CA2285581A1 - Deformation element, method for its production and its use - Google Patents
Deformation element, method for its production and its use Download PDFInfo
- Publication number
- CA2285581A1 CA2285581A1 CA002285581A CA2285581A CA2285581A1 CA 2285581 A1 CA2285581 A1 CA 2285581A1 CA 002285581 A CA002285581 A CA 002285581A CA 2285581 A CA2285581 A CA 2285581A CA 2285581 A1 CA2285581 A1 CA 2285581A1
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- Prior art keywords
- deformation
- deformation element
- depression
- reinforcing
- impact
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Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
- F16F7/00—Vibration-dampers; Shock-absorbers
- F16F7/12—Vibration-dampers; Shock-absorbers using plastic deformation of members
- F16F7/123—Deformation involving a bending action, e.g. strap moving through multiple rollers, folding of members
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
- B60R21/00—Arrangements or fittings on vehicles for protecting or preventing injuries to occupants or pedestrians in case of accidents or other traffic risks
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
- B62D—MOTOR VEHICLES; TRAILERS
- B62D1/00—Steering controls, i.e. means for initiating a change of direction of the vehicle
- B62D1/02—Steering controls, i.e. means for initiating a change of direction of the vehicle vehicle-mounted
- B62D1/16—Steering columns
- B62D1/18—Steering columns yieldable or adjustable, e.g. tiltable
- B62D1/19—Steering columns yieldable or adjustable, e.g. tiltable incorporating energy-absorbing arrangements, e.g. by being yieldable or collapsible
- B62D1/192—Yieldable or collapsible columns
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Transportation (AREA)
- Body Structure For Vehicles (AREA)
- Vibration Dampers (AREA)
- Steering Controls (AREA)
- Finger-Pressure Massage (AREA)
- Non-Reversible Transmitting Devices (AREA)
- Magnetic Heads (AREA)
- Shaping Metal By Deep-Drawing, Or The Like (AREA)
Abstract
The invention concerns a deformation element for the controlled dissipation of energy with an inelastically deformable hollow part having at least one prefabricated depression (12) which acts as a predetermined buckling point when an impact having a force component in a direction perpendicular to the depression (12) is applied. The invention also concerns a method of producing this deformation element by: introducing or partially introducing into a mould a pipe which has optionally already been bent;
applying internal high pressure; removing the reshaped part and optionally subjecting it to mechanical further or after-treatment, for example by laser or by honing. The invention further concerns the use of these deformation elements as lateral reinforcement pipes for vehicles, deformation elements between vehicle bumpers and side members, steering column elements, and supports.
applying internal high pressure; removing the reshaped part and optionally subjecting it to mechanical further or after-treatment, for example by laser or by honing. The invention further concerns the use of these deformation elements as lateral reinforcement pipes for vehicles, deformation elements between vehicle bumpers and side members, steering column elements, and supports.
Description
Deformation Element Method For Its Production and Its Use The invention relates to a deformation element for the controlled dissipation of energy which impacts with a component in the direction of the longitudinal axis of the deformation element, and to a method for the production and use of such element.
Deformation elements are known, for example, from DE-A-38 36 724, DE-A-20 42 931, as well as from EP-A-0467340.
Such familiar deformation elements consisted of several parts and required high production costs, thus resulting in complicated parts and in an undesirably high weight of such parts, especially if an increased buckling strength or load capacity was required.
It is, therefore, the object of the invention to create simpler and lighter deformation elements.
The invention solves this problem by creating a deformation element for the controlled dissipation of energy with an inelastically deformable hollow part having at least one prefabricated depression which acts as a predetermined buckling point when an impact having a force component in a direction perpendicular to the depression is applied.
In doing so, impact energy is converted over a longer period into deformation energy, thus delaying the negative acceleration of the part and protecting, for example, passengers.
Furthermore, a deformation at certain predetermined areas - for example, outside a passenger space, fuel tank or engine - is rendered possible so that these sensitive areas can be safeguarded as a result thereof.
If may be preferable to provide at least one depression in an undulatory area and thus allowing the deformation element, upon impact in the direction of the deformation, to fold like bellows in the undulatory area.
However, it is also possible to provide - for example, for side members with lateral impact protection in motor vehicles - at least one depression running lengthwise. In this case such member, defined by transverse forces, is deformable whilst being resistant to longitudinal forces.
It is also possible to provide one transverse depression. This, for example, is the case with areas folded like bellows in which, upon impact, such bellows-like part folds inelastically.
It is also possible that at least one depression be stepped so that the upper area of the step slides into the lower area upon deformation.
It is also possible to construct such depressions as preformed areas in which the deformation element, upon impact with a force component, pushes together along its longitudinal axis and thus is still protected against buckling during such deformation.
The deformation elements, according to the invention, are preferably made of a cold-deformable material, which is preferably subjected to strain-hardened in the deforming process. Suitable for this purpose is, for example, steel, such as ST 34 or ST
52, ST 30, ST 40, deep-drawing cold rolled steel, light metal, aluminum, magnesium, titanium or an alloy thereof, or a fibre-reinforced material. Depending on the purpose for which it is to be used, it can also be made of suitable plastic with which the expert is familiar. The deformation element is preferably made, at least partially, of metal according to the internal high pressure method (IHM).
Frequently, a connecting section, which can be tip-stretched, is provided at least on one end of the hollow deformation element.
Especially preferred uses of the deformation elements are as lateral reinforcing pipes for motor vehicles, deformation elements between bumper bars and side members of motor vehicles, steering-column elements and supports.
Due to the fact that a deformation element is now provided in one piece, such element can be produced more easily whilst maintaining the same or having even better stress properties than the familiar parts composed of several individual components.
