower part in FIG. FIG. 4 is a cross-sectional view of the left and right frames, the lower plate, the cross member, and the like when viewed from the direction of arrows VI-VI in FIG. 3. It is sectional drawing which looked at the right flame | frame, the upper board, the lower board, the cross member, the mount member, etc. from the arrow VII-VII direction in FIG. FIG. 8 is a cross-sectional view of the left and right frames, the upper plate, the lower plate, the mount member, and the like when viewed from the direction of arrows VIII-VIII in FIG. 7. It is a top view similar to FIG. 4 which shows the vehicle body frame by 2nd Embodiment. It is sectional drawing similar to FIG. 6 which shows the cross member of the vehicle body frame by 2nd Embodiment. It is sectional drawing similar to FIG. 6 which shows the vehicle body frame by a modification.

  Hereinafter, dump trucks according to embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  1 to 8 show a first embodiment of the present invention. In the figure, 1 indicates a dump truck which is a large transport vehicle. The dump truck 1 transports a transport object such as a crushed stone mined in a mine. Here, the dump truck 1 is capable of tilting (raising and lowering) on the vehicle body 2 for loading a transportation object and a self-propelled vehicle body 2 having left and right front wheels 3 and rear wheels 5 described later. This is generally constituted by a loading platform 8 to be described later. The vehicle body 2 of the dump truck 1 includes a building 12, a floor 14, a cab 15, a vehicle body frame 21 and the like which will be described later.

  The left and right front wheels 3 are rotatably provided on the front side of the vehicle body 2 and constitute steering wheels. The front wheel side suspension 4 elastically supports the left and right front wheels 3 with respect to the vehicle body 2 (only the left side is shown in FIG. 1). The front wheel side suspension 4 cushions the vibration of the front wheel 3 from being transmitted to the vehicle body 2.

  The left and right rear wheels 5 are rotatably provided on the rear side of the vehicle body 2. The left and right rear wheels 5 are rotationally driven by the traveling drive device 6 and constitute drive wheels of the dump truck 1. The travel drive device 6 includes a travel axle, a reduction gear (not shown) and the like, and a cylindrical axle housing 6A that extends left and right and a bracket 6B that protrudes forward from the axle housing 6A. Have. The protruding end of the bracket 6B of the travel drive device 6 is rotatably attached to a mount member 38, which will be described later, via a joint. A rear wheel side suspension 7 is provided between the axle housing 6 </ b> A of the travel drive device 6 and the rear portion of the vehicle body frame 21. The rear wheel side suspension 7 is configured by, for example, a hydraulic shock absorber or the like, and buffers the vibration of the rear wheel 5 transmitted to the vehicle body 2, as with the front wheel side suspension 4.

  The loading platform 8 is attached to the body frame 21 so as to be tiltable (can be undulated). The loading platform 8 is formed as a large bottomed container having a total length of 10 to 14 meters in order to load a large amount of minerals mined by a hydraulic excavator (not shown), for example. The rear bottom portion of the loading platform 8 is connected to left and right rear end brackets 33 and 34 (described later) provided on the vehicle body frame 21 via a connection pin 10 so as to be tiltable. On the front side of the loading platform 8, a flange portion 8 </ b> A that extends horizontally from the top to the front is integrally provided, and this flange portion 8 </ b> A is close to the front end position of the floor 14 with a cab 15 to be described later covered from above. It extends.

  The front side of the loading platform 8 is rotated (lifted and lowered) upward and downward with the connecting pin 10 as a fulcrum by extending or contracting a hoist cylinder 11 described later. As a result, the loading platform 8 tilts between the transport position (the position in FIG. 1) in which the collar portion 8A covers the cab 15 from the upper side and the soil removal position in which the collar portion 8A has rotated upward. A rubber pad 9 as a cushioning material is provided on the bottom surface of the loading platform 8 to suppress an impact when the loading platform 8 moves from the soil removal position to the transport position and is seated on the vehicle body frame 21.

  The hoist cylinder 11 is provided between the vehicle body frame 21 and the loading platform 8 as a pair in the left and right directions (only the left side is shown in FIG. 1). The hoist cylinder 11 is composed of, for example, a hydraulic cylinder, and tilts the loading platform 8 up and down with respect to the vehicle body frame 21. The lower end side (rod side) of the hoist cylinder 11 is rotatably attached to a cylinder support shaft 32 described later, and the upper end side (tube side) of the hoist cylinder 11 is rotatably attached to the lower surface side of the loading platform 8. ing. Therefore, when the hoist cylinder 11 is extended or contracted, the front side of the cargo bed 8 (the flange portion 8A side) is rotated (lifted / lowered) upward and downward with the connecting pin 10 as a fulcrum. Thereby, the loading platform 8 can be tilted to the soil removal position where the front side is lifted upward, and the transport object loaded on the loading platform 8 can be discharged.

