JP2005271702A - Side rail for vehicle body frame and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a side rail for a vehicle body frame low in manufacturing cost, and its manufacturing method. <P>SOLUTION: The side rail 2 for a vehicle body frame has in a front part a front kick-down part 4 which extends in the longitudinal direction of a vehicle with its upper surface tilting downward, and also has in a rear part a rear kick-up part 5 with its lower surface tilting upward. The side rail is constituted of two or more members including at least a front member 2a equipped with the front kick-down part 5 and a rear member 2b equipped with the rear kick-up part 5, the front kick-down part 4 of the front member 2a and the rear kick-up part 5 of the rear member 2b having the same shape. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a vehicle body frame side rail and a method for manufacturing the same, and more particularly to a vehicle body frame side rail and a method for manufacturing the same.

  FIG. 4 shows a schematic configuration of a body frame used in a vehicle such as a truck.

  As shown in the figure, the vehicle body frame a extends in the front-rear direction of the vehicle and spans between a pair of side rails b, b disposed at a predetermined interval in the vehicle width direction, and the side rails b, b. Cross member c. A plurality of cross members c are provided at intervals in the longitudinal direction of the side rails b and b.

  The side rail b is generally formed from a metal plate having a U-shaped cross section, and has a front kick-down portion d whose upper surface is inclined downward toward the front at the front portion thereof, and the lower surface at the rear portion at the rear. And a rear kick-up portion e inclined upward.

  The front kick-down portion d is formed for reasons of layout such as a problem of interference with a cab (not shown) attached to the upper front portion of the vehicle body frame a and vehicle height regulations, and the rear kick-up portion e is formed of the vehicle body frame a. In many cases, it is formed for the purpose of weight reduction. As described above, since the front kick-down part d and the rear kick-up part e have different formation purposes, their shapes (angle and length of the inclined part) are designed independently and generally have different shapes. It was the target. Such a vehicle body frame a and side rails b are also disclosed in, for example, Patent Document 1.

Japanese Patent Laid-Open No. 8-101872

  By the way, since the side rail b provided with the front kick-down part d and the rear kick-up part e as described above is difficult to manufacture by roll forming, it is usually manufactured integrally over the entire length by press forming. doing.

  However, since there are large-sized side rails such as trucks that have a total length exceeding 10 m, a large press is necessary, leading to an increase in equipment cost and manufacturing cost. In addition, when manufacturing side rails b having different lengths and shapes, a process of adding or exchanging molds (mold changing process) is required, leading to an increase in the number of processes and a longer manufacturing period. It was.

  Further, the side rail b has a portion that requires higher strength than other portions, such as a suspension mounting portion. If the thickness of the side rail b is increased to achieve this, the strength is increased. The plate thickness of an unnecessary part will also increase, and the whole weight and manufacturing cost will increase. In order to avoid this problem, a separately manufactured reinforcing member is assembled to the high-strength required portion of the side rail b. In this case, the reinforcing member manufacturing facility (mold, etc.) is also used. In addition, the manufacturing process and the assembling process of the reinforcing member are required, which increases the manufacturing cost.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-described problems and provide a side rail for a vehicle body frame and a method for manufacturing the same.

  In order to achieve the above object, the present invention has a rear kick that extends in the front-rear direction of the vehicle, has a front kick-down portion whose upper surface is inclined downward at the front portion thereof, and has a lower surface inclined upward at the rear portion. A side rail for a vehicle body frame having an up portion, which is composed of two or more members including at least a front member having the front kick-down portion and a rear member having the rear kick-up portion, and The front kick down portion of the front member and the rear kick up portion of the rear member have the same shape.

  Here, you may further provide the 1 or several intermediate member connected between the said front member and the said back member.

  Furthermore, the present invention provides a vehicle body frame having a front kick-down portion that extends in the front-rear direction of the vehicle, has an upper surface inclined downward at a front portion thereof, and a rear kick-up portion that has a lower surface inclined upward at a rear portion. A method for manufacturing a side rail for an automobile, wherein two members having inclined upper or lower surfaces are formed using the same mold, and the two members are arranged so as to be reversed in the vertical and horizontal directions. One member constitutes a front member provided with the front kick-down portion, and the other member constitutes a rear member provided with a rear kick-up portion having the same shape as the front kick-down portion. The members are connected in series.

  Here, one or a plurality of intermediate members may be connected in series between the front member and the rear member.

