JP5027523B2 - Chassis frame side member structure - Google Patents

Description

  The present invention relates to an improvement in a side member structure of a welded assembly chassis frame used in a vehicle such as a truck.

Conventionally, as shown in FIG. 7, a chassis frame 30 such as a track generally has a rectangular cross section or a groove-type cross section, and a plurality of cross members 30B, 30B,... And a variety of parts such as axles, suspensions, fuel tanks and the like (not shown) are attached to the chassis frame 30 as a base.
The side member 30A extends substantially horizontally at the central portion thereof to support the vehicle body body, and extends from the body support portion 32 toward the front of the vehicle (left direction in the figure) when assembled. From a substantially wave shape comprising a front part 31 having a flat front end and a rear part 33 extending from the rear end of the main body support part 32 toward the rear (rightward in the figure) and gradually rising to have a flat front end. The balance of thickness and height is determined in accordance with the distribution of the bending moment caused by the load applied to each part.
In order to form the side member 30A, conventionally, for example, as in Japanese Utility Model Laid-Open No. 60-68869 and Japanese Utility Model Laid-Open No. 4-26182, members are divided into a plurality of parts in the longitudinal direction, and each divided member is welded. A structure for connecting them integrally by such means is known. This type of divided structure is schematically shown in FIG.
In the above structure, there is a problem that the strength of the material is reduced by heat input during welding, and the fatigue durability performance of the side members and thus the chassis frame is significantly reduced.
In particular, in vehicles such as trucks used for harsh applications, there is a risk of causing a fatal decline in the commercial value as the merchantability is impaired.

On the other hand, as shown in FIG. 9, a structure in which the strength of the material is not reduced by forming the side members 30A integrally in the longitudinal direction and eliminating the joints is also known.
However, in this case, since the members are long, the material yield is poor, and there is a problem that the material cost is higher than the divided structure in which the side members are divided and joined.

That is, as shown in FIG. 10, the shape of the side member blank 30 </ b> A ′ cut by the steel plate material K is formed by developing the side member (or its constituent member) when the side member (or its constituent member) has a grooved cross section. In addition, the pitch width P11 in the feed direction (x direction) during blank shearing of the steel plate material K is widened from the height difference between the front portion 31 ′ and the rear portion 33 ′ and the main body support portion 32 ′ in the blank shape.
The main body support portion 32 ′ of the blank 30A ′, which is steel plate material K and is cut to the front end edge K1 side in the feed direction, is greatly recessed with respect to the front end edge K1, so the first scrap amount S11 is large. Since the front portion 31 ″ and the rear portion 33 ″ of another blank 30A ″ arranged on the rear end edge K2 side in the feeding direction are recessed with respect to the rear end edge K2 of the steel plate material K, the second scrap amount S12. Will increase.
Therefore, there has been a problem that the yield of the material is deteriorated when the blank shape of the side member is removed from the steel plate material.
Japanese Utility Model Sho 60-68869 Japanese Utility Model Publication No. 4-26182

  The present invention was devised in view of the above circumstances, and its main problem is that it has durability equivalent to that of a side member of an integrated structure for a long chassis frame used in severe applications requiring durability. The object is to reduce the material cost by improving the material yield at the time of blank forming while maintaining the above.

In order to solve the above problem, the invention of claim 1
In the side member structure for a chassis frame that forms a series of side members with a rectangular cross-section by combining two groove-shaped cross-section side member components,
The side member constituting member has a main body support portion in the center in the longitudinal direction, and has a front portion and a rear portion that extend in the extension direction and are connected to both ends of the main body support portion and extend obliquely with respect to the main body support portion. The groove-shaped cross section is composed of a side surface standing at the time of assembling the chassis, and a pair of flanges bent at the top and bottom of the side surface.
The cut portion is formed in a part of the blank of the side member component,
The notch extends vertically from the flange that is the upper part during chassis assembly to the middle of the part that corresponds to the side surface at the center part corresponding to the body support part of the blank, and the flange that is lower when the chassis is assembled is bent. It is set at a position that does not reach the bent part of the lower corner,
The blank is formed into a groove-shaped cross section, and the cut portion is joined by welding.
In the invention of claim 2,
The notch is characterized in that the opening side of the notch is wide and the leading end side of the notch is narrow.
In the invention according to claim 3,
The notch is formed by welding.
Furthermore, in the invention of claim 4,
One or a plurality of the notches are present.

