JP6533561B2 - Method of manufacturing frame and down frame of straddle type vehicle - Google Patents

Description

  The present invention relates to a method of manufacturing a frame and a down frame of a straddle-type vehicle.

  The frame of the straddle-type vehicle includes a head pipe for supporting a front fork, a down frame hanging downward from the head pipe, and two side frames extending rearward from the lower end of the down frame. Prepare. The down frame is a hollow rod, and is often formed by welding opposite ends of a half-cylindrical left frame half and a right frame half (for example, Patent Document 1). .

  Here, the down frame is required to have a certain degree of flexibility at the central portion, but rigidity is required at the lower end where the side frames are joined. Therefore, Patent Document 1 shows that a frame half used for the down frame is formed by welding blanks with different plate thicknesses.

JP, 2006-281890, A

  According to the down frame of Patent Document 1, although the rigidity of the lower end portion can be improved by using a thick blank at the lower end portion to which the side frame is connected, the weight is increased accordingly. Therefore, in order to improve the rigidity of the lower end portion while suppressing the increase in weight, it is considered to make the lower end portion thicker than the central portion and to increase the cross-sectional area thereof. However, simply increasing the cross-sectional area can not effectively improve the rigidity, and there is a possibility that the cross-sectional shape may change when a bending load is applied.

  An object of the present invention is to provide a method of manufacturing a frame and a down frame of a saddle-ride type vehicle which can improve rigidity while suppressing an increase in weight.

  (1) The frame of the straddle-type vehicle of the present invention (for example, the vehicle body frame 1 described later) includes a head pipe (for example, the head pipe 2 described below) and a down frame hanging down from the head pipe (for example The frame 3) and the end surfaces (for example, left connection end surface 51L and right connection end surface 51R described later) of the lower end portion (for example, the lower end portion 5 described later) of the down frame Side frames (for example, side frames 7L and 7R to be described later), and the width (for example, width b to be described later) of the lower end in a front view is a central portion above the lower end (for example, The width (for example, the width c described later) of the central portion 33 described later is larger than the front surface (for example the front surface 4F described later) and the rear surface (for example the rear surface 4R described later) of the lower end In at least one of these, a pair of steps extending in the longitudinal direction (for example, a pair of front left step 53L and front right step 53R described later, or a pair of rear left step 54L and rear right step 54R The pair is formed on both sides in the vehicle width direction.

  (2) In this case, it is preferable that the pair of stepped portions be formed on both the front surface portion and the rear surface portion.

  (3) In this case, the distance along the vehicle width direction from the axis of the down frame (for example, the axis O described later) to the step is the distance from the axis to the side of the central portion Preferably, the distance is substantially the same.

  (4) In this case, the down frame is a semi-cylindrical left frame half (for example, left frame half 6L described later) and a semi-cylindrical right frame half (for example, right frame half 6R described later) Are formed by welding opposite end portions (for example, end portions 61L, 62L, 61R, 62R described later), and the stepped portion is a weld bead of the down frame (for example, weld bead 63 described later) It is preferable to form in the approximate center in front view between the and the end face of the lower end.

  (5) In the manufacturing method of the present invention, the head pipe (for example, the head pipe 2 described later) is connected to the upper end (for example the upper end 31 described later) and the lower end (for example the lower end 5 described later) Down frame in which two side frames (for example, side frames 7L and 7R described later) are respectively connected to end surfaces on both sides in the vehicle width direction (for example, end surfaces 51L and 51R described later) A frame half manufacturing process for manufacturing a pair of semi-cylindrical frame halves (for example, frame halves 6L and 6R described later) from a plate material, and opposing ends of the pair of frame halves The width of the lower end portion in a front view is larger than the width of the central portion above the lower end portion by joining the portions, and at least one of the front portion and the rear portion of the lower end portion. And a joining step of manufacturing a down frame in which a pair of step portions (for example, step portions 53L, 53R, 64L, 54R described later) extending along the longitudinal direction are formed on both sides in the vehicle width direction, The half manufacturing process is a drawing process (e.g., described later) for forming a convex deep drawn portion (e.g., deep drawn portion 69L described later) in a portion to be the lower end portion of a plate material (e.g. A drawing step) and a bending step (for example, a bending step described later) for forming the stepped portion by bending the outside of the deep drawn portion of the plate material subjected to the drawing step (for example, a bending step described later) A portion (for example, an edge portion 6001 L described later) which is outside the portion where the deep drawing portion is formed in the plate material and which is bent in the bending step, Characterized by shaping the al the deep drawing unit.