Furthermore, a savings in materials, in comparison to the familiar parts, can be achieved.
It is appropriate to cold-form such parts by way of the internal high pressure deformation method. Cold deformation, according to the internal high pressure method, will result in strain-hardening, which provides the element with especially advantageous strength properties. In addition, cold-forming processes are energetically advantageous and save energy.
The internal high-pressure method is well known. By internal high-pressure method, or also called IHM, is meant the method which, for example, was described in Industrial Gazette No. 20 of March 9, 1984, or also in "Metal Deformation Technique", Issue 1 D/91, Page 15 and following pages: A. Ebbinghaus: Precision Workpieces of Light-Weight Construction produced through Internal High-Pressure Deformation", or also "Material and Operation", 123 to 243: A. Ebbinghaus: "Economic Construction with Precision Workpieces produced through Internal High-Pressure Deformation", or also "Material and Operation"
122, (1991 ), 11, (1989), Pages 933 to 938. To avoid repetition, reference to the disclosure thereof will be made hereinafter to the full extent. This method has been applied up to now to produce hollow parts of various shapes as, for example, to produce built-up camshafts for attaching cams to a pipe, to produce hollow camshafts (EP-A-730705), space steering control shafts (EP-A-0814998), but also motor vehicle space frames) (EP-A-658232) or bicycle frames.
Owing to this internal high-pressure method, it is possible to produce hollow elements of metal construction which are completely new, and in which the fibres of the walls run mainly parallel to the outer contour. Due to the great wall strength resulting from the advantageous fibre flow, the hollow structural elements can, therefore, be constructed parallel to the outer contours, and strain hardening can be achieved in a lighter form than has been the case up to now, thus rendering a substantial savings in weight possible. It is also possible to use laminated materials for the mould, provided these can be deformed jointly. By selecting appropriate materials, laminates can be lighter than solid materials and have the additional advantage of absorbing vibration, or they can have other coatings on the surfaces, according to the ambient stress (corrosion due to acids, etc.) or for aesthetic reasons (colour), so that such a part has, in addition also advantageous damping characteristics.
By having the material follow along the longitudinal axis of the pipe during the deformation, for example, by way of movable mould elements, it is possible to achieve a basically uniform thickness of wall in the formed part - also when tip-stretching connecting elements - so that weaknesses of the wall thickness can be at least partially balanced by the hearing of investigations [sic]* and so that this is achieved without weakening.
It is advantageous that the length of the depression on the deformation element equals about half the diameter of the deformation element. It can be practical if its wall thickness is basically uniform across the entire deformation element.
Translator's Note: * It may be a typographical error. If it should read "Anhohung von Erhebungen", the meaning would change to "the raising of elevations".
The fact that the hollow deformation element has been provided with ribs for reinforcement may also be advantageous. This can result in a further savings of material.
If the reinforcing ribs are only constructed in the deformation area, a better reinforcement of the deformation areas will result in the longitudinal direction of the reinforcing ribs, whilst even facilitating the pushing in of the depression in case of impact.
The deformation element is preferably made, at least partially, of steel, such as ST 34 or ST 52, light metal, aluminum, titanium or an alloy thereof, or of a fibre-reinforced material.
The depression can be of symmetrical construction so that even an impact offset to the longitudinal axis of the deformation element will result in an evenly deformed element. It has proven to be practical if the area of the part which particularly serves to dissipate energy is basically hexagonal or polygonal or round, thus providing adequate resistance to buckling in one direction. The depression itself deforms upon impact so that energy can de dissipated.
If at least one depression is of asymmetrical construction, a preferred contraction of the deformation element in one direction can be effected upon impact, which is particularly important if a straight contraction of the deformation element which, for example, could lead to the deformation element entering an undesirable space upon impact, is not desirable.
In a case such as this, an asymmetrical construction of the depression - which means, for example, a shorter depression at one part of the deformation element - can be provided, which effects a preferred direction of contraction.
It is practical if a connecting section is formed at least at one end of the hollow deformation element in order to simplify the attachment of the deformation element, for example, to the side member of a motor vehicle. However, it is also possible to provide reinforcing parts, for example, metal sheets at or inside the deformation elements, which can be fastened to the latter in the customary way in order to influence the deformation behaviour through reinforcement.
The deformation element can be, for example, - naturally of corresponding dimensions and, optionally, also of appropriate material - a lateral reinforcing pipe, for example, for motor vehicles, a deformation element between vehicle bumpers and side members for all kinds of vehicles, a steering column element, etc.
It is possible that the material of the deformation element consists of several layers and that the layers are of the same or of a different material, which may be metallic or also non-metallic, plastic or ceramic. The choice of material can determine its suitability for respective realms of application. It is possible, for example, to produce a metal part that is corrosion resistant.
It can be advantageous if the outer formed part has several mating layers, running parallel to one another, which are made of the same or of different materials whose fibres run parallel to one another.
Especially for the purpose of weight savings, the entire structural part can basically consist of the same or of various light metals. The light metal, for example, can be aluminum or an alloy thereof which could be made corrosion resistant as an advantageous characteristic.
According to an advantageous method of producing hollow, shaped parts, a hollow, outer mould is produced in the customary manner by drawing, casting, extruding or by internal high-pressure deformation, which is subsequently finished by applying the familiar internal high-pressure method.
Depending on the demands made on the material, a multilayered metal pipe can also be chosen as the initial part. Multilayered designs have the advantage that the surface of the hollow part is subjected to variable stress and that vibrations of any kind are more difficult to guide, which in turn decisively improves the vibration characteristics of the hollow part when used.