  The building 12 defines a machine room on the front side of the vehicle body 2, and an engine 13 and the like are accommodated therein. Here, the building 12 also has a function of supporting a floor 14, a cab 15 and the like, which will be described later, from below. That is, the floor 14 is provided on the upper side of the building 12. On the floor 14, a control cabinet 16 and the like for controlling operations of the cab 15 and the traveling motor are installed.

  Next, the body frame used in the present embodiment will be described.

  The vehicle body frame 21 serves as a base of the vehicle body 2 and is composed of a strong support structure extending in the front and rear directions. Here, the vehicle body frame 21 includes a left frame 22, a right frame 23, a front frame 24, a rear frame 25, an upper plate 26, a lower plate 27, a mount member 38, front and rear cross members 39 and 40 which will be described later. It is configured.

  The left frame 22 is disposed on the left side of the body frame 21 and extends in the front and rear directions. The left frame 22 includes a left inner plate 22A positioned inside the vehicle body frame 21, a left outer plate 22B positioned outside the vehicle body frame 21 and facing the left inner plate 22A with a left-right spacing and a left inner plate 22B. The upper plate 26 that closes the upper ends of the plate 22A and the left outer plate 22B, and the lower plate 27 that connects the lower inner plate 22A and the lower end of the left outer plate 22B are configured.

  The right frame 23 is disposed on the right side of the vehicle body frame 21 while facing the left frame 22 in the left and right directions, and extends in the front and rear directions. The right frame 23 includes a right inner plate 23A located inside the vehicle body frame 21, a right outer plate 23B located outside the vehicle body frame 21 and facing the right inner plate 23A with a space in the left and right directions. The upper plate 26 that closes the upper ends of the plate 23A and the right outer plate 23B, and the lower plate 27 that connects the lower inner plate 23A and the lower end of the right outer plate 23B are configured.

  Here, as shown in FIG. 4, the rear portion 22A1 of the left frame 22 and the rear portion 23A1 of the right frame 23 are in the front and rear directions with a constant distance A (parallel to each other). It extends. On the other hand, the front part 22A2 of the left frame 22 and the front part 23A2 of the right frame 23 maintain a constant distance B (B> A) larger than the distance A between the rear parts 22A1 and 23A1 (a state parallel to each other). It extends forward and backward. Further, the front and rear intermediate portions 22A3 of the left frame 22 and the front and rear intermediate portions 23A3 of the right frame 23 are directed from the narrow rear portions 22A1 and 23A1 toward the wide front portions 22A2 and 23A2. The width dimension in the left and right directions is gradually increased.

  The boundary between the rear part 22A1 of the left frame 22 and the intermediate part 22A3 is a rear bent part 22A4 in which the extending direction of the left frame 22 changes, and the boundary part between the front part 22A2 and the intermediate part 22A3 of the left frame 22 is It is the front bending part 22A5. Similarly, the boundary between the rear part 23A1 of the right frame 23 and the intermediate part 23A3 becomes a rear bent part 23A4 in which the extending direction of the right frame 23 changes, and the front part 23A2 and the intermediate part 23A3 of the right frame 23 The boundary portion is a front bent portion 23A5.

  Accordingly, the left and right width dimensions of the body frame 21 are set so that the front side is larger than the rear side. On the other hand, a portion of the left inner plate 22A of the left frame 22 near the rear bent portion 22A4 and a portion of the right inner plate 23A of the right frame 23 near the rear bent portion 23A4 are a front cross member 39 and a rear cross described later. The members 40 are connected to each other via members 40.

  The front frame 24 connects between the front end of the left frame 22 and the front end of the right frame 23. The front frame 24 is located on the outside of the body frame 21 and extends to the left and right, and the rear plate 24B is located on the inside of the body frame 21 and faces the front plate 24A with a distance in the front and rear directions. The upper plate 26 closes the upper ends of the front plate 24A and the rear plate 24B, and the lower plate 27 closes the lower ends of the front plate 24A and the rear plate 24B.

  Both left and right ends of the front plate 24A are joined to the left outer plate 22B of the left frame 22 and the right outer plate 23B of the right frame 23 by welding, respectively. Both left and right ends of the rear plate 24B are joined to the left inner plate 22A of the left frame 22 and the right inner plate 23A of the right frame 23 by welding, respectively. Thereby, the front ends of the left frame 22 and the right frame 23 are integrally connected via the front frame 24.

  The rear frame 25 connects the rear end of the left frame 22 and the rear end of the right frame 23. The rear frame 25 is located on the inner side of the vehicle body frame 21 and extends to the left and right, and the rear plate 25B is located on the outer side of the vehicle body frame 21 and faces the front plate 25A with a distance in the front and rear directions. And an upper plate 26 that closes the upper ends of the front plate 25A and the rear plate 25B, and a lower plate 27 that closes the lower ends of the front plate 25A and the rear plate 25B.