  (6) In this case, in the bending step, the outer side of the plate member which has been subjected to the drawing step along the longitudinal direction than the bending portion (for example, bending portions 63L and 64L described later) formed on the periphery of the deep drawing portion It is preferable to shape | mold the part used as the said step part by bending.

  (1) In the frame of the present invention, the width of the lower end portion of the down frame hanging down from the head pipe to which two side frames are connected in the front view is made larger than the width of the central portion. A pair of step portions extending along the longitudinal direction are formed on both sides in the vehicle width direction on at least one of the front surface portion and the rear surface portion. In the present invention, by forming such a step along the longitudinal direction of the down frame, it is possible to improve the rigidity of the lower end of the down frame while minimizing the increase in weight of the frame.

  (2) In the frame of the present invention, a pair of steps extending in the longitudinal direction on both sides in the vehicle width direction is formed on both the front and rear portions of the down frame. Thereby, the rigidity of the lower end portion can be further improved while minimizing the increase in the weight of the frame.

  (3) In the frame of the present invention, the distance between the step formed at the lower end of the down frame and its axis along the vehicle width direction and the distance between the side surface of the center of the down frame and the coaxial line The distance along the vehicle width direction is substantially equal. This makes it possible to make the surface of the step portion and the side surface of the central portion flush with each other, thereby further improving the rigidity of the lower end portion of the down frame.

  (4) In the frame of the present invention, the stepped portion is formed substantially at the center in a front view between the end face of the lower end portion of the down frame to which the weld bead and the side frame are connected. This can further improve the rigidity to a bending load acting in the direction perpendicular to the longitudinal direction of the down frame.

  (5) In the method of manufacturing a down frame according to the present invention, a pair of semi-cylindrical frame halves are manufactured, and the opposing ends of the pair of frame halves are joined to make the width wider than the central portion. And, a down frame comprising a lower end portion formed with a pair of steps extending along the longitudinal direction is manufactured. Further, in the present invention, a drawing step of forming a deep drawn portion in a portion to be a lower end portion while holding a portion to be bent in a later bending step of a plate material and bending the outside of the deep drawn portion Such a frame half is manufactured through a bending step of forming a step. As described above, the down frame provided with the lower end portion wider than the central portion and in which the step portion is formed is manufactured by one draw forming without dividing into the drawing step and the bending step as in the present invention. It is also possible. However, in this case, in the draw forming, it is necessary to hold the outside of the plate material with the holder outside the portion where the deep drawn portion and the step portion are formed, and after the draw forming, it is necessary to cut off the portion held by the holder. On the other hand, in the manufacturing method of the present invention, the frame half is manufactured by dividing it into the drawing process and the bending process, and in the drawing process, the holder can hold the part to be bent in the later bending process. The rate can be improved.

  (6) In general, when a portion once molded is re-shaped, the portion becomes brittle. On the other hand, in the present invention, in the bending process of the frame half body, the outside of the plate member which has been subjected to the drawing process is bent along the longitudinal direction outside the bent part formed on the periphery of the deep drawn part By molding, the rigidity of the step can be improved.

FIG. 1 is a perspective view showing a configuration of a vehicle body frame of a straddle-type vehicle according to an embodiment of the present invention. It is a left view of a down frame. It is a front view of a down frame. It is sectional drawing perpendicular | vertical to the axis line in the center part of a down frame. It is sectional drawing perpendicular | vertical to the axis line in the lower end part of a down frame. It is a flowchart which shows the procedure which manufactures a flame | frame half body from a board | plate material. It is a top view which shows the structure of the left flame | frame board | plate material and right flame | frame board | plate material which are manufactured through a blanking process. It is a figure which shows the procedure of a drawing process typically. It is a figure which shows the procedure of a trim process typically. It is a figure which shows the procedure of bend formation typically. It is a figure which shows the procedure of bend formation typically. It is a figure which shows typically the procedure of the re-pressing process in a restriking process.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a perspective view showing a configuration of a vehicle body frame 1 of a straddle-type vehicle according to the present embodiment. The body frame 1 includes a tubular head pipe 2 provided in front of the vehicle, a tubular down frame 3 hanging downward from the head pipe 2 in the vertical direction, and a vehicle width at the lower end 5 of the down frame 3. It has two tubular left side frames 7L and right side frames 7R extending toward the rear of the vehicle from left connection end faces 51L, 51R which are end faces on both left and right sides of the direction.

