Pressing forming die for variable cross-section hollow front axle pipe fitting of mini-truck

Abstract

The invention provides a pressing forming die for a variable cross-section hollow front axle pipe fitting of a mini-truck, which belongs to the technical field of automobile manufacturing and comprises an upper die plate, an upper die, a plurality of socket head cap screws, a guide sleeve, a guide column, a lower die plate, a lower die, an ejector rod, a guide plate, a sliding plate, a side die and a side die plate. The upper die plate and the upper die are connected through a plurality of inner hexagon screws, the lower die plate and the lower die are connected through a plurality of inner hexagon screws, the upper die plate and the lower die plate are the same in boundary dimension, the side dies are of an arch-shaped structure with two high sides and a low middle, the side dies are arranged on the two sides of the upper die and the lower die, the side die plates are arranged on the outer sides of the side dies, and the side die plates are connected with the side dies. Guiding between the upper die plate and the lower die plate is guaranteed through a guide sleeve arranged on the upper die plate and a guide column arranged on the lower die plate, the side die plate slides on the lower die plate through a guide plate and a sliding plate, and the upper portion of the ejector rod enters the lower die through the lower die plate. The hollow round pipe can be integrally pressed and formed at a time; and the produced hollow front axle pipe fitting is good in forming quality.

Description

Technical Field

[0001] The invention relates to the technical field of automobile manufacturing, in particular to a pressing and forming die for a hollow front axle pipe with a variable cross-section of a mini truck. Background Art

[0002] The front axle is one of the important parts of the car. It has a complex shape and bears impact loads. It plays an important role in bearing and steering. Its strength, stiffness and fatigue life directly affect the stability of the car's transmission system and the safety of the whole vehicle. The components of the front axle generally include the middle crossbeam, the two side bends and the fists.

[0003] At present, forged front axles and assembly welded front axles are mainly used in automobiles. The Chinese patent "A hollow front axle of a micro-light truck and its manufacturing method" (application number: 202410396167.8) discloses a method for forming a hollow front axle of an automobile: selecting a round tube blank of a certain size - upsetting - stamping and bending - pressing and forming - machining - welding accessories - quenching and tempering. The front axle fist, neck and crossbeam manufactured by this method are formed in one piece. The crossbeam part is a hollow circular structure, and the neck part transitions from a hollow circle to a hollow rectangular structure with a smaller circumference. It can replace the existing forged front axle and assembly welded front axle, and greatly improve the bending and torsional resistance while reducing the weight of the product.

[0004] The hollow front axle pipe fittings for mini trucks are formed by pressing preformed tube blanks. They are hollow variable-section bow-shaped beams formed as a whole under the pressure of external molds. The shape of the pipe fittings after pressing is complex: the neck part is a variable-section structure from a hollow circle to a hollow rectangle, and the front and rear sides of the neck part connected to the left and right fists directly form internal compacted stepped blind holes. The front and rear sides of the left and right fists are pressed with curved limit block grooves, and the fists are transformed from hollow circles to thick-walled rectangles. The forming accuracy requirements are extremely high, so a specially designed mold with a special structure is required. At present, no pressing mold that can be used for the actual production of variable-section hollow automobile front axle pipe fittings has been found. Summary of the invention

[0005] The purpose of the present invention is to provide a mini truck variable-section hollow front axle pipe pressing and forming die, which can press and form the hollow round pipe as a whole at one time; when used on a three-way hydraulic press, the die has high guiding accuracy and the hollow front axle pipe produced has good forming quality.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] In the first aspect, a variable-section hollow front axle pipe pressing and forming die for a mini truck is characterized in that it includes an upper template, an upper die, a plurality of hexagon socket screws, a guide sleeve, a guide column, a lower template, a lower die, a push rod, a guide plate, a slide plate, a side mold and a side mold.

[0008] The upper mold is connected to the upper mold by a plurality of hexagon socket screws, the lower mold is connected to the lower mold by a plurality of hexagon socket screws, the upper mold has the same outer dimensions as the lower mold, the side mold is an arched structure with high sides and a low middle, the side mold is arranged on both sides of the upper mold and the lower mold, the side mold is arranged on the outside of the side mold, and the side mold is connected to the side mold.

[0009] The upper template and the lower template are guided by a guide sleeve arranged on the upper template and a guide column arranged on the lower template. The side template slides on the lower template through a guide plate and a slide plate. The upper part of the push rod enters into the lower template through the lower template.

[0010] Furthermore, the upper template includes an upper template plate body, an upper template boss and an upper template keyway.

[0011] The upper template plate body is a rectangular plate, and upper template bosses are respectively arranged at both ends of the bottom of the upper template plate body. A hole for installing a guide sleeve is opened at the center of the upper template boss, and an upper template keyway is arranged at the center of the interior of the upper template plate body.

