CN101529118A - Tubular tapered crushable structures and manufacturing methods - Google Patents

Abstract

The present invention discloses a method includes steps of providing round tubing, providing a compression box and wedging dies, and reshaping the round tubing into a single or double-tapered rectangular tube including using the compression box to control an outside shape, while using the wedging dies to force material of the tubing outwardly toward the compression box. This arrangement minimizes material thinning. A tubular crushable structure is produced that is designed for longitudinal impact-energy-absorbing capability. The crushable structure includes a single or double-tapered rectangular tube made of material having a tensile strength of at least 40 KSI. In a narrower form the tensile strength is at least 80 KSI, though it can be 100 KSI or higher.

Description

Tubular tapered crushable structures and manufacture method

The cross reference of related application

[0001] the application requires to enjoy the provisional application No.60/863 that is entitled as " tubular tapered crushable structures and manufacture method " that submitted on October 30th, 2006,488 right according to 35U.S.C. § 1.19 (e).

Technical field

[0002] but the present invention relates to a kind of for example conquassation (crushable) structure of the power absorption during vehicle collision and energy management that is configured for.

Background technique

[0003] vehicle component is designed to reduce property loss and provide safety to the occupant of the vehicle that is impacted by energy management.This typically realizes by being designed for vehicle component measurable and repeatably distortion.In low speed impact, be designed to when being impacted to absorb big energy via the distortion of these parts such as the parts of bumper and bumper holder.For higher-speed impacts, vehicle chassis is designed to absorb energy by distortion.Side impact also uses the deformable component such as bottom girder, rocker panel, post and car door crash beam.In side impact components and those main difference between the front portion of vehicle or the parts on the rear portion is how they are designed to absorb energy via distortion.Side impact components absorbs energy via the distortion that is associated with the lateral bending musical form alteration of form of these parts.Front and rear parts such as bumper holder and vehicle chassis component are designed to along the direction parallel with impact force with collapsible mode conquassation.Forwardly with rear impacts in, collision occur in the vehicle of motion and the object (wall, obstacle, pillar, tree etc.) fixed between or between the vehicle of two motions.Impact energy is because speed and crash dynamics and normally high.Vehicle chassis component must with measurable and repeatably mode be out of shape safety to be provided to the occupant and to reduce property loss.

[0004] dissimilar parts destroy according to energy and how to absorb and will produce different response curves and efficiency change degree.Impact energy absorption multiplies each other by the impact stroke that makes impact resistance power and parts and calculates.Parts with efficient energy absorption illustrate generally to absorb the parts of the energy of the maximum flow of expecting continuously on the range distance of expectation.Tubular structure in flexing when being impacted near axial direction has absorbed energy, but is not to have absorbed energy in very effective mode.If pipe self is folded up in collapsible mode, then will be more effective response.The foldable type distortion provides the power absorption of maximum flow in the packaging space that is provided with.Parts after the final distortion show as the stack material in minimum package space.But illustrated invention is a kind of conquassation tubular structure in this article, but described conquassation tubular structure will self subside in collapsible mode when being impacted near axial direction.This invention design can be used for such as the less application of bumper holder in proportion or be used for bigger application such as vehicle chassis component.

[0005] it is not novel being used for the two the use of tubular structure of vehicle chassis component and/or bumper holder.The tubular structure of these types has been used on the multiple parts that spread all over vehicle.The most application of such tubular structure is not subjected to axially with protection or is consistent near axial bump.The multiple manufacture process that can produce at the tubular structure that will self subside in collapsible mode when being impacted near axial direction is arranged.Complexity that is associated with manufacture process and intrinsic cost trend towards increasing and increasing along with the energy management efficiency of design.The tubular design that can produce tube-shaped structural components and comprise hydraulic forming, carried out simple expansion and have the simple rolling forming of crush initiator by axle (mandrels) in grab bucket design of making spot-welded together, deep-draw forming, the use by two stamping part by the manufacture process that cost is arranged from high in the end.Tubular part can be handled by hydraulic forming and form the complicated shape that has along the inhomogeneous cross section of its length change, and described inhomogeneous cross section is adapted to specific needs and the characteristic such as power absorption.For example, vehicle frame often comprises the parts of hydraulic forming.Yet that hydraulic forming is handled is expensive, trouble (arranging fluid and pressure fluid then in the pipe because they are included in), and trends towards requiring long cycle time.In addition, when the material that uses such as the higher-strength of High-Strength Low-Alloy (HSLA) material and/or senior Ultrastrength Steel (AUHSS) material, because these materials are difficult to form, have the formability of low stretchability and difference and trend towards making instrument to wear and tear fast, so they become unsatisfactory usually.