  The head pipe 2 is tubular and forms a predetermined caster angle with the vertical direction. A front pipe (not shown) of the vehicle and a steering stem of a front fork supporting the front wheel are supported by the head pipe 2. The vehicle rear side of the outer peripheral surface of the head pipe 2 is welded to a joint portion formed on the upper end portion 31 of the down frame 3 by welding.

  The side frames 7L and 7R respectively extend downward from the connection end surfaces 51L and 51R along the substantially horizontal direction to the rear frames of the lower frames 71L and 71R, and are directed vertically upward from the rear ends of the lower frames 71L and 71R. And a rear frame 73L, 73R extending obliquely. The side frames 7L, 7R are connected by cross members 74, 75, 76 extending in a substantially horizontal direction, and have a frame shape in top view. A seat rail 77 on which a seat (not shown) is provided is formed by the rear frames 73L and 73R.

  The down frame 3 is a hollow tubular member extending along an axis O substantially parallel to the vertical direction. The down frame 3 is an end on the upper side in the vertical direction and is an upper end 31 joined to the head pipe 2, and an end on the lower side in the vertical direction is a lower end 5 joined to the side frames 7L and 7R. The central portion 33 is divided between the upper end portion 31 and the lower end portion 5.

  FIG. 2 is a left side view of the down frame 3, and FIG. 3 is a front view of the down frame 3. 4 is a cross-sectional view (cross-sectional view along line A-A in FIG. 2) perpendicular to the axis O at the central portion 33 of the down frame 3. FIG. 5 is an axial line at the lower end 5 of the down frame 3. It is sectional drawing (sectional drawing in alignment with line B-B of FIG. 2) perpendicular | vertical to O. FIG.

  The down frame 3 includes a front half 61L, 61R and a rear end 62L opposite to the half cylindrical left frame half 6L formed from a plate and the half cylindrical right frame half 6R formed from a plate. , 62R by welding. As shown in FIGS. 4 and 5, in the following, the front end 61L and the rear end 62L of the left frame half 6L are the same as the front end 61R and the rear end 62R of the right frame 6R. Although the case where it provides in the outer side is explained, the present invention is not limited to this. The front side end 61L and the rear side end 62L of the left frame half 6L may be provided more inside than the front side end 61R and the rear side end 62R of the right frame half 6R.

  As described above, the down frame 3 is a frame connecting the head pipe 2 supporting the front wheel (not shown) and the side frames 7L and 7R. Therefore, during steering, a load acts on the lower end portion 5 of the down frame 3 along the vehicle width direction. For this reason, the lower end portion 5 of the down frame 3 needs to secure rigidity against a load along the vehicle width direction more than the front-rear direction. Therefore, the width b (see FIG. 3) of the lower end 5 along the vehicle width direction in the front view is larger than the width a (see FIG. 2) along the front-rear direction in the side view (a <b). More specifically, the width b along the vehicle width direction in the front view of the lower end portion 5 is a surface to which the side frames 7L and 7R are connected, and the axis O in each of the left and right side portions of the lower end portion 5 Is a distance along the vehicle width direction between the left connection end surface 51L and the right connection end surface 51R formed in parallel with each other.

  The width of the central portion 33 of the down frame 3 in the front-rear direction in a side view and the width in the front-rear direction of the lower end portion 5 in a side view are substantially equal (see, eg, FIG. 2). On the other hand, the width b along the vehicle width direction in the front view of the lower end portion 5 of the down frame 3 is larger than the width c along the vehicle width direction in the front view of the central portion 33 (b> c). More specifically, the width c along the vehicle width direction in the front view of the central portion 33 is more specifically, along the vehicle width direction between the left side surface 34L of the central portion 33 and the right side surface 34R opposite thereto. It is a distance.

  Further, on the left side of the lower end portion 5, a left inclined surface 52L which extends obliquely with respect to the axis O and which smoothly connects the left connection end surface 51L of the lower end portion 5 and the left side surface 34L of the central portion 33 is formed. . Further, on the right side of the lower end portion 5, a right inclined surface 52R extending obliquely with respect to the axis O and smoothly connecting the right connection end surface 51R of the lower end portion 5 and the right side surface 34R of the central portion 33 is formed. .