  The upper plate 26 closes the upper ends of the left frame 22, the right frame 23, the front frame 24, and the rear frame 25 and connects the left frame 22 and the right frame 23. As shown in FIGS. 2 to 4, the upper plate 26 is located on the rear side (rear side portion) of the rear curved portion 26 </ b> E <b> 1 of the front opening portion 26 </ b> E described later and connects the left frame 22 and the right frame 23. Connecting the connecting part 26A, the bifurcated left branching part 26B and the right branching part 26C located on the front side (front part) of the connecting part 26A, and the front end sides of the left and right branching parts 26B and 26C. It is comprised by the front connection part 26D. The upper plate 26 is formed with a rectangular front opening 26E located between the left and right branch parts 26B and 26C and an elliptical rear opening 26F located at the center of the connection part 26A. Yes.

  Here, the connection portion 26A of the upper plate 26 is arranged on the left side from the left inner plate 22A of the left frame 22 and to the right side from the right inner plate 23A of the right frame 23 and the left closing plate 26A1 closing the upper end of the left frame 22. A right closing plate 26A2 disposed and closing the upper end of the right frame 23; and a rear closing plate 26A3 surrounded by the front plate 25A, the left inner plate 22A and the right inner plate 23A of the rear frame 25 and closing the upper end of the rear frame 25; And a connecting plate 26A4 that is surrounded by the left inner plate 22A, the right inner plate 23A, and the front plate 25A on the rear side of the rear curved portion 26E1 of the front opening 26E and connects the left and right frames 22 and 23. Has been.

  The left branch portion 26B of the upper plate 26 closes the upper end of the left frame 22 located on the front side of the connection portion 26A, and the right branch portion 26C of the upper plate 26 is the right frame 23 located on the front side of the connection portion 26A. The top of the is closed. The front connection portion 26 </ b> D of the upper plate 26 closes the upper end of the front frame 24. The front opening 26E and the rear opening 26F are intended to reduce the weight of the upper plate 26 and to secure a work space during welding work.

  The lower plate 27 closes the lower ends of the left frame 22, the right frame 23, the front frame 24, and the rear frame 25 while facing the upper plate 26 in the upward and downward directions, and between the left frame 22 and the right frame 23. It is what connects between. The lower plate 27 is located on the rear side (rear side portion) of the rear curved portion 27E1 of the front opening portion 27E described later, and connects the left frame 22 and the right frame 23, and the connection portion 27A. It is composed of a bifurcated left branching portion 27B and a right branching portion 27C located on the front side (front side portion), and a front connecting portion 27D that connects the front end sides of the left and right branching portions 27B and 27C. . The lower plate 27 is formed with a rectangular front opening 27E located between the left and right branch parts 27B and 27C and an elliptical rear opening 27F located at the center of the connection part 27A. Yes.

  Here, the connection portion 27A of the lower plate 27 is arranged on the left side from the left inner plate 22A of the left frame 22 and to the right side from the right inner plate 23A of the right frame 23 and the left closing plate 27A1 closing the lower end of the left frame 22. A right closing plate 27A2 disposed and closing the lower end of the right frame 23; and a rear closing plate 27A3 surrounded by the front plate 25A, the left inner plate 22A and the right inner plate 23A of the rear frame 25 and closing the lower end of the rear frame 25; And a connecting plate 27A4 that is surrounded by the left inner plate 22A, the right inner plate 23A, and the front plate 25A on the rear side of the rear curved portion 27E1 of the front opening 27E and connects the left and right frames 22 and 23. Has been.

  The left branch portion 27B of the lower plate 27 closes the lower end of the left frame 22 positioned in front of the connection portion 26A, and the right branch portion 27C of the lower plate 27 is in the right frame 23 positioned in front of the connection portion 26A. The lower end of is closed. The front connection portion 26 </ b> D of the lower plate 27 closes the lower end of the front frame 24. The front opening 27E and the rear opening 27F are intended to reduce the weight of the lower plate 27 and to secure a work space during welding work.

  The left support column 28 and the right support column 29 are provided at positions closer to the front side than the front and rear center portions of the body frame 21 and face each other in the left and right directions. These left and right support columns 28 and 29 are made of a hollow can-making structure having a mountain shape, and the left support column 28 protrudes upward from a left branch portion 26B of the upper plate 26 constituting the left frame 22. The right support column 29 protrudes upward from the right branch portion 26 </ b> C of the upper plate 26 constituting the right frame 23.