In most cases the deformation element is produced by: introducing or partially introducing a pipe into a mould; applying internal high pressure and removing the reshaped part.
Such part, of course, can be subjected to mechanical further or after-treatment, such as hammering, deep-drawing, honing, laser-hardening, etc., - preferably worked by way of cold-deforming methods - in order not to influence the strain-hardening of the structure when deforming according to the internal high-pressure method. The part can also be further treated by laser, by chopping or sawing.
The pipe section can also be preformed prior to the internal high-pressure deformation, for example, by bending, etc, or also through a separate internal high-pressure predeformation step in which a preform would be produced which would be further treated in at least one further internal high-pressure processing step.
It may be practical to insert reinforcing elements into the deformation element, or to attach to the deformation element reinforcing elements, such as metal sheets, pipe sections, etc., which might be attached only by way of a mating fit. However, they can also be attached according to familiar methods such as bonding, welding, soldering or bolting, etc.
The reinforcing element can also be a foam part made, for example, of metal foam, such as aluminum foam or also of plastic foam, which is inserted either as a finished foam body, fastened inside the deformation element, or, however, by producing within the deformation element a foam filling, consisting at least partially of metal or plastic foam, by way of frothing the foam starting material inside the deformation element.
Due to the application of the internal high-pressure deformation method, it is possible to produce already in one forming procedure elevations and depressions, screw threads, openings, etc. at the outer hollow part. This makes it possible to reduce reworking steps.
Variable hollow sections, such as rectangular sections, angle section, pipes, etc. can be used as hollow parts.
Thus, a part is created which, compared to previous parts, weighs less, whilst the load capacity is the same, or whilst the load capacity is higher at a low weight and which, in addition, can be manufactured at high production accuracy with a reduced scrap percentage rate.
The invention is explained below in greater detail, based on the attached drawings which show the following:
Fig. 1 is a perspective view of a form of construction of the deformation element, according to the invention.
Fig. 2 is a longitudinal view of the deformation element, as shown in Fig. 1.
Fig. 3 is a perspective view of a deformation element with longitudinal ribs, according to the invention, and Fig. 4 is a perspective view of a deformation element, according to the invention, which has partially been provided with longitudinal ribs.
Fig. 5 shows a longitudinal cross section of the wall of a deformation element, deformed through impact.
Fig.6 is a force/energy-dissipating diagram of the deformation element, shown in Fig. 4, upon an experimental impact.
Fig.
7a, b, c, d show another form of construction of a deformation element in which the deformation occurs outside the longitudinal or transverse axis.
Fig. 8 shows a part which protects a motor-vehicle door against lateral impact, and Fig. 9 shows another part protecting against lateral impact.
As can be ascertained from Fig. 1 and 2, which show the same structural part in longitudinal and cross-section, respectively, a deformation element, according to the invention, consists of a steel pipe, as a preferred form of construction. The steel pipe was tridimensionally reshaped by applying the internal high-pressure method. What is meant by pipe here is any elongated body which does not have to be round in cross-section.
It should be noted that in parts, produced according to the deformation method, - the deformation element - purposely moulded grooves/depressions (12) are constructed in certain areas of the pipe in order to weaken the element (10) later on at certain points, so that predetermined deformation points are created there.
The hollow sections of the structural element can vary in diameter along their length, as well as in cross-section.
Fig. 3 shows another form of application of an element, according to the invention. It concerns here a structural element which has been provided with longitudinal ribs (16) on its periphery. Since such ribbed form elements (16) produce a reinforcing effect in the longitudinal direction, a further savings in weight, whilst maintaining the same mechanical behaviour upon impact in the longitudinal direction, can be achieved The direction of impact for which the deformation element has been mainly designed (direction of maximum energy absorption) is generally marked on the drawings as "yo" or as "direction of motion".
A preferred deformation element which can be used as impact deflector for passenger cars, is made of ST 34 or ST 52 or of a material with similar properties. Said element has a wall thickness of about 1.2 to 3 mm, a diameter of 8 to 12 cm, and a length of the depression ranging between 5 and 15 cm.
Fig. 4 shows a structural element, according to the invention, which has been provided only partially with longitudinal ribs (18, 20) in the areas which should deform upon impact. Thus, the buckling behaviour can be controlled further so that a deformation occurs only in the deformation depression (12).
Fig. 5 shows a longitudinal section of a deformed wall of a structural element, according to the invention, which was produced through impact along the longitudinal axis of the deformation element (10). Shown here is the desired folding in the area of the depression (12) whilst the other areas (6, 8) of the deformation element remain practically undeformed.
Fig. 6 shows the force/energy dissipating diagram of a form of construction of the deformation element, according to the invention (experiment as shown in Fig.
5). It becomes apparent that the force exerted on the vehicle by the deformation of the deformation element by a predetermined stretch "s" is absorbed and dissipated without any special peaks of force. Although a passenger in a vehicle equipped with such deformation element will be subjected upon impact to a force as a result of the negative acceleration upon impact, such force, however, will be built up relatively very much slower and does not result in the feared, very high forces of short duration which lead to the most serious injuries.
Fig. 7a, b, c, d show another form of construction of a deformation element in which the deformation occurs beyond the direction of the longitudinal or traverse axis.
At part of a support, which is bent approximately at right angles, a deformation element area is moulded on an angle leg. Upon impact in direction "yo" (in the direction of such angle leg), such angle leg will fold together, whilst the other support is reinforced against deformation in direction "yo" by means of moulded transverse sections. Owing to this design, deformation of the bent deformation element will occur only in one area of the part, whilst the other areas are reinforced against deformation by way of respective construction. Such part is suitable, for example, as a support part for a bumper which can be attached to the carrier shaft.