  A front left step portion 53L and a front right step portion 53R extending along an axis O which is the longitudinal direction of the down frame 3 are formed on both sides in the vehicle width direction on the front surface 4F of the lower end 5 . Further, in the rear surface 4R on the rear surface side of the lower end 5, a rear left step 54L and a rear right step 54R extending along the axis O are formed on both sides in the vehicle width direction.

  The left step portions 53L and 54L are formed by bending a plate material. The left step portions 53L and 54L respectively have bottom surface portions 531L and 541L extending substantially perpendicularly to the left connection end surface 51L or the left inclined surface 52L in a cross sectional view, and shoulder surface portions extending to incline outward with respect to the bottom surface portions 531L and 541L. And 532L and 542L.

  The right step portions 53R and 54R are formed by bending a plate material. The right step portions 53R and 54R respectively have bottom surface portions 531R and 541R extending substantially perpendicularly to the right connection end surface 51R or the right inclined surface 52R in a cross sectional view, and shoulder surface portions extending to incline outward with respect to the bottom surface portions 531R and 541R. And 532R and 542R.

  As shown in FIG. 5, these left step portions 53L and 54L are formed substantially at the center in a front view between the welding bead 63 of the wire connecting the frame halves 6L and 6R and the left connecting end surface 51L. In other words, the distance d1 along the vehicle width direction in the front view from the weld bead 63 to the left step 53L, 54L, and the vehicle width direction in the front view from the left step 53L, 54L to the left connection end surface 51L The distance d2 is approximately equal (d1 ≒ d2).

  The right step portions 53R and 54R are formed substantially at the center in a front view between the welding bead 63 and the right connection end surface 51R. In other words, a distance d3 along the vehicle width direction in a front view from welding bead 63 to right step 53R, 54R, and a vehicle width direction in a front view from right step 53R, 54R to right connection end face 51R The distance d4 is substantially equal (d3 ≒ d4). Further, these distances d1, d2, d3 and d4 are substantially equal (d1 ≒ d2 ≒ d3 ≒ d4).

  As shown in FIG. 3, the distance from the axis O of the down frame 3 to the shoulder surface 532L of the front left step 53L along the vehicle width direction in front view is the front from the axis O to the left side 34L of the center 33 The distance is substantially the same as the distance along the vehicle width direction as viewed. The distance from the axis O of the down frame 3 to the shoulder surface 532R of the front right step 53R along the vehicle width direction in the front view is in the vehicle width direction from the axis O to the right side 34R of the center 33 in the front view It is almost the same as the distance along. Accordingly, the shoulder surface portions 532L and 532R of the step portions 53L and 53R are flush with the side surfaces 34L and 34R of the central portion 33, respectively.

  Although not shown, the distance along the vehicle width direction from the axis O of the down frame 3 to the shoulder surface 542L of the left step 54L from the axis O to the left side 34L of the center 33 from the axis O The distance along the vehicle width direction in the front view from the axis O of the down frame 3 to the shoulder surface 542R of the rear right step 54R is substantially the same as the distance along the vehicle width in the front view The distance along the vehicle width direction in the front view to the right side surface 34R of the central portion 33 is substantially the same. Accordingly, the shoulder surface portions 542L and 542R of the step portions 54L and 54R are flush with the side surfaces 34L and 34R of the central portion 33, respectively.

According to the vehicle body frame 1 as described above, the following effects can be obtained.
(1) In the vehicle body frame 1, the width b of the lower end 5 of the down frame 3 hanging down from the head pipe 2 to which the two side frames 7L and 7R are connected is larger than the width c of the central portion 33 in front view Furthermore, on both the front surface 4F and the rear surface 4R of the lower end 5, a pair of steps 53L, 53R and a pair of steps 54L, 54R extending along the longitudinal direction are formed on both sides in the vehicle width direction. Do. By forming the steps 53L, 53R, 54L, 54R along the longitudinal direction of the down frame 3, the rigidity of the lower end 5 of the down frame 3 is improved while minimizing the increase in weight of the vehicle body frame 1. can do.