  The left support column 28 is formed in an arc shape from the upper surface side of the left branch portion 26B, and the right support column 29 is formed in an arc shape from the upper surface side of the right branch portion 26C. Thereby, the device which avoids that stress concentration etc. generate | occur | produce between the left branch part 26B and the left support | pillar 28 and between the right branch part 26C and the right support | pillar 29 is made | formed. Upper horizontal beams (not shown) that support the rear side of the floor 14 and the cab 15 are attached to the upper ends of the left column 28 and the right column 29.

  The left cylinder bracket 30 and the right cylinder bracket 31 are provided at positions in front of the vehicle body frame 21 and at the rear of the middle part in the rear direction, and face each other in the left and right directions. These left and right cylinder brackets 30 and 31 are formed as plate bodies having a mountain shape using a steel plate material. The left cylinder bracket 30 is welded to the left closing plate 27A1 and the left branch portion 27B of the lower plate 27 constituting the left frame 22 and protrudes downward, and the right cylinder bracket 31 is formed of the lower plate 27 constituting the right frame 23. It is welded and joined downward to the right closing plate 27A2 and the right branch portion 27C.

  Cylinder support shafts 32 extending in the left and right directions are inserted into lower end sides (projecting end sides) of the left and right cylinder brackets 30 and 31. The lower end side of the hoist cylinder 11 is attached to both left and right ends of the cylinder support shaft 32 protruding left and right from the left and right cylinder brackets 30 and 31.

  The left rear end bracket 33 and the right rear end bracket 34 are provided at the rear end portion of the vehicle body frame 21 and face each other in the left and right directions. These left and right rear end brackets 33 and 34 are formed using thick steel plates. The left rear end bracket 33 is welded to the left closing plate 26A1 of the upper plate 26 constituting the left frame 22 and the rear plate 25B of the rear frame 25 and protrudes rearward. The right rear end bracket 34 is welded to the right closing plate 26A2 of the upper plate 26 constituting the right frame 23 and the rear plate 25B of the rear frame 25 and protrudes rearward.

  The left and right rear end brackets 33 and 34 support the bottom surface of the cargo bed 8 through the connecting pin 10 so as to be rotatable. On the other hand, the upper end side of the rear wheel suspension 7 is rotatably attached to the left and right rear end brackets 33 and 34 via a connecting pin 35.

  The left front wheel bracket 36 and the right front wheel bracket 37 are provided on the front end side of the vehicle body frame 21 and face each other in the left and right directions. These left and right front wheel brackets 36 and 37 are attached with trailing arms (not shown) for supporting the left and right front wheels 3, respectively. These left and right trailing arms are the front wheels shown in FIG. It is elastically supported by the side suspension 4.

  The mount member 38 is located on the lower side of the vehicle body frame 21 between the left and right cylinder brackets 30 and 31, and is positioned behind the vehicle frame 21 in the front and rear intermediate portions. The mount member 38 is attached with a traveling drive device 6 for driving the left and right rear wheels 5 (see FIG. 1).

  As shown in FIGS. 5 and 8, the mount member 38 is formed of a solid structure including a pair of flange portions 38 </ b> A that face each other in the left and right directions, and has a front opening 27 </ b> E formed in the lower plate 27. And the rear opening 27F, which is welded to the lower surface of the connection plate 27A4 and protrudes downward. A bracket 6B of the travel drive device 6 is rotatably attached to each flange portion 38A of the mount member 38 via a joint. Here, the mount member 38 is disposed below the box structure 41 to be described later, and a load acting on the mount member 38 via the left and right rear wheels 5 and the travel drive device 6 is applied to the vehicle body frame 21. It can be transmitted smoothly.

  Next, two cross members used in the first embodiment will be described.

  The front cross member 39 and the rear cross member 40 are provided between the upper plate 26 and the lower plate 27 at positions corresponding to the connection site 26A of the upper plate 26 and the connection site 27A of the lower plate 27. The front cross member 39 and the rear cross member 40 are formed of a rectangular plate body that is formed of a steel plate and extends in the left and right directions, and faces the left frame 22 and the right frame while facing each other with a gap in the front and rear directions. 23 is connected.

  As shown in FIG. 7, the front cross member 39 is located behind the rear curved portion 26E1 of the front opening 26E formed in the upper plate 26 and the rear curved portion 27E1 of the front opening 27E formed in the lower plate 27. Arranged on the side. The front cross member 39 has a left end edge 39A welded to the left inner plate 22A of the left frame 22, and a right end edge 39B welded to the right inner plate 23A of the right frame 23. The front cross member 39 has an upper end edge 39C welded to the connection plate 26A4 of the upper plate 26 and a lower end edge 39D welded to the connection plate 27A4 of the lower plate 27. On the other hand, the rear cross member 40 is disposed in front of the front curved portion 26F1 of the rear opening 26F formed in the upper plate 26 and the front curved portion 27F1 of the rear opening 27F formed in the lower plate 27. ing. The rear cross member 40 has a left end edge 40A welded to the left inner plate 22A of the left frame 22 and a right end edge 40B welded to the right inner plate 23A of the right frame 23. The rear cross member 40 has an upper end edge 40C welded to the connection plate 26A4 of the upper plate 26 and a lower end edge 40D welded to the connection plate 27A4 of the lower plate 27.