[0012] Furthermore, the upper mold is a block that is wide at the top and narrow at the bottom, and the upper mold includes an upper mold cavity, an upper mold support body and an upper mold boss.

[0013] An upper mold boss is arranged on the upper side of the upper mold support body, and the upper mold boss is fixedly arranged inside the keyway of the upper mold plate. The upper mold cavity is arranged at the bottom of the upper mold support body, and the upper mold cavity is an arched structure with a low middle and two ends warped upward.

[0014] The upper mold cavity comprises an upper mold middle portion, an upper mold bent neck and an upper mold extension portion.

[0015] The middle part of the upper mold is arranged at the center of the upper model cavity, the middle part of the upper mold is a partial cylindrical through hole, the cross-section of the cavity in the middle part of the upper mold is an arc, and upwardly curved upper mold necks are arranged on both sides of the middle part of the upper mold. The cross-section of the upper mold neck transitions from an arc to a plane, and the upper mold extension part is arranged on the side of the upper mold necks on both sides away from the middle part of the upper mold, and the cavity of the upper mold extension part is a plane.

[0016] Furthermore, the lower template includes a lower template plate body, a lower template boss, a lower template keyway and a lower template groove.

[0017] The lower template plate body is a rectangular plate, and lower template bosses are respectively provided at the two ends of the top of the lower template plate body. A hole for installing the guide column is opened at the center of the lower template boss. A lower template keyway is provided at the center of the lower template plate body, and two cylindrical through holes for accommodating the push rods are symmetrically provided inside the lower template keyway. The bottom surface of the lower template is provided with four lower template grooves that are symmetrical front to back and left to right, and the lower template grooves are used to install the guide plate.

[0018] Furthermore, the lower mold is a block that is wide at the top and narrow at the bottom, and the lower mold includes a lower mold cavity, a lower mold support body and a lower mold boss.

[0019] A lower mold boss is arranged on the lower side of the lower mold support body, and the lower mold boss is fixedly arranged inside the keyway of the lower mold plate. The lower mold cavity is arranged on the top of the lower mold support body. The lower mold cavity is an arched structure with a low middle and two ends warped upward. The shape and size of the lower mold cavity are the same as those of the upper mold cavity. Two stepped cylindrical holes for accommodating ejector pins are symmetrically arranged inside the lower mold.

[0020] Furthermore, the side mold includes a side mold cavity, a side mold support body and a side mold boss.

[0021] A side mold boss is arranged on the rear side of the side mold support body, and a side mold cavity is arranged on the front side of the side mold support body. The side mold cavity is an arched structure with a low middle and two ends warped upward.

[0022] The side mold cavity includes a side mold middle part, a side mold bent neck, and a side mold extension part. The side mold middle part is arranged at the center of the side mold cavity. The side mold middle part is a partially cylindrical through hole. The cross-section of the side mold middle part is an arc. The middle part of the side mold is provided with upwardly warped side mold bent necks on both sides. The cross-section of the side mold bent neck transitions from an arc shape to a plane. A cylindrical boss is provided on the side mold bent neck, and the outer end face of the cylindrical boss is a circle.

[0023] A side mold extension portion is provided on the side of the side mold bending neck away from the middle of the side mold. The cavity of the side mold extension portion is two-section plane with an arc transition between the two sections of plane. The side mold extension portion is provided with a right-side mold oblique conical protrusion.

[0024] Furthermore, the side template is a rectangular plate, the side template includes a side template keyway and a step groove, the side template keyway is arranged inside the side template, the side template boss is fixedly arranged inside the side template keyway, and the lower part of the side template is provided with a step groove.

[0025] The stepped groove comprises a lower step and an upper groove, wherein the upper groove is arranged at the top of the lower step, the slide plate is mounted on the lower step, and the upper part of the guide plate is arranged inside the upper groove.

[0026] Furthermore, the guide plate is C-shaped, and the slide plate is L-shaped.

[0027] In a second aspect, a method for forming a die for a hollow front axle pipe with a variable cross-section for a mini truck is characterized by comprising the following steps:

[0028] Step 1. The mold is installed on a three-way hydraulic press and the preformed tube is placed in it.

[0029] After the upper slide, left slide and right slide of the hydraulic press return and the workpiece is taken out, the preformed tube blank is placed in the cavity of the fixed lower die.

[0030] Step 2: Feed and position the side molds on both sides.

[0031] The left and right slide blocks of the hydraulic press respectively drive the left and right side molds to feed toward the preformed tube blank. When the left and right side molds contact the preformed tube blank, the feeding is stopped to center and fix the preformed tube blank.

[0032] Step 3: Pressing with upper mold.

[0033] The upper die is fed downward to press the preformed tube blank until the upper and lower side surfaces are basically in contact with the cavities of the upper and lower dies. The upper die stops after being fed to the set position.