  According to the present invention, since the side rail is divided into a plurality of members, the side rail can be manufactured using a relatively small press machine, and the equipment cost and the manufacturing cost can be reduced. Moreover, since only the plate thickness of a member corresponding to a portion where high strength is required can be increased, the overall weight does not increase excessively, and an increase in cost due to the provision of a reinforcing member can be avoided. Furthermore, since the front kick-down portion and the rear kick-up portion have the same shape, the front member and the rear member can be manufactured using the same mold, and the mold type and manufacturing cost can be reduced.

  Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a perspective view of a vehicle body frame configured using the side rail of the present embodiment, and FIG. 2 is a side view of the side rail of the present embodiment.

  The schematic structure of the vehicle body frame 1 configured using the side rails 2 of the present embodiment is the same as that shown in FIG. That is, the vehicle body frame 1 extends in the front-rear direction of the vehicle and is arranged with a pair of side rails 2 and 2 arranged at a predetermined interval in the vehicle width direction, and a cross member spanned between the side rails 2 and 2. 3. A plurality of cross members 3 are provided at intervals in the longitudinal direction of the side rails 2 and 2.

  The side rail 2 is formed of a metal plate having a U-shaped cross section, and has a front kick down portion 4 whose upper surface is inclined downward toward the front at a front portion thereof, and a lower surface at a rear portion thereof toward the rear. The rear kick-up portion 5 is inclined upward.

  The feature of the side rail 2 of this embodiment is that it is divided into a plurality of members in its longitudinal direction. Specifically, the side rail 2 is disposed between the front member 2a having the front kick-down portion 4, the rear member 2b having the rear kick-up portion 5, and the front member 2a and the rear member 2b. A straight intermediate member 2c, and the front member 2a, the intermediate member 2c, and the rear member 2b are connected in series.

  Each of the front member 2a and the rear member 2b includes a front kick-down portion 4 or a rear kick-up portion 5, and substantially linear portions extending in the front-rear direction from the front kick-down portion 4 and the rear kick-up portion 5, respectively. Have

  The intermediate member 2c is formed such that its cross-sectional shape is slightly smaller than the cross-sectional shape of the rear end portion (straight portion) of the front member 2a and the front end portion (straight portion) of the rear member 2b, and the front member 2a and rear member 2b. A predetermined length Na, Nb (see FIG. 2) is inserted inside and superimposed. The front member 2a and the intermediate member 2c, and the intermediate member 2c and the rear member 2b are coupled to each other by a rivet 6 at the overlapping portion.

  What is important here is that the front kick-down portion 4 of the front member 2a and the rear kick-up portion 5 of the rear member 2b have the same shape. That is, as shown in FIG. 2, the inclination angle θa and the inclination length La of the front kick-down part 4 and the inclination angle θb and the inclination length Lb of the rear kick-up part 5 are set to be equal to each other. Accordingly, the height H1a of the front end portion (straight portion) of the front member 2a and the height H1b of the rear end portion (straight portion) of the rear member 2b are equal to each other, and the height H2a of the rear end portion of the front member 2a. And the height H2b of the front end portion of the rear member 2b are equal to each other.

  Here, the reason why the front kick-down portion 4 and the rear kick-up portion 5 can be formed in the same shape will be described. As explained in the section of “Background Technology”, the front kick-down part 4 is formed due to layout problems, so the degree of freedom in design (shape) is relatively low, but the rear kick-up part 5 is mainly lightweight. The degree of freedom of design is relatively high because it is formed for the purpose of making it easier. For this reason, if the shape of the rear kick-up part 5 is designed according to the shape of the front kick-down part 4, the shape can be unified. The present inventors have focused on the difference in the degree of freedom in shape between the front kick-down portion 4 and the rear kick-up portion 5 to unify both shapes.

  Thus, the side rail 2 of this embodiment is divided into three in the longitudinal direction, and the front kick-down portion 4 and the rear kick-up portion 5 have the same shape.

  Next, a method for manufacturing the side rail 2 will be described.

  First, a mold having an inclined molding surface having the same shape as the front kick-down portion 4 and rear kick-up portion 5 of the side rail 2 to be manufactured and a linear molding surface continuous before and after the inclined molding surface is prepared. Then, the metal plate is pressed with the mold to form two U-shaped members whose upper surface or lower surface is inclined. The two members having the same inclined surface constitute the front member 2a and the rear member 2b shown in FIGS. 1 and 2, respectively.