Fig. 8 a, b, c show a support part for a motor vehicle. Such part has in selected areas longitudinal depressions at which it controls its cross-section and reduces it upon impact with a transverse component.* In other areas it is reinforced against transverse deformation in the transverse direction by way of formed elevations. By moulding preferable areas, via a part in one piece, it is possible to achieve a variable behaviour of the part to the effects of force.
Fig. 9 shows a part which protects a door from lateral impact. Such part also has longitudinal depressions, which definitely anticipate the deformation of the part upon lateral impact in this area. Transverse sections have been provided against deformation vertically to the impact axis "yo", as well as a built-in reinforcement plate which serves to further reinforce the part against undesirable deformations in the end area.
Translator's Note: * The meaning of the sentence is not clearly expressed in German.
Due to the geometric design of the deformation element, it is possible, according to the invention, to achieve the desired energy-dissipating behaviour, by using considerably lighter and simpler deformation elements, which has not been possible up to now.
The hollow formed parts can be made of a single material, for example, steel or a light metal alloy. However, it is also possible, depending on the case-hardening method * used in each case, to reshape laminated material, as well as plastic coated pipes, depending on the purpose for which they are to be used.
By providing respective layers, it is possible to achieve corrosion resistance or also colouring without further work protection becoming necessary.
Due to the fact that reinforcing parts can also be attached to and within the deformation elements, for example, through bolting, riveting, welding, inserting into a mating fit or mating form, etc., a further reinforcement against deformation, and even in-preferred areas, can be accomplished.
Other forms of construction and further developments will be obvious to the expert within the protective scope of the claims. The scope of protection is in no way limited to the specific embodiments cited by way of example here, because they are intended for explanatory purposes only.
Translator's Note: * Can also mean "method used".
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Deformation elements are known, for example, from DE-A-38 36 724, DE-A-20 42 931, as well as from EP-A-0467340.
Such familiar deformation elements consisted of several parts and required high production costs, thus resulting in complicated parts and in an undesirably high weight of such parts, especially if an increased buckling strength or load capacity was required.
It is, therefore, the object of the invention to create simpler and lighter deformation elements.
The invention solves this problem by creating a deformation element for the controlled dissipation of energy with an inelastically deformable hollow part having at least one prefabricated depression which acts as a predetermined buckling point when an impact having a force component in a direction perpendicular to the depression is applied.
In doing so, impact energy is converted over a longer period into deformation energy, thus delaying the negative acceleration of the part and protecting, for example, passengers.
Furthermore, a deformation at certain predetermined areas - for example, outside a passenger space, fuel tank or engine - is rendered possible so that these sensitive areas can be safeguarded as a result thereof.
If may be preferable to provide at least one depression in an undulatory area and thus allowing the deformation element, upon impact in the direction of the deformation, to fold like bellows in the undulatory area.
However, it is also possible to provide - for example, for side members with lateral impact protection in motor vehicles - at least one depression running lengthwise. In this case such member, defined by transverse forces, is deformable whilst being resistant to longitudinal forces.
It is also possible to provide one transverse depression. This, for example, is the case with areas folded like bellows in which, upon impact, such bellows-like part folds inelastically.
It is also possible that at least one depression be stepped so that the upper area of the step slides into the lower area upon deformation.
It is also possible to construct such depressions as preformed areas in which the deformation element, upon impact with a force component, pushes together along its longitudinal axis and thus is still protected against buckling during such deformation.
The deformation elements, according to the invention, are preferably made of a cold-deformable material, which is preferably subjected to strain-hardened in the deforming process. Suitable for this purpose is, for example, steel, such as ST 34 or ST
52, ST 30, ST 40, deep-drawing cold rolled steel, light metal, aluminum, magnesium, titanium or an alloy thereof, or a fibre-reinforced material. Depending on the purpose for which it is to be used, it can also be made of suitable plastic with which the expert is familiar. The deformation element is preferably made, at least partially, of metal according to the internal high pressure method (IHM).
Frequently, a connecting section, which can be tip-stretched, is provided at least on one end of the hollow deformation element.
Especially preferred uses of the deformation elements are as lateral reinforcing pipes for motor vehicles, deformation elements between bumper bars and side members of motor vehicles, steering-column elements and supports.
Due to the fact that a deformation element is now provided in one piece, such element can be produced more easily whilst maintaining the same or having even better stress properties than the familiar parts composed of several individual components.
Furthermore, a savings in materials, in comparison to the familiar parts, can be achieved.
It is appropriate to cold-form such parts by way of the internal high pressure deformation method. Cold deformation, according to the internal high pressure method, will result in strain-hardening, which provides the element with especially advantageous strength properties. In addition, cold-forming processes are energetically advantageous and save energy.
The internal high-pressure method is well known. By internal high-pressure method, or also called IHM, is meant the method which, for example, was described in Industrial Gazette No. 20 of March 9, 1984, or also in "Metal Deformation Technique", Issue 1 D/91, Page 15 and following pages: A. Ebbinghaus: Precision Workpieces of Light-Weight Construction produced through Internal High-Pressure Deformation", or also "Material and Operation", 123 to 243: A. Ebbinghaus: "Economic Construction with Precision Workpieces produced through Internal High-Pressure Deformation", or also "Material and Operation"
122, (1991 ), 11, (1989), Pages 933 to 938. To avoid repetition, reference to the disclosure thereof will be made hereinafter to the full extent. This method has been applied up to now to produce hollow parts of various shapes as, for example, to produce built-up camshafts for attaching cams to a pipe, to produce hollow camshafts (EP-A-730705), space steering control shafts (EP-A-0814998), but also motor vehicle space frames) (EP-A-658232) or bicycle frames.
