JP3475720B2 - Chassis frame for dump truck - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chassis frame for a dump truck.

[0002]

2. Description of the Related Art The structure of a conventional dump truck will be described with reference to the schematic side view of FIG. In the drawings, reference numeral 10 generally indicates a dump truck, which extends in the vehicle front-rear direction and has a pair of left and right side rails 12 each having a U-shaped cross section and extending in the vehicle width direction. A ladder-type chassis frame 14 is provided, which has a plurality of cross members (not shown) that are arranged and have both ends fixed to the side rails 12.

A cab 16 is mounted on the front end portion of the chassis frame 14, and a dump carrier or vessel 18 is mounted on the chassis frame 14 behind the cab 16. A front shaft that supports the front wheel 22 is suspended from the front portion of the chassis frame 14 via the front leaf spring 20.
Is pivoted at its front and rear ends to front and rear spring brackets 24 and 26 mounted on the side rail 12, respectively. Further, a rear shaft that supports a rear wheel 32 is suspended at a rear portion of the chassis frame 14 via a main leaf spring 28 and a helper leaf spring 30, and the main leaf spring 28 has its front and rear ends at the side rail 12 Is attached to the front and rear spring brackets 34 and 36 respectively, and the front and rear ends of the helper leaf spring 30 are attached to the side rails 12 when the load acting on the rear shaft exceeds a set value. The pair of front and rear helper stoppers 38 and 40 that are mounted are configured to abut.

Left and right side rails 1 behind the cab 16
A pair of left and right sub-frames 44 are mounted on the top of the two through a plurality of U-bolts 42 and a fixture such as a keeper (not shown), and the dump carrier 18 is attached to the rear end of the sub-frame 44 by a pivot 46. , Is tiltably supported as shown in the drawing. Further, a dump hoist support shaft 48 extending in the vehicle width direction is disposed at an intermediate portion in the front-rear direction of the left and right sub-frames 44, and one end of a dump hoist 50 composed of a hydraulic cylinder is supported on the support shaft 48. The other end of the dump hoist 50 is pivotally attached to the lower side of the intermediate portion of the dump platform 18 in the front-rear direction by a pivot shaft 52.

FIG. 6 exemplifies a single-stage direct-loading type dump hoist 50 for the sake of simplicity. However, as is well known in the art, a direct-loading type dump hoist having two or more stages and a hydraulic hoist. Various types of link-combined dump hoists using both cylinders and links are appropriately adopted. During normal traveling and at rest of the dump truck 10, the dump hoist 50 contracts, and the dump carrier 18 rotates around the pivot 46 in the counterclockwise direction from the position shown in the drawing, and the front end portion thereof is the subframe 44. And is held in a substantially horizontal position. Further, when discharging the earth and sand loaded on the dump platform 18 and other loads, the dump hoist 50 extends and the dump platform 18 rotates around the pivot 46 in the clockwise direction from the rest position to a desired angle. As a result, the cargo slides on the floor surface of the cargo bed and is discharged downward through the gap with the tailgate 54.

In the conventional dump truck 10 described above, the dump truck 18, the dump hoist 50, etc.
Since it is mounted on a large subframe 44 extending over substantially the entire length of 8, the vehicle weight increases, and the mounting position of the dump truck 18 increases by the height of the subframe 44. Since the position of the center of gravity becomes high, there is a problem that running stability, especially turning performance is inferior.

[0007]

SUMMARY OF THE INVENTION The present invention was devised in view of the above circumstances, and in the conventional dump truck, by omitting the subframe stacked on the upper side of the side rail of the chassis frame. In addition to reducing the vehicle weight, it is possible to improve the traveling stability by lowering the mounting position of the dump bed, and to reduce the load acting on the dump hoist support shaft that supports the dump hoist. The chassis frame for the dump truck that has excellent durability and reliability is inexpensive because the stress generated by widely distributed and transmitted to the chassis frame components near the support shaft and effectively preventing stress concentration is reduced. The primary purpose is to provide

[0008]

In order to achieve the above object, the present invention is directed to a pair of left and right side rails extending in the vehicle front-rear direction and each having a U-shaped cross-sectional shape, and a front-rear vehicle of the left and right side rails. Left and right closed cross-section frame portions formed by facing and internally fitting an auxiliary frame having a U-shaped cross section in a U-shaped opening in a part of the direction,
A dump hoist support shaft, which is arranged to extend in the vehicle width direction and whose both ends are supported by brackets provided on the closed cross section frame part, and between the left and right closed cross section frame parts in the vicinity of the dump hoist support shaft. Placed in the
Penetrate both ends through the auxiliary frame and the left and right sides
Cross members fixed to the vertical wall portions of the rails, strip plate-shaped brackets fixed to the inner portions of the left and right side rails of the cross members and extending vertically, and the left and right strip plates. dump truck the outer end of which is secured to upper and lower edges of the respective Jo brackets by rivets and bolts, characterized by comprising a gusset fastened respectively fastened to the upper and lower flanges of the left and right side rails and the auxiliary frame It proposes a chassis frame for cars.