  As a result, the front and rear cross members 39, 40, the left inner plate 22A of the left frame 22, the right inner plate 23A of the right frame 23, and the upper plate 26 are connected to the front and rear intermediate portions of the body frame 21. A box structure 41 is formed which is surrounded by the connection plate 27A4 of the plate 26A4 and the lower plate 27 and has a closed section space inside. The box structure 41 has a strong closed cross-sectional structure surrounded by the cross members 39 and 40, left and right inner plates 22A and 23A, and upper and lower connecting plates 26A4 and 27A4. Therefore, by connecting the left inner plate 22A of the left frame 22 and the right inner plate 23A of the right frame 23 via the box structure 41, the rigidity of the entire body frame 21 is increased and a load acts. It is the structure which can suppress the deformation | transformation by this.

  Here, as shown in FIG. 6, the front cross member 39 and the rear cross member 40 sandwich the rear bent portions 22A4 and 23A4 of the left frame 22 (left inner plate 22A) and the right frame 23 (right inner plate 23A). It is arranged before and after. That is, the front cross member 39 and the rear cross member 40 are disposed in the vicinity of the rear bent portions 22A4 and 23A4 of the left frame 22 and the right frame 23.

  As a result, in the left frame 22 and the right frame 23, the vicinity of the rear bent portions 22A4 and 23A4 where stress is likely to concentrate can be connected to each other via the front and rear cross members 39 and 40. As a result, the rigidity of the entire body frame 21 can be increased by using the front and rear cross members 39 and 40. Further, a mount member 38 for attaching the travel drive device 6 is provided below the box structure 41 that increases the rigidity of the body frame 21. Thus, the load can be efficiently transmitted between the vehicle body frame 21 and the mount member 38.

  On the other hand, the thickness t1 of the front cross member 39 is formed larger than the thickness t2 of the rear cross member 40 (t1> t2). Specifically, the plate thickness t1 of the front cross member 39 is set in the range of 1.1 to 2.0 times the plate thickness t2 of the rear cross member 40, and preferably about 1.5 times. Is set to

  Thus, by forming the plate thickness t1 of the front cross member 39 to be larger than the plate thickness t2 of the rear cross member 40, the front cross member 39 is formed at the joint between the left inner plate 22A and the right inner plate 23A. It has a configuration that can reduce stress. Therefore, the left and right width dimensions of the left frame 22 and the right frame 23 are formed larger on the front side than on the rear side of the body frame 21, so that the top of the body frame 21 when the dump truck 1 is traveling, Even if the amount of deformation in the downward direction is larger on the front side than on the rear side of the vehicle body frame 21, the strength of the joint portion between the left and right frames 22 and 23 and the front cross member 39 can be increased. ing.

  The dump truck 1 according to the first embodiment has the above-described configuration. Next, the operation thereof will be described.

  When the dump truck 1 travels on the work site with an object to be transported on the loading platform 8, the load of the loading platform 8 and the traveling load act on the vehicle body frame 21, and the vehicle body frame 21 is deformed.

  On the other hand, the dump truck 1 according to the first embodiment is located at a position corresponding to the connection portion 26A of the upper plate 26 and the connection portion 27A of the lower plate 27, that is, at the front and rear intermediate portions of the vehicle body frame 21. A front cross member 39 and a rear cross member 40 are provided. The front and rear cross members 39, 40 have left end edges 39A, 40A joined to the left inner plate 22A of the left frame 22, right end edges 39B, 40B joined to the right inner plate 23A of the right frame 23, and upper end edges. 39C and 40C are joined to the connection plate 26A4 of the upper plate 26, and lower end edges 39D and 40D are joined to the connection plate 27A4 of the lower plate 27.

  As a result, the front and rear cross members 39, 40, the left inner plate 22A of the left frame 22, the right inner plate 23A of the right frame 23, and the upper plate 26 are connected to the front and rear intermediate portions of the body frame 21. A box structure 41 is formed which is surrounded by the connection plate 27A4 of the plate 26A4 and the lower plate 27 and has a closed section space inside. Therefore, the rigidity of the entire body frame 21 can be increased by connecting the left inner plate 22A of the left frame 22 and the right inner plate 23A of the right frame 23 via the box structure 41.