[0034] Step 4. Press the left side mold and the right side mold towards each other.

[0035] After the upper mold stops feeding, the left side mold and the right side mold start to feed in the center until the upper and lower positioning surfaces of the left side mold and the right side mold fit with the sides of the upper and lower model cavities respectively, and the left and right slides of the hydraulic press stop feeding.

[0036] Step 5. The left side mold, the right side mold and the upper mold return and the parts are removed.

[0037] The upper die, the left side die and the right side die are driven by the hydraulic press slide to return respectively, and the formed blank remains in the cavity of the lower die; the ejector moves upward to eject the pressed blank, which is taken out by the removal mechanism, and then the ejector cylinder returns.

[0038] Advantages of the present invention:

[0039] 1. The present invention solves the problem that there is no pressing and forming mold for actually producing hollow front axle pipes with variable cross-sections in the prior art. Using the mold of the present invention, a hollow front axle pipe with variable cross-sections for mini trucks is pressed and formed as a whole from a hollow round tube at one time. The middle part is a round tube crossbeam, and the cross-section of the necks on both sides transitions from a hollow circle to a hollow rectangle. The outer fist of the neck is a thick-walled rectangular cross-section. A stepped blind hole is formed at the neck part close to the fist, and a curved limit block groove is formed at the front and rear sides of the fist.

[0040] 2. The present invention is used on a three-way hydraulic press, the mold guiding accuracy is high, and the hollow front axle pipe produced has good forming quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is the front view of the hollow front axle of the mini truck;

[0042] Figure 2 It is a top view of the hollow front axle of a mini truck;

[0043] Figure 3 It is the front view of the hollow front axle pipe of the mini truck;

[0044] Figure 4 This is a typical cross section of a hollow front axle tube for a mini truck;

[0045] Figure 5 A top view of a hollow front axle tube of a mini truck;

[0046] Figure 6 Preformed tube blanks for hollow front axle tubes for mini trucks;

[0047] Figure 7 is a cross-sectional view along the longitudinal symmetry plane of the present invention;

[0048] Figure 8 for Figure 5 Sectional view along section DD;

[0049] Fig. 9 for Figure 5 Cross-sectional view along section EE;

[0050] Fig.10 It is the front view of the upper mold in the present invention;

[0051] Fig.11 A bottom view of the upper die in the present invention;

[0052] Fig.12 for Figure 8 Sectional view along section FF;

[0053] Fig.13 It is the front view of the lower mold in the present invention;

[0054] Fig.14 for Fig.13 Cross-sectional view along section GG;

[0055] Fig.15 It is a top view of the lower template in the present invention;

[0056] Fig.16 for Fig.15 Cross-sectional view along section HH;

[0057] Fig.17 It is a bottom view of the upper template in the present invention;

[0058] Fig.18 It is a front view of the side mold in the present invention;

[0059] Fig.19 for Fig.18 Cross-sectional view along section KK;

[0060] Fig. 20 A top view of the side mold in the present invention;

[0061] Fig.21 It is the front view of the side formwork in the present invention;

[0062] Fig. 22 for Fig.21 Sectional view along section LL;

[0063] In the figure: 1, hollow front axle of mini truck, 1a, cross beam, 1b, bent neck, 1c, fist, 1d, shock absorber pin hole, 1e, limit block, 1f, metal plugging, 1g, shock absorber ring;

[0064] 2. Hollow front axle pipe fittings for mini trucks, 2a. Hollow round tube crossbeam, 2b. Pipe bending neck, 2c. Pipe fist, 2d. Step blind hole, 2e. Limit block slot;

[0065] 3. Upper template, 3a. Upper template plate body, 3b. Upper template boss, 3c. Upper template keyway;

[0066] 4. upper mold, 4a. upper mold cavity, 4a1. middle part of upper mold, 4a2. upper mold neck, 4a3. upper mold extension, 4b. upper mold support body, 4c. upper mold boss, 4d. left side of upper mold cavity, 4e. right side of upper mold cavity;

[0067] 5. Hexagon socket screws;

[0068] 6. Guide sleeve;

[0069] 7. Guide pillar;

[0070] 8. lower template, 8a. lower template plate body, 8b. lower template boss, 8c. lower template keyway, 8d. lower template groove;

[0071] 9, lower die, 9a, lower mold cavity, 9b, lower die support body, 9c, lower die boss, 9d, left side of lower mold cavity, 9e, right side of lower mold cavity, 9f, stepped cylindrical hole;

[0072] 10. Ejector rod;

[0073] 11. Guide plate;

[0074] 12. Skateboard;

[0075] 13. Side mold, 13a. Side mold cavity, 13a1. Middle part of side mold, 13a2. Side mold bent neck, 13a3. Side mold extension part, 13b. Side mold support body, 13c. Side mold boss, 13d. Side mold cylindrical boss, 13e. Side mold oblique conical protrusion, 13f. Side mold upper positioning surface, 13g. Side mold lower positioning surface;

[0076] 14. Side template, 14a. Side template keyway, 14b. Step groove, 14b1. Lower step, 14b2. Upper groove. DETAILED DESCRIPTION

[0077] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention.