According to the above construction, the cross member is arranged in the vicinity of the dump hoist support shaft on which a large load acts when the dump hoist of the dump hoist is pushed up. Both ends of the cross member and the dump hoist support shaft in the vehicle width direction are arranged. The parts are respectively supported by a closed cross-section frame part formed by a side rail having a U-shaped cross section and an auxiliary frame having a U-shaped cross section which is internally fitted to face into the U-shaped opening of the side rail. And that the cross member is a strip-shaped bracket fixed to an inner part of the end member,
A large load acting on the dump hoist support shaft is secured by being fastened to the closed cross-section frame portion through a strong reinforcing structure consisting of upper and lower gussets fixed to the upper and lower edges of the strip plate bracket. The stress is effectively avoided by being widely dispersed and transmitted to the frame member and the cross member having the closed cross section. Further, by the outer end of the upper and lower gussets are fastened together fastened to the upper and lower flanges of the side rail and the auxiliary frame by rivets and bolts, compared to when it is fixed by the welding, stress generated fastening portion is reduced To be done.

In the present invention, it is preferable that the front and rear end edges of the strip-shaped bracket and the front and rear end edges of the auxiliary frame are spaced apart from each other in the vehicle front and rear direction. With this configuration, a sudden change in the second moment of area of the portion where the cross member is attached to the closed cross-section frame portion is prevented, and stress concentration is prevented.

Further, in the present invention, it is preferable that the frame portion having the closed cross section is formed from a front adjacent portion of a cross member arranged near the dump hoist support shaft to a rear end portion of the side rail. With this configuration,
(EN) A chassis frame which can sufficiently bear the load of a rear shaft that bears most of the weight of a dump truck and its load and the load acting on a dump hoist support shaft when the truck hoist of a dump hoist is pushed up.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention will be specifically described below with reference to FIGS. (Note that substantially the same members and parts as those of the conventional dump truck described above with reference to FIG.
A duplicate description will be omitted. ) By comparing FIG. 1, which is a schematic side view of a dump truck 10 according to the present invention, with FIG. 6, which is a similar schematic side view of a conventional dump truck, the present invention can be easily understood. The dump truck 10 is provided with a pair of left and right subframes 44 that are conventionally mounted on the upper side of the side rail 12 of the chassis frame 14 and fixed to the side rail 12 by a fixture such as a U bolt 42. First, the dump bed or vessel 18 is rotatably supported by the pivot 46 at the rear end of the side rail 12, and the dump hoist 50 is directly supported by the chassis frame 14 at the lower end thereof as described in detail later. ing.

In FIG. 1, when the vehicle is loaded with a set amount of earth and sand or the like on the chassis frame 14 located behind the position indicated by the line AA, that is, the dump truck 18, a load much larger than that of the front axle is applied. Rear axle suspension part and dump hoist 50
2 to 5 show the detailed configuration of the rear half of the chassis frame 14 including the mounting portion of the dump hoist support shaft to which a large load is applied during the pushing up operation of FIG. (Note that the configuration of the chassis frame 14 in front of the line AA is the same as the chassis frame 14 in the conventional dump truck.
The detailed description is omitted. )

First, the plan view of FIG. 2 and the side view of FIG. 3 (in this figure, in order to avoid excessive congestion, front and rear spring brackets 34 supporting the main leaf spring 28).
And 36 and the front and rear helper stoppers 38 and 40 supporting the helper leaf spring 30 are not shown. ), The first cross member 5 is provided in the vicinity of and in front of the front spring bracket 34.
6 is arranged, a second cross member 58 is arranged at a position immediately behind the spring bracket 36, and a third cross member 60 is arranged in front of the first cross member 56.

A dump hoist support shaft 62, which supports the lower end of the dump hoist 50 formed of a single-stage or multi-stage hydraulic cylinder, is arranged near and behind the first cross member 56 and extends in the vehicle width direction. Both ends of the support shaft 62 are pivotally supported by left and right brackets 64. The bracket 64 is attached to the left and right side rails 12 via a support structure described later.

