DE1483023A1 - Method for producing a narrowed leaf spring - Google Patents

Description

P 14 83 023.0 (R 42 071 Vla / I8o)
Rockwell Standard Corp.

Our reference: R 643

Method for dividing a tapered leaf spring

The invention relates to a method for dividing a tapered leaf spring, "with which a blank conical rolled, heat-treated and then on one side under tension kuge ige radiates -will, -which the tensile side of the finished Spring iat.

From the German patent specification 850 620 it is known, in the manufacture of leaf springs, the tensile stressed side and to subject their longitudinal edges to a shot peening treatment under tension.

From the German patent 573 606 a method for increasing the number of vibrations of leather is known. Duroh a solidification of a very thin surface layer should be able to increase the number of vibrations of leather by 600 - 1000 $, whereby a solidification duroh small Impact occurs as it would through a sand strand

aei / H. 909828/0516

Taläs can be made. This patent specification contains the note that this maximum effect only occurs if other causes of fatigue, such as notches in particular, either do not exist in the first place or already exist are eliminated »

For a long time it was standard practice, with vehicles only recording common from road bumps. multiple leaf springs to use existing spring bundles. Such bundles of springs are generally capable of accommodating a large percentage of normal road shocks »These bundles however, are undesirably heavy and considerable friction is generated between the leaf springs, which is disadvantageous Way the spring deflection by an increase influenced by the spring constant. A different, serious disadvantage of the spring bundle consisting of several leaf springs is that it is generally impossible to have uniform I-spring constancy under different road conditions with the same load level changes the same spring deflection changes cause.

When trying to find this in the case of leaf spring bundles To eliminate problems, an attempt has been made to develop parabolic tapered steel leaf springs and the present invention is directed to one further improvement of such leathers in order to

Ö09826 / OS16

ORiQfNA IKSPECTBD

borrowed to increase the fatigue strength of these springs.

Among the main factors involving a reduction in fatigue strength and consequently fractions are attributed to belong chich the decarburization of the metal surfaces Surface irregularities, which include rolled-in splinters and oxide inclusions and the action of certain mechanical treatments.

TJm to improve the fatigue strength and thus the resistance to fatigue, the leaf springs have so far been according to " However, a heat treatment under tension shot peened So far, the expected percentage of increase in the life span of the leaf springs due to the peening has been below Voltage not fully reached.

The invention provides a novel, improved process for the production of tapered leaf springs is provided, in which the leaf springs are subjected to at least on certain Oberfläqhen an abrasive machining, karburierungsfilme to de _(, surface irregularities, chippings and oxides before the spring-rolled to remove and peened or It has been found that by grinding the blank in this way prior to rolling and prior to tension shot peening, a tapered leaf spring of unexpected fatigue strength is obtained compared to the fatigue strength of tapered ones

909825/0516

Leaf springs,

Leaf springs that are shot-peened under tension without the new sole processing «. In the case of the invention, therefore, a preparatory "grinding" is used in order to

part of an extension of the life of the leaf spring achieve. Although ee is preferred, sole elbow machining before the rolling operations, the heat treatment and to carry out the shot peening, alternatively the "sole processing after the Eoniaqhwaleen" can be carried out unprocessed leaf spring is subjected to a new sole processing before the Konisohwaleen and before the Ball peening in a process in which the Shot peening with tension sioh on the Konlsohwalzen and on dl heat treatment follows

Si is a further »aim of the invention,» in a new * process for the production of an eioh tapered leaf spring ! zuhaffen, at welöhe * a steel spring blank of the series ι is shaped conically, then heat-treated and then peened or hammered under tension, the Surface of the leaf spring, which is the adjoining side in the finished spring and the adjacent longitudinal edges of the Leaf springs are subjected to sole processing before the spring is blasted or hammered under tension.

According to the invention, the voltage surface and the

009S2S / 0516 similar

OHIGiNAL ¹ INSPBCTEP

naohbarten Längaaeltenkanten before Kugelfltrahlbehand ^v lung geaohliffen under tension such that a minimum depth of Oberfläohenachioht ao is removed that Dekarburierungseinsohlüase and subsurface Einsohlüsae spannungaerhöhende and other media are removed "

The sole grinding is advantageously carried out in such a way that a surface depth of at least 0.02 cm Depth is removed · The sole grinding can advantageously take place before the hollowing is rolled can also be carried out with advantage in connection with the conical rolling and carried out before the heat treatment of the hollow part.