[0006] expectation provide a kind of crushable structures, this crushable structures can be made by high tensile steel, still has rational cost, and will conquassation during clashing into, and has fabulous repeating and measurable result.Thereby, expect a kind of similarly have above-mentioned advantage and the parts that address the above problem and manufacturing equipment and method.

Summary of the invention

[0007] in one aspect of the invention, a kind ofly be formed for that the method for endergonic axial crushable structures comprises during axial impact: provide one section tubing; Compression box and wedging mould are provided; And tubing is positioned in the compression box, and the wedging mould is positioned in the tubing at least in part.At least a portion of tubing is shaped to the taper polygonal tubular form with non-circular cross sections again, is included in when using the wedging mould that the material of tubing outwards is pressed into to engage with compression box, uses compression box to control profile.

[0008] in another aspect of this invention in, a kind of tubulose crushable structures is that the longitudinal impact energy absorption capability designs.Crushable structures comprises the polygonal pipe of the second non-tapering part that has tapering part and aim at this tapering part.This pipe is by the tensile strength with 40KSI at least and have along the material of the substantially invariable wall thickness of its whole length and make.

[0009] in another aspect of this invention in, a kind of tubulose crushable structures is that the longitudinal impact energy absorption capability designs.Crushable structures comprises the polygonal pipe, and this polygonal pipe has taper polygonal part and non-tapering part, and has along the substantially invariable wall thickness of its whole length.

[0010] those skilled in the art will understand and understand of the present invention aspect these and other, purpose and feature behind following specification, claim and the accompanying drawing in study.

Description of drawings

[0011] Fig. 1 is the perspective view that has the raw material tubing parts of constant cross-section and be used as the tubulose double-tapered rectangular tube parts of finishing of buffer conquassation tower;

[0012] Fig. 2 is the perspective view that is used to form the taper die of raw material tubing parts;

[0013] Fig. 3 is the perspective view that is used for the straight section guide tube that uses with taper die;

[0014] Fig. 4 is the perspective view that is used for the circular pipe parts are shifted onto the promotion neck ring of taper die;

[0015] Fig. 5 a is the perspective view of the biconial circular pipe that forms from raw material tubing parts, and Fig. 5 b is the double-tapered rectangular tube parts of being made by the pipe of Fig. 5 a, and Fig. 5 c and 5d are the end elevations of Fig. 5 a and 5b;

[0016] Fig. 6 is the perspective view of axle group, and Fig. 6 a and 6b are respectively the perspective views of outer axle and interior axle;

[0017] Fig. 7 is the perspective view of compression box, and this compression box can be used from the double-tapered rectangular tube parts of Fig. 5 b with the axle one of Fig. 6 a and 6b;

[0018] Fig. 8 is the perspective view with biconial rectangular member of finishing of crush initiator.

