JP2011183992A - Trailer frame structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a trailer frame structure which reinforces a section low in beam height. <P>SOLUTION: In the frame structure 2 of the trailer 1 having a beam member 4 on a floor section thereof, the beam member 4 includes an upper flange section 11, a lower flange section 12, and web sections 13. An overlapping section 33, in which the plurality of web sections 13 are arranged side by side, is formed in at least part of the beam member 4 in a longitudinal direction. The beam member 4 constitutes a main beam 10 extended in a vehicle longitudinal direction. The main beam 10 includes an apron section 20, a neck section 1, and a wheelbase section 22. The overlapping section 33 is extended rearward from the front end of the main beam 10, and is formed to include at least a boundary part between the apron section 20 and the neck section 21. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a trailer frame structure.

  The trailer frame structure, like the platform trailer and container chassis, handles the bending load due to the load with a pair of left and right main beams (beam material), and like the van trailer, it takes the bending load with the side face body. It can be broadly divided into those that do not have Of these, those having a main beam are generally constructed by integrally connecting the left and right main beams with cross members and left and right connecting members.

  A conventional main beam is formed by connecting upper and lower flange members with a web (see, for example, Patent Document 1), and has a configuration in which stiffeners are appropriately provided and reinforced.

JP 2007-45310 A

  By the way, the main beam may be restricted by the height dimension (beam height) at the connecting portion with the tractor. Therefore, conventionally, the beam height of the main beam has been adjusted by appropriately bending the upper and lower flange members and connecting the flange members with a web whose height has been adjusted. However, there is a problem in that when the height of the web is not constant and the main beam has a portion where the beam height is high and a portion where the beam height is low, a portion that does not match the bending moment distribution due to the load appears. Therefore, it is required to further reinforce the portion where the beam height of the main beam is low. However, there is a restriction on the frame height, and it is difficult to reinforce.

  Accordingly, the present invention has been devised to solve the above-described problems, and an object thereof is to provide a trailer frame structure that can reinforce even a portion having a low beam height.

  The invention according to claim 1 for solving the above-mentioned problems is a trailer frame structure including a beam member on a floor, wherein the beam member includes an upper flange portion, a lower flange portion, and a web portion. The trailer frame structure is characterized in that a superposed portion comprising a plurality of web portions arranged in parallel is formed at least in a part of the beam material in the longitudinal direction.

  The beam material of the present invention is a member provided on the floor portion of the trailer, and can be applied to a beam material extending in any direction such as a vehicle length direction or a vehicle width direction. According to such a configuration, the strength of the beam material can be efficiently increased by forming the overlapping portion even in a portion where the height dimension (beam height) of the web portion is low.

  The beam material constitutes a main beam extending in the vehicle length direction. The main beam is formed by connecting a plurality of portions having different beam heights in the longitudinal direction, and is connected to the tractor. A low beam height apron portion provided with a pin, a high beam height wheel base portion located behind the tractor, and a beam height between the apron portion and the wheel base portion. In the case of including a neck portion that increases toward the base portion, the overlapping portion extends rearward from the front end of the main beam and includes at least a boundary portion between the apron portion and the neck portion. What is formed in this way is preferable. According to such a configuration, it is possible to efficiently increase the strength of the beam material even in the apron portion where the large beam height dimension cannot be secured in the connection portion with the tractor.

  Further, in the present invention, the neck portion is formed by changing the increase rate of the beam height in two stages. The neck portion is arranged at the front portion, the gently inclined portion having a low increase rate, and the rear portion, and the increase rate is increased. A plurality of web portions, a pair of side web portions extending rearward from the front end at both side portions in the vehicle width direction of the main beam, and an intermediate portion in the vehicle width direction of the main beam. An intermediate web portion extending forward from the rear end at the portion, and the rear end of the side web portion is located behind the boundary portion between the gently inclined portion and the steeply inclined portion, It is preferable that the front end of the intermediate web portion is positioned further forward than the boundary portion between the gently inclined portion and the steeply inclined portion. According to such a configuration, two overlapping portions of the web portion are formed at the front end portion of the main beam, and three overlapping portions of the web portion are formed behind the main portion. Therefore, even in the apron part where the large beam height cannot be secured at the connecting part with the tractor, or in the part where a large moment force is applied at the boundary between the gently inclined part and the steeply inclined part of the neck part, The strength of can be further increased.