A cross-sectional shape is formed in a U-shaped opening of the side rail 12 from a part of the left and right side rails 12 in the vehicle front-rear direction, in this embodiment, from a rear end B to a position C slightly forward of the first cross member 56. Is inserted into the side rails facing each side rail, and the upper and lower flanges of the side rail 12 and the upper and lower flanges of the auxiliary frame 66 are fastened with a large number of rivets and bolts, respectively. Figure 4
As is well shown in the cross-sectional view of FIG. 1, a closed cross-section frame portion 68 having a substantially rectangular cross-section in the vertical plane in the vehicle width direction is formed.

The first cross member 56 is composed of a closed cross-section member having high rigidity and strength against bending and twisting, preferably a circular pipe member which is easily available and lightweight. Mounting flanges 70 are fixed by welding or the like to the left and right ends that extend outward in the vehicle width direction through the through holes formed in the wall. The mounting flange 70 is fastened to the webs or the vertical walls of the left and right side rails 12 by a plurality of bolts 72.

Further, the first cross member 56 has a portion on the vehicle width direction center side from the end portion on the vehicle width direction outer side, that is, a portion of the chassis frame 14 near the vehicle front-rear direction center line OO, the vehicle width. The strip-shaped bracket 74, which has a mountain-shaped planar shape that spreads outwards in the outward direction and extends in the up-down direction, is fitted into the burring-processed through hole 76, and the strip-shaped bracket is welded at the burring portion. It is fixed to 74.

The upper edge of the strip-shaped bracket 74 is fixed to the upper and lower gussets 78 by welding. The gusset 78 has its outer end in the vehicle width direction at a portion rearward from the C position. , The upper and lower flanges of the side rail 12 and the upper and lower flanges of the auxiliary frame 66 are fastened together by a plurality of bolts 80 and rivets 82, respectively, and in the portion in front of the C position, the side rails are fixed by the bolts 80 'and rivets 82'. It is fastened to 12 upper flanges.

Further, as best shown in FIG.
The front ends of the upper and lower gussets 78 extend to a position slightly overlapping the fastening ends of the side rails 12 of the normal alligator-type cross member 60 to the web, and the rear ends thereof extend to a position slightly rearward of the front helper stopper 38. It is extended. On the other hand, the front end 74a of the strip-shaped bracket 74
Is a front end of the auxiliary frame 66, that is, a closed cross-section frame portion 68
Is disposed so as to be located in front of the front end of the auxiliary frame 66, and its rearward extension 74b extends from the front position of the bracket 64 that pivotally supports the support shaft 62 to the web of the auxiliary frame 66 beyond the attachment position of the bracket 64. Running along.

As shown in FIG.
As best shown in the cross-sectional view of FIG.
A pillar member 84 having a hat-shaped cross section extending in the vertical direction, and upper and lower flange members 86 fixed to the upper and lower ends of the pillar member 84 by welding, and front and rear flange portions 84 'of the pillar member 84, The extension portion 74b of the strip plate bracket 74 and the web of the auxiliary frame 66 are fastened together by a plurality of bolts 88, so that the horizontal cross-sectional shape is a substantially rectangular closed cross-section structure extending in the vertical direction. 90 is formed.

The upper gusset 78 is abutted on the upper flange member 86 of the closed section structure 90, and the lateral side 64a of the L-shaped bracket 64 is mounted on the gusset 78. , Are fastened together and fixed by a plurality of bolts 92. As best shown in FIG. 4, a bearing hole for rotatably supporting the end portion of the support shaft 62 is provided on the vertical side 64b of the bracket 64 that hangs along the side surface of the column member 84. There is. In FIG. 4, reference numeral 94 denotes the side rail 1 of the portion to which the front spring bracket 34 and the helper stopper 38 are attached.
2 is a reinforcing plate arranged inside the web.

Next, the second cross member 58 arranged near the rear end of the chassis frame 14 has a closed cross-section member having large rigidity and strength against bending and twisting, like the first cross member 56. Preferably, the circular pipe member is easily available, lightweight and inexpensive, and mounting flanges 96 are fixed to both ends in the vehicle width direction by welding. The mounting flange 96 is fastened to the web of the auxiliary frame 66 by a plurality of bolts 98.