Embodiment

[0019] this notion combines the low-cost manufacture process of standard of the pipe of producing high-strength material, the pipe of described high-strength material will produce the light-weight parts with the amount of deflection of forcing response when being subjected near axial bump, and this is with to handle the parts that produced by expensive hydraulic forming similar.The notion of the present invention that proposes is based on making circular pipe form the ability of biconial rectangular member again.Crush initiator is given the biconial rectangular member on strategy during the manufacture process.Here the article that comprises will concentrate on the biconial rectangular design, but it should be noted that this notion and manufacture process can be used in arbitrary tubular part that the polygonal shape on limit is arranged.Should be apparent that for the arbitrary technician in the sector the manufacture process that is limited in this article has overcome and the restriction that straight constant geometry is formed again the common material that difform biconial geometrical shape is associated.

[0020] the notion utilization of the present invention of Ti Chuing with as the benefit of the rational qualitative correlation connection of higher building of these materials of structural steel, High-Strength Low-Alloy (HSLA) steel and senior Ultrastrength Steel (AUHSS) and the formability that overcomes these materials limit.In this article, when the multiple steel of our references, our limiting structure steel is as the material with at least about 40KSI or higher tensile strength, High-Strength Low-Alloy (HSLA) steel is as the material that has at least about 80KSI or higher tensile strength, and senior Ultrastrength Steel (AUHSS) is as the material with at least about 100KSI or higher tensile strength.The higher physical property that is associated with these materials provides better energy to absorb between deformation phases, and allows the thickness specification to reduce to obtain the performance with the rudimentary materials similar of thicker specification.The ability that the thickness specification is reduced and keep performance shows as and partly reduces cost and reduce unit price potentially.The important shortcoming that use has the material of higher physical property is that the material with higher physical property has also reduced formability when physical property becomes higher.When surrender and tensile strength increase, specific elongation reduces and the formability reduction of material then.Notion of the present invention has overcome the formability restriction that is associated with the material that uses higher physical property, and the performance of the chance that the reduces material specification materials similar to obtain and can easier formation is provided.

[0021] following process overcomes explanation with the formability problem of using more senior material to be associated with from the necessary step of pipe of the circular pipe production double-tapered rectangular shape of shaping again.By term " biconial ", our meaning is a kind of pipe with first tapering part and different second portion (can be taper or non-taper).For purpose of illustration, commercially available circular drawing axle (Drawn-Over Mandrel) (DOM) will be formed again to produce double-tapered rectangular tube.The DOM pipe is owing to the extra hardening step that is associated with the DOM process has the physical property that is higher than those physical propertys that are associated with the pipe of resistance welding (ERW).The DOM material that is used for this example has following physical property: yield strength=67.021psi, tensile strength=83.775psi, and 0.2% specific elongation=12.65%.Use has about 24 inches of the length of the DOM tubing of 4.75 inches external diameters and pipe.These physical propertys meet structural steel and HSLA steel.

[0022] initial round tubular parts 20 (being also referred to as " circular pipe ") at this (Fig. 1) in, the outside dimension of DOM tubing be designed so that with the girth of the big end of the double-tapered rectangular tube 20B that finishes of part relatively the time circumferential size of this pipe slightly little.The double-tapered rectangular tube 20B that finishes of part has double-tapered rectangular shape, comprises have first taper first rectangle part and second rectangle part (referring to Fig. 1) with second different tapers of (perhaps not having taper).The circular pipe outside dimension is designed to allow the require girth of a certain less expansion with the big end that obtains the biconial rectangle by this way.Again form and inflation process general specific definition in the paragraph in the back.It is minimum to reduce the stress on the material that swell increment from the circle to the rectangle will keep.Expectation is used for the formability of reduction of more advanced material of deformable energy management components of these types and opinion, it is important keeping minimum the expansion.

[0023] circular DOM tubing 20 is forced into (Fig. 2) in the taper die 25.This mould is made and can be produced on lathe by Chilled Hardened Steel.Mould 25 is made in section 26 and 27 easy processing to be provided and also to provide flexibility aspect change angle of taper and the taper depth.Collide the care that (column bucking) is associated if exist when circular pipe 20 is forced into (Fig. 3) in the main mould 25 of taper with the post of circular pipe 20, then the straight section 28 of mould 25 can be used for circular pipe 20 is guided and supported to the tapered end of main mould 25.For this specific example, the straight section 28 of guiding and supporting circular pipe 20 is unnecessary, and therefore is not used in DOM tubing.