  On the other hand, a mold having a substantially linear forming surface is prepared separately, and a metal plate is pressed by the mold to form one U-shaped member extending in a substantially straight line. This member constitutes the intermediate member 2c shown in FIGS.

  Next, two members having the same inclined surface, that is, the front member 2a and the rear member 2b are arranged in a state where they are reversed in the vertical and horizontal directions. That is, as shown in FIG. 2, one member (the front member 2a) has an inclined surface up, a linear surface facing down, and the height (vertical length) increases toward the right side. The other member (rear member 2b) is disposed such that its inclined surface is downward, the linear surface is directed upward, and the height (vertical length) increases toward the left side. Therefore, both members 2a and 2b are opposed to each other at the end portion on the side with the larger cross-sectional shape (the side with the longer vertical length).

  Then, a linear member (intermediate member 2c) is disposed between the two members 2a and 2b, the front end portion of the intermediate member 2c is placed in the rear end portion of the front member 2a, and the rear end portion of the intermediate member 2c is placed in the rear member 2b. The front members 2a and the intermediate member 2c and the intermediate member 2c and the rear member 2b are joined together using rivets 6, respectively, by inserting them into the front end portion by a predetermined length Na and Nb.

  Thereby, as shown in FIG. 2, the front member 2a provided with the front kick-down portion 4, the rear member 2b provided with the rear kick-up portion 5 having the same shape as the front kick-down portion 4, and both the members 2a, One side rail 2 constituted by the intermediate member 2c provided between 2b is manufactured.

  According to the side rail 2 and the manufacturing method thereof according to the present embodiment as described above, since the side rail 2 is divided in the longitudinal direction, the press machine (each member 2a, 2b) used for manufacturing the side rail 2 is used. , 2c) can be significantly reduced compared to the prior art, and equipment costs and manufacturing costs can be reduced.

  Moreover, since the side rail 2 is divided into a plurality of members, only the plate thickness of the member corresponding to the high strength required portion is increased, and the optimum plate thickness distribution according to the required strength of each portion is obtained. realizable. Accordingly, the overall weight of the side rail 2 does not increase excessively, and an increase in cost due to the provision of the reinforcing member can be avoided. In addition, it turned out that about 50% of manufacturing cost can be reduced in the side rail of a specific shape compared with the conventional side rail which provides a reinforcement member. This is because the processing and assembly cost of the reinforcing member, the cost of the mold for manufacturing the reinforcing member, and the like can be completely eliminated.

  Moreover, since the side rail 2 is divided into a plurality of members, the members such as the cross member 3 can be assembled to the members 2a, 2b, 2c before being joined. Therefore, the assembly workability is improved, and the degree of freedom in the assembly process and the assembly method of the body frame 1 is improved.

  Moreover, since the shape of the front kickdown part 4 and the rear kickup part 5 is the same, the front member 2a and the rear member 2b can be manufactured using the same metal mold | die. As a result, the number of molds can be reduced, leading to a significant reduction in manufacturing costs. That is, in the conventional method of integrally forming the side rail 2 over its entire length, all molds for forming each part of the side rail 2 are necessary. However, in the side rail 2 of the present embodiment, the front member Since the mold for molding 2a and the mold for molding the rear member 2b can be made common, the number of molds can be reduced as compared with the prior art. For example, the side rail 2 of this embodiment can be manufactured if there are two molds. It has been found that the manufacturing cost can be reduced by about 30% for a side rail having a specific shape as compared with a conventional side rail manufactured integrally.

  Furthermore, according to the side rail 2 and the manufacturing method thereof according to the present embodiment, the same mold can be used for the side rail 2 of a vehicle having a different wheel base and rear overhang. This makes it possible to develop vehicle types (variations) at low cost. For example, when the wheel base is different, the length of the intermediate member 2c is changed by changing the length of the material put into the mold for manufacturing the intermediate member 2c, or the intermediate member 2c, the front member 2a, and the rear member 2b This can be dealt with by changing the overlapping lengths Na and Nb.

  In addition, when the rear overhang is different, the length of the material put into the mold for manufacturing the rear member 2b (the same as the mold for manufacturing the front member 2a) is changed, and the straight portion continuous with the inclined portion is changed. This can be done by changing the length.

  That is, if the size of the mold for manufacturing the intermediate member 2c and the size of the mold for manufacturing the front member 2a and the rear member 2b are designed in accordance with the side rail 2 of the largest size, the length of the material to be charged can be reduced. It can respond to manufacture of the side rail 2 of all vehicle types by changing. In addition, it was found that the manufacturing cost can be reduced by about 50% for a side rail having a specific shape as compared with the conventional manufacturing method in which the mold is changed every time the wheel base and the rear overhang are different.