  As a result, the vehicle body frame 21 can be prevented from being deformed by the load of the loading platform 8 or the traveling load, the left inner plate 22A of the left frame 22 and the joint portion of the left outer plate 22B and the upper plate 26, the left frame 22 It is possible to suppress the stress concentration from occurring at the joint between the left inner plate 22A and the left outer plate 22B and the lower plate 27. On the other hand, stress concentration occurs at the joint between the right inner plate 23A and the right outer plate 23B and the upper plate 26 of the right frame 23, and at the joint between the right inner plate 23A and the right outer plate 23B and the lower plate 27 of the right frame 23. Can be suppressed. Therefore, the rigidity and durability of the body frame 21 can be increased, and the reliability of the dump truck 1 can be increased.

  Moreover, the box structure 41 can be formed at the front and rear intermediate portions of the vehicle body frame 21 simply by installing a cross member composed of two plates of the front cross member 39 and the rear cross member 40. . Accordingly, the rigidity of the vehicle body frame 21 can be increased without significantly increasing the weight of the vehicle body frame 21.

  On the other hand, according to the first embodiment, the mount member 38 for attaching the traveling drive device 6 is located on the lower side of the box structure 41 and attached to the lower plate 27 of the vehicle body frame 21. As a result, the load of the loading platform 8 on which the object to be transported is directly transmitted to the mount member 38 via the box structure 41 and the rear wheel 5 via the travel drive device 6 attached to the mount member 38. Can be communicated to. As a result, the deformation amount of the lower plate 27 can be suppressed, and the rigidity of the entire body frame 21 can be increased.

  Further, since the plate thickness t1 of the front cross member 39 is formed larger than the plate thickness t2 of the rear cross member 40, the stress generated at the junction between the front cross member 39 and the left inner plate 22A and the right inner plate 23A. Can be reduced. As a result, even when the amount of deformation in the upper and lower direction of the body frame 21 when the dump truck 1 is traveling is larger on the front side than the rear side of the body frame 21, the left and right frames 22 and 23 and the front cross The strength of the joint portion with the member 39 can be increased, and the rigidity of the entire body frame 21 can be increased. Moreover, by making the plate thickness t2 of the rear cross member 40 smaller than the plate thickness of the front cross member 39, it is possible to increase the rigidity of the vehicle body frame 21 while suppressing an increase in the weight of the vehicle body frame 21.

  Further, the front cross member 39 and the rear cross member 40 are disposed in front and rear with the rear bent portions 22A4 and 23A4 of the left frame 22 (left inner plate 22A) and the right frame 23 (right inner plate 23A) interposed therebetween. . As a result, in the left frame 22 and the right frame 23, the vicinity of the rear bent portions 22A4 and 23A4 where stress is likely to concentrate can be connected to each other via the front and rear cross members 39 and 40. As a result, the rear bent portion 22A4 of the left frame 22 and the rear bent portion 23A4 of the right frame 23 can be reinforced by the front and rear cross members 39, 40, and the rigidity of the entire body frame 21 can be increased. .

  Next, FIG. 9 and FIG. 10 show a second embodiment of the present invention. The feature of the second embodiment is that the left and right sides of each cross member are formed as bent portions. is there. In the second 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.

  The vehicle body frame 51 according to the second embodiment is substantially the same as the vehicle body frame 21 according to the first embodiment. The left frame 22, the right frame 23, the front frame 24, a rear frame 52, an upper plate 26, The plate 27, a front cross member 53 described later, a rear cross member 54, and the like are included. However, the vehicle body frame 51 according to the second embodiment is different from the first embodiment in the configuration of the rear frame 52, the front cross member 53, and the rear cross member 54.

  The rear frame 52 connects the rear end of the left frame 22 and the rear end of the right frame 23. The rear frame 52 is located on the inner side of the vehicle body frame 51 and extends in the left and right directions, and the rear plate 52B is located on the outer side of the vehicle body frame 51 and faces the front plate 52A with a distance in the front and rear directions. And the upper plate 26 that closes the upper ends of the front plate 52A and the rear plate 52B, and the lower plate 27 that closes the lower ends of the front plate 52A and the rear plate 52B.

  The left end side of the front plate 52A is a left bent portion 52A1 bent forward, and the right end side of the front plate 52A is a right bent portion 52A2 bent forward. Here, the angle θ1 on the rear plate 52B side formed by the left inner plate 22A and the left bent portion 52A1 of the left frame 22, and the angle on the rear plate 52B side formed by the right inner plate 23A and the right bent portion 52A2 of the right frame 23. θ1 is set to an acute angle.

  The front cross member 53 and the rear cross member 54 are provided on the front side of the rear frame 52 and on the rear side of the front frame 24 and are provided between the upper plate 26 and the lower plate 27, and are spaced in the front and rear directions. The left frame 22 and the right frame 23 are connected while facing each other.