The second cross member 58 is a strip-shaped bracket having an S-shaped planar shape and extending in the vertical direction at a portion closer to the center line OO than the end portion on the outer side in the vehicle width direction. 1
00 is burred into the through hole 102,
The burring portion is fixed to the strip plate bracket 100 by welding.

The upper and lower edges of the strip plate bracket 100 are fixed to the upper and lower gussets 104 by welding,
The gusset 104 has an outer end in the vehicle width direction at the upper and lower flanges of the side rail 12 and the auxiliary frame 66.
The upper and lower flanges are fastened together by a plurality of bolts 106. In addition, two reinforcing plates 108 are provided inside the auxiliary frame 66 adjacent to the mounting flange 96.
Are fixed by welding or the like.

At the rear ends of the left and right side rails 12,
Axis 4 for rotatably supporting the rear end portion of the dump truck 18
The bearing bracket 110 for supporting the shaft 6 is provided, and in order to limit the maximum tilt angle of the dump truck 18, the bearing bracket 110 shown in FIG.
3, the stopper member 112 having a triangular side surface is fixed. 1 and 3, reference numeral 114 is a rear bumper, and 116 is a bumper stay connecting the rear bumper to the left and right side rails 12.

According to the above configuration, in the conventional dump truck 10, the dump carrier 18 and the dump hoist 50 are provided.
The sub-frame 44, which has been stacked on the side rails 12 of the chassis frame 14 to support the dump frame 1 and the dump hoist 50, is directly supported by the chassis frame 14.
The position of the center of gravity of 8 can be lowered by the height of the sub-frame 44, so that the running stability, especially during turning running can be improved.

In order to make it possible to omit the sub-frame 44 in the conventional dump truck 10, first, in the vicinity of the dump hoist support shaft 62 that supports the dump hoist 50 and is arranged to extend in the vehicle width direction, The first cross member 56 is arranged, and a portion behind the dump support shaft 62 from the front position C of the first cross member 56,
That is, in this embodiment, an auxiliary frame 66 having a U-shaped cross-sectional shape is internally fitted in the U-shaped openings of the left and right side rails 12 across the rear end position B so as to face the upper and lower flanges of the side rail 12. The upper and lower flanges of the auxiliary frame 66 are integrally fastened together by a large number of bolts 80, 106 and rivets 82, and the cross-sectional shape in the vertical plane in the vehicle width direction is substantially rectangular and extends in the vehicle front-rear direction. 68 is formed. As a result, during the operation of the rear axle load and the dump hoist 50, the dump truck 18 particularly in the loaded state.
The chassis frame part that acts in combination with a large load when pushing up is reinforced.

Next, both ends of the first cross member 56 in the vehicle width direction are fastened to the webs of the left and right side rails 12 by the mounting flanges 70 and the bolts 72, and the center line O- of the chassis frame 14 in the vehicle front-rear direction. A strip-shaped bracket 74 having a chevron shape in an inward portion near the O
Is fixed to the upper and lower gussets 78 by welding, and the upper and lower gussets 78 are attached to the upper and lower gussets 78, and the upper and lower gussets 78 are attached to the plurality of bolts 80, 80 'and the rivets 82. , 82 'are fastened together to the upper and lower flanges of the side rail 12 and the auxiliary frame 66, so that the span between the both-end supporting portions of the first cross member 56 has a short length shown by symbol S in FIG. And the chassis frame 14 including the cross member 56.
The rigidity and strength of the flexure against torsional and torsional loads are increased.
In addition, when the outer ends of the upper and lower gussets 78 in the vehicle width direction are fixed to the upper and lower flanges of the side rail 12 by welding, stress is concentrated on the ends of the welding line, which often causes damage. As described above, the structure in which the side rail 12 and the upper and lower flanges of the auxiliary frame 66 are fastened to each other by the large number of bolts 80, 80 'and the rivets 82, 82' effectively prevents the stress concentration and prevents the stress generated. Can be reduced.