  (2) In the vehicle body frame 1, the distance along the vehicle width direction between the step portion 53 L, 53 R, 54 L, 54 R formed on the lower end portion 5 of the down frame 3 and its axis O and the center of the down frame 3 The distance between the side surfaces 34L, 34R of the portion 33 and the coaxial line O along the vehicle width direction is substantially equal. As a result, the shoulder surface portions 532L and 542L of the stepped portions 53L and 54L and the left side surface 34L of the central portion 33 are made flush, and further, the shoulder surface portions 532R and 542R of the stepped portions 53R and 54R and the right side surface 34R of the central portion 33 are formed. Since it can be flush, the rigidity of the lower end 5 of the down frame 3 can be further improved.

  (3) In the vehicle body frame 1, the stepped portions 53L, 53R, 54L, 54R are between the weld bead 63 and the connection end faces 51L, 51R of the lower end 5 to which the side frames 7L, 7R are connected. It is formed substantially at the center in front view. Thereby, the rigidity against the bending load acting in the direction perpendicular to the longitudinal direction of the down frame 3 can be further improved.

  In the above embodiment, the pair of step portions 53L and 53R and step portions 53R and 54R are formed on both the front surface portion 4F and the rear surface portion 4R of the down frame 3. However, the present invention is not limited thereto. . The pair of steps may be formed on only one of the front surface 4F and the rear surface 4R.

  Next, a procedure for manufacturing the down frame 3 of the vehicle body frame 1 according to the present embodiment as described above will be described. As described above, the down frame 3 is formed by welding opposite ends of the half cylindrical left frame half 6L and the half cylindrical right frame half 6R respectively formed of plate materials. .

  FIG. 6 is a flow chart showing a procedure of manufacturing each frame half 6L, 6R from a plate material. As shown in FIG. 6, each frame half 6L, 6R includes a blanking step (S1), a draw step (S2), a trim step (S3), a bend step (S4), and a restike step (S5). ) And are manufactured. Hereinafter, specific procedures of each step will be described in detail with reference to the drawings.

<Blanking process>
FIG. 7 is a plan view showing a configuration of the left frame plate member 6000L and the right frame plate member 6000R manufactured through the blanking process. In the blanking step, a left frame plate 6000L and a right frame plate 6000R having a substantially product shape as shown in FIG. 7 are cut out by laser or die cutting of the plate.

<Drawing process>
In the drawing process, the frame plate members 6000L and 6000R manufactured through the blanking process are deep drawn to finally connect the connection end faces 51L and 51R of the side surfaces 34L and 34R of the central portion 33 and the lower end portion 5; A deep drawn portion including portions to be the inclined surfaces 52L, 52R and the bottom portions 531L, 531R, 541L, 541R of the stepped portions 53L, 53R, 54L, 54R is formed.

  FIG. 8 is a diagram schematically showing the procedure of the drawing process. More specifically, it is a figure which shows typically the procedure of the deep draw forming given with respect to left frame board | plate material 6000L. The upper part of FIG. 8 is a plan view of the frame plate member 6000L and the lower die 81 for performing deep drawing, and the lower portion is a side view of the frame plate member 6000L and the lower die 81.

  As shown in FIG. 8, in the lower mold 81, since a deep drawn portion convex in the vehicle width direction is formed at a portion which finally becomes the lower end portion 5 in the plate member 6000L, the center of the plate member 6000L is finally formed. A portion 82 for forming a surface to be the left side surface 34L of the portion 33, a portion 83 for forming a surface to be finally the left connection end surface 51L of the lower end portion 5 with respect to the plate member 6000L, and a left inclined surface to the plate member 6000L finally A portion 84 for forming a surface to be 52L, a portion 85 for forming a surface to be finally a bottom portion 531L of the front left step portion 53L to the plate member 6000L, and a rear step left step portion 54L to the plate member 6000L. And a portion 86 for forming a surface to be the bottom surface portion 541L.

