JP6532166B2 - Dump truck - Google Patents

Description

  The present invention relates to a dump truck that transports an object to be transported such as soil.

  Generally, in a dump truck, a vehicle body frame in which four wheels are disposed and a loading platform are attached from the center to the rear of the vehicle body frame. A body frame, which is one of the main structures, includes a pair of side frames disposed on the left and right sides and extending in the front-rear direction, a front member connecting the front ends of the side frames, and a rear end of each side frame And at least a rear member connecting the two.

  Each side frame includes an inner side plate and an outer side plate extending in the longitudinal direction at intervals in the left and right direction, an upper plate closing the upper end of the inner side plate and the outer side plate, and a lower plate closing the lower end of the inner side plate and the outer side plate , And a bending plate connecting the rear ends of the upper and lower plates. Since the side frame with such a configuration is a long structure in the front-rear direction, a relatively thin plate material is used. For example, the upper plate, the lower plate, and both side plates are joined by welding to form a hollow box structure By doing this, the rigidity of the side frame is secured (see, for example, Patent Documents 1 and 2).

  The dump truck carrier is connected to the vehicle body frame by a hinge pin attached to the rear of the vehicle body frame via a mount and a hoist cylinder attached to the front of the vehicle body frame from the hinge pin. As a result, the loading platform is pivoted up and down around the hinge pin in response to the expansion and contraction operation of the hoist cylinder.

  On such a loading platform, for example, objects to be transported such as earth and sand and crushed stone are stacked by a hydraulic shovel or the like. The dump truck is configured to be able to unload the object to be transported loaded on the loading platform by shifting the loading platform from the laid state to the upright state. On the other hand, a rubber pad as a shock absorbing material is provided at the bottom of the loading platform, and the loading platform is seated on the upper plate of each side frame via the rubber pad. Therefore, the vehicle body frame receives the load of the loading platform on which the object to be transported is loaded, via the rubber pad and the hinge pin.

  Therefore, when the objects to be transported are piled up on the loading section of the loading platform, the loading platform receives a high load from the objects to be transported, and the load applied to the loading platform is the rails attached to the bottom plate forming the bottom of the loading platform. It is received by the part connected to the hinge pin, i.e. the mount. In particular, since the mount is a member for supporting a hinge pin which is a pivot shaft of the loading platform, a high load is applied when the loading platform is raised to lower the object to be transported. Further, considering that the mount is a partial member, relatively thick plate members are used among members used for the vehicle body frame and the cargo bed, and high rigidity is secured.

Unexamined-Japanese-Patent No. 2010-30581 Japanese Utility Model Publication 7-7268

  In the prior art disclosed in Patent Documents 1 and 2, since the thick plate mount is installed on a relatively thin bent plate that constitutes a tail frame at the rear of the vehicle body frame, the rigidity of the mount and the bent plate Due to the difference, the bending plate side becomes high stress. Further, in the prior art attachment structure of the outer plate and the bending plate, the outer plate is disposed on the side of the bending plate so that no gap is generated in the joint portion of these members. Such a structure is not ideal considering rigidity, and the load from the mount makes the bending plate easily deformable. As a result, stress concentration occurs particularly in the welded joint between the outer plate and the bending plate, and the welded joint becomes highly stressed.

  By the way, in the case where the welded joint has a high stress, the welded joint may be damaged due to the accumulation of fatigue due to the stress and the frequency. In order to prevent the occurrence of such damage to the welded joint, it is effective to suppress the stress below the allowable stress, that is, to suppress the deformation. Therefore, one way to suppress the deformation of the tail frame is to increase the thickness of the bending plate, but in this case, the installation range of the bending plate is wider than the mount, so the vehicle mass increases. Unfavorably, this results in a decrease in allowable load mass, deterioration in traveling fuel efficiency, and a decrease in tire life.

  The present invention has been made in the light of the above-mentioned prior art, and its object is to provide a dump truck capable of suppressing the deformation of the tail frame without increasing the body mass.