  Furthermore, in the present invention, the neck portion is formed by changing the increase rate of the beam height in two stages. The neck portion is arranged at the front portion and the gently inclined portion with a low increase rate is arranged at the rear portion and the increase rate is increased. A plurality of web portions, the intermediate web portion extending from the front end to the rear end in the vehicle width direction intermediate portion of the main beam, and the vehicle width direction side portion of the main beam. A side web portion extending rearward from the front end, and the rear end of the side web portion is located behind the boundary between the gently inclined portion and the steeply inclined portion. Is preferred. According to such a configuration, two or three overlapping portions of the web portion are formed from the front end portion of the main beam to the boundary portion between the gently inclined portion and the steeply inclined portion. Therefore, even in the apron part where the large beam height cannot be secured at the connection part with the tractor and the part where a large moment force is applied at the boundary part between the apron part and the wheel base part, the strength of the beam material is improved. Can be enhanced.

  Furthermore, in the present invention, it is preferable that the longitudinal end surface of the web portion in the overlapping portion is recessed in a concave shape. According to such a configuration, an abrupt change in the cross-sectional area of the web portion can be suppressed at a portion where the number of web portions changes, so that an improvement in fatigue fracture strength can be achieved.

  In the present invention, it is preferable that a longitudinal end portion of the overlapping portion is provided with a lid member that closes a space surrounded by the upper flange portion, the lower flange portion, and the plurality of web portions. . According to such a configuration, it is possible to prevent water from flowing into the inside of the superposed portion, which is difficult to prevent rusting, so that the rust prevention effect is improved. In addition, when the beam material is formed of a material having corrosion resistance such as an aluminum alloy, the lid member may not be provided.

  According to the present invention, it is possible to effectively reinforce even a portion where the beam height is low.

It is the figure which showed the beam material of the frame structure of the trailer which concerns on embodiment of this invention, Comprising: (a) is a side view, (b) is DD sectional view taken on the line. It is the figure which showed the beam material of the frame structure of the trailer which concerns on embodiment of this invention, Comprising: (a) is the sectional view on the AA line of FIG. 1, (b) is the sectional view on the BB line, (c). Is a cross-sectional view taken along line CC. It is the perspective view which showed the beam material of the frame structure of the trailer which concerns on embodiment of this invention. It is the side view which showed the use condition of the beam material of the frame structure of the trailer which concerns on embodiment of this invention. It is the top view which showed the state which assembled | attached the pair of beam material of the frame structure of the trailer which concerns on embodiment of this invention. It is sectional drawing which showed a pair of beam material of the frame structure of the trailer which concerns on other embodiment of this invention. (A), (b), (c) is sectional drawing which showed the beam material of the frame structure of the trailer which concerns on further another embodiment of this invention. It is the side view which showed the beam material of the frame structure of the trailer which concerns on other embodiment of this invention. It is the top view which showed the state which assembled | attached the pair of beam material of the frame structure of the trailer which concerns on other embodiment of this invention.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the accompanying drawings.

  As shown in FIG. 4, the frame structure 2 of the trailer 1 according to the present embodiment is provided on the floor of the trailer 1 pulled by the tractor 3. As shown in FIGS. 1 to 3, the frame structure 2 (see FIG. 4) of the trailer 1 includes a beam member 4 provided on the floor. In the present embodiment, the beam material 4 constitutes the main beam 10 extending in the vehicle length direction. The beam member 4 (main beam 10) includes an upper flange portion 11, a lower flange portion 12, and three web portions 13. A superposed portion 33 formed by arranging a plurality of web portions 13 in parallel is formed in a part of the beam member 4 in the longitudinal direction. The three web parts 13 are comprised from the intermediate | middle web part 32 mentioned later and a pair of side web parts 31 and 31. As shown in FIG. Hereinafter, the three web portions 13 are simply referred to as a plurality of web portions 13 when the side web portion 31 and the intermediate web portion 32 are not distinguished. The overlapping part 33 includes a three-part overlapping part 33a where three web parts 13 are overlapped and a two-part overlapping part 33b where two web parts 13 are overlapped. Hereinafter, when the number of the web portions 13 is not distinguished, it is simply referred to as the overlapping portion 33.