The invention is intended with reference to the figures of Drawing will be explained · It show:

Fig. 1 is a schematic diagram showing the preparatory surface grinding of a flat Represents Stahlfederrohl ^ nga according to the invention,

2 shows a schematic diagram of an induction heating furnace for heating the ground leaf spring blank to hot working temperature,

Fig. 3 shows an aohematiaohe Anaioht of a device for · Konisohwalzen or for rolling in the aich tapering shape, ■

4 shows an aohematia-related analysis of an optionally provided

909825/0516 aeaehentn

INSPECTED

seen device for pushing and drilling the peder, this device being used when a peder requires an opening,

fig · 5 a side view of a sioh tapering leaf spring near the orphan and the drilling »

Pig, 6 a schematic view of a heating oven, if provided, which is used to produce the To prepare leaf springs for the formation of peder eyes, if necessary,

Pig. Figure 7 is a schematic view of an apparatus which can be provided to attach peder eyes if necessary,

Pig. θ a sohematic view of a furnace to a

To heat the leaf spring in preparation for a bend,

Pig _# 9 a similar view of a device for bending a leaf spring,

Tig.10 a schematic view of a tempering furnace for a leaf spring,

Pig 11 a similar view of a device for shot peening a peder under tension,

Pig. 12 a similar view of a preload device, Pig. 13 a sohwmatisohe view of a leaf spring testing station,

fig * 1 # a thematic view of a leaf spring coating station to make a corrosion-resistant PiIm to apply to the finished leaf spring,

ORIGINAL! NSFEGTED MgVi 5 elaie enlarged sonitta not the leaf spring,

»44» in detail represents the grinding process and fig · 16 emetine further enlarged «feileohnittansioht one falls "of the leaf spring before the sole elf processing *

Ee eei on Pig. 1 eye taken. A steel spring blank or billets 40 with flat sides on the right side Length is independent, 1st in a grinding device 4-2 arranged around the surface 44 of the blank 40 too grind, which the tension surface of the leaf spring is to be when this leaf spring is completed. The device 42 preferably has sole strap 46 which against the surface 44. · The sole device 42 also has sole belts or the like (see Hg · 15) to both edge surfaces 41 and 43 next to the Grind the pulling side of the blank «Although for some springs can suffice, only to grind the traction surface, it was found to be an essential element of the invention that the sole elimination of both the surface 44 and the The adjacent edge surfaces 41 and 43 are also extremely advantageous in order to further improve the fatigue strength the. to raise the spring «Other forms of sole hoofs, which are not shown »can also be used», such as sole wheels or sole wheels · By grinding the surface according to the invention 44 and the edge surfaces 41 and 43 are all Deka » buration films »surface incompleteness» splinters

909826/0816

and

ι rwreCTED

and oxides are removed, leaving smooth, flat surfaces generated. For example, a typical steel leaf spring has been found to have a decarburized surface layer of about 0.037 centimeters deep, the hardness being of an external surface hardness of a Rookwell 'degree of hardness O 35 up to an inner uniform spring hardness Ranges from about 46 degrees of Rockwell hardness O · This harmful Layer was removed from the tension side and the adjacent edges by the sole process to create a leaf spring mil; to produce high quality

Reference is now made specifically to FIGS. 15 and 16. The tube 40 is shown in the Sohnijrfc and has a lower surface 47 which is the compression surface and a top surface 44 which will fläohe the train upper. Both surfaces are laterally connected to one another by opposing edge surfaces 41 and 43 tied together·

In order to grind the traction surface 44, the blank 40 is used on the table of the grinding machine 116, a conveyor or the like with the pulling surface on top and a number of grinding wheels, grinding belts 46, etc. are applied against the pulling surface 44. The outermost grinding device 49 extends around the edges 45 of the Edge surfaces 41 and 43 around to at the same time the upper parts of the sides immediately adjacent to the pulling side 44-to ribbons,

