JP4364017B2 - Manufacturing method of side member - Google Patents

Description

  The present invention relates to a method for manufacturing a side member of a ladder-type vehicle frame by press molding.

  As shown in FIG. 7, a ladder-type vehicle frame 51 used in a vehicle such as a truck is composed of a pair of left and right side members 52 and a plurality of cross members 53 spanned between the side members 52 ( (See Patent Documents 1 and 2, etc.).

  The press molding of the side member 52 is generally performed by first punching and cutting the shape of the plate material, and then performing shape molding on the plate material.

  As shown in FIG. 8A, in the drilling step, a plurality of device mounting holes 57 for mounting various devices such as a suspension and an engine, and a plurality of positioning holes (location pins) for inserting positioning pins (location pins) are provided. A location hole 58 is provided in the plate 55. The plurality of positioning holes 58 are provided at intervals along the longitudinal direction of the plate material 55. Further, in the shape cutting step, all or a part of the outer edge of the plate material 55 (for example, a portion indicated by hatching in FIG. 8A) is cut.

  By the way, when a hole is made in the plate material 55 or the outer edge of the plate material 55 is cut, the balance of the residual stress when the steel material is rolled is lost, and a lateral curve as shown by an arrow C in FIG. The lateral bending amount C is about 3 mm at the maximum although there is variation depending on the production lot. When the shape molding is performed, if the lateral bending amount C of the plate material 55 is not zero, the hole position accuracy of the device mounting hole 57 cannot be sufficiently secured. Therefore, the lateral bending of the plate material 55 is corrected by inserting the positioning pins into the positioning holes 58 of the plate material 55.

  As shown in FIG. 8B, in the shape forming step, the plate material 55 that has been drilled and cut is formed into a processed product 56 having a predetermined cross-sectional shape using a mold. At the time of forming the shape, the positioning pins provided on the mold are respectively inserted into the plurality of positioning holes 58 of the plate material 55 so that the positional deviation when the plate material 55 is installed in the mold is corrected and processed. Misalignment between the left and right is prevented. Thereby, the hole position accuracy of the apparatus mounting hole 57 provided in the processed product 56 is sufficiently ensured.

JP 11-78961 A JP 2000-326864 A

  By the way, the wheel bases of different types of vehicles have no regularity, and the positions of the device mounting holes are different for each side member of various vehicles. On the other hand, it is necessary to set the positioning hole so as not to interfere with the device mounting hole for each side member of various vehicles. Therefore, conventionally, the position of the positioning hole has to be changed for each side member of various vehicles. Therefore, the position of the positioning pin is changed in the shape forming process by changing the position of the piercing punch that opens the positioning hole. There was a need to do the work. This changeover operation causes an increase in manufacturing time, and this increase in manufacturing time leads to an increase in manufacturing cost.

  Accordingly, an object of the present invention is to provide a method of manufacturing a side member that can reduce the manufacturing cost by making the hole positions of a plurality of positioning holes common to the side members of different types of vehicles.

  In order to achieve the above object, the invention of claim 1 is a method of manufacturing a side member of a ladder-type vehicle frame by press molding, wherein a plurality of positioning pins are inserted into a longitudinally extending plate member. A step of providing positioning holes at intervals along the longitudinal direction, a step of inserting the positioning pins into the plurality of positioning holes of the plate material, and a predetermined cross section of the plate material in the mold in the inserted state. A front axle position and a rear axle position are provided on the plate material, and a distance between the front axle position and the rear axle position is set on a preset reference wheel base. The side member manufacturing method is characterized in that a value obtained by adding an integer multiple of the pitch is set, and the interval between the plurality of positioning holes is set to a positive integer multiple of the reference pitch.

  The invention according to claim 2 is the method for manufacturing a side member according to claim 1, wherein the reference wheel base is set to a positive integer multiple of the reference pitch.

  According to a third aspect of the present invention, the positioning positions of the plurality of positioning holes are such that a positioning hole adjacent to the front axle position or the rear axle position is provided at a distance from the front axle position or the rear axle position. The method of manufacturing a side member according to claim 1 or 2, wherein: is set.