  The front cross member 53 is formed as a rectangular plate extending in the left and right directions, and both end sides in the left and right directions are bent forward. Thereby, the left side of the front cross member 53 is a left bent portion 53A, and the right side is a right bent portion 53B. In the front cross member 53, the left end edge 53A1 of the left bent portion 53A is welded to the left inner plate 22A, the right end edge 53B1 of the right bent portion 53B is welded to the right inner plate 23A, and the upper end edge is connected to the upper plate 26. While being welded to the plate 26A4, the lower end edge is welded to the connection plate 27A4 of the lower plate 27.

  The rear cross member 54 is formed as a rectangular plate extending in the left and right directions, an intermediate portion in the left and right directions linearly extends in the left and right directions, and both end sides are bent toward the rear. . Thereby, the left and right intermediate portions of the rear cross member 54 are straight portions 54A, the left side is a left bent portion 54B, and the right side is a right bent portion 54C. The rear cross member 54 has a left end edge 54B1 of the left bent portion 54B welded to the left inner plate 22A, a right end edge 54C1 of the right bent portion 54C welded to the right inner plate 23A, and an upper end edge connected to the upper plate 26. While being welded to the plate 26A4, the lower end edge is welded to the connection plate 27A4 of the lower plate 27.

  As a result, the front and rear cross members 53 and 54, the left inner plate 22A of the left frame 22, the right inner plate 23A of the right frame 23, and the upper plate 26 are connected to the front and rear intermediate portions of the body frame 51. A box structure 55 surrounded by the connection plate 27A4 of the plate 26A4 and the lower plate 27 and having a closed cross-sectional space inside is formed.

  Here, the left bent portion 53A of the front cross member 53 is formed such that an angle θ2 formed with respect to the left inner plate 22A of the left frame 22 in the box structure 55 is an acute angle. Similarly, the right bent portion 53B of the front cross member 53 is formed so that the angle θ2 formed with respect to the right inner plate 23A of the right frame 23 in the box structure 55 is an acute angle. Desirably, the angle θ2 in the box structure 55 where the left bent portion 53A of the front cross member 53 and the left inner plate 22A intersect, and the box structure where the right bent portion 53B of the front cross member 53 and the right inner plate 23A intersect. The angle θ2 within 55 is set in a range of 30 degrees or more and less than 90 degrees (30 ° ≦ θ2 <90 °).

  On the other hand, the left bent portion 54B of the rear cross member 54 is formed such that an angle θ3 formed with respect to the left inner plate 22A of the left frame 22 within the box structure 55 is an acute angle. Similarly, the right bent portion 54C of the rear cross member 54 is formed such that an angle θ3 formed with respect to the right inner plate 23A of the right frame 23 in the box structure 55 is an acute angle. Desirably, an angle θ3 in the box structure 55 where the left bent portion 54B of the rear cross member 54 and the left inner plate 22A intersect, and a box structure where the right bent portion 54C of the rear cross member 54 and the right inner plate 23A intersect. The angle θ3 within 55 is set in a range of 30 degrees or more and less than 90 degrees (30 ° ≦ θ3 <90 °).

  The vehicle body frame 51 according to the second embodiment has the above-described configuration, and the basic operational effects thereof are not particularly different from those of the vehicle body frame 21 according to the first embodiment.

  However, in the vehicle body frame 51 according to the second embodiment, the left bent portion 53A of the front cross member 53 is formed so that the angle θ2 formed with respect to the left inner plate 22A of the left frame 22 is an acute angle, and the front cross member 53A is formed. The right bent portion 53B of the member 53 is formed such that an angle θ2 formed with respect to the right inner plate 23A of the right frame 23 is an acute angle.

  On the other hand, in the vehicle body frame 51, the left bent portion 54B of the rear cross member 54 is formed so that the angle θ3 formed with respect to the left inner plate 22A of the left frame 22 is an acute angle, and the right bent portion 54C of the rear cross member 54 is formed. Is formed so that an angle θ3 formed with respect to the right inner plate 23A of the right frame 23 is an acute angle.

  Thereby, the load from the loading platform 8 is smoothly transmitted from the left bent portion 53A of the front cross member 53 to the left frame 22, and is smoothly transmitted from the right bent portion 53B of the front cross member 53 to the right frame 23. Can do. Similarly, the load from the loading platform 8 is smoothly transmitted from the left bent portion 54B of the rear cross member 54 to the left frame 22, and is smoothly transmitted from the right bent portion 54C of the rear cross member 54 to the right frame 23. Can do.

  As a result, the stress is prevented from concentrating on the joint between the front cross member 53 and the left and right side frames 22 and 23, and the stress is applied to the joint between the rear cross member 54 and the left and right side frames 22 and 23. Therefore, the rigidity of the body frame 51 can be increased.