Owing to this internal high-pressure method, it is possible to produce hollow elements of metal construction which are completely new, and in which the fibres of the walls run mainly parallel to the outer contour. Due to the great wall strength resulting from the advantageous fibre flow, the hollow structural elements can, therefore, be constructed parallel to the outer contours, and strain hardening can be achieved in a lighter form than has been the case up to now, thus rendering a substantial savings in weight possible. It is also possible to use laminated materials for the mould, provided these can be deformed jointly. By selecting appropriate materials, laminates can be lighter than solid materials and have the additional advantage of absorbing vibration, or they can have other coatings on the surfaces, according to the ambient stress (corrosion due to acids, etc.) or for aesthetic reasons (colour), so that such a part has, in addition also advantageous damping characteristics.
By having the material follow along the longitudinal axis of the pipe during the deformation, for example, by way of movable mould elements, it is possible to achieve a basically uniform thickness of wall in the formed part - also when tip-stretching connecting elements - so that weaknesses of the wall thickness can be at least partially balanced by the hearing of investigations [sic]* and so that this is achieved without weakening.
It is advantageous that the length of the depression on the deformation element equals about half the diameter of the deformation element. It can be practical if its wall thickness is basically uniform across the entire deformation element.
Translator's Note: * It may be a typographical error. If it should read "Anhohung von Erhebungen", the meaning would change to "the raising of elevations".
The fact that the hollow deformation element has been provided with ribs for reinforcement may also be advantageous. This can result in a further savings of material.
If the reinforcing ribs are only constructed in the deformation area, a better reinforcement of the deformation areas will result in the longitudinal direction of the reinforcing ribs, whilst even facilitating the pushing in of the depression in case of impact.
The deformation element is preferably made, at least partially, of steel, such as ST 34 or ST 52, light metal, aluminum, titanium or an alloy thereof, or of a fibre-reinforced material.
The depression can be of symmetrical construction so that even an impact offset to the longitudinal axis of the deformation element will result in an evenly deformed element. It has proven to be practical if the area of the part which particularly serves to dissipate energy is basically hexagonal or polygonal or round, thus providing adequate resistance to buckling in one direction. The depression itself deforms upon impact so that energy can de dissipated.
If at least one depression is of asymmetrical construction, a preferred contraction of the deformation element in one direction can be effected upon impact, which is particularly important if a straight contraction of the deformation element which, for example, could lead to the deformation element entering an undesirable space upon impact, is not desirable.
In a case such as this, an asymmetrical construction of the depression - which means, for example, a shorter depression at one part of the deformation element - can be provided, which effects a preferred direction of contraction.
It is practical if a connecting section is formed at least at one end of the hollow deformation element in order to simplify the attachment of the deformation element, for example, to the side member of a motor vehicle. However, it is also possible to provide reinforcing parts, for example, metal sheets at or inside the deformation elements, which can be fastened to the latter in the customary way in order to influence the deformation behaviour through reinforcement.
The deformation element can be, for example, - naturally of corresponding dimensions and, optionally, also of appropriate material - a lateral reinforcing pipe, for example, for motor vehicles, a deformation element between vehicle bumpers and side members for all kinds of vehicles, a steering column element, etc.
It is possible that the material of the deformation element consists of several layers and that the layers are of the same or of a different material, which may be metallic or also non-metallic, plastic or ceramic. The choice of material can determine its suitability for respective realms of application. It is possible, for example, to produce a metal part that is corrosion resistant.
It can be advantageous if the outer formed part has several mating layers, running parallel to one another, which are made of the same or of different materials whose fibres run parallel to one another.
Especially for the purpose of weight savings, the entire structural part can basically consist of the same or of various light metals. The light metal, for example, can be aluminum or an alloy thereof which could be made corrosion resistant as an advantageous characteristic.
According to an advantageous method of producing hollow, shaped parts, a hollow, outer mould is produced in the customary manner by drawing, casting, extruding or by internal high-pressure deformation, which is subsequently finished by applying the familiar internal high-pressure method.
Depending on the demands made on the material, a multilayered metal pipe can also be chosen as the initial part. Multilayered designs have the advantage that the surface of the hollow part is subjected to variable stress and that vibrations of any kind are more difficult to guide, which in turn decisively improves the vibration characteristics of the hollow part when used.
In most cases the deformation element is produced by: introducing or partially introducing a pipe into a mould; applying internal high pressure and removing the reshaped part.
Such part, of course, can be subjected to mechanical further or after-treatment, such as hammering, deep-drawing, honing, laser-hardening, etc., - preferably worked by way of cold-deforming methods - in order not to influence the strain-hardening of the structure when deforming according to the internal high-pressure method. The part can also be further treated by laser, by chopping or sawing.
The pipe section can also be preformed prior to the internal high-pressure deformation, for example, by bending, etc, or also through a separate internal high-pressure predeformation step in which a preform would be produced which would be further treated in at least one further internal high-pressure processing step.
It may be practical to insert reinforcing elements into the deformation element, or to attach to the deformation element reinforcing elements, such as metal sheets, pipe sections, etc., which might be attached only by way of a mating fit. However, they can also be attached according to familiar methods such as bonding, welding, soldering or bolting, etc.
The reinforcing element can also be a foam part made, for example, of metal foam, such as aluminum foam or also of plastic foam, which is inserted either as a finished foam body, fastened inside the deformation element, or, however, by producing within the deformation element a foam filling, consisting at least partially of metal or plastic foam, by way of frothing the foam starting material inside the deformation element.