  In order to achieve the above object, the dump truck of the present invention comprises a vehicle body frame, a mount provided at a rear end of the vehicle body frame, a hinge pin attached to the mount, and the vehicle body frame via the hinge pin. It is a dump truck provided with a loading platform rotatably mounted in the vertical direction with respect to the loading platform and carrying the objects to be transported loaded on the loading platform, wherein the vehicle body frames are disposed on both left and right sides A pair of extending side frames and a rear member connected to the rear end of each side frame and extending in the left and right direction, the side frames are an inner side plate and an outer side plate extending in the front and rear direction with an interval in the left and right direction An upper plate closing the upper ends of the inner and outer plates, a lower plate closing the lower ends of the inner and outer plates, and the upper plate A rear end of the lower plate is connected to the rear side of the vehicle body frame, and a rear side of the vehicle body frame is a rear end portion of the outer side plate of each side frame. The rear end portions of these outer plates are accommodated inside the bent plate so that the peripheral edge and the inner peripheral surface of the bent plate are in contact, and both ends of the rear member are on the inner side surfaces of the left and right outer plates. The tail frame comprises a joined box structure, and the tail frame is welded from the outside and inside of the box structure to the contact portion between the peripheral edge of the rear end of the outer plate and the inner circumferential surface of the bent plate. It is characterized by having a plurality of welding parts formed.

  According to the dump truck of the present invention, the deformation of the tail frame can be suppressed without increasing the body mass. Problems, configurations, and effects other than those described above will be apparent from the description of the embodiments below.

It is a side view of a dump truck concerning a 1st embodiment of the present invention. It is a side view of the vehicle body frame of the dump truck shown in FIG. It is a top view of the vehicle body frame shown in FIG. It is a bottom view of the vehicle body frame shown in FIG. It is sectional drawing which cut | disconnected the principal part along the BB line of FIG. It is sectional drawing which cut | disconnected the principal part along the CC line | wire of FIG. It is sectional drawing which cut | disconnected the principal part along the DD line of FIG. It is a figure which expands and shows the junction part of the outer side board and bending board which are shown in FIG. It is sectional drawing which cut | disconnected the principal part which concerns on 2nd Embodiment of this invention in the same position as the DD line of FIG. It is a figure which expands and shows the junction part of the outer side board which concerns on 2nd Embodiment of this invention, and a bending board. It is a figure which shows the other example of arrangement | positioning of the rear member with respect to the load carrier and rear suspension mount shown in FIG.

  Hereinafter, an embodiment for carrying out a dump truck according to the present invention will be described based on the drawings.

First Embodiment
As shown in FIG. 1, the dump truck 1 according to the first embodiment of the present invention includes a vehicle body frame 2, a pair of front wheels 3, a pair of rear wheels 4, and a loading platform 5. The pair of front wheels 3 is rotatably attached to the left and right ends of the front of the vehicle body frame 2. Further, the pair of rear wheels 4 is rotatably attached to the left and right ends of the rear of the vehicle body frame 2. Furthermore, the loading platform 5 is a portion for loading the object to be transported A such as soil, crushed stone, etc., and is mounted on the vehicle body frame 2 so as to be able to be undulated.

  The vehicle body frame 2 is a so-called vehicle body, and includes a pair of side frames 21 (see FIG. 3) disposed on both left and right sides. The pair of side frames 21 has a frame shape elongated in the front-rear direction, and in a state where the loading block 5 is seated on the vehicle body frame 2, the pair of rails 12 of the loading block 5 is mounted on the pair of side frames 21. It is configured to be. That is, the width of the side frame 21 and the width of the rail 12 are formed substantially equal. The details of the structure of the vehicle body frame 2 will be described later.

  Further, at the rear of the vehicle body frame 2, a hinge pin 6 is attached as a rotation center when raising or lowering the loading space 5 (turning in the vertical direction). A pair of hoist cylinders 7 as hydraulic cylinders connecting the vehicle body frame 2 and the loading platform 5 are attached to the front of the hinge pins 6 in the vehicle body frame 2.

  The pair of hoist cylinders 7 are attached to a substantially central portion in the front-rear direction of the vehicle body frame 2. Further, above the front wheel 3 on the left side of the vehicle body frame 2, a cab 8 which is a cab for the operator to ride is provided, and an engine, hydraulic equipment, etc. (not shown) are accommodated at the front of the vehicle body frame 2. A power unit 10 is provided.

  Therefore, when the operator drives the hoist cylinder 7 from the cab 8, the bed 5 rotates downward about the hinge pin 6 with the contraction operation of the hoist cylinder 7 to be in the laid posture to be seated on the vehicle body frame 2. In addition, the loading platform 5 pivots upward about the hinge pin 6 with the extension operation of the hoist cylinder 7, and is in a standing posture in which the object to be transported A is discharged rearward.