  In the drawing process, the plate member 6000L is set along the plurality of convex guides 87a to 87f provided on the lower die 81, and the deep die is formed by the lower die 81 of the plate member 6000L by a blank holder not shown. The plate 88 is provided with a pad 88 provided opposite to a portion 83 for sandwiching an edge 6001L (in FIG. 8, this edge 6001L is indicated by hatching) around the portion to be formed and further forming a surface to be the left connection end surface 51L. By bringing the plate material 6000L close to the lower die 81 while pressing the 6000L to the portion 83 side, a deep drawn portion 69L having a shape corresponding to the portions 82 to 86 and convex in the vehicle width direction (for example, FIG. And FIG. 11 grade | etc.,) Is formed in the board | plate material 6000L. Further, in the drawing step, the edge 6001L held by the blank holder is a portion which is outside the portion of the plate member 6000L where the deep drawn portion is formed and which is bent in a bending step described later (bending in FIG. Sections 67L and 68L). As described above, in the drawing process, by sandwiching the part to be the product later with the blank holder, it is possible to suppress the occurrence of deforming when forming the deep drawn part. In the drawing step, the same deep drawing is performed on the right frame plate member 6000R to form a deep drawn portion.

<Trim process>
In the trimming process, the left frame plate and the right frame plate manufactured through the drawing process are trimmed to cut unnecessary portions, or a through hole is formed.

  FIG. 9 is a diagram schematically showing the procedure of the trimming process. More specifically, it is a figure which shows typically the procedure of the trim process given with respect to 600 L of left flame | frame board | plate materials manufactured through the drawing process. In the trimming process, the left frame plate member 600L is placed on the table along the guides 90a to 90c, and cut off along the thick broken lines 89a and 89b in FIG. 9 to finally obtain the front end 61L and the rear end A portion to be the portion 62L is formed. As described above, the end portions 61R and 62R of the right frame half 6R are provided inside the end portions 61L and 62L of the left frame half 6L. Therefore, the trimming process of the end portion is performed only on the left frame plate member 600L, and does not need to be performed positively on the right frame plate member 600R.

<Bend process>
In the bending process, the left frame plate and the right frame plate manufactured through the trimming process are subjected to bend forming to finally connect the connection end faces 51L, 51R of the side portions 34L, 34R of the central portion 33 and the lower end portion 5; The inclined surfaces 52L and 52R, the step portions 53L, 53R, 54L and 54R, and the portions to be the front surface portion 4F and the rear surface portion 4R are formed.

  FIGS. 10 and 11 are diagrams schematically showing a procedure of bend forming applied to the left frame plate 60L manufactured through the trimming process. More specifically, FIG. 10 is a cross-sectional view of a portion of the left frame plate 60L at the time of bend forming which will finally be the central portion 33 (more specifically, a cross section taken along line C-C in FIG. Figure). 11 is a cross-sectional view of a portion including the deep drawn portion 69L formed in the drawing process in the left frame plate member 60L at the time of bend forming (more specifically, a cross-sectional view taken along line D-D in FIG. 9) ). Further, in FIGS. 10 and 11, the upper mold 91 for performing the bend forming is in the vicinity of the top dead center with respect to the lower mold 92 in order from the upper stage to the lower stage, respectively. A state in the vicinity of the bottom dead center and a state in which the upper mold 91 is lowered to the bottom dead center with respect to the lower mold 92 are shown. That is, bend forming proceeds in order from the upper stage to the lower stage.

  As shown in FIG. 10, in the bend forming, the upper mold 91 is lowered toward the lower mold 92 while the surface of the left frame plate 60L that will finally become the left side 34L is pressed against the lower mold 92 by the pad 93. As a result, the left frame plate 60L is bent on both sides of the pad 93, and a portion to be the central portion 33 is finally formed. Particularly in the vicinity of the bottom dead center, the both end portions 60La, 60Lb of the left frame plate 60L are extended downward while being sandwiched between the upper mold 91 and the lower mold 92. As described above, the end portions 61R and 62R of the right frame half 6R are provided inside the end portions 61L and 62L of the left frame half 6L. Therefore, when the right frame plate material is subjected to bend forming, the flange bending angle θ is made larger than in the case where the left frame plate material 60L is subjected to bend formation.

  Further, as shown in FIG. 11, in the bend forming, while the surface to be the left connection end surface 51L and the left inclined surface 52L in the left frame plate member 60L is finally held down to the lower die 92 by the pad 93, the upper die 91 is lowered. Lower to the mold 92, bend the outside of the left frame plate 60L in the vertical direction below the deep drawn part 69L formed in the drawing process, and finally make the stepped parts 53L, 54L and the lower end part 5 Molding.