  The upper flange portion 11 and the lower flange portion 12 are members constituting the upper and lower portions of the main beam 10 and are each configured to spread in the vehicle width direction. The upper flange portion 11 and the lower flange portion 12 are formed in a plate shape and have the same width dimension. The web portion 13 is formed in a plate shape. The upper flange portion 11, the lower flange portion 12, and the web portion 13 are made of an aluminum alloy plate or extruded shape member. The upper end portion of the web portion 13 is welded and fixed to the lower surface of the upper flange portion 11, and the lower end portion is welded and fixed to the upper surface of the lower flange portion 12, so that the main beam 10 is integrally formed. Since the welding is performed linearly along the longitudinal direction of the main beam 10, it is easy to construct and the accuracy can be improved.

  In addition, the joining method of the upper flange part 11 and the web part 13, and the lower flange part 12 and the web part 13 is not limited to welding, Other methods, such as friction stir welding, may be used. The material of the main beam 10 is not limited to the aluminum alloy, and may be other materials as long as the material has a required strength. However, as in this embodiment, an aluminum alloy that is lightweight and has corrosion resistance is preferable.

  As shown in FIG. 5, the main beams 10 are respectively arranged on the left and right sides in the vehicle width direction, and extend linearly from the front end to the rear end along the vehicle length direction. The pair of main beams 10, 10 are arranged so as to be parallel to each other with a gap in the vehicle width direction. The pair of main beams 10 and 10 are connected to each other by a plurality of connecting members 19 extending in the vehicle width direction. In the present embodiment, a pair of main beams 10 are provided with a gap in the vehicle width direction, but the number of main beams is not limited to this, and may be one, for example. Three or more may be sufficient.

  As shown in FIGS. 1A and 4, the main beam 10 has a height dimension (beam height) that varies depending on the front-rear position. The main beam 10 of the present embodiment includes an apron portion 20, a neck portion 21, a wheel base portion 22, a suspension mounting portion 23, and a rear overhang portion 24 from the front to the rear. The upper flange portion 11 of the main beam 10 is formed at the same level from the front end to the rear end, and has a planar shape with a horizontal upper surface. On the other hand, the lower flange portion 12 is formed to bend according to the change in the height of the web portion 13.

  The apron portion 20 is a portion to which an apron plate 29 (see FIG. 5) having a king pin 28 for connecting the trailer 1 to the tractor 3 is attached. The king pin 28 is fixed to the coupler 5 (see FIG. 4) provided at the vehicle body rear portion 3a of the tractor 3. The apron portion 20 is located above the vehicle body rear portion 3 a of the tractor 3 and is the portion of the main beam 10 having the lowest beam height. The apron portion 20 has a constant beam height, and the lower flange portion 12 extends horizontally.

  The neck portion 21 is a portion where the beam height gradually increases (expands downward) from the rear end of the apron portion 20 to the front end of the wheel base portion 22. The lower flange portion 12 of the neck portion 21 is inclined so as to be lowered toward the rear. The neck portion 21 is formed by changing the rate of increase of the beam height in two stages. The neck portion 21 is disposed at the front portion and has a low slope portion 21a, and the rear portion has a steep slope portion 21b that has a high increase rate. And. The gentle inclined portion 21 a is located above the vehicle body rear portion 3 a of the tractor 3. The lower flange portion 12 is bent at the boundary portion between the apron portion 20 and the gently inclined portion 21a and at the boundary portion between the gently inclined portion 21a and the steeply inclined portion 21b.