  In addition, the code | symbol 9 of FIG. 1 is a guide contact | abutted with the side part of the vehicle body frame 2, in order to prevent that the loading platform 5 moves to the left-right direction. Further, a front suspension cylinder (not shown) for supporting the loading platform 5 via the vehicle body frame 2 is interposed between the vehicle body frame 2 and the front wheel 3, and between the vehicle body frame 2 and the rear wheel 4. The rear suspension cylinder (not shown) which supports the loading platform 5 via the vehicle body frame 2 is interposed there.

  The loading platform 5 has a substantially box-like shape whose upper and rear portions are opened by a bottom plate (floor) 11a, a front plate (front) 11b, and a pair of side plates (sides) 11c. A loading unit for loading is formed. The bottom plate 11a, the front plate 11b, and the side plate 11c are respectively joined by welding. And the loading platform 5 is seated on the vehicle body frame 2 in a state in which the bottom plate 11a is slightly inclined forward.

  Further, a substantially plate-like top plate (canopy) 11 d is attached to the upper portion of the front plate 11 b. The top plate 11 d is attached so as to project forward from the upper portion of the front plate 11 b so as to cover the front upper portion of the dump truck 1. That is, the top plate 11 d is provided to prevent damage to the cab 8, the power unit 10 and the like due to the fall of the object to be transported A from the loading platform 5 in the lying posture in which the loading platform 5 is seated on the vehicle body frame 2. There is.

  Furthermore, a pair of rails 12 having a hollow box structure is attached to the lower surface of the bottom plate 11a in the front-rear direction of the vehicle body frame 2, and the impact is mitigated between the vehicle body frame 2 and the loading platform 5. A plurality of rubber pads 13 are provided for this purpose. In the first embodiment of the present invention, five rubber pads 13 are attached to the lower surfaces of the pair of rails 12, and a total of ten rubber pads 13 are disposed between the vehicle body frame 2 and the bed 5 in the lying posture of the bed 5. It intervenes.

  Each rail 12 has a shape similar to that of each side frame 21 so as to be mounted on the upper surface of each side frame 21 of the vehicle body frame 2 when the loading platform 5 is seated on the vehicle body frame 2. The rubber pad 13 is used to prevent the loading space 5 from vibrating while the dump truck 1 is traveling, and to absorb an impact on the vehicle body frame 2 when loading the object to be transferred A onto the loading space 5.

  A hinge pin bracket 14 for rotatably inserting the hinge pin 6 is attached at a position slightly behind the longitudinal middle portion of each rail 12. Since these hinge pin brackets 14 are members for rotatably supporting the hinge pins 6, a relatively thick plate material is used in the same manner as the bed and rear suspension mount 27 described later, and high rigidity is secured. .

  Next, the specific configuration of the vehicle body frame 2 will be described in detail with reference to FIGS.

  As shown in FIGS. 2 to 4, the vehicle body frame 2 is connected to the front end of each side frame 21 and extends in the left-right direction, and is connected to the rear end of each side frame 21 in the left-right direction A plurality of cross members (two cross members in the present embodiment) provided at a position between the extending rear member 23 and the front member 22 and the rear member 23 in the front-rear direction and connected to each side frame 21 and extending in the left-right direction ) And 24).

  The side frame 21 is in contact with the inner side plate 211 and the outer side plate 212 extending in the front-rear direction at intervals in the left-right direction, the flat upper end face of the inner side plate 211 and the flat upper end face of the outer side plate 212 An upper plate 213 closing the upper end of the upper plate 212; a lower plate 214 contacting the flat lower end surface of the inner plate 211 and the flat lower end surface of the outer plate 212; and closing lower ends of the inner plate 211 and the outer plate 212; The rear ends of the upper plate 213 and the lower plate 214 are connected to each other, and a bending plate 215 formed to be curved to the rear side of the vehicle body frame 2 is provided.

  Accordingly, the side frame 21 has a hollow box structure in which a space is formed by the inner plate 211, the outer plate 212, the upper plate 213, the lower plate 214, and the bending plate 215. Both the inner side plate 211 and the outer side plate 212 face each other at an interval in the left-right direction (the left-right direction in FIG. 5) of the side frame 21.