[0078] Mini truck hollow front axle, such as Figure 1 and Figure 2 As shown, it includes a crossbeam 1a, a bent neck 1b and a fist 1c, and a shock absorber pin hole 1d is provided near the fist 1c, and a shock absorber ring 1g is welded to the outside of the shock absorber pin hole 1d; steering limit blocks 1e are provided on the front and rear sides of the fist 1c, and the outermost end is a machined arc surface, a rectangular hole is machined on the center of the end surface, and a metal seal 1f is welded.

[0079] Mini truck hollow front axle pipe 2, such as Figure 3-5 As shown, the hollow front axle pipe is in the shape of an arch with warped ends and a low middle. The middle part is a hollow circular tube 2a with a diameter of φdm and a wall thickness of tm. The two sides connected to the hollow circular tube 2a are upwardly warped pipe necks 2b. The cross section of the pipe neck 2b transitions from a hollow circle to a hollow rectangle. A stepped blind hole 2d is provided near the pipe fist 2c, which is subsequently processed into a shock absorber pin hole 1d. The pipe fist 2c connected to the pipe neck 2b has an outer height of hq, and limit block grooves 2e are provided on the front and rear sides of the pipe fist 2c, and limit blocks 1e are welded at the limit block grooves 2e.

[0080] The preformed tube before pressing is the tube after stamping and bending, such as Figure 6 As shown, the bow-shaped circular tube beam with a diameter of φdm has a total length of Lw, and the height difference between the center line of the end and the center line of the beam is hw.

[0081] like Figure 7-Figure 9 As shown, the mini truck variable-section hollow front axle pipe pressing and forming mold includes an upper mold plate 3, an upper mold 4, a plurality of hexagon socket screws 5, a guide sleeve 6, a guide column 7, a lower mold plate 8, a lower mold 9, a push rod 10, a guide plate 11, a slide plate 12, a side mold 13 and a side mold plate 14.

[0082] The upper mold 3 is connected to the upper mold 4 by a plurality of hexagon socket screws 5, and the lower mold 8 is connected to the lower mold 9 by a plurality of hexagon socket screws 5. The upper mold 3 and the lower mold 8 have the same outer dimensions. The side mold 13 is an arched structure with high sides and a low middle. The side mold 13 is arranged on both sides of the upper mold 4 and the lower mold 9. The side mold 14 is arranged on the outside of the side mold 13, and the side mold 14 is connected to the side mold 13.

[0083] The upper template 3 and the lower template 8 are guided by a guide sleeve 6 provided on the upper template 3 and a guide column 7 provided on the lower template 8. The side template 14 slides on the lower template 8 through a guide plate 11 and a slide plate 12. The upper part of the push rod 10 enters into the lower mold 9 through the lower template 8.

[0084] As a preferred embodiment of the present invention, Fig.17 As shown, the upper template 3 includes an upper template plate body 3a, an upper template boss 3b and an upper template keyway 3c.

[0085] The upper template plate body 3a is a rectangular plate, the length of the upper template plate body 3a is L6, the width is B2=700mm, and the thickness is H4, wherein L6=2300mm, B2=700mm, and H4=160mm. Upper template bosses 3b are respectively provided at the two ends of the bottom of the upper template plate body 3a, and a hole for installing the guide sleeve 6 is opened at the center of the upper template boss 3b. An upper template keyway 3c is provided at the center of the upper template plate body 3a, and the length of the upper template keyway 3c is L1, the width is B0, and the depth is H1, wherein L1=1780mm, B0=160mm, and H1=40mm.

[0086] As a preferred embodiment of the present invention, Figure 10-12 As shown, the upper mold 4 is a block that is wide at the top and narrow at the bottom. The upper mold 4 includes an upper mold cavity 4a, an upper mold support body 4b and an upper mold boss 4c.

[0087] The length of the upper mold support body 4b is L0, and the width is B0, wherein L0=1980mm, and the width B0=160mm. An upper mold boss 4c is arranged on the upper side of the upper mold support body 4b. The length of the upper mold boss 4c is L1, the width is B0, and the height is H1, wherein L1=1780mm, B0=160mm, and H1=40mm. The upper mold boss 4c is fixedly arranged inside the key groove 3c of the upper mold plate. The upper model cavity 4a is arranged at the bottom of the upper mold support body 4b. The upper model cavity 4a is an arched structure with a low middle and upward warping at both ends. The total length of the upper model cavity 4a is L2, the height at each location is H0, and the width is B1, wherein L2=1466mm, H0=44mm, and B1=55mm, which is used to ensure the overall strength of the mold.