Due to the application of the internal high-pressure deformation method, it is possible to produce already in one forming procedure elevations and depressions, screw threads, openings, etc. at the outer hollow part. This makes it possible to reduce reworking steps.
Variable hollow sections, such as rectangular sections, angle section, pipes, etc. can be used as hollow parts.
Thus, a part is created which, compared to previous parts, weighs less, whilst the load capacity is the same, or whilst the load capacity is higher at a low weight and which, in addition, can be manufactured at high production accuracy with a reduced scrap percentage rate.
The invention is explained below in greater detail, based on the attached drawings which show the following:
Fig. 1 is a perspective view of a form of construction of the deformation element, according to the invention.
Fig. 2 is a longitudinal view of the deformation element, as shown in Fig. 1.
Fig. 3 is a perspective view of a deformation element with longitudinal ribs, according to the invention, and Fig. 4 is a perspective view of a deformation element, according to the invention, which has partially been provided with longitudinal ribs.
Fig. 5 shows a longitudinal cross section of the wall of a deformation element, deformed through impact.
Fig.6 is a force/energy-dissipating diagram of the deformation element, shown in Fig. 4, upon an experimental impact.
Fig.
7a, b, c, d show another form of construction of a deformation element in which the deformation occurs outside the longitudinal or transverse axis.
Fig. 8 shows a part which protects a motor-vehicle door against lateral impact, and Fig. 9 shows another part protecting against lateral impact.
As can be ascertained from Fig. 1 and 2, which show the same structural part in longitudinal and cross-section, respectively, a deformation element, according to the invention, consists of a steel pipe, as a preferred form of construction. The steel pipe was tridimensionally reshaped by applying the internal high-pressure method. What is meant by pipe here is any elongated body which does not have to be round in cross-section.
It should be noted that in parts, produced according to the deformation method, - the deformation element - purposely moulded grooves/depressions (12) are constructed in certain areas of the pipe in order to weaken the element (10) later on at certain points, so that predetermined deformation points are created there.
The hollow sections of the structural element can vary in diameter along their length, as well as in cross-section.
Fig. 3 shows another form of application of an element, according to the invention. It concerns here a structural element which has been provided with longitudinal ribs (16) on its periphery. Since such ribbed form elements (16) produce a reinforcing effect in the longitudinal direction, a further savings in weight, whilst maintaining the same mechanical behaviour upon impact in the longitudinal direction, can be achieved The direction of impact for which the deformation element has been mainly designed (direction of maximum energy absorption) is generally marked on the drawings as "yo" or as "direction of motion".
A preferred deformation element which can be used as impact deflector for passenger cars, is made of ST 34 or ST 52 or of a material with similar properties. Said element has a wall thickness of about 1.2 to 3 mm, a diameter of 8 to 12 cm, and a length of the depression ranging between 5 and 15 cm.
Fig. 4 shows a structural element, according to the invention, which has been provided only partially with longitudinal ribs (18, 20) in the areas which should deform upon impact. Thus, the buckling behaviour can be controlled further so that a deformation occurs only in the deformation depression (12).
Fig. 5 shows a longitudinal section of a deformed wall of a structural element, according to the invention, which was produced through impact along the longitudinal axis of the deformation element (10). Shown here is the desired folding in the area of the depression (12) whilst the other areas (6, 8) of the deformation element remain practically undeformed.
Fig. 6 shows the force/energy dissipating diagram of a form of construction of the deformation element, according to the invention (experiment as shown in Fig.
5). It becomes apparent that the force exerted on the vehicle by the deformation of the deformation element by a predetermined stretch "s" is absorbed and dissipated without any special peaks of force. Although a passenger in a vehicle equipped with such deformation element will be subjected upon impact to a force as a result of the negative acceleration upon impact, such force, however, will be built up relatively very much slower and does not result in the feared, very high forces of short duration which lead to the most serious injuries.
Fig. 7a, b, c, d show another form of construction of a deformation element in which the deformation occurs beyond the direction of the longitudinal or traverse axis.
At part of a support, which is bent approximately at right angles, a deformation element area is moulded on an angle leg. Upon impact in direction "yo" (in the direction of such angle leg), such angle leg will fold together, whilst the other support is reinforced against deformation in direction "yo" by means of moulded transverse sections. Owing to this design, deformation of the bent deformation element will occur only in one area of the part, whilst the other areas are reinforced against deformation by way of respective construction. Such part is suitable, for example, as a support part for a bumper which can be attached to the carrier shaft.
Fig. 8 a, b, c show a support part for a motor vehicle. Such part has in selected areas longitudinal depressions at which it controls its cross-section and reduces it upon impact with a transverse component.* In other areas it is reinforced against transverse deformation in the transverse direction by way of formed elevations. By moulding preferable areas, via a part in one piece, it is possible to achieve a variable behaviour of the part to the effects of force.
Fig. 9 shows a part which protects a door from lateral impact. Such part also has longitudinal depressions, which definitely anticipate the deformation of the part upon lateral impact in this area. Transverse sections have been provided against deformation vertically to the impact axis "yo", as well as a built-in reinforcement plate which serves to further reinforce the part against undesirable deformations in the end area.
Translator's Note: * The meaning of the sentence is not clearly expressed in German.
Due to the geometric design of the deformation element, it is possible, according to the invention, to achieve the desired energy-dissipating behaviour, by using considerably lighter and simpler deformation elements, which has not been possible up to now.
The hollow formed parts can be made of a single material, for example, steel or a light metal alloy. However, it is also possible, depending on the case-hardening method * used in each case, to reshape laminated material, as well as plastic coated pipes, depending on the purpose for which they are to be used.
By providing respective layers, it is possible to achieve corrosion resistance or also colouring without further work protection becoming necessary.