[0024] developed special promotion neck ring 29 (Fig. 4), it is engaged in the inside of circular pipe 20, shifts promoting load when being forced in the taper die 25 at tubing 20 to the outward edge of tubing 20.Circular pipe 20 is forced in the taper die 25 (Fig. 2) by the distance consistent with the length of its expectation.End points place in being inserted into mould 25, size was slightly little when the circumference of the less tapered end of the circular pipe 20A that part is finished compared at the last girth (Fig. 5) with the small end of finishing the tapered rectangular shape in the parts 21.Present tapered round tube 20A removes from mould 25 by apply power upwards to tapered end, forces pipe 20A to return top by mould 25 in the opposite direction.It should be noted that the described mould 25 that is used to make circular pipe 20A become taper is prototype tools, and different mould structures can be more suitable for being used for a large amount of productions.

[0025] taper forming process can make one section original tube 20 increase less amount according to the amount of taper.Especially, perimeter change causes the material in these materials that are difficult to form mainly to move along the length direction of pipe 20.Under the situation of this example, pipe 20A increases about 0.25 inch.The amount that the length of pipe 20A increases depends on type of material, material thickness and the amount that gives the taper on the mother tube 20.Can increase a little aspect the thickness of circular pipe 20A, yet this varied in thickness is not thought significantly.If exist a certain thickness to increase, the place, end of the circular pipe of the taper that is increased in the experience maximum flow of thickness is the most tangible (referring to Fig. 5, diameter " a ").In fact specific elongation at taper shaping circular pipe 20A makes the amount that the some place varied in thickness of maximum taper takes place on pipe reduce to minimum.For the example here, the material thickness of locating in the end of taper has only increased about 0.009 inch.Average material thickness in this and about 0.132 inch this example relatively, varied in thickness is less than 7%.Also it should be noted that for being used for the material that this notion is advised, be used in this example typically+/-0.005 inch as the material thickness variation of the roll coil of strip storage of generally acknowledging, or about 4%.Therefore, only 7% material thickness variation is thought inapparent in this example.For this discussion, be considered to along the substantially invariable wall thickness of the whole length of conical pipe along about 7% or still less material thickness variation of one section pipe.

[0026] the circular pipe 20A of taper prepares to be used for shaping again now.The present preparation of circular pipe 20A of taper is shaped to biconial rectangle 20B again.Again shaping and a certain less expansion realize shaping process again purely by combination.Expansion will be held in minimum, with the integrity of the wall thickness of keeping pipe.Three axles 30 are used for circular pipe 20A shaping again (Fig. 6).Two parts 31 in the outside of axle 30 and 32 shapes form the short side that shows rectangle, and (Fig. 6 a).These axles 31 and 32 comprise the corner radius of the rectangular shape of finishing.The third part 33 of axle 30 is central segment (Fig. 6 b).Two axles 31 and 32 are combined together by key lock (keyed) and the central segment 33 by axle 30.The central segment 33 of axle 30 is tapers, thereby central segment 33 moves downward between two axles 31 and 32, and axle 31 and 32 trails to produce tapered rectangular mandrel 30.Fig. 6 illustrates the constant angle tapering of central segment 33, and still in fact central segment 33 and/or axle 31 and 32 can be made by the section of taper and/or the section of non-taper.