[0088] The upper mold cavity 4a includes an upper mold middle portion 4a1, an upper mold neck 4a2 and an upper mold extension portion 4a3.

[0089] The middle part 4a1 of the upper mold is arranged at the center of the upper mold cavity 4a. The middle part 4a1 of the upper mold is a partially cylindrical through hole, which contacts the upper side of the hollow round tube beam 2a during pressing. The length of the middle part 4a1 of the upper mold is L3, wherein L3=853mm. The cross section of the cavity of the middle part 4a1 of the upper mold is an arc, the radius of the arc is R0, and the angle is θ1, wherein R0=39mm, θ1=70°. The upper mold neck 4a2 that is warped upward is arranged on both sides of the middle part 4a1 of the upper mold, the angle between the middle part 4a1 of the upper mold and the upper mold neck 4a2 is α1, and the transition radius is R1 , wherein α1=60°, R1=80mm, the cross-section of the upper die neck 4a2 transitions from an arc to a plane, and contacts the upper side of the pipe neck 2b during pressing; the upper die necks 4a2 on both sides are provided with upper die extension portions 4a3 on the side away from the upper die middle portion 4a1, the transition fillet radius between the upper die neck 4a2 and the upper die extension portion 4a3 is R2, the angle between the upper die extension portion 4a3 and the arc center line of the upper die middle portion 4a1 is β1, wherein R2=115mm, β1=7°, the cavity of the upper die extension portion 4a3 is a plane, and contacts the upper surface of the pipe fist 2c during pressing.

[0090] As a preferred embodiment of the present invention, Figure 15-16 As shown, the lower template 8 includes a lower template plate body 8a, a lower template boss 8b, a lower template keyway 8c and a lower template groove 8d.

[0091] The lower template plate body 8a is a rectangular plate, the length of the lower template plate body 8a is L6, the width is B2=700mm, and the thickness is H4, wherein L6=2300mm, B2=700mm, and H4=160mm. The top two ends of the lower template plate body 8a are respectively provided with lower template bosses 8b, and the center of the lower template boss 8b is provided with a hole for installing the guide column 7. The center of the lower template plate body 8a is provided with a lower template keyway 8c, and the length of the lower template keyway 8c is L4, the width is B0, and the depth is is H2, wherein L4=1500mm, B0=160mm, H2=80mm, two cylindrical through holes for accommodating the push rod 10 are symmetrically arranged inside the lower template keyway 8c, and the center distance between the two cylindrical through holes is L5, wherein L5=240mm, and the bottom surface of the lower template 8 is provided with four lower template grooves 8d which are symmetrical front to back and left to right, and the width of the lower template groove 8d is B3 and the height is H5, wherein B3=80mm, H5=70mm, and the lower template groove 8d is used to install the guide plate 11.

[0092] As a preferred embodiment of the present invention, Figure 13-14As shown, the lower mold 9 is a block that is wide at the top and narrow at the bottom. The lower mold 9 includes a lower mold cavity 9a, a lower mold support body 9b and a lower mold boss 9c.

[0093] A lower die boss 9c is arranged on the lower side of the lower die support body 9b, and the length of the lower die boss 9c is L4, the width is B0, and the height is H2, wherein L4=1500mm, B0=160mm, and H2=80mm. The lower die boss 9c is fixedly arranged inside the lower template keyway 8c, and the lower model cavity 9a is arranged on the top of the lower die support body 9b. The lower model cavity 9a is an arched structure with a low middle and upward warping at both ends. The total length of the lower model cavity 9a is L2, the height at each location is H3, and the width is B1, wherein L2=1466mm, H3=74mm, and B1=55mm. The shape and size of the lower model cavity 9a are the same as those of the upper model cavity 4a. Two stepped cylindrical holes 9f for accommodating the ejector pin 10 are symmetrically arranged inside the lower die 9, and the center distance between the two stepped cylindrical holes 9f is L5, wherein L5=240mm.

[0094] As a preferred embodiment of the present invention, Figure 18-Figure 20 As shown, the side mold 13 includes a side mold cavity 13a, a side mold support body 13b and a side mold boss 13c.

[0095] The side mold support body 13b is provided with a side mold boss 13c at the rear side, and the side mold support bodies 13b on both sides of the side mold boss 13c are closely attached to the surface of the side mold plate 14. The side mold boss 13c has a length of L7, a height of H6, and a thickness of B4, wherein L7=1000mm, H6=225mm, and B4=25mm. The side mold support body 13b is provided with a side mold cavity 13a at the front side, and the side mold cavity 13a is an arched structure with a low middle and two ends warped upward.

[0096] The side mold cavity 13a includes a side mold middle portion 13a1, a side mold neck 13a2, and a side mold extension portion 13a3.