  The wheel base portion 22 is a portion located between the neck portion 21 and the suspension mounting portion 23. The wheel base portion 22 includes, in order from the front, the same beam as the high beam portion 22a having the highest beam height, the inclined portion 22b in which the beam height gradually decreases, and the rear suspension mounting portion 23 and the rear overhang portion 24. And a medium beam portion 22c at a height. A landing gear 25 is extendably provided at a boundary portion between the neck portion 21 and the wheel base portion 22. The landing gear 25 becomes a leg portion that extends to the ground and supports the front portion of the trailer 1 when the trailer 1 is separated from the tractor 3. The lower flange portion 12 is bent at the boundary portion between the steeply inclined portion 21b and the high beam portion 22a, the boundary portion between the high beam portion 22a and the inclined portion 22b, and the boundary portion between the inclined portion 22b and the middle beam portion 22c. ing.

  The suspension mounting portion 23 is a portion where a mound portion 27 for supporting the wheels 26 of the trailer 1 is provided. The suspension mounting portion 23 has the same beam height as the middle beam portion 22c, and the lower flange portion 12 extends horizontally.

  The rear overhang portion 24 is a portion projecting rearward from the suspension mounting portion 23. The rear overhang portion 24 has the same beam height as the suspension mounting portion 23 and the middle beam portion 22c, and the lower flange portion 12 extends horizontally.

  The shape and various names of the main beam 10 described above are merely examples, and the present invention is not intended to be limited to those of the present embodiment.

  The web portion 13 is formed in a plurality of heights in accordance with the respective heights from the apron portion 20 to the rear overhang portion 24 toward the front and rear of the trailer 1. That is, the beam height of the main beam 10 is changed by changing the height dimension of the web portion 13.

  As shown in FIG. 1B and FIG. 3, a plurality of web portions 13 are provided and arranged separately in the width direction of the main beam 10. The web portion 13 is a part of the main beam 10 in the longitudinal direction, and forms the overlapping portion 33 in parallel with each other. The overlapping portion 33 extends rearward from the front end of the main beam 10 and is formed to include at least a boundary portion between the apron portion 20 and the neck portion 21.

  Specifically, the web portion 13 is located on both sides in the vehicle width direction of the main beam 10 (hereinafter referred to as a side web portion 31), and is located on the middle portion in the vehicle width direction of the main beam 10 ( Hereinafter, it is referred to as an intermediate web portion 32). The side web portion 31 extends rearward from the front end of the main beam 10. The rear end 31a of the side web portion 31 is located behind the boundary portion between the gently inclined portion 21a and the steeply inclined portion 21b of the neck portion 21. The intermediate web portion 32 extends forward from the rear end of the main beam 10. The front end 32a of the intermediate web portion 32 is located in front of the boundary portion between the gently inclined portion 21a and the steeply inclined portion 21b.

  Thus, three web portions 13 are juxtaposed in the width direction from the front end 32a of the intermediate web portion 32 to the rear end 31a of the side web portion 31 to form the overlapping portion 33 (three-piece overlapping portion 33a). (See (a) of FIG. 2). In addition, since the two side web portions 31 are arranged in front of the front end 32a of the intermediate web portion 32, the overlapping portion 33 (double overlapping portion 33b) is formed ((b in FIG. 2). )reference).

  As shown in FIGS. 1A and 3, the longitudinal end surface of the web portion 13 in the overlapping portion 33, that is, the front end surface of the intermediate web portion 32 and the rear end surface of the side web portion 31 are recessed in a concave shape. Is formed. The front end surface of the intermediate web portion 32 and the rear end surface of the side web portion 31 have a curved shape when viewed from the side, and the cross-sectional area of the web portion 13 gradually changes along the longitudinal direction. .

  According to the frame structure 2 of the trailer 1 as described above, the overlapping portion 33 in which a plurality of web portions 13 are arranged in parallel is formed on at least a part of the beam member 4 (main beam 10) in the longitudinal direction. Even in the portion where the beam height 13 is low, the strength of the beam material 4 can be increased efficiently.

  Specifically, in the apron section 20, as shown in FIG. 2A, the web section 13 has a low beam height, but the web section 13 is composed of a pair of side web sections 31, 31. Since the overlapping portion 33 (two-sheet overlapping portion 33b) is formed, it is reinforced.