[0027] three axle 30 often can not be used to make tapered round tube 20A to be shaped to the biconial rectangle again separately because of the formation restriction of the material of expectation.Shape is changed over the needed mandrel action of rectangle from circle causes significant material attenuate just in time to leave the radius of rectangle last part potentially.When shaping methods does not again allow material when a shape flows to another shape attenuate can take place.For axle in using carries out shaping again and makes the attenuate of material reduce to minimum simultaneously, expect extra anchor clamps.Having developed compression box 35 (Fig. 7) flows during using inner three axles 31 to 33 to carry out shaping again to help material.Compression box 35 is a kind of tapered box, the shape of finishing of three side performance biconial rectangles of this box.Three sides of finishing are in two short sides of rectangle and the long side surface.Compression box 35 does not have to imitate the radius of the shape of finishing, but the overall positions of only imitating the wall of tapered rectangular.The on-fixed face 36 of compression box 35 also is one of long side surface of rectangle.This on-fixed face 36 of compression box 35 is adjusted to inwardly and against tapered round tube 20A, and axle 31 to 33 is stressed along the length of tapered round tube 20A simultaneously.Regulate the ability motion of auxiliary material with the following methods of the on-fixed face 36 of compression box 35: the round-shaped rectangular shape that is shaped to the parts of finishing 21 again that under the situation about dying down that does not have attenuate and do not expect, promotes to manage 20A.

[0028] compression box 35 has reduced the amount that needs the amount of the expansion of orthopaedic component again and reduced the material attenuate then.The amount that the expansion that reduces is carried out in expectation is necessary for the end sizing that helps tapered rectangular and for the repeatability of oppressing end geometries simultaneously.The detail design that it should be noted that illustrated compression box 35 has only illustrated a can regulate and movable surface.Yet, expect and prospect be that a plurality of sides of compression box 35 can be made for movable or regulate.In case what expect is that those skilled in the art understands this notion, then they will understand and how do.The use of a plurality of moving surfaces of compression box 35 is the motion of auxiliary material, and this can be that more complicated polygonal shape is carried out shaping again is needed.Tolerance on the surface of the shape that the movabie surfaces that increases may be finished for increase and the physical dimension of end also is necessary.

[0029] in production model, prospect be that compression box 35 can pass through hydraulic pressure, pneumatics and/or servomechanism is regulated.Prospect be being adjusted in axle 31 to 32 and when the length of circular pipe is moved, can being adjusted to and their position synchronous of the on-fixed face 36 of compression box 35.Such control will be based on closed loop control system, and wherein the location of the one side of process is used for control procedure on the other hand.

[0030] conical in shape in the parts of finishing 21 helps to promote subsiding of collapsible form when being impacted near axial direction at pipe.The repeatability of such conquassation since along loading direction change a little and along the deformation position of the length of pipe but suspicious.In order to improve the repeatability of conquassation effect, crush initiator 40 (Fig. 8) but typically increase to crushable parts.Type, layout and the number that crush initiator 40 requires often requires R﹠D work to determine optimized design.Crush initiator 40 can preferably increase to parts after net shape forms.For this example, crush initiator 40 will increase to double-tapered rectangular shape.

[0031] in production model, crush initiator 40 can use the arbitrary type in process for stamping, hydraulic pressure, the pneumatics etc. to increase.When being stamped in the parts, crush initiator 40 will more may need inner support.Prospect be that crush initiator 40 can increase to parts when the shaping axle is positioned in the parts again in inside.Inner outer axle 31,32 waits that at each the position of arranging starter 40 will need to discharge.Central mandrel 33 can be left parts and regain, and this allows two outer axles 31,32 freely from the crush initiator 40 that just in time is stamped into.In the stepping beam type production process, crush initiator 40 can increase to the parts in the independent position.It should be noted that also hole, slit etc. are in the past usually as crush initiator.The manufacture process that is associated with increase hole or slit and the crush initiator of javelin (dart) type are similar.Two types crush initiator will need the supporting member of a certain type in pipe inside, that is, and and axle, die steel etc.