In the blank shape of the side member, a main body is provided by forming a cut portion in the vehicle body support portion and bending the portion extending in a substantially straight shape into a substantially square shape with the cut portion as a bent portion and placing the cut portion on the steel plate material. The inclination angle of the front part and the rear part with respect to the support part can be reduced.
Thereby, in the feed direction (x direction) at the time of blank formation of the steel plate material in a blank state, the distance of the feed pitch of each blank is suppressed short.
Therefore, it is possible to increase the number of blanks that can be taken from one steel sheet material determined by the rolling size in the blast furnace, and to reduce scrap at the front and rear edge portions in the feed direction of the steel sheet material. This can dramatically improve the yield and reduce material costs.
In the vicinity of the center of the vehicle body support portion, the side member is pulled downward by a vertical bending input, and this portion needs durability. However, in the present invention, no cut portion is provided below the side member. As a result, there is no seam and the durability is not degraded.

This invention forms a notch in the blank of the central part of the side member constituting member, and suppresses the blank shape narrower than the width of the unevenness of the side member constituting member to be molded, thereby improving the efficiency of plate cutting without reducing the strength. Realized.
A preferred embodiment of a side member structure of a welded assembly chassis frame according to the present invention will be described below with reference to the drawings.

[Side member component]
As shown in FIG. 1, the side member structure of the chassis frame of the present embodiment has two groove-shaped side member constituting members 1 overlapped and joined by welding (see FIG. 1 (b)), and shown in FIG. A side member of a chassis frame having a substantially rectangular closed cross section is configured, and the overall shape is substantially the same (see FIG. 1A).

That is, as shown in FIG. 1, the side member constituting member 1 is a main body support portion 3 that supports a vehicle body main body with a central portion extending substantially horizontally. The front part 2 extending toward the middle left direction and gradually rising and the tip becomes flat, and the rear end extending from the rear end of the main body support part 3 toward the rear (right direction in the figure) and rising gradually It consists of the rear part 4 which becomes flat, but the welding seam 5 is provided in the middle position of the main body support part 3.
[blank]

  A blank (hereinafter simply referred to as a “blank”) 10 serving as the side member constituting member 1 has a planar shape in which flanges 1a and 1c that are bent above and below the central side surface portion 1b of the side member constituting member 1 are developed. As shown in FIG. 3, a plurality of the plates are arranged on the steel plate material 20.

[Incision]
Each blank 10 is formed with a substantially V-shaped cut portion 15 having a wide cut opening side and a narrow cut end at a central portion 12 corresponding to the vehicle body support portion.
The cut portion 15 is a central portion 12 corresponding to the main body support portion of the blank 10 and extends downward from a flange 1a which is an upper portion when the chassis is assembled to a midway position corresponding to the side surface 1b.
Therefore, the front end of the cut portion 15 has a cut amount that does not reach the bent portion (R portion) of the lower corner portion where the lower flange 1c is bent below the side surface portion 1b (FIG. 2). (See (b)).

  Then, when blanking the blank 10 from the steel plate material 20, as shown in FIG. 3, it is not a blank 30A ′ shape as in the developed shape of the side member constituting member 1 as shown in FIG. It is characterized in that it has a shape that is bent into a substantially square shape such that the both sides in the longitudinal direction of the central portion 12 of the blank are gradually bent downward (toward the vehicle lower side) starting from the portion 15.

The blanking of the present embodiment is a blank 10 shape in which the height difference is reduced as shown in FIG. 4 (b), compared to the blank 30A ′ shape of FIG. It has become.
That is, in FIG. 4B, the open angle of the vertical line C passing through the groove bottom of the cut portion 5 is the left side in the drawing, that is, the angle near the front portion 11 is θ1, and the right side in the drawing, that is, the rear portion. The angle θ2 is close to 13.