[0097] The middle part 13a1 of the side mold is arranged at the center of the side mold cavity 13a. The middle part 13a1 of the side mold is a partially cylindrical through hole. The cross section of the middle part 13a1 of the side mold is an arc. The radius of the arc is R0, and the angle is θ2, wherein R0=39mm, θ2=90°, and the distance between the center line of the cross section arc and the upper surface is H7, wherein H7=70mm. The two sides of the middle part 13a1 of the side mold are provided with upwardly warped side mold necks 13a2, and the angle between the middle part 13a1 of the side mold and the side mold neck 13a2 is α2, and the transition circle The angle is R6, wherein α2=120°, R6=100mm, the cross section of the side mold neck 13a2 transitions from an arc shape to a plane, and a cylindrical boss 13d is provided on the side mold neck 13a2, the outer end face of the cylindrical boss 13d is a circle, the diameter of the circle is d0, wherein d0=φ28mm, the height from the end face of the cylindrical boss 13d to the upper positioning face 13f is B5, wherein B5=14.5mm, the draft taper is θ3, θ3=5°, which is used to press out the stepped blind hole 2d on the pipe neck 2b during forming.

[0098] The side mold necks 13a2 on both sides are provided with side mold extension parts 13a3 on the side away from the side mold middle part 13a1, the transition fillet radius of the center line between the side mold neck 13a2 and the side mold extension part 13a3 is R7, the angle between the center line of the side mold extension part 13a3 and the center line of the side mold middle part 13a1 is β2, wherein R7=90mm, β2=7°, the mold cavity of the side mold extension part 13a3 is two-section plane, there is an arc transition between the two sections of the plane, the radius of the arc is R8, wherein R8=23mm, the side mold extension part 13a3 is provided with a right-side mold oblique conical protrusion 13e, which is used to press out the limit block groove 2e on the hollow front axle pipe 2 of the mini truck during forming.

[0099] After pressing and closing the mold, the upper positioning surface 13f of the right side mold fits with the right side surface 4e of the upper model cavity, and the lower positioning surface 13g of the right side mold fits with the right side surface 9e of the lower model cavity; the upper positioning surface 13f of the left side mold fits with the left side surface 4d of the upper model cavity, and the lower positioning surface 13g of the left side mold fits with the left side surface 9d of the lower model cavity.

[0100] As a preferred embodiment of the present invention, Figure 21-22 As shown, the side template 14 is a rectangular plate with a length of L8, a height of H8, and a thickness of B6, wherein L8=1980mm, H8=570mm, and B6=170mm. The side template 14 includes a side template keyway 14a and a step groove 14b.

[0101] The side template keyway 14a is arranged inside the side template 14, and the length of the side template keyway 14a is L7, the height is H6, and the depth is B4, wherein L7=1000mm, H6=225mm, and B4=25mm. The side template boss 13c is fixedly arranged inside the side template keyway 14a, and the distance between the lower side surface of the side template keyway 14a and the center line of the side template 14 is H9, wherein H9=135mm. The lower part of the side template 14 is provided with a stepped groove 14b, and the height of the stepped groove 14b is H 10 , where H 10 =185mm.

[0102] The stepped groove 14b includes a lower step 14b1 and an upper groove 14b2; the upper groove 14b2 is arranged at the top of the lower step 14b1, the slide plate 12 is installed on the lower step 14b1, and the height of the lower step 14b1 is H 11 The upper portion of the guide plate 11 is disposed inside the upper groove 14b2, and the height of the upper groove 14b2 is H 12 , where H 11 =85mm, H 12 = 100mm. The upper groove 14b2 provides guidance for the side template 14 when it moves forward and backward, and the guide plate 11 contacts the slide plate 12 to reduce friction.

[0103] As a preferred embodiment of the present invention, the guide plate 11 is C-shaped, and the slide plate 12 is L-shaped.

[0104] The present invention also provides a method for pressing a die for a hollow front axle pipe with a variable cross-section for a mini truck, comprising the following steps:

[0105] Step 1. The mold is installed on a three-way hydraulic press and the preformed tube is placed;

[0106] After the upper slide, left slide and right slide of the hydraulic press return and the piece is taken out, the preformed tube blank is placed in the cavity of the fixed lower die 9 in the center;

[0107] Step 2. Feed and position the side molds 13 on both sides;

[0108] The left and right slide blocks of the hydraulic press drive the left and right side molds 13 to feed the preformed tube blank respectively. When the left and right side molds 13 and 13 contact the preformed tube blank, the left and right side molds 13 stop feeding and fix the preformed tube blank in the center.

[0109] Step 3: upper mold pressing;

[0110] The upper die 4 is fed downward to press the preformed tube blank until the upper and lower side surfaces are basically in contact with the cavities of the upper die 4 and the lower die 9. The upper die 4 stops moving after being fed to the set position.