  Further, in the vicinity of the boundary portion between the gently inclined portion 21a and the steeply inclined portion 21b of the neck portion 21, as shown in FIG. 2 (b), the web portion 13 includes a pair of side web portions 31, 31 and an intermediate web portion. 32, the superposition | polymerization part 33 (three piece superposition | polymerization part 33a) is formed. In particular, in this portion, the beam height of the web portion 13 is relatively low and the distance from the kingpin 28 is long and a large moment force is applied to concentrate the stress. However, since the three web portions 13 are arranged in parallel, A sufficient reinforcing effect can be obtained. In addition, since the beam height of the web part 13 is high in the wheel base part 22 as shown in FIG.2 (c), it has sufficient intensity | strength.

  As described above, according to the present embodiment, the apron portion 20 that is in the connection portion with the tractor 3 and cannot secure a large beam height dimension, and the gently inclined portion 21a and the steeply inclined portion 21b of the neck portion 21 are provided. It is possible to efficiently increase the strength of the beam member 4 even at the boundary portion where a large moment force is applied.

  Moreover, in this embodiment, since the longitudinal direction end surface (the front end 32a of the intermediate | middle web part 32 and the rear end 31a of the side web part 31) of the web part 13 in the superposition | polymerization part 33 is dented in a concave shape, The cross-sectional area gradually changes along the longitudinal direction. Therefore, a rapid change in the cross-sectional area of the web portion can be suppressed at a portion where the number of the web portions 13 changes. In particular, the effect of suppressing a sudden change in the cross-sectional area of the web portion 13 at a portion where the number of the web portions 13 changes (a portion corresponding to the front end 32a of the intermediate web portion 32 and the rear end 31a of the side web portion 31). It can greatly improve fatigue fracture strength.

  When the main beam is made of a material such as iron, a lid member (not shown in the present embodiment) is provided. The lid member is a member provided at an end portion in the longitudinal direction of the overlapping portion, and closes a space surrounded by the upper flange portion, the lower flange portion, and the plurality of web portions. The lid member is provided at the front end of the main beam (front end of the side web portion) and the rear end of the side web portion. The lid member is made of a plate material made of the same material as the main beam.

  The front lid member at the front end of the main beam is made of a plate material having the same shape as the cross section of the space formed by the upper flange portion, the lower flange portion, and the pair of side web portions. The front lid member is fixed to the main beam by attaching the plate material to the front end opening of the space and performing welding along the entire circumference of the outer periphery. The rear lid member at the rear end of the side web portion is made of a plate material having the same shape as the cross section of the space formed by the upper flange portion, the lower flange portion, the one side web portion, and the intermediate web portion. The rear cover member is fixed to the main beam by attaching the plate material to the rear end opening of the space and performing welding along the entire circumference of the outer periphery. The rear lid member is provided on each side of the intermediate web portion.

  According to such a configuration, even in the main beam formed of a member such as iron, it is difficult to prevent rusting, and it is possible to prevent water from flowing into the inside of the overlapped portion, so that the rust prevention effect is improved. . In this embodiment, since the main beam 10 (beam material 4) is formed of a material having corrosion resistance such as an aluminum alloy, it is not necessary to provide a lid member.

  Next, a main beam 50 according to another embodiment of the present invention will be described with reference to FIG. The main beam 50 according to the present embodiment is also configured to include an upper flange portion (not shown), a lower flange portion 12 and a web portion 13 as in the above embodiment. The main beam 10 of the embodiment includes the three web portions 13 (two side web portions 31, 31 and one intermediate web portion 32), whereas the main beam of the present embodiment. 50 includes two web portions 13 (one side web portion 31 and one intermediate web portion 32).

  The intermediate web portion 32 extends from the front end to the rear end of the main beam 50. The side web portion 31 extends rearward from the front end of the main beam 50. The rear end 31a of the side web portion 31 is located behind the boundary portion between the gently inclined portion 21a and the steeply inclined portion 21b of the neck portion 21. The side web portion 31 is arranged only on one side of the main beam 50 side by side.