Due to the fact that reinforcing parts can also be attached to and within the deformation elements, for example, through bolting, riveting, welding, inserting into a mating fit or mating form, etc., a further reinforcement against deformation, and even in-preferred areas, can be accomplished.
Other forms of construction and further developments will be obvious to the expert within the protective scope of the claims. The scope of protection is in no way limited to the specific embodiments cited by way of example here, because they are intended for explanatory purposes only.
Translator's Note: * Can also mean "method used".
i f C
C
C
C
Claims (15)
1. Deformation element, in one piece, for the controlled dissipation of energy with an inelastically deformable hollow part having at least one prefabricated depression (12) which acts as a predetermined buckling point when an impact having a force component in the direction perpendicular to the depression (12) is applied, and whereby the deformation element upon impact in the direction of the deformation can fold together in such undulatory or bellows-like area (12).
2. Deformation element, according to Claim 1, wherein at least one depression (32), running lengthwise, has been provided.
3. Deformation element, according to Claim 1, wherein at least one transverse depression has been provided.
4. Deformation element, according to one of the preceding claims, wherein the depression (12) is stepped, so that the upper area of the step slides into the lower area upon deformation.
5. Deformation element, according to one of the preceding claims, is characterized by being provided at least partially with reinforcing ribs which make an inelastic deformation in the resulting reinforced area of the deformation element more difficult.
6. Deformation element, according to one of the preceding claims, is characterized by being made of a material that can be cold-formed and which is preferably subjected to strain-hardening in the deformation process.
7. Deformation element, according to one of the preceding claims, is characterized by being made, at least partially, of steel, such as ST 34 or ST 52, St 30, ST
40, deep-drawing cold rolled steel, light metal, aluminum, magnesium, titanium or an alloy thereof, or of a fibre-reinforced material.
40, deep-drawing cold rolled steel, light metal, aluminum, magnesium, titanium or an alloy thereof, or of a fibre-reinforced material.
8. Deformation element, according to one of the preceding claims, is characterized by being produced by way of the internal high-pressure deformation method.
9. Deformation element, according to one of the preceding claims, is characterized by being provided with reinforcing parts (36) at least at one end or inside its hollow area.
10. Deformation element, according to one of the preceding claims, wherein the reinforcing element includes at least a partial foam filling, composed of metal foam, inside the deformation element.
11. Use of the deformation element, according to one of the preceding claims, as a laterally reinforcing pipe for motor vehicles, deformation element between bumpers and side members of motor vehicles, steering column elements, and supports.
12. Method for producing a one-piece deformation element, according to one of the preceding claims, is characterized by:
introducing or partially introducing into a mould a pipe which has optionally already been bent;
applying internal high pressure;
removing the reshaped part;
optionally subjecting it to mechanical further or after treatment, for example, by laser, sawing or chopping, etc.
introducing or partially introducing into a mould a pipe which has optionally already been bent;
applying internal high pressure;
removing the reshaped part;
optionally subjecting it to mechanical further or after treatment, for example, by laser, sawing or chopping, etc.
13. Method, according to Claim 12, is characterized by preforming the pipe section prior to it being subjected to internal high-pressure deformation.
14. Method, according to Claims 12 or 13, is characterized by attaching at least one reinforcing element to/inside the deformation element.
15. Method, according to Claim 14, wherein the introduction of a reinforcing element includes the production of at least a partial foam filling, composed of metal foam, inside the deformation element.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE29703843.5 | 1997-03-04 | ||
| DE29703843U DE29703843U1 (en) | 1997-03-04 | 1997-03-04 | Deformation element |
| PCT/DE1998/000611 WO1998039106A2 (en) | 1997-03-04 | 1998-03-03 | Deformation element, method for its production and its use |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2285581A1 true CA2285581A1 (en) | 1998-09-11 |
Family
ID=8036882
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002285581A Abandoned CA2285581A1 (en) | 1997-03-04 | 1998-03-03 | Deformation element, method for its production and its use |
Country Status (8)
| Country | Link |
|---|---|
| EP (1) | EP0965005B1 (en) |
| JP (1) | JP2001525039A (en) |
| KR (1) | KR20000075975A (en) |
| AU (1) | AU7029498A (en) |
| BR (1) | BR9808151A (en) |
| CA (1) | CA2285581A1 (en) |
| DE (3) | DE29703843U1 (en) |
| WO (1) | WO1998039106A2 (en) |
Families Citing this family (23)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA2194195C (en) * | 1996-12-31 | 2005-09-20 | Changize Sadr | Energy absorbing bolster for vehicle door |