  On the other hand, the upper plate 213 and the lower plate 214 are both joined to the inner plate 211 and the outer plate 212 by welding. Similarly, the bending plate 215 is joined to the upper plate 213 and the lower plate 214 by welding. Since each side frame 21 formed in this manner is integrated with the left and right inner and outer plates 211 and 212 and the upper and lower plates 213 and 214 by welding, high rigidity is achieved even if it is hollow. It is secured.

  Further, as shown in FIGS. 3 and 4, the upper plate 213 and the lower plate 214 have connection portions for connecting the side frames 21 at the rear side portion, and the front portion is more bifurcated than the connection portion. It is formed as a branched branch site. Two cross members 24 are disposed between the upper plate 213 and the lower plate 214 in a state where they face each other at an interval in the front-rear direction at positions corresponding to the connection portions of the upper plate 213 and the lower plate 214. .

  The left and right ends of these cross members 24 are joined to the inner plates 211 of the side frames 21, and the upper ends and the lower ends thereof are joined to the connection portions of the upper plates 213 and the lower plates 214 of the side frames 21. Therefore, the vehicle body frame 2 includes a hollow box structure in which a space is formed inside by the cross members 24, the inner side plates 211 of the side frames 21, the upper side plate 213 and the lower side plate 214.

  Further, as shown in FIG. 2, a hoist plate 25 for supporting the hoist cylinder 7 is attached slightly behind the middle portion in the longitudinal direction of the vehicle body frame 2, and the rear wheel 4 is mounted below each cross member 24. A speed reducer mount 26 is attached to which a speed reducer (not shown) for transmitting a driving force is mounted. Further, on the bending plate 215 of the rear end portion of the vehicle body frame 2, a pair of loading platform and rear suspension mounts 27 disposed at an interval from each other inside the pair of hinge pin brackets 14 of the loading platform 5 are attached. There is.

  The load carrier / rear suspension mount 27 supports the hinge pin 6 which is the pivot shaft of the load carrier 5 together with the hinge pin bracket 14. Therefore, a high load is applied when the load carrier 5 is raised and the object to be transported A is lowered. In particular, the load support / rear suspension mount 27 supports the rear suspension cylinder, which relieves the load and impact acting on the rear of the vehicle body frame 2 by the internal hydraulic pressure, in addition to the hinge pin 6. It also costs. Therefore, in view of the fact that the load carrier / rear suspension mount 27 is also a local component, among members used for the vehicle body frame 2 and the load carrier 5, a relatively thick plate material is used, and the rigidity is high. Is secured.

  By the way, since the bed 27 and the rear suspension mount 27 are installed on the bending plate 215 of the vehicle body frame 2, the bending plate 215 side is highly stressed due to the difference in rigidity between the bed and rear suspension mounting 27 and the bending plate 215. . Therefore, in consideration of the rigidity of the vehicle body frame 2, it is ideal to dispose the outer side plate 212 on the inner peripheral side of the bending plate 215, but the following problems occur.

  That is, since the vehicle body frame 2 has a box structure, depending on the arrangement relationship of the inner side plate 211, the outer side plate 212, and the rear member 23, it is sufficient to weld the outer side plate 212 and the bending plate 215 from the inside of the vehicle body frame 2. It will be difficult. In addition, when the outer side plate 212 is disposed on the inner peripheral side of the bending plate 215 to join the two members, a gap is generated in the joint portion between the outer side plate 212 and the bending plate 215 in manufacturing the vehicle body frame 2. The reliability of the strength of the inner side of the joint becomes low.

  Therefore, in the first embodiment of the present invention, as shown in FIG. 5, at the rear of the vehicle body frame 2, the peripheral edge 212A of the rear end portion of the outer side plate 212 of each side frame 21 and the inner peripheral surface 215A of the bending plate 215 From the hollow box structure in which the rear end portions of the outer plates 212 are accommodated inside the bending plate 215 and the both ends of the rear member 23 are joined to the inner side surfaces 212 b of the left and right outer plates 212 so that A tail frame 31 is provided.

  And this tail frame 31 is a plurality of welds formed by welding from the outside and the inside of the box structure at the contact portion between the peripheral edge 212A of the rear end of the outer side plate 212 and the inner peripheral surface 215A of the bending plate 215. (Hereafter, for convenience, the weld portion on the outside of the box structure is denoted by 32A, and the weld portion on the inside of the box structure is denoted by 32B).