  The present invention is not limited to the above-described embodiment, and various modifications and application examples can be considered.

  For example, although the example which divided the side rail 2 into 3 in the longitudinal direction was shown in the said embodiment, this invention is not limited in this point, It is good also as 2 divisions or 4 divisions or more. For example, when manufacturing the short side rail 2, the side rail 2 is divided into two parts, a front member 2a having a front kick-down portion 4 and a rear member 2b having a rear kick-up portion 5. You may manufacture by connecting the front member 2a and the back member 2b directly. Alternatively, when manufacturing the side rail 2 having a long length, the intermediate member 2c may be divided into a plurality of parts in the longitudinal direction.

  Moreover, as shown in FIG. 3, in the overlapping part of the front and rear members 2a, 2b and the intermediate member 2c, a portion having a low contribution to the strength improvement of the side rail 2 may be cut out to reduce the weight. That is, since the side rail 2 is subjected to a vertical bending force due to the ground reaction force transmitted through the wheels, the strength on the outside of the side rail 2 in the vertical direction (height direction) is important. The central part has a relatively low contribution to the required strength. Therefore, as shown in FIG. 3, if the notch 7 is formed at the substantially central portion in the vertical direction of the end portions of the front and rear members 2a and 2b (the end portion on the side overlapped with the intermediate member 2c), the strength is remarkably increased. It is possible to reduce the weight without reducing it. Of course, the notch 7 may be formed at the end of the intermediate member 2c.

  Further, the overlapping lengths Na and Nb of the front member 2a and the rear member 2b and the intermediate member 2c are not limited to those shown in FIG. The overlapping lengths Na and Nb are appropriately set in consideration of the size of the side rail 2, the required strength, the number and arrangement of rivets, and the like. For example, the overlapping lengths Na and Nb may be set longer as the length and height of the side rail 2 are increased. Furthermore, the overlapping length Na of the front member 2a and the intermediate member 2c and the overlapping length Nb of the intermediate member 2c and the rear member 2b are not necessarily the same.

  Further, the means for joining the front and rear members 2a, 2b and the intermediate member 2c is not limited to rivets, and any means such as welding or bolting can be applied.

  Further, in FIGS. 1 and 2, the intermediate member 2c is inserted into the front and rear members 2a and 2b. Conversely, the front and rear members 2a and 2b are inserted into the intermediate member 2c. You may do it.

  Furthermore, the order of the manufacturing method of the side rail 2 mentioned above was demonstrated as an example, and does not intend to limit this invention.

It is a perspective view of the body frame constituted using the side rail of one embodiment of the present invention. It is a side view of the side rail of this embodiment. It is a side view of the side rail of other embodiments of the present invention. It is a perspective view of the vehicle body frame comprised using the conventional side rail.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Body frame 2 Side rail 2a Front member 2b Rear member 2c Intermediate member 3 Cross member 4 Front kick down part 5 Rear kick up part

Claims (4)

A vehicle body frame side rail that extends in the front-rear direction of the vehicle, has a front kick-down portion whose upper surface is inclined downward at a front portion thereof, and a rear kick-up portion whose lower surface is inclined upward at a rear portion thereof. And
It is composed of two or more members including at least a front member provided with the front kick-down portion and a rear member provided with the rear kick-up portion, and the front kick-down portion and the rear member of the front member A side rail for a vehicle body frame, wherein the rear kick-up portion has the same shape.   The side rail for a vehicle body frame according to claim 1, further comprising one or a plurality of intermediate members connected between the front member and the rear member. Manufacture of a vehicle body frame side rail having a front kick-down portion extending in the front-rear direction of the vehicle and having a front kick-down portion inclined downward at the front portion and a rear kick-up portion inclined downward at the rear portion. A method,
Two members whose upper surface or lower surface is inclined are formed by using the same mold, and the two members are arranged so as to be reversed in the vertical and horizontal directions. A rear member having a rear kick-up portion having the same shape as the front kick-down portion is constituted by the other member, and the front member and the rear member are connected in series. A method for manufacturing a side rail for a vehicle body frame. The method for manufacturing a side rail for a vehicle body frame according to claim 3, wherein one or a plurality of intermediate members are connected in series between the front member and the rear member.

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