  As described above, in the previous drawing process, by subjecting the plate material to draw forming, the left frame plate member 60L is substantially at the periphery of the deep drawn portion 69L and finally in the cross-sectional view that becomes each step portion 53L, 54L. L-shaped bent portions 63L and 64L are formed. Therefore, in the bend forming, in order to secure the rigidity of the portion finally to be the step parts 53L and 54L, the bending parts 63L and 64L already formed by drawing are not extended as much as possible, while the bending parts 63L and 64L are not extended. By bending the outside along the longitudinal direction, bending portions 67L and 68L are further formed outside these bending portions 63L and 64L. Thus, the step portions 53L and 54L are formed between the bending portions 67L and 68L and the bending portions 63L and 64L. Further, in order to prevent the bent portions 63L and 64L from being extended as much as possible, the upper mold 91 is used which is in contact with the bent portions 63L and 64L only when reaching the vicinity of the bottom dead center.

  More specifically, in the bend forming, as shown in the top step in FIG. 11, first, portions of the left frame plate 60L outside the bent portions 63L and 64L are bent by the upper die 91. After that, as shown in the middle and lower stages in FIG. 11, the both end portions 65L and 66L of the left frame plate member 60L were extended while being sandwiched between the upper mold 91 and the lower mold 92 and reached near the bottom dead center. The upper mold 91 and the bent portions 63L and 64L are brought into contact with each other for the first time. As described above, in the bend forming, of the portions to be the lower end 5 finally, the portions to be the step portions 53L and 54L are formed when the upper die 91 reaches the vicinity of the bottom dead center. In the bending process, the same bend forming is applied to the right frame plate manufactured through the trimming process.

<Striking process>
In the restriking process, the left frame plate and the right frame plate manufactured through the bending process are re-pressed to form the left frame half 6L and the right frame half 6R.

  FIG. 12 is a diagram schematically showing a re-pressing process in the restriking process. More specifically, FIG. 12 is a view schematically showing a procedure for forming the lower end portion 5 of the left frame half 6L by re-pressing.

  As shown in FIG. 12, in the restriking process, the left frame plate manufactured through the bending process is placed on the lower mold 95 having the same shape as the final product, and the end 61L, The left frame plate placed on the lower mold 95 is held down by a pad 96 having the same shape as that of the portion other than 62L. In the restriking process, the end portions 61L and 62L are obtained by pressing the cam punches 97 and 98 having the same shape as the end portions 61L and 62L in the final product against the end portions of the left frame plate material pressed by the pad 96. , The left frame half 6L including the step portions 53L and 54L and the left connection end face 51L. In the restriking process, the right frame half 6R is formed by subjecting the right frame plate material manufactured through the bending process to the same repressing process as well.

According to the method of manufacturing a down frame as described above, the following effects can be obtained.
(4) In the method of manufacturing the down frame, a pair of semi-cylindrical frame halves are manufactured, and by joining the opposing ends of the pair of frame halves, the width is wider than in the central portion and in the longitudinal direction A down frame is provided comprising a lower end formed with a pair of steps extending along the Further, in the present invention, a drawing step of forming a deep drawn portion in a portion to be a lower end portion while holding a portion to be bent in a later bending step of a plate material and bending the outside of the deep drawn portion Such a frame half is manufactured through a bending step of forming a step. As described above, the down frame provided with the lower end portion wider than the central portion and in which the step portion is formed is manufactured by one draw forming without dividing into the drawing step and the bending step as in the present invention. It is also possible. However, in this case, in the draw forming, it is necessary to hold the outside of the plate material with the holder outside the portion where the deep drawn portion and the step portion are formed, and after the draw forming, it is necessary to cut off the portion held by the holder. On the other hand, in the manufacturing method of the present invention, the frame half is manufactured by dividing it into the drawing process and the bending process, and in the drawing process, the holder can hold the part to be bent in the later bending process. The rate can be improved.

  (5) In general, if a portion once molded is re-shaped, the portion becomes brittle. On the other hand, in the present invention, in the bending process of the frame half body, the outside of the plate member which has been subjected to the drawing process is bent along the longitudinal direction outside the bent part formed on the periphery of the deep drawn part By molding, the rigidity of the step can be improved.