  The tail frame 31 according to the first embodiment of the present invention includes the left and right inner plates 211, the left and right outer plates 212, the upper plate 213, the lower plate 214, the bending plate 215, the rear member 23, and the bed 27 and rear suspension mount 27. It is formed. Hereinafter, a specific configuration of such a tail frame 31 will be described in detail with reference to FIGS. 5 to 8.

  In the first embodiment of the present invention, the bed 27 and rear suspension mount 27 of the tail frame 31 is set to have a thickness greater than that of the outer side plate 212 as shown in FIGS. A flat support member 271 is provided upright on the outer circumferential surface 215B. The support member 271 is disposed parallel to the outer side plate 212 and is disposed on an extension of the outer side plate 212 in the vertical direction.

  Specifically, the support member 271 according to the first embodiment of the present invention has the outer peripheral surface of the bending plate 215 such that the position of the outer surface 271a and the position of the outer surface 212a of the outer plate 212 coincide in the left-right direction. It is joined to 215B by welding. That is, in FIG. 6, the outer side surface 212a of the outer side plate 212 is positioned on the same vertical plane as the outer side surface 271a of the support member 271, and the inner side surface 212b of the outer side plate 212 is more than the outer side surface 271a of the support member 271. It is located outside the inner side and the inner side surface 271b.

  Further, as shown in FIG. 7, the support member 271 is provided with a base end 271A including a recess curved along the outer peripheral surface 215B so as to cover the bending plate 215, and from above both sides of the recess of the base end 271A. It has an upper end portion 271B and a lower end portion 271C protruding toward the plate 213 side and the lower plate 214 side.

  A hinge pin fitting portion 272 for inserting and fitting the shaft portion of the hinge pin 6 is provided in the upper portion of the base end portion 271A, and at a lower portion of the base end portion 271A, at the tip of a rod of a rear suspension cylinder. A suspension cylinder fitting portion 273 is provided for inserting and fitting the shaft portion of the attached connection pin (not shown). Of the upper end 271B and the lower end 271C, for example, the upper end 271B is extended to a position on an extension of the rear member 23 in the vertical direction. The rear member 23 is disposed perpendicularly to the upper plate 213 and the lower plate 214.

  On the other hand, in FIG. 6, the inner side plate 211 is positioned inside the inner side surface 271b of the support member 271, and the rear end of the inner side plate 211 is welded to the front side of the rear member 23 as shown in FIG. It is joined. Further, in FIG. 6, a worker may use a box of the tail frame 31 to weld the outer plate 212 and the bending plate 215 between the left and right inner plates 211 of the rear member 23, for example, at the central portion of the rear member 23. A manhole 231 is drilled into the structure which can pass through.

  The manhole 231 is formed only when the tail frame 31 is manufactured, and when the welding operation of the outer plate 212 and the bending plate 215 is completed, the lid 232 closing the manhole 231 is attached to the rear member 23 by welding or the like. The space inside is sealed. Therefore, the rear member 23 is a flat plate, and by maintaining the strength of the rear member 23, the support state of the bending plate 215 by the rear member 23 can be maintained well, so that the central side of the bending plate 215 is downward. Can be suppressed.

  In the welding operation of the outer plate 212 and the bending plate 215, for example, as shown in FIG. 8, a fillet welding in which two orthogonal surfaces of the outer plate 212 and the bending plate 215 are welded from the outside and the inside of the tail frame 31 is used. As a result, welds 32A and 32B made of weld beads are respectively formed on the left and right sides of the rear end of the outer side plate 212. The throat thicknesses La and Lb and the leg lengths Sa and Sb of the welds 32A and 32B are set to be equal to each other on the left and right sides (La = Lb, Sa = Sb).

  According to the dump truck 1 according to the first embodiment of the present invention configured as described above, the tail frame 31 at the rear of the vehicle body frame 2 has the rear end portions of the left and right outer plates 212 on the inner peripheral side of the bending plate 215 It has a box structure in which the rear member 23 is disposed between the outer plates 212 while being disposed. The outer plate 212 and the bending plate 215 are joined by welding from the outside and the inside of the box structure, thereby improving the rigidity of the tail frame 31 and receiving a load from the bed 27 and the rear suspension mount 27. The bent plate 215 can be firmly held from the lower side by the outer side plate 212.