The center portion 12 is substantially square since the front portion 12A on the left side in FIG. 4 is inclined at θ1 and the rear portion 12B on the right side in FIG. 4 is inclined downward at an angle of θ2 in FIG. It becomes a shape.
Further, along with the inclination of the front part 12A of the central part 12, the front part 11 connected thereto is inclined downward in the figure by an angle θ1 with respect to the horizontal line C2, and similarly, the inclination of the rear part 12B of the central part 12 is inclined. Along with this, the rear portion 13 connected thereto is inclined downward in the drawing by an angle θ2 with respect to the horizontal line C2.

Here, the front portion 11 is inclined upward in the figure at a portion connected to the central portion 12 at an angle of θ3, and the rear portion 13 is upward in the drawing at an angle of θ4 at a portion connected to the central portion 12. Inclined.
In the illustrated example, since θ3> θ1 and θ4> θ2, the front portion 11 is inclined upward in the drawing by an angle (θ3-θ1) with respect to the horizontal line H, and the rear portion 13 is (θ4-θ2). ) Is inclined upward in the figure, so that the entire blank 10 shape can be a wave shape having a small height difference.

In the present embodiment, the cut portion 15 has been described by taking the blank shape of FIG. 4B as an example. However, in the present invention, the blank shape is not limited to the above embodiment.
In that case, the angle of the notch is designed so that the overall blank shape has a small corrugated shape, taking into consideration the vehicle's durability, layout requirements, the number and arrangement of the notches, and kicking up the front and rear ends of the vehicle. It is preferable to set the optimum bending angle in consideration of the difference in amount.

Thus, the shape of the blank 10 disposed on the steel plate material 20 is such that the central portion 12 corresponding to the main body support portion is bent in a substantially square shape starting from the cut portion 15.
Then, as shown in FIG. 4 (b), the blank shape of the front portion 11 and the rear portion 13 with respect to the central portion 12 can be arranged at a slight angle so that the end portion is obliquely downward, The level difference in the waveform shape of the blank 10 as a whole can be set to be significantly smaller than in the prior art.

Accordingly, the inclination angle of the front portion 11 and the rear portion 13 with respect to the central portion 12 of the blank 10 shown in FIGS. 3 and 4B is set to be narrower than the conventional one without causing a large jump in the vertical direction in the drawings. be able to.
In this embodiment, the conventional blanking (see FIG. 10) was able to cut only four blanks 30A ′ on one steel plate material K. In this embodiment, the same as shown in FIG. It is possible to take up five blanks 10 which are larger by one in the steel plate material 20 of the size, and greatly reduce the scrap amounts S1 and S2 at the front edge 21 and the rear edge 22 in the feeding direction during shearing. be able to.

[Seam structure]
Next, the cut portion 15 is joined to form a single seam 5 by means of welding or the like with the end edges 16 and 17 being in contact (see FIG. 5A).
The welding can correspond to various welding means such as carbon dioxide arc welding, MAG welding, plasma welding, and laser welding.

  When this blank 10 is welded (longitudinal bend) with the edge portions 15 and 16 of the cut portion 15 in the state of the flat plate in FIG. 5A, the flange end bent at the lower side when being formed into a groove-shaped cross section. Pulling in the surface direction may cause a reduction in plate thickness or end cracks.

Therefore, when forming, as shown in FIG. 5 (b), the blank 10 is first formed into a groove-type cross section by bending the upper and lower flanges 1a, 1c of the side surface portion 1b substantially at right angles, and then FIG. 5 (c). ), The end edges 16 and 17 of the cut portion 15 are integrally welded in the state of the groove type cross section, and the seam 5 is formed.
As a result, the lower flange 1c of the main body support portion 3 is formed in the bending direction instead of being pulled in the surface direction, so that no reduction in plate thickness or end cracks occurs, and the forming load can be kept low. it can.

  In the present embodiment, one cut portion 15 is formed in the main body support portion 3 in the vicinity of the center of the side member constituting member 1. You may do it.

  Further, in this embodiment, the cut portion 15 of the blank 10 has a V-shape, and the seam is formed in a straight line extending vertically at the time of welding, but the cut portion 15 of the present invention is open at the top. The cut is not limited to the above shape as long as the leading end of the cut is narrow, and can be appropriately changed according to the use of the side member.