Further, the frame section 68 having a closed cross section in the vehicle front-rear direction in which both ends of the dump hoist support shaft 62 are located.
A plurality of flange portions 84 'of the support member 84 having a hat-shaped cross section, which are arranged to extend in the vertical direction on the rear extension portion 74b of the strip-shaped bracket 74 and the web of the auxiliary frame 66 on the inner side in the vehicle width direction. By tightening and fastening together with bolts 88, a vertical closed cross-section structure portion 90 having a substantially rectangular horizontal cross-sectional shape is formed, and the gusset is provided on the flange member 86 fixed to the upper end of the column member 84. 78 is piled up, the lateral side 64a of the bracket 64 is mounted on the gusset 78, and firmly fastened together by the plurality of bolts 92. Therefore, the dump hoist support shaft 6
A large load that occurs when the dump hoist 50 acts on the chassis 2 includes the chassis including the first cross member 56 via the closed cross-section frame portion 68 and the closed cross-section structure portion 90, the gusset 78, and the strip plate bracket 74. Frame 14
Will be widely distributed and transmitted. Therefore, in the chassis frame 14 for a dump truck, sufficient rigidity and strength can be secured in the most important part where the rear axle load and the load of the dump hoist 50 act in combination.

The length of the auxiliary frame 66, which is inserted into the left and right side rails 12 and forms the closed cross-section frame portion 68, in the vehicle front-rear direction is approximately the entire length of the dump truck 18 in the conventional dump truck. It is much shorter than the sub-frame 44, while the gusset 7
8, the weight of each member forming the strip-shaped bracket 74 and the vertical closed cross-section structure portion 90, and the both end mounting portions of the cross member arranged in the rear axle load carrying portion of the chassis frame in the conventional dump truck. Since the difference between the weight of the reinforcing structural member such as the gusset and the weight of the reinforcing structural member of the portion of the sub-frame 44 where the dump hoist support shaft is attached is small, it is possible to achieve a comprehensive weight reduction.

The front end position C of the auxiliary frame 66
And the front end 74a of the strip-shaped bracket 74 are preferably spaced apart from each other in the vehicle front-rear direction, and by this configuration, a cross section of a portion of the first cross member 56 attached to the closed cross-section frame portion 68. It is possible to avoid sudden changes in the second moment and effectively prevent stress concentration.

The first cross member 56 is preferably a member having a closed cross-section structure, particularly a circular pipe member, and the front end of the gusset 78 is arranged in front of the first cross member 56. It is preferable that the third cross member of the mold is slightly overlapped with the both end mounting portions in the vehicle front-rear direction, and this has an additional advantage that stress concentration can be avoided and the generated stress can be reduced. Further, it is arranged in the vicinity of the rear spring bracket 36 and the helper stopper 40, and the bearing bracket 110, and the rear shaft load and a considerable portion of the weight of the same carrier and the load via the pivot 46 when the dump carrier 18 is tilted. Similarly to the first cross member 56, the second cross member 58 for carrying and is also a closed cross-section structural member, preferably a circular pipe member, in order to secure bending and torsional rigidity and strength, and to reduce weight and cost. It is advantageous in terms.

The end of the second cross member 58 in the vehicle width direction is fixed to the web of the auxiliary frame 66 via the flange member 96, and the inner portion of the cross member 58 in the vehicle width direction is vertically moved. Extended strip bracket 100
To be fixedly fitted into the through holes provided in the gusset, and further, the gussets 104 are fixed to the upper and lower edges of the strip plate bracket 100 by welding, respectively, and the ends of the gussets on the outer side in the vehicle width direction are fixed to the plurality of bolts. By adopting a structure in which the side rails 12 and the upper and lower flanges of the auxiliary frame 66 are tightened together by 106, that is, a structure substantially similar to the mounting structure of the first cross member 56, the rear end portion of the chassis frame 14 is bent. And there is the additional advantage that torsional rigidity and strength can be ensured.

[0035]

As described above, the chassis frame for a dump truck according to the present invention has a pair of left and right side rails extending in the vehicle front-rear direction and each having a U-shaped cross section, and a vehicle having the same left and right side rails. Left and right closed cross-section frame portions formed by facing and fitting an auxiliary frame having a U-shaped cross-section inside a U-shaped opening in a part in the front-rear direction, and extending in the vehicle width direction. A dump hoist support shaft whose both end portions are supported by brackets provided on the closed cross-section frame portion, and a cross member disposed between the left and right closed cross-section frame portions in the vicinity of the dump hoist support shaft, The strip-shaped brackets that are fixed to the inwardly spaced parts of the cross member from the left and right side rails and extend in the up-and-down direction, and the upper and lower edges of the left and right strip-shaped brackets. The left and right side rails and the gussets fixed to the upper and lower flanges of the auxiliary frame are fastened together by rivets and bolts. Supporting and connecting both end portions of the cross member arranged in the vicinity of the dump hoist support shaft to the closed cross-section frame portion by a mounting structure including the strip plate bracket and gusset, and the gusset side rails by rivets and bolts. By tightening together with the upper and lower flanges of the auxiliary frame, a large load during dump operation of the dump hoist can be widely distributed and transmitted to each member of the chassis frame to achieve reduction of generated stress. It has bending and torsional rigidity, and has excellent durability and reliability. It is also possible to provide a lightweight and inexpensive chassis frame for dump trucks, and by omitting the subframe that was conventionally stacked on the chassis frame, the center of gravity position of the dump truck can be lowered, There is an advantage that the running stability can be improved.