  Therefore, the bending plate 215 is difficult to be deformed by the load from the bed and rear suspension mount 27. Therefore, the welded joint between the outer plate 212 and the bending plate 215 is generated without increasing the thickness of the bending plate 215. Stress concentration can be sufficiently mitigated. As a result, since deformation of the tail frame 31 can be suppressed without increasing the vehicle body mass, weight reduction of the dump truck 1 can be realized, and excellent reliability can be obtained.

  Further, in the dump truck 1 according to the first embodiment of the present invention, the support member 271 of the bed 27 and the rear suspension mount 27 is located just above the outer side plate 212 so that the position in the left and right direction overlaps the outer side plate 212. The load from the bed and rear suspension mount 27 can be smoothly transmitted to the outer side plate 212 via the bending plate 215. Thereby, the load applied to the welded joint portion of the outer side plate 212 and the bending plate 215 can be reduced.

  Further, in the dump truck 1 according to the first embodiment of the present invention, the upper end portion 271B of the support member 271 is extended to a position just above the rear member 23 so that the position in the front and rear direction overlaps with the rear member 23. Therefore, when the object to be transported A is unloaded from the loading platform 5, the load which the bending plate 215 receives from the loading platform and rear suspension mount 27 can be dispersed to the rear member 23. As a result, the bending of the bending plate 215 can be suppressed, so that it is possible to prevent the side fall of the bed 27 and the rear suspension mount 27 in advance, and it is possible to provide the tail frame 31 having a stable structure.

  Further, in the dump truck 1 according to the first embodiment of the present invention, the rear end of the inner side plate 211 is joined to the front surface of the rear member 23, so the rear side of the tail frame 31 with respect to the rear member 23 is the inner side plate 211 There is a box structure including a working space divided by the outer side plate 212, the bending plate 215, and the rear member 23 without the presence of Therefore, the worker can enter the box structure from the manhole 231 of the rear member 23 and easily weld the outer side plate 212 and the bending plate 215 from the inside. Thereby, the convenience in the welding operation of the outer side plate 212 and the bending board 215 can be improved.

  Moreover, by adopting such an arrangement relationship between the inner side plate 211 and the rear member 23, the inner side plate 211 can support the bed 27 and the rear suspension mount 27 via the rear member 23 and the bending plate 215. As described above, in the first embodiment of the present invention, the box structure of the tail frame 31 is reinforced by the inner side plate 211, so that the durability of the tail frame 31 can be improved.

Second Embodiment
The second embodiment of the present invention is different from the first embodiment described above in the first embodiment in that the upper end 271B of the upper end 271B and the lower end 271C of the support member 271 is as shown in FIG. In the second embodiment, as shown in FIG. 9, the lower end 271C of the upper end 271B and the lower end 271C of the support member 271 is extended to a position on the extension of the rear member 23 in the vertical direction. It is extended to a position on an extension of the rear member 23 in the vertical direction.

  In the second embodiment of the present invention, for example, as shown in FIG. 10, a groove is provided on the outer side of the peripheral edge 212A of the rear end of the outer side plate 212, and the groove and the inner peripheral surface of the bending plate 215. By using corner fillet welding in which the butt portion with 215A is welded from the outside and the inside of tail frame 31, welds 32C and 32D made of weld beads are formed on the left and right sides of the rear end of outer plate 212, respectively. Be done.

  The throat thickness Lc and the leg length Sc in the welded portion 32C are respectively set to be larger than the throat thickness Ld and the leg length Sd in the welded portion 32D (Lc> Ld, Sc> Sd). That is, in the second embodiment of the present invention, although machining for forming the groove on the peripheral edge 212A of the rear end portion of the outer side plate 212 is required, the strength of the weld portion 32C on the outer side of the tail frame 31 is Since the strength of the welded portion 32A according to the first embodiment is increased, the reliability of the welded joint between the outer plate 212 and the bending plate 215 can be improved. The configuration of the other second embodiment is the same as the configuration of the first embodiment, and the same or corresponding parts are denoted with the same reference numerals.

  According to the dump truck 1 according to the second embodiment of the present invention, in addition to the same function and effect as the first embodiment described above, the lower end portion 271C of the support member 271 has a position in the front-rear direction overlapping the rear member 23 As described above, since the load is extended to a position just below the rear member 23, the load received by the bending plate 215 from the bed and rear suspension mount 27 can be dispersed to the rear member 23 as the dump truck 1 travels. As a result, the amount of deformation of the bending plate 215 can be reduced, so that fatigue and damage of the welded joint between the outer plate 212 and the bending plate 215 can be reduced.