  In addition, since the length of the front cross member 53 is increased by providing the left bent portion 53A and the right bent portion 53B on the left and right sides of the front cross member 53, the front cross member 53 and the upper plate 26 The welding length of the front cross member 53 and the lower plate 27 can be increased. Similarly, the length of the rear cross member 54 is increased by providing the left bent portion 54B and the right bent portion 54C on the left and right sides of the rear cross member 54. Therefore, the rear cross member 54 and the upper plate 26 are increased. And the welding length between the rear cross member 54 and the lower plate 27 can be increased.

  As a result, it is possible to disperse the load acting on the joint between the front and rear cross members 53 and 54 and the upper plate 26 and the joint between the front and rear cross members 53 and 54 and the lower plate 27. Therefore, the stress at each joint can be reduced, and the rigidity of the body frame 51 can be increased.

  In the first embodiment described above, the front cross member 39 and the rear cross member 40 are used as cross members that connect the left inner plate 22A of the left frame 22 and the right inner plate 23A of the right frame 23. The case where a total of two cross members are used is illustrated.

  However, the present invention is not limited to this, and a configuration using a total of three cross members in which intermediate cross members 56 are added between the front cross member 39 and the rear cross member 40 as in the modification shown in FIG. It is good. Furthermore, it is good also as a structure using four or more cross members. The same applies to the second embodiment.

DESCRIPTION OF SYMBOLS 1 Dump truck 3 Front wheel 5 Rear wheel 6 Travel drive device 8 Loading platform 21,51 Body frame 22 Left frame 22A Left inner plate 22B Left outer plate 22A4, 23A4 Rear bending part 23 Right frame 23A Right inner plate 23B Right outer plate 24 Front frame 25, 52 Rear frame 26 Upper plate 26A, 27A Connection portion 26B, 27B Left branch portion 26C, 27C Right branch portion 27 Lower plate 38 Mount member 39, 53 Front cross member 39A, 40A, 53A1, 54B1 Left end edge (left end)
39B, 40B, 53B1, 54C1 Right edge (right edge)
40, 54 Rear cross member 41, 55 Box structure 53A, 54B Left bent portion 53B, 54C Right bent portion 56 Intermediate cross member

Claims (5)

A vehicle body frame that forms a support structure and to which front wheels and rear wheels are attached; and a loading platform that can be tilted with the rear end position of the vehicle body frame as a fulcrum for loading an object to be transported,
The body frame is
A left frame that is arranged on the left side in the left and right directions and extends in the front and rear directions;
A right frame that is placed on the right side of the left and right direction and extends forward and backward,
A front frame connecting the front end of the left frame and the front end of the right frame and extending left and right;
A rear frame connecting the rear end of the left frame and the rear end of the right frame and extending left and right;
The left frame includes a left inner plate and a left outer plate extending in the left and right directions with an interval in the front and rear directions, an upper plate closing the upper end of the left inner plate and the left outer plate, the left inner plate, A lower plate that closes the lower end of the left outer plate,
The right frame includes a right inner plate and a right outer plate extending in the left and right directions with an interval in the front and rear directions, the upper plate closing the upper ends of the right inner plate and the right outer plate, and the right inner plate. And the lower plate closing the lower end of the right outer plate,
The upper plate and the lower plate are formed as a branch portion where a rear portion serves as a connection portion connecting the left frame and the right frame, and a front portion of the connection portion branches into a bifurcated shape. In the dump truck
At a position corresponding to the connection portion of the upper plate and the lower plate, at least two cross members arranged between the upper plate and the lower plate in a state of facing each other in the front and rear directions are provided. ,
Each cross member has a left end joined to the left inner plate of the left frame, a right end joined to the right inner plate of the right frame, an upper end joined to a connection portion of the upper plate, and a lower end joined to the lower plate. It adheres by joining to the connection part of the board,
A dump truck characterized in that a box structure body is formed with a closed cross-sectional space by each cross member, left inner plate, right inner plate, upper plate and lower plate. The vehicle body frame is provided with a mount member for attaching a travel drive device for driving the rear wheel,
The dump truck according to claim 1, wherein the mount member is arranged to be positioned below the box structure.   Each of the cross members is composed of two plates that are spaced apart from each other at the front and rear, and the thickness of the front cross member that is located on the front side is larger than the thickness of the rear cross member that is located on the rear side. The dump truck according to claim 1 or 2. Each cross member is formed as a bent portion that is bent on both sides in the left and right directions forward and backward,
With the left and right ends of each cross member joined to the left inner plate and the right inner plate, the left bent portion of each cross member has an acute angle with respect to the left inner plate. 4. The dump truck according to claim 1, wherein the right bent portion of each cross member is formed so that an angle formed with respect to the right inner plate is an acute angle. The left frame and the right frame have a bent portion that bends so that an interval in the left and right directions changes on the front end side of the connection portion constituting the upper plate and the lower plate,
5. The dump truck according to claim 1, 2, 3, or 4, wherein each of the cross members is provided in the vicinity of a bent portion of the left frame and the right frame.

Images