  Thus, two web portions 13 are arranged in parallel in the width direction from the front end of the main beam 50 (the front end of the side web portion 31) to the rear end 31a of the side web portion 31. The superposition | polymerization part 33 will be formed.

  The rear end surface of the side web portion 31 is formed in a concave shape. This end surface has a curved surface shape in a side view, and the cross-sectional area of the web portion 13 gradually changes along the longitudinal direction. Since other configurations are the same as those in the above embodiment, the same reference numerals are given and description thereof is omitted.

  Even with such a configuration, the strength of the beam material 4 (main beam 50) can be efficiently increased by forming the overlapping portion 33 even in a portion where the beam height of the web portion 13 is low, as in the above-described embodiment. Can be increased. In the present embodiment, there are two web portions 13 at the boundary portion between the gently inclined portion 21a and the steeply inclined portion 21b of the neck portion 21. This is less in comparison with the above embodiment and the reinforcing effect is small. However, the stress applied to the boundary portion in the case where the beam height of the apron portion 20 can be ensured large or the total length of the trailer is short is greater than that in the above embodiment. It is possible to implement when it is small.

  In the present embodiment, since the side web portion 31 is provided only on one side in the width direction and is disposed on the side of the main beam 50 arranged side by side, a space can be secured outside the intermediate web portion 32, Various members can be easily installed on the main beam 50.

  As mentioned above, although the form for implementing this invention was demonstrated, it is not the meaning which limits this invention to the said embodiment, A design change is possible suitably in the range which does not deviate from the meaning of this invention. For example, the shape of the main beams 10 and 50 is not limited to the shape of the above embodiment, and may be various shapes.

  For example, in the main beam 51 shown in FIG. 7A, the front end of the intermediate web portion 32 of the main beam 10 shown in FIG. 51 extends from the rear end to the entire front end. Other configurations are the same as those of the main beam 10 of FIG. According to such a configuration, since the overlapping portion 33 including the three web portions 13 is formed from the apron portion 20 to the rear of the boundary portion between the gently inclined portion 21a and the steeply inclined portion 21b of the neck portion 21, The beam height of the apron portion 20 can be made smaller than that of the main beam 10 in FIG. Thereby, the floor surface of the loading platform can be lowered.

  Further, in the main beam 53 shown in FIG. 7B, the intermediate web portion 32 extends from the rear end to the front end of the main beam 53, and the side web portions 31 and 31 on both sides in the width direction. Is provided so as to extend in the front-rear direction across a boundary portion between the gently inclined portion 21a and the steeply inclined portion 21b of the neck portion 21. According to such a configuration, at the boundary portion between the gently inclined portion 21a and the steeply inclined portion 21b where the stress is concentrated, the overlapping portion 33 including the three web portions 13 is formed, and the strength is efficiently increased. . On the other hand, since the web part 13 is formed only by the intermediate web part 32 in the apron part 20, it is applicable when the beam height of the apron part 20 can be ensured comparatively high. In FIG. 7B, reference numeral 54 denotes a lid member.

  The main beam 55 shown in FIG. 7 (c) has front and rear ends of the side web portion 31 of the main beam 53 shown in FIG. 7 (b) extending forward and backward, respectively, and on the intermediate web portion 32 side. The inclined portion 56 is formed by bending. The front end (front end) of the front inclined portion 56 is in contact with and welded to the side surface of the intermediate web portion 32. The front end (rear end) of the rear inclined portion 56 is in contact with and welded to the side surface of the intermediate web portion 32. According to such a configuration, at the boundary portion between the gently inclined portion 21a and the steeply inclined portion 21b where the stress is concentrated, the overlapping portion 33 including the three web portions 13 is formed, and the web portion 13 is box-shaped. Therefore, the strength can be increased more efficiently. On the other hand, the main beam 55 can also be applied to the case where the apron portion 20 can be ensured with a relatively high beam height since the web portion 13 is formed only by the intermediate web portion 32 in the apron portion 20.