  For example, FIG. 6 (a) shows an oblique seam structure, and the seam 5 after welding the cut portion extends perpendicularly to the end at the portion 5a on the upper flange 1a of the groove section, and the upper corner. The portion 5b on the side surface portion 1b of the side member constituent member that exceeds the portion may be an inclined straight line.

  FIG. 6 (b) shows a corrugated seam structure. The seam 5 after welding the cut portion extends perpendicularly to the end at the portion 5a on the flange 1a above the groove section, The portion 5b on the side surface portion 1b beyond the upper corner portion may be a polygonal line bent in a waveform.

Furthermore, FIG. 6C shows a round hole cutting structure, which has a round hole 16 at the tip of the cut portion 15, and the round hole 6 is formed at the tip of the joint 5 after welding.
The round hole 6 is used for riveting or fastening bolts or the like, and can increase the strength of the end face of welding.

Each of the structures is welding by abutment, but may be a structure in which a fillet 18 is provided at one end edge of the cut portion 15 and welded.
FIG. 6 (d) shows a fillet welded seam structure. For example, the fillet 18 is formed in a step shape on one end edge 17 of the V-shaped cut portion 15.
By providing this fillet 18, a sufficient amount of penetration can be obtained at the time of welding, and the strength of welding can be improved.
In addition, it goes without saying that various design changes can be made without departing from the scope of the present invention.

(A) is a side view of the side member of Example 1, (b) is sectional drawing. It is the principal part perspective view of a side member structural member, (a) is the figure seen from diagonally upward, (b) is the figure seen from diagonally downward. It is the top view which blanked the blank on the steel plate material. It is a top view explaining the shape and pitch width of the blank on a steel plate material, (a) is the conventional shape without a notch part, (b) is the case of Example 1 with a notch part. It is a perspective view which shows the shaping | molding procedure of a blank, (a) is a figure which shows the flat plate state of a blank, (b) is a figure of the state which bent the upper and lower flange, (c) is a figure of the state which welded the notch part. is there. It is a perspective view which shows the different shape of a notch | incision part, (a) is a diagonal seam structure in which a seam inclines on the side surface of a side member structural member, (b) is a wave type seam structure in which a seam becomes a waveform on the side surface, Is a round hole cutting structure having a round hole at the seam tip, and (d) is a fillet weld seam structure. It is a perspective view which shows a chassis frame. It is a front view which shows the side member of the conventional division structure. It is a front view which shows the conventional integrated type side member. It is the top view which plate-cuts the conventional blank of FIG. 9 to the steel plate material.

Explanation of symbols

1 Side member component 1a Flange (upper part)
1b Side surface 1c Flange (bottom)
2 Front part 3 Main body support part 4 Rear part 5 Seam 10 Blank 12 Central part 11 Front part 13 Rear part 15 Cut part 16, 17 Edge 18 Fillet 20 Steel plate material 21 Front edge 22 Rear edge

Claims (4)

In the side member structure for a chassis frame that forms a series of side members with a rectangular cross-section by combining two groove-shaped cross-section side member components,
The side member constituting member has a main body support portion in the center in the longitudinal direction, and has a front portion and a rear portion that extend in the extension direction and are connected to both ends of the main body support portion and extend obliquely with respect to the main body support portion. The groove-shaped cross section is composed of a side surface standing at the time of assembling the chassis, and a pair of flanges bent at the top and bottom of the side surface.
The cut portion is formed in a part of the blank of the side member component,
The notch extends vertically from the flange that is the upper part during chassis assembly to the middle of the part that corresponds to the side surface at the center part corresponding to the body support part of the blank, and the flange that is lower when the chassis is assembled is bent. It is set at a position that does not reach the bent part of the lower corner,
A side member structure for a chassis frame, wherein the blank is formed into a groove-shaped cross section and the cut portion is joined by welding.   The side member structure of a chassis frame according to claim 1, wherein the cut portion is formed so that the opening side of the cut is wide and the tip end side is narrow. The side member structure of a chassis frame according to claim 1 or 2, wherein the cut portion is joined by welding. 4. The chassis frame side member structure according to claim 1, wherein one or a plurality of cut portions are present.

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