Further, in the present invention, the front and rear end edges of the strip-shaped bracket and the front and rear end edges of the auxiliary frame are spaced apart from each other in the front and rear direction of the vehicle, whereby the cross member is formed. There is an advantage that stress concentration can be effectively prevented by avoiding a sudden change of the second moment of area of the mounting structure portion. Further, in the present invention, the closed cross-section frame portion is formed from the front adjacent portion of the cross member arranged in the vicinity of the dump hoist support shaft to the rear end portion of the side rail, so that the dump operation of the dump hoist is performed. There is an advantage that it is possible to provide a chassis frame having sufficient rigidity and strength capable of safely carrying a large load and a rear axle load.

[Brief description of drawings]

FIG. 1 is a schematic side view of a dump truck that employs a chassis frame according to the present invention.

FIG. 2 is a plan view showing, on an enlarged scale, a portion behind the AA line of the chassis frame in FIG.

3 is a side view of the rear half chassis frame shown in FIG. 2. FIG.

FIG. 4 is a sectional view taken along the line IV-IV of FIG. 3 and viewed in the direction of the arrow.

5 is a partial perspective view showing a configuration of a second closed cross-section structure portion 90 in FIG.

FIG. 6 is a schematic side view of a conventional dump truck.

[Explanation of symbols]

10 ... Dump truck, 12 ... Side rail, 14 ... Chassis frame, 18 ... Dump carrier, 20 ... Front leaf spring, 22 ... Front wheel, 28 ... Main leaf spring, 30 ... Helper leaf spring, 32 ... Rear wheel, 3
4 and 36 ... Spring bracket, 38 and 40 ... Helper stopper, 50 ... Dump hoist, 56 ... First cross member, 58 ... Second cross member, 60 ... Third cross member, 62 ... Dump hoist support shaft, 64 ... Bracket , 66 ... Auxiliary frame, 68 ... Frame section with closed cross section, 7
0 ... Mounting flange, 74 ... Strip plate bracket, 78 ... Gusset, 90 ... Closed-section structure part.

Continuation of the front page (56) Reference JP-A-59-11931 (JP, A) JP-A-60-31840 (JP, A) JP-A-63-212182 (JP, A) JP-A-6-298119 (JP , A) Actual break 63-104711 (JP, U) Actual break 3-77785 (JP, U) Actual break 2-13884 (JP, U) Actual Kohei 6-35702 (JP, Y2) (58) Fields surveyed (Int.Cl. ⁷ , DB name) B62D 21/02 B62D 21/09 B62D 25/20

Claims (3)

(57) [Claims] 1. A pair of left and right side rails extending in the vehicle front-rear direction and each having a U-shaped cross-sectional shape, and a U-shaped cross-section in a U-shaped opening in a part of the left and right side rails in the vehicle front-rear direction. Right and left closed cross-section frame parts formed by facing and fitting in a rectangular auxiliary frame, and both ends of the frame are supported by brackets provided in the closed cross-section frame part. and dump hoist support shaft that is, in the vicinity of the dump hoist support shaft disposed between the closed section frame portions of the left and right, the auxiliary frame both ends thereof
Through the holes and on the vertical walls of the left and right side rails, respectively.
The fixed cross member, the strip plate brackets fixed inwardly from the left and right side rails of the cross member and extending in the vertical direction, and the upper and lower edges of the left and right strip plate brackets. The outer ends are fixed and fastened together with rivets and bolts to the left and right side rails and the upper and lower flanges of the auxiliary frame.
A chassis frame for a dump truck, comprising a fastened gusset. 2. The front and rear end edges of the strip plate bracket and the front and rear end edges of the auxiliary frame are arranged so as to be spaced apart from each other in the front and rear direction of the vehicle. Item 1. The chassis frame for a dump truck according to item 1. 3. The closed cross-section frame portion is formed from a front adjacent portion of a cross member arranged in the vicinity of the dump hoist support shaft to a rear end portion of a side rail. The chassis frame for a dump truck according to item 2.