  The embodiments of the present invention described above are described in detail in order to explain the present invention in an easy-to-understand manner, and are not necessarily limited to those having all the configurations described. Further, part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment.

  In this embodiment, as shown in FIGS. 7 and 9, one of the upper end 271B and the lower end 271C of the support member 271 in the bed and rear suspension mount 27 is a position on the extension of the rear member 23 in the vertical direction. However, the present invention is not limited to this case. For example, as shown in FIG. 11, both the upper end 271B and the lower end 271C of the support member 271 are extension lines of the rear member 23 in the vertical direction. It may be configured to extend to the position of.

  Further, in the present embodiment, as shown in FIGS. 7 and 9, the case where the rear member 23 is disposed perpendicularly to the upper plate 213 and the lower plate 214 has been described, but the present invention is not limited to this case. For example, as shown in FIG. 11, the rear member 23 may not necessarily be disposed perpendicularly to the upper plate 213 and the lower plate 214.

DESCRIPTION OF SYMBOLS 1 ... dump truck, 2 ... vehicle body frame, 5 ... loading frame, 6 ... hinge pin, 7 ... hoist cylinder, 12 ... rail, 14 ... hinge pin bracket, 21 ... side frame, 22 ... front member, 23 ... rear member, 24 ... cross member , 25: Hoist plate, 26: mount for reduction gear, 27: mount for carrier and rear suspension, 31: tail frame, 32A to 32D, weld portion 211, inner plate, 212, outer plate, 212A, rim, 212a, outside Side surface, 212b: inner surface, 213: upper plate, 214: lower plate, 215: bending plate, 215A: inner circumferential surface, 215B: outer circumferential surface, 231: manhole, 232: lid, 271: supporting member, 271A: base end Part, 271 B ... upper end, 271 C ... lower end, 271 a ... outer side, 271 b ... inner side, 272 ... hinge pin Fitting part, 273 ... Suspension cylinder fitting part

Claims (4)

A vehicle body frame, a mount provided at a rear end portion of the vehicle body frame, a hinge pin attached to the mount, and a loading platform rotatably attached to the vehicle body frame via the hinge pin are provided. A dump truck for transporting the objects to be transported loaded on the loading platform,
The body frame is
A pair of side frames disposed on the left and right sides and extending in the front-rear direction,
A rear member connected to the rear end of each of the side frames and extending in the left-right direction;
Each side frame is
An inner plate and an outer plate extending in the front-rear direction with a space in the left-right direction;
An upper plate closing an upper end of the inner plate and the outer plate;
A lower plate closing a lower end of the inner plate and the outer plate;
A rear end of the upper plate and a lower end of the lower plate are connected to each other, and a bending plate formed by being curved to the rear side of the vehicle body frame;
At the rear of the vehicle body frame, the rear ends of these outer plates are on the inner side of the bending plate so that the peripheral edge of the rear end of the outer plate of each side frame and the inner peripheral surface of the bending plate are in contact. And a tail frame having a box structure in which both ends of the rear member are joined to the inner side surfaces of the left and right outer plates,
The tail frame has a plurality of welds formed by welding from the outside and the inside of the box structure at the contact portion between the peripheral edge of the rear end of the outer plate and the inner circumferential surface of the bent plate. Characteristic dump truck. In the dump truck according to claim 1,
The mount is provided with a flat support member whose thickness is set larger than the outer side plate and which is provided on the outer peripheral surface of the bending plate.
The dump truck according to claim 1, wherein the support member is disposed in parallel with the outer side plate, and is disposed on an extension of the outer side plate in the vertical direction. In the dump truck according to claim 1,
The mount is provided with a flat support member whose thickness is set larger than the outer side plate and which is provided on the outer peripheral surface of the bending plate.
The support member is
A hinge pin fitting portion for fitting the shaft portion of the hinge pin, and a base end portion including a concave portion curved along an outer peripheral surface so as to cover the bending plate;
It has an upper end and a lower end projecting toward the upper plate side and the lower plate side from both sides of the recess of the base end portion,
At least one of the upper end portion and the lower end portion is extended to a position on an extension of the rear member in the vertical direction. In the dump truck according to claim 3,
A rear end of the inner plate is joined to a front surface of the rear member.