  In the embodiments described so far, the main beams 10, 50, 51, 53, and 55 are formed at the same level from the front end to the rear end and have a planar shape, but are not limited thereto. It is not a thing. For example, like the main beam 60 shown in FIG. 8, the neck portion 21 may be formed obliquely (goose neck), and the rear portion of the wheel base portion 22 may be formed lower than the apron portion 20. According to such a configuration, the floor surface of the loading platform can be lowered, the volume of the loading platform can be increased, and the loading and unloading work can be facilitated.

  Furthermore, the main beam according to the present invention is not limited to a shape in which the main beam is linearly formed in the longitudinal direction as shown in FIG. 5, but as shown in FIG. The main beam 61 may be a main beam 61 that is bent outward in the vehicle width direction and has a crank shape. The rear part of the main beam 61 that is bent and spreads outward in the vehicle width direction is bent again and extends along the vehicle length direction. As a result, the distance between the main beams 61 and 61 arranged side by side is wider at the rear part than at the front part of the main beam 61.

  Moreover, in the said embodiment, although the superposition | polymerization part 33 is formed in the front parts of the trailers 1, such as the apron part 20 and the neck part 21, it is not limited to this. For example, the overlapping portion may be formed in the main beam located in the suspension mounting portion around the axle behind the trailer. According to such a configuration, the suspension mounting portion where the weight of the trailer is concentrated can be efficiently reinforced.

DESCRIPTION OF SYMBOLS 1 Trailer 2 Frame structure 10 Main beam 11 Upper flange part 12 Lower flange part 13 Web part 20 Apron part 21 Neck part 21a Slightly inclined part 21b Steeply inclined part 22 Wheel base part 31 Side web part 31a (side web part) Rear end 32 Intermediate web portion 32a Front end (intermediate web portion) 33 Overlapping portion 50 Main beam

Claims (6)

In the trailer frame structure with beam material on the floor,
The beam material is configured to include an upper flange portion, a lower flange portion, and a web portion,
A trailer frame structure, wherein at least a part of the beam member in the longitudinal direction is formed with a plurality of overlapping portions of the web portions. The beam material constitutes a main beam extending in the vehicle length direction,
The main beam is formed by connecting a plurality of portions having different beam heights in the longitudinal direction, a low beam height apron portion provided with a connecting pin with the tractor, and a high beam positioned behind the tractor. A wheel base portion having a height, and a neck portion positioned between the apron portion and the wheel base portion and having a beam height that increases toward the wheel base portion;
2. The trailer according to claim 1, wherein the overlapping portion extends rearward from a front end of the main beam and includes at least a boundary portion between the apron portion and the neck portion. Frame structure. The neck portion is formed by changing the increasing rate of the beam height in two stages, and includes a gently inclined portion arranged at the front portion and a low increasing rate, and a steeply inclined portion arranged at the rear portion and having a high increasing rate. Prepared
The plurality of web portions include a pair of side web portions extending rearward from the front end at both sides of the main beam in the vehicle width direction, and extending forward from the rear end at the vehicle width direction intermediate portion of the main beam. And an intermediate web part
The rear end of the side web portion is located behind the boundary between the gently inclined portion and the steeply inclined portion,
The trailer frame structure according to claim 2, wherein a front end of the intermediate web portion is positioned further forward than a boundary portion between the gently inclined portion and the steeply inclined portion. The neck portion is formed by changing the increasing rate of the beam height in two stages, and includes a gently inclined portion arranged at the front portion and a low increasing rate, and a steeply inclined portion arranged at the rear portion and having a high increasing rate. Prepared
The plurality of web portions include an intermediate web portion extending from a front end to a rear end at a vehicle width direction intermediate portion of the main beam, and a side portion extending rearward from the front end at a vehicle width direction side portion of the main beam. Web part and
3. The trailer frame structure according to claim 2, wherein a rear end of the side web portion is located behind a boundary portion between the gently inclined portion and the steeply inclined portion. 5. The trailer frame structure according to claim 1, wherein a longitudinal end surface of the web portion in the overlapping portion is recessed in a concave shape. A lid member that closes a space surrounded by the upper flange portion, the lower flange portion, and the plurality of web portions is provided at an end portion in the longitudinal direction of the overlapping portion. The frame structure of the trailer according to claim 5.

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