| DE19711647C2 (en) * | 1997-03-20 | 2002-05-02 | Daimler Chrysler Ag | Energy-consuming element, in particular for impact energy reduction in motor vehicles |
| DE19757857A1 (en) * | 1997-12-24 | 1999-07-01 | Alstom Lhb Gmbh | Shock absorption device with deformation tube |
| US6282769B1 (en) * | 1998-07-15 | 2001-09-04 | Cosma International Inc. | Motor vehicle end module assembly |
| DE19847877A1 (en) * | 1998-10-16 | 2000-04-20 | Volkswagen Ag | Bodywork bearer for front or rear end of vehicle, with at least one fixing device produced directly in manufacture of bearer by internal high pressure deformation |
| DE19853128C2 (en) * | 1998-11-18 | 2003-04-03 | Daimler Chrysler Ag | Bumper arrangement of a motor vehicle and method for its production |
| FR2792384B1 (en) | 1999-04-15 | 2001-06-01 | Lorraine Laminage | SHOCK ABSORBER AND MANUFACTURING METHOD |
| US6543266B1 (en) * | 1999-08-24 | 2003-04-08 | Magna International Inc. | Hydroformed collapsible driveshaft and steering shaft and methods of making the same |
| JP2001182769A (en) * | 1999-12-27 | 2001-07-06 | Showa Alum Corp | Shock-absorbing member |
| DE10055608A1 (en) | 2000-11-09 | 2002-05-23 | Daimler Chrysler Ag | Steering spindle assembly has walls of both ends resting against each other in form of interference fit over area of frictional engagement |
| JP2002155980A (en) * | 2000-11-21 | 2002-05-31 | Aisin Seiki Co Ltd | Impact absorbing member and bumper |
| US7070217B2 (en) | 2002-04-19 | 2006-07-04 | Magna International Inc. | Collision energy-absorbing device |
| JP4133302B2 (en) * | 2002-12-25 | 2008-08-13 | 株式会社神戸製鋼所 | Energy absorption member for car body |
| JP4621883B2 (en) * | 2003-06-10 | 2011-01-26 | 株式会社 ニッセイ | Shock absorber for vehicle |
| JP4637715B2 (en) * | 2005-10-17 | 2011-02-23 | 日信工業株式会社 | Method for manufacturing support structure for vehicle |
| JP4998097B2 (en) * | 2007-06-07 | 2012-08-15 | マツダ株式会社 | Energy absorbing member |
| JP5465849B2 (en) * | 2008-07-30 | 2014-04-09 | アイシン精機株式会社 | Shock absorber and bumper device for vehicle |
| JP2010047209A (en) * | 2008-08-25 | 2010-03-04 | Sanko Gosei Ltd | Vehicular shock-absorbing member, and vehicular occupant crash protector |
| JP2010163121A (en) * | 2009-01-19 | 2010-07-29 | Nsk Ltd | Electric power steering device |
| DE102009029814C5 (en) * | 2009-06-18 | 2017-01-26 | Rheinmetall Landsysteme Gmbh | Device for energy absorption and use of the device as a mine protection device or crash cushion for a motor vehicle |
| DE102012103036A1 (en) | 2012-04-10 | 2013-10-10 | Krauss-Maffei Wegmann Gmbh & Co. Kg | Housing, especially against detonation protected vehicle housing |
| EP4110654A4 (en) * | 2020-02-27 | 2024-04-17 | Tesseract Structural Innovations, Inc. | Multilayer uniform deceleration unit |
| JP7460910B2 (en) | 2020-11-27 | 2024-04-03 | キョーラク株式会社 | Shock absorber |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2042931A1 (en) | 1970-08-29 | 1972-03-02 | Schickedanz, Gerhard, 6070 Langen | Valve disc for spray cans |
| US4531619A (en) * | 1982-09-24 | 1985-07-30 | Eckels Robert E | Collapsible steering column |
| US4684151A (en) * | 1986-03-21 | 1987-08-04 | General Motors Corporation | Controlled collapsible frame rail |
| DE3836724A1 (en) | 1988-10-28 | 1990-05-03 | Daimler Benz Ag | Deflection-type absorber |
| JP2595724B2 (en) * | 1989-08-30 | 1997-04-02 | 日産自動車株式会社 | Manufacturing method of strength member |
| DE4028164A1 (en) | 1990-07-17 | 1992-01-23 | Schneider Gesenkschmiede | IMPACT DAMPER |
| DE4240237C2 (en) * | 1992-11-30 | 1995-02-16 | Gkn Automotive Ag | Upsetting pipe |
| DE59704565D1 (en) * | 1996-03-02 | 2001-10-18 | Volkswagen Ag | Energy absorption body |
| FR2749557B1 (en) * | 1996-06-06 | 1998-08-28 | Peugeot | ENERGY ABSORPTION BEAM, PARTICULARLY FOR THE LONGERON OR CROSS OF A MOTOR VEHICLE |
-
1997
- 1997-03-04 DE DE29703843U patent/DE29703843U1/en not_active Expired - Lifetime
-
1998
- 1998-03-03 CA CA002285581A patent/CA2285581A1/en not_active Abandoned
- 1998-03-03 JP JP53805898A patent/JP2001525039A/en active Pending
- 1998-03-03 EP EP98916825A patent/EP0965005B1/en not_active Expired - Lifetime
- 1998-03-03 DE DE59805798T patent/DE59805798D1/en not_active Expired - Fee Related
- 1998-03-03 KR KR1019997008060A patent/KR20000075975A/en not_active Application Discontinuation
- 1998-03-03 WO PCT/DE1998/000611 patent/WO1998039106A2/en not_active Application Discontinuation
- 1998-03-03 DE DE19880237T patent/DE19880237D2/en not_active Ceased
- 1998-03-03 BR BR9808151-9A patent/BR9808151A/en not_active IP Right Cessation
- 1998-03-03 AU AU70294/98A patent/AU7029498A/en not_active Abandoned
Also Published As
| Publication number | Publication date |
|---|---|
| EP0965005B1 (en) | 2002-10-02 |
| BR9808151A (en) | 2000-05-16 |
| KR20000075975A (en) | 2000-12-26 |
| EP0965005A2 (en) | 1999-12-22 |
| AU7029498A (en) | 1998-09-22 |
| WO1998039106A2 (en) | 1998-09-11 |
| DE29703843U1 (en) | 1997-05-22 |
| JP2001525039A (en) | 2001-12-04 |
| DE19880237D2 (en) | 2000-01-13 |
| WO1998039106A3 (en) | 1998-12-10 |
| DE59805798D1 (en) | 2002-11-07 |
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Legal Events
| Date | Code | Title | Description |
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| EEER | Examination request | ||
| FZDE | Dead |