  A fourth aspect of the present invention is the method for manufacturing a side member according to any one of the first to third aspects, wherein the plurality of positioning holes are provided at the center of the width of the plate member.

  A fifth aspect of the present invention is the method of manufacturing a side member according to any one of the first to fourth aspects, wherein the plurality of positioning holes have the same hole diameter.

  According to the present invention, by making the hole positions of the plurality of positioning holes common to the side members of different types of vehicles, there is an excellent effect that the manufacturing cost can be reduced.

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

  The manufacturing method of the side member of this Embodiment is related with the method of manufacturing the side member of a ladder-type vehicle frame by press molding. First, the side member according to the present embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 is a side view of a side member. 2 is a cross-sectional view taken along line 2-2 of FIG. In addition, the apparatus attachment hole is abbreviate | omitted in the figure.

  As shown in FIGS. 1 and 2, the side member 10 extends in the front-rear direction. The front end portion of the side member 10 has a lower upper edge than the other portions, and is formed asymmetric in the vertical direction with respect to the center in the height direction. The side member 10 is formed in a U-shaped cross section.

  The side member 10 is provided with a plurality of device mounting holes (see reference numeral 57 in FIG. 7) for mounting various devices such as a suspension and an engine. In addition, the side member 10 is provided with a plurality of positioning holes 11 for inserting positioning pins at the time of press molding at intervals along the front-rear direction of the side member 10.

  Next, a method for manufacturing the side member 10 by press molding will be described with reference to FIG. FIG. 3 is a plan view of a plate material as a material.

  As shown in FIG. 3, the plate member 12 extends in the longitudinal direction. The width of the plate 12 is assumed to be Wa.

  First, a vehicle reference wheel base WB and a reference pitch P, which are commonly applied to side members of different types of vehicles, are set. These reference wheelbase WB and reference pitch P are comprehensively or statistically considered for all vehicle types to be manufactured, vehicle types, and wheelbases of the applications (dumpers, tank trucks, flat bodies, etc.) and device mounting conditions. Is set. For example, the reference pitch P is set to 300 mm. Preferably, the reference wheel base WB is a positive integer (natural number) times the reference pitch P. For example, the reference wheel base WB is set to 2700 mm, which is nine times the reference pitch P.

  Next, based on the reference wheel base WB and the reference pitch P set in this way, the front axle position 13 and the rear axle position 14 are set. The front axle position 13 and the rear axle position 14 serve as a reference for a device mounting hole that is applied to each side member of various vehicles.

  Here, the interval between the front axle position 13 and the rear axle position 14 is set to a value obtained by adding an integer multiple (m times) of the reference pitch P to the reference wheel base WB (that is, WB + m × P). m is assumed to be any of a positive integer (natural number), a negative integer, and 0 (zero). In the illustrated example, m = 1, but it may be 2 or 3.

  Next, the hole position of the device mounting hole is set according to the device mounting state of the vehicle to be manufactured. Devices disposed on the front side of the vehicle include a front suspension, an engine, a mission, an air tank, a battery, and the like, and these device mounting holes can often be determined based on the front axle position 13. In addition, devices disposed on the rear side of the vehicle include a rear suspension, a fuel tank, a spare tire, and the like, and these device mounting holes can often be determined based on the rear axle position 14.

  Next, based on the reference pitch P, the hole positions of the plurality of positioning holes 11 are set. Here, the interval between the plurality of positioning holes 11 is set to a positive integer (natural number) times (n times) (that is, n × P) of the reference pitch P. In the present embodiment, the intervals between the plurality of positioning holes 11 are all set to the same value P (that is, n = 1). Further, the positioning positions of the plurality of positioning holes 11 are set so that the positioning hole 11 adjacent to the front axle position 13 or the rear axle position 14 is provided at a distance from the front axle position 13 or the rear axle position 14. Yes. Preferably, the interval between the positioning hole 11 adjacent to the front axle position 13 or the rear axle position 14 and the front axle position 13 or the rear axle position 14 is set to half the reference pitch P (P / 2).