[0032] below the advantage of notion of the present invention comprises at least.Parts can be diconical, described biconial be a kind of when when loading near axial direction verified himself for being very firm kind of design with subsiding of collapsible mode.Make the height formability that " construction " notion does not require to consider to use the material of High Quality Steel.Conceptual expansion of the present invention is to be the used acceptable raw steel of the application, and it comprises structural steel (having the tensile strength of 40KSI at least), High-Strength Low-Alloy (HSLA) steel (having the tensile strength of 80KSI at least) and senior Ultrastrength Steel (AUHSS) (having 100KSI or higher tensile strength at least).These acceptable material rates are much higher than those and are used for acceptable material rate such as other manufacture process of hydraulic forming and expansion.The manufacturing step that needs is not unique, and what replace is that the uniqueness of this notion is that these manufacture processes are how in conjunction with to produce these end product.Suitable material is selected to cause by making material thickness reduce specification and utilizing the higher level material to obtain parts than light weight.Can cause reducing unit price like this.

[0033] is understood that, under the prerequisite that does not break away from notion of the present invention, can on said structure, change and revise, and it should be understood that these notions are intended to cover by these claims except following claim is set forth in addition especially by their language.

The present invention requires the right of exclusiveness or the embodiment of privilege to limit in following claims.

Claims (20)

1. method that forms axial crushable structures, described axial crushable structures is used for the power absorption during the axial impact, said method comprising the steps of:

One section tubing is provided;

Compression box and wedging mould are provided;

Described tubing is positioned in the described compression box, and described wedging mould is positioned in the described tubing at least in part; And

At least a portion of described tubing is shaped to the taper polygonal tubular form with non-circular cross sections again, is included in and uses described compression box control profile when using described wedging mould to force the material of described tubing outwards to engage with described compression box.

2. method according to claim 1, wherein said wedging mould comprises crew-served axle and central segment, when described central segment axial motion, causes that described crew-served axle towards the inner surface movement of described compression box separately.

3. method according to claim 2, the internal surface of wherein said compression box and described crew-served axle comprise crush initiator are formed into structure in the wall of described tubing.

4. method according to claim 3, wherein said tubing is made by the material of the tensile strength with about at least 40KSI.

5. method according to claim 4, wherein said tubing is made by the material of the tensile strength with about at least 80KSI.

6. method according to claim 5, wherein said tubing is made by the material of the tensile strength with about at least 100KSI.

7. method according to claim 2, at least one in the internal surface of wherein said compression box is adjustable, so that limit different shapes.

8. method according to claim 1, wherein said tubing has circular cross section, and described method is included in the step that described shaping step again forms described circular pipe first polygonal shape before.

9. method according to claim 1 comprises crush initiator is formed in the described taper polygonal tubular form, the tubulose polygonal crushable structures of finishing with formation.

10. method according to claim 1, wherein said shaping step again comprise that the first portion with the described tubing of a length forms the taper polygonal shape, and the second portion of the described tubing of described length is formed non-taper polygonal shape.

11. method according to claim 1, wherein said shaping step again is included in the described tubing and forms rectangular cross section.

12. comprising by having at least approximately the material of the tensile strength of 40KSI, method according to claim 1, the wherein said step that tubing is provided make circular pipe.

13. comprising, method according to claim 1, wherein said shaping step again keep along the material thickness of described tubing less than 10% material thickness variation.

14. comprising, method according to claim 13, wherein said shaping step again keep along the material thickness of described tubing less than 7% material thickness variation.

15. method according to claim 1, wherein said shaping step again comprise material mainly along the length direction of described tubing and is not moved along the circumferencial direction of described circular pipe.

16. a tubulose crushable structures that designs for the longitudinal impact energy absorption capability, it comprises:

The polygonal pipe of the second non-tapering part that has tapering part and aim at described tapering part, described pipe are by the tensile strength with 40KSI at least and have along the single sheet material of the substantially invariable wall thickness of its whole length and make.

17. method according to claim 16, wherein said wall thickness have along its length less than 10% varied in thickness.

18. method according to claim 16, wherein said material have the tensile strength of 40KSI at least.

19. method according to claim 18, wherein said material have the tensile strength of 80KSI at least.

20. method according to claim 16, wherein said second portion have the same with described tapering part at least big circumference.

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