[0111] Step 4. The left side mold and the right side mold are pressed oppositely;

[0112] After the upper mold 4 stops feeding, the left side mold 13 and the right side mold 13 start to feed in the center until the upper and lower positioning surfaces of the left side mold 13 and the right side mold 13 fit the side surfaces of the upper and lower mold cavities respectively, and the left and right slide blocks of the hydraulic press stop feeding;

[0113] Step 5. The left side mold, the right side mold and the upper mold return and take out the parts;

[0114] The upper die 4, the left side die 13 and the right side die 13 are driven by the hydraulic press slide to return respectively, and the formed blank remains in the cavity of the lower die 9; the ejector 10 moves upward to eject the pressed blank, which is taken out by the removal mechanism, and then the ejector cylinder returns.

[0115] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art can still adjust the technical solutions described in the above embodiments or replace some of the technical features by equivalents. Therefore, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention is also intended to include these modifications and variations.

Claims

1. The die for pressing and forming the hollow front axle pipe with variable cross-section for mini trucks is characterized by: It comprises an upper mold plate (3), an upper mold (4), a plurality of hexagon socket screws (5), a guide sleeve (6), a guide column (7), a lower mold plate (8), a lower mold (9), a push rod (10), a guide plate (11), a slide plate (12), a side mold (13) and a side mold plate (14); The upper mold (3) is connected to the upper mold (4) by a plurality of hexagon socket screws (5), and the lower mold (8) is connected to the lower mold (9) by a plurality of hexagon socket screws (5). The upper mold (3) and the lower mold (8) have the same outer dimensions. The side mold (13) is an arched structure with high sides and low middle. The side mold (13) is arranged on both sides of the upper mold (4) and the lower mold (9). The side mold (14) is arranged on the outside of the side mold (13), and the side mold (14) is connected to the side mold (13); The upper mold plate (3) and the lower mold plate (8) are guided by a guide sleeve (6) provided on the upper mold plate (3) and a guide column (7) provided on the lower mold plate (8); the side mold plate (14) slides on the lower mold plate (8) through a guide plate (11) and a slide plate (12); and the upper part of the ejector rod (10) enters the interior of the lower mold (9) through the lower mold plate (8).

2. The mini truck variable cross-section hollow front axle pipe pressing and forming die according to claim 1, characterized in that: The upper template (3) comprises an upper template plate body (3a), an upper template boss (3b) and an upper template keyway (3c); The upper template plate body (3a) is a rectangular plate, and upper template bosses (3b) are respectively arranged at both ends of the bottom of the upper template plate body (3a), a hole for installing a guide sleeve (6) is opened at the center of the upper template boss (3b), and an upper template keyway (3c) is arranged at the center of the upper template plate body (3a).

3. The mini truck variable cross-section hollow front axle pipe pressing and forming die according to claim 2, characterized in that: The upper mold (4) is a block that is wide at the top and narrow at the bottom, and comprises an upper mold cavity (4a), an upper mold support body (4b) and an upper mold boss (4c); An upper die boss (4c) is arranged on the upper side of the upper die support body (4b), and the upper die boss (4c) is fixedly arranged inside the upper die plate keyway (3c); the upper die cavity (4a) is arranged at the bottom of the upper die support body (4b), and the upper die cavity (4a) is an arched structure with a low middle and two ends warped upward; The upper mold cavity (4a) comprises an upper mold middle portion (4a1), an upper mold neck (4a2) and an upper mold extension portion (4a3); The middle part (4a1) of the upper mold is arranged at the center of the upper mold cavity (4a); the middle part (4a1) of the upper mold is a partially cylindrical through hole; the cross section of the cavity of the middle part (4a1) of the upper mold is an arc; upper mold necks (4a2) that are bent upward are arranged on both sides of the middle part (4a1); the cross section of the upper mold necks (4a2) transitions from an arc to a plane; upper mold extension parts (4a3) are arranged on the side of the upper mold necks (4a2) on both sides away from the middle part (4a1) of the upper mold; and the cavity of the upper mold extension parts (4a3) is a plane.

4. The mini truck variable cross-section hollow front axle pipe pressing and forming die according to claim 3, characterized in that: The lower template (8) comprises a lower template plate body (8a), a lower template boss (8b), a lower template keyway (8c) and a lower template groove (8d); The lower template plate body (8a) is a rectangular plate, and lower template bosses (8b) are respectively arranged at the two ends of the top of the lower template plate body (8a), and a hole for installing the guide column (7) is opened at the center of the lower template boss (8b). A lower template keyway (8c) is arranged at the center of the lower template plate body (8a), and two cylindrical through holes for accommodating the push rod (10) are symmetrically arranged inside the lower template keyway (8c). The bottom surface of the lower template (8) is provided with four lower template grooves (8d) symmetrically arranged in front, back, left and right directions, and the lower template grooves (8d) are used to install the guide plate (11).