  As described above, in the present embodiment, the front axle position 13 and the rear axle position 14 are provided on the plate member 12, and the distance between the front axle position 13 and the rear axle position 14 and the distance between the plurality of positioning holes 11 are determined. The reference pitch P is set in association with each other. Therefore, even if the interval between the front axle position 13 and the rear axle position 14 or the interval between the plurality of positioning holes 11 is changed, the possibility that the device mounting hole interferes with the positioning hole 11 is low. Here, when the device mounting hole interferes with the positioning hole 11, the positioning hole 11 is omitted. By doing in this way, the several positioning hole 11 of the side member of a dissimilar vehicle can be easily set to a common position. Thereby, the piercing punch and the positioning pin changing work for making the positioning hole can be omitted or greatly omitted for each side member of various vehicles. By doing in this way, the versatility of a manufacturing machine (press machine) increases and it becomes possible to reduce manufacturing cost.

  Next, a procedure for press-molding the plate material 12 will be described.

  First, the plate material 12 is punched and cut. Although not shown, the mold used in the drilling step includes a die for installing the plate material 12 and a piercing punch provided so as to be movable up and down. When drilling the plate material 12, a plurality of device mounting holes and a plurality of positioning holes 11 are processed in the plate material 12 by lowering the piercing punch while the plate material 12 is placed on the die.

  Although not shown in the drawings, the mold used for the shape cutting process includes a die for installing the plate material 12, a pad that is provided so as to be movable up and down, and a plate for pressing the plate material 12 on the die, and is moved vertically to the side of the pad. And a freely provided cutting blade. When cutting the shape into the plate material 12, a part of the outer edge of the plate material 12 (the portion indicated by hatching in FIG. 3) is lowered by lowering the pad and the cutting blade while the plate material 12 is placed on the die. Disconnect. In addition, you may perform these drilling processes and a shape cutting process in one process.

  Next, shape forming is performed on the plate 12 that has been punched and cut. As shown in FIG. 4A, the mold 20 used in the shape forming process includes an upper mold 21 and a lower mold 22. The upper mold 21 includes a punch 23 provided so as to be movable up and down and a positioning pin 24 provided on the punch 23. The lower mold 22 includes a die 26 in which a groove 25 is formed, and a cushion pad 27 provided between the grooves 25 of the die 26 so as to be movable up and down.

  First, the plate 12 is placed on the die 26. At this time, it is assumed that there is a positional deviation as indicated by an arrow A between the positioning hole 11 of the plate member 12 and the positioning pin 24. As shown in FIG. 4B, when the punch 23 is lowered and the positioning pins 24 are respectively inserted into the plurality of positioning holes 11 of the plate member 12, the positional deviation A is corrected. Next, as shown in FIG. 4C, when the punch 23 is further lowered while the positioning pin 24 is inserted into the positioning hole 11 of the plate member 12, the plate member 12 is pushed into the groove 25 of the die 26. The plate 12 starts to bend. At this time, since the positioning pin 24 is inserted into the positioning hole 11 of the plate member 12, the right and left misalignment as shown by the arrow B is prevented. Then, as shown in FIG. 4D, when the punch 23 is further lowered between the grooves 25 of the die 26, the plate member 12 is formed into a U-shaped cross section.

  In this way, by providing the positioning hole 11 in the plate material 12, it is possible to correct the positional deviation A when the plate material 12 is placed on the die 26 of the mold 20 during shape forming, Left-right misalignment B of the plate 12 during processing can be prevented. Thereby, the hole position accuracy of the device mounting hole provided in the side member 10 can be sufficiently secured.

  As described above, according to the method for manufacturing the side member of the present embodiment, the hole positions of the plurality of positioning holes 11 can be set in common for the side members of different types of vehicles. Therefore, it is possible to eliminate or greatly omit the step of changing the piercing punch and the positioning pin 24 to open the positioning hole 11, thereby reducing the manufacturing cost.

  Here, the hole diameters of the plurality of positioning holes 11 may be set to be the same (for example, φ30 mm). In this way, the piercing punch used in the drilling process and the positioning pin 24 used in the shape forming process are all the same, and the cost of the mold and the cost of the side member 10 can be reduced.