1 ... Body frame (frame)
DESCRIPTION OF SYMBOLS 2 ... Head pipe 3 ... Down frame 31 ... Upper end part 33 ... Central part 4F ... Front part 4 R ... Back surface part 5 ... Lower end part 51 L ... Left connection end face (end face)
51R ... Right connection end face (end face)
53L ... front left step (step)
53R ... front right step (step)
54L ... back surface left step (step)
54R ... back surface right step (step)
6L: left frame half body 61L: front end (end)
62L ... Rear end (end)
6R: Right frame half body 61R: Front end (end)
62R ... rear end (end)
63 ... weld bead 63 ... weld bead 7L ... left side frame (side frame)
7R ... right side frame (side frame)

Claims (7)

A frame of a saddle-ride type vehicle comprising a head pipe, a down frame hanging from the head pipe, and two side frames extending rearward from end faces on both sides in the vehicle width direction at the lower end of the down frame. There,
The width of the lower end in a front view is larger than the width of the central portion above the lower end,
In at least one of the front surface and rear surface of the lower end, a pair of steps extending along the longitudinal direction are formed on both sides in the vehicle width direction ,
Each of the pair of step portions includes a bottom portion and a shoulder portion which is inclined outward with respect to the bottom portion in order from the outer side to the inner side in the vehicle width direction in a cross sectional view. .   The frame of a saddle-ride type vehicle according to claim 1, wherein the pair of step portions are formed on both the front surface portion and the rear surface portion. A frame of a saddle-ride type vehicle comprising a head pipe, a down frame hanging from the head pipe, and two side frames extending rearward from end faces on both sides in the vehicle width direction at the lower end of the down frame. There,
The width of the lower end in a front view is larger than the width of the central portion above the lower end,
In at least one of the front surface and rear surface of the lower end, a pair of steps extending along the longitudinal direction are formed on both sides in the vehicle width direction ,
A frame of a saddle-ride type vehicle, wherein a thick portion extending along a longitudinal direction and having a thickness greater than that of the step portion is formed between the pair of step portions . A frame of a saddle-ride type vehicle comprising a head pipe, a down frame hanging from the head pipe, and two side frames extending rearward from end faces on both sides in the vehicle width direction at the lower end of the down frame. There,
The width of the lower end in a front view is larger than the width of the central portion above the lower end,
In at least one of the front surface and rear surface of the lower end, a pair of steps extending along the longitudinal direction are formed on both sides in the vehicle width direction ,
A distance from the axis of the down frame to the step in the vehicle width direction is substantially the same as a distance from the axis to the side surface of the central portion in the vehicle width direction. Vehicle frame. A frame of a saddle-ride type vehicle comprising a head pipe, a down frame hanging from the head pipe, and two side frames extending rearward from end faces on both sides in the vehicle width direction at the lower end of the down frame. There,
The width of the lower end in a front view is larger than the width of the central portion above the lower end,
In at least one of the front surface and rear surface of the lower end, a pair of steps extending along the longitudinal direction are formed on both sides in the vehicle width direction ,
The down frame is formed by welding opposite ends of a half cylindrical left frame half and a half cylindrical right frame half by welding.
The frame of a saddle-ride type vehicle according to claim 1, wherein the stepped portion is formed substantially in the center in a front view between a weld bead of the down frame and the end face of the lower end portion . A head pipe is connected to the upper end portion thereof, and a method of manufacturing a down frame in which two side frames are respectively connected to end surfaces on both ends in the vehicle width direction at the lower end portion,
A frame half manufacturing process for manufacturing a pair of semi-cylindrical frame halves from a plate material;
By joining the opposing ends of the pair of frame halves, the width of the lower end in a front view is larger than the width of the central portion above the lower end, and the front and rear of the lower end And a joining step of manufacturing a down frame in which a pair of step portions extending along the longitudinal direction is formed on both sides in the vehicle width direction on at least one of the surface portions,
The frame half manufacturing process
A drawing step of forming a convex deep drawn portion in a portion to be the lower end portion of the plate material;
And a bending step of forming the stepped portion by bending the outside of the deep drawn portion of the plate material subjected to the drawing step.
A down frame characterized in that in the drawing step, the deep drawn portion is formed while holding a portion which is outside the portion where the deep drawn portion is formed among the plate material and which is bent in the bend step with a holder. Manufacturing method. In the bending step, the step portion is formed by bending the outside of the plate member which has undergone the drawing step along the longitudinal direction outside the bending portion formed on the periphery of the deep drawn portion. The manufacturing method of the down frame according to claim 6 .

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