5. The mini truck variable cross-section hollow front axle pipe pressing and forming die according to claim 4, characterized in that: The lower mold (9) is a block body that is wide at the top and narrow at the bottom, and comprises a lower mold cavity (9a), a lower mold support body (9b) and a lower mold boss (9c); A lower die boss (9c) is arranged on the lower side of the lower die support body (9b), and the lower die boss (9c) is fixedly arranged inside the lower die plate keyway (8c). The lower mold cavity (9a) is arranged on the top of the lower die support body (9b). The lower mold cavity (9a) is an arched structure with a low middle and two ends bent upward. The shape and size of the lower mold cavity (9a) are the same as those of the upper mold cavity (4a). Two stepped cylindrical holes (9f) for accommodating ejector pins (10) are symmetrically arranged inside the lower die (9).

6. The mini truck variable cross-section hollow front axle pipe pressing and forming die according to claim 5, characterized in that: The side mold (13) comprises a side mold cavity (13a), a side mold support body (13b) and a side mold boss (13c); A side mold boss (13c) is arranged on the rear side of the side mold support body (13b), and a side mold cavity (13a) is arranged on the front side of the side mold support body (13b). The side mold cavity (13a) is an arched structure with a low middle and two ends warped upwards. The side mold cavity (13a) comprises a side mold middle portion (13a1), a side mold bent neck (13a2), and a side mold extension portion (13a3); the side mold middle portion (13a1) is arranged at the center of the side mold cavity (13a); the side mold middle portion (13a1) is a partially cylindrical through hole; the cross section of the side mold middle portion (13a1) is an arc; upwardly curved side mold bent necks (13a2) are arranged on both sides of the side mold middle portion (13a1); the cross section of the side mold bent neck (13a2) transitions from an arc shape to a plane; a columnar boss (13d) is arranged on the side mold bent neck (13a2); and the outer end surface of the columnar boss (13d) is a circle; A side mold extension part (13a3) is provided on the side of the side mold bending neck (13a2) away from the side mold middle part (13a1), the mold cavity of the side mold extension part (13a3) is two-section plane, and there is an arc surface transition between the two sections of the plane, and a right side mold oblique cone protrusion (13e) is provided on the side mold extension part (13a3).

7. The mini truck variable cross-section hollow front axle pipe pressing and forming die according to claim 6, characterized in that: The side template (14) is a rectangular plate, and the side template (14) comprises a side template keyway (14a) and a stepped groove (14b), wherein the side template keyway (14a) is arranged inside the side template (14), the side template boss (13c) is fixedly arranged inside the side template keyway (14a), and the lower part of the side template (14) is provided with a stepped groove (14b); The stepped groove (14b) comprises a lower step (14b1) and an upper groove (14b2), wherein the upper groove (14b2) is arranged at the top of the lower step (14b1), the slide plate (12) is mounted on the lower step (14b1), and the upper part of the guide plate (11) is arranged inside the upper groove (14b2).

8. The mini truck variable cross-section hollow front axle pipe pressing and forming die according to claim 7, characterized in that: The guide plate (11) is C-shaped, and the slide plate (12) is L-shaped.

9. A method for forming a die for a hollow front axle pipe with a variable cross-section for a mini truck, characterized in that: The following steps are involved: Step 1. The mold is installed on a three-way hydraulic press and the preformed tube is placed; After the upper slide, left slide and right slide of the hydraulic press have returned and the piece has been taken out, the preformed tube blank is placed in the cavity of the fixed lower die (9) in a centered manner; Step 2. Feed and position the side molds (13) on both sides; The left and right slide blocks of the hydraulic press respectively drive the left side mold (13) and the right side mold (13) to feed toward the preformed tube blank. When the left side mold (13) and the right side mold (13) contact the preformed tube blank, the feeding is stopped to center and fix the preformed tube blank. Step 3: upper mold pressing; The upper die (4) is fed downward to press the preformed tube blank until the upper and lower side surfaces are substantially in contact with the cavities of the upper die (4) and the lower die (9), and the upper die (4) stops moving after being fed to a set position; Step 4. The left side mold and the right side mold are pressed oppositely; After the upper mold (4) stops feeding, the left side mold (13) and the right side mold (13) start to feed in a centering manner until the upper and lower positioning surfaces of the left side mold (13) and the right side mold (13) are respectively fitted with the side surfaces of the upper and lower mold cavities, and the left and right slide blocks of the hydraulic press stop feeding; Step 5. The left side mold, the right side mold and the upper mold return and take out the parts; The upper die (4), the left side die (13) and the right side die (13) are driven by the hydraulic press slide to return respectively, and the formed blank remains in the cavity of the lower die (9); the ejector rod (10) moves upward to eject the pressed blank, which is taken out by the take-out mechanism, and then the ejector cylinder returns.

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