  A plurality of positioning holes 11 may be provided at the center of the width Wa of the plate material 12 (that is, the position of Wa / 2 from the outer edge of the plate material 12). If it does in this way, as shown in Drawing 5 (a) and Drawing 5 (b), even if the front and back of board material 12 are exchanged, a plurality of positioning holes 11 will be located in the center of width Wa of board material 12 without changing. Therefore, when the left and right side members 10 are manufactured, the plate member 12 having the same shape is processed in the drilling and shape cutting step, and the front and back sides of the plate member 12 are exchanged in the shape forming step. Can be processed. For example, as shown in the figure, when a die that processes the front end portion of the side member 10 and a die that processes a portion other than the front end portion are divided, the front end die is divided into a right 26b and a left 26c. The left and right side members 10 can be manufactured by separately providing and shaping the shape by replacing the right 26b and the left 26c. In this case, since the die (see reference numeral 26a in FIG. 5A and FIG. 5B) excluding the front end portion can be used in common for the left and right side members 10, the die cost can be reduced. Manufacturing costs can be reduced.

  In the above-described embodiment, the cross-sectional shape of the side member 10 has been described as a U-shaped cross-section. However, the present invention is not limited to this, and can be applied even if the cross-sectional shape of the side member 10 is another cross-sectional shape such as a C-shaped cross-section.

  Moreover, in the above-mentioned embodiment, it demonstrated as performing a drilling and shape cutting process by press molding. However, the present invention is not limited to this, and the drilling and shape cutting process may be performed by other means. However, press molding is more advantageous than other means in terms of manufacturing cost and processing accuracy (particularly, hole position accuracy of device mounting holes).

  Moreover, in the above-mentioned embodiment, it demonstrated that the space | interval of the some positioning hole 11 was set to the same value altogether. However, the present invention is not limited to this. For example, as shown in FIG. 6, the interval between the plurality of positioning holes 11 may be partially set to be one time the reference pitch P or twice the reference pitch P.

It is a side view of a side member. FIG. 2 is a sectional view taken along line 2-2 of FIG. It is a top view of a board | plate material. (A)-(d) is the schematic which shows the procedure of a shape shaping | molding process. (A) And (b) is a top view which shows the state installed on the die | dye of the metal mold | die used for a shape forming process. It is a top view of a board | plate material. It is a perspective view of a ladder-type vehicle frame. (A) And (b) is the schematic which shows an example of the procedure of press molding.

Explanation of symbols

10 Side member 11 Positioning hole (Location hole)
12 Plate material 13 Front axle position 14 Rear axle position 20 Mold 24 Positioning pin (location pin)
Wa Width WB Reference wheelbase P Reference pitch

Claims (5)

  A method of manufacturing a side member of a ladder-type vehicle frame by press molding, wherein a plurality of positioning holes for inserting positioning pins are provided at intervals along the longitudinal direction in a plate material extended in the longitudinal direction. A step of inserting each of the positioning pins into the plurality of positioning holes of the plate material, and a step of forming the plate material into a predetermined cross-sectional shape in the mold in the inserted state, and the front axle position on the plate material And the rear axle position, and the interval between the front axle position and the rear axle position is set to a value obtained by adding an integer multiple of a preset reference pitch to a preset reference wheel base, A method for manufacturing a side member, characterized in that the interval between the positioning holes is set to a positive integer multiple of the reference pitch.   The method for manufacturing a side member according to claim 1, wherein the reference wheel base is set to a positive integer multiple of the reference pitch.   The hole positions of the plurality of positioning holes are set such that a positioning hole adjacent to the front axle position or the rear axle position is provided at a distance from the front axle position or the rear axle position. 3. A method for producing a side member according to 2.   The method for manufacturing a side member according to any one of claims 1 to 3, wherein the plurality of positioning holes are provided in the center of the width of the plate member. The method for manufacturing a side member according to any one of claims 1 to 4, wherein all of the plurality of positioning holes have the same hole diameter.

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