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JlS

ORiGINALiNSPECTED

Ea aei on Pig. 16 Beaug taken. When the blank 14 arrives at the Walswerk, it has "a surface layer made of decarburized material 118 which can extend continuously over all surfaces or only over a part of these surfaces)" effective "surface treatment of the leaf spring blanks when Koniaohwalzen, etc in the shot peening · and" vas · particularly on the side that is to become the Zugoberfläohe example, can be pressed into the surface during Konisohwalzens burrs or splinters, and this similar results in the occurrence of stress increases in the The surface layer of the tension side and these places can become the starting point for fatigue problems and lead to an early Bruoh of leaf springs «

Although the decarburization involves grinding can be removed from all surfaces of the blank, it is only necessary to remove them from the side that becomes the pulling side of the leather and from the rushes of the sides immediately adjacent to the pull side, as indicated in Mg. 16, since the edge portions of the Sides that extend from the tension side are subjected to tensile stresses, and if only the Pull side is sanded, and if Dekarburierungssohten remain on the Eoken surfaces 41 and 43, can early Fatigue brews occur which are incomplete on the surfaces. resistance to high tensile stresses

ORIGINAL INSPECTED!

On page 47 of the «blanks 40, which lies opposite the so-called traino" btrflÄ-ohe 44, the Kompreeeioneoberflloh · and can also be "ground in the same way as surface 44" although this is not necessary Let and the surface can be shot-peened for the final heat treatment in order to clean the fiohling and to remove splinters and burrs. Rolls were created in the rolling mill. However, a grinding or shot peening of the side 47 is the hollow ring 40 »the opposite the tension side 44 is normally not necessary, since the presence of decarburized brackets and increased stresses on the surface, which is only exposed to compression, result in a long service life which does not stand in the way of teder

Subsequently fen to the Sohl ·!, The blank is then heated 40 in a suitable oven 54 (Fig x 2) to a! Temperature clay 1200 ° J to 2250 P in order for the blank to hot rolling in the SiOH tapered shape prepare · The heating However, the blank 40 is advantageously not necessarily carried out by induction heating in order to achieve a gradual increase in temperature towards the ends of the blank 40 depending on the hot rolling work required in forming to the aloh tapered shape. This treatment minimizes the grain size in spring blanks that are exposed to relatively little hot work during rolling and

909825/0516 _di “.

this heat treatment is duroli a special design of induction heating, the blank 40 is easily brought to a hot working temperature is heated, it then becomes a rolling device 56 (Fig. 3), and in this device the blank is warmed into a sioh tapered or conical shape gewalit · Alternatively, the surface 44 and the neighboring Edge sides 41 and 43 even after the heat treatment in furnace 54 and prior to tapering in the apparatus 56 to be grounded

In the case of sioh tapered leaf springs, the spring must be designed in such a way that the operating stresses are distributed uniformly over the length of the spring. In other words, the spring must ^'a: veriüideriiohe thickness or width or verendliche S ¹ OWOhI "have strength and width eine'veränderliche In order to simplify the production and to reduce the cost and out." Variable is üideren Sründen preferably a tapered leaf spring is produced, in which only the thickness changes. The taper preferably extends from a maximum strength in the vicinity of the spring assembly block or on the spring assembly block to a minimum strength at the ends of the spring or in the vicinity of the ends of the spring. The spring ends can have a constant strength "in order to be able to form fastening eyes.""' SO 9825 / OB 16 _r Um

Vn is the set forth in the foregoing, eioh tapering · fom lu obtained can Ur lohllag 40 preferably genftl a · »procedures and gewallt conical with finer device will besohritbtn in the TTS Patent 3,145,591» # Bin Such a method and such a Vorriohtung are shown in jig · 3 only in a dtr-like dimension βohema / tisoli, we loh an understanding of the invention is necessary eafsohtint · This device. is suitable for the production of heavy leaf springs and for light leaf springs can generally be used with WalBTorriohtung, wit Bio in the US patent application Serial Ko. 205 333 from 26 _f , June 1962 will be heeohrieben *

To make a single leaf spring, use a ί corresponding AuilenlcungiTi * r # ioh: §ufriedentteilendt Suspensions are due to * Hf t ^, let the air tolerant the feather long? dee eioh Tti-jjäageaden parta on one Value το »plue for Binua 0.0 ^ 2 centimeters compared to a theoretically held in the same parabolic shape " The surface Ute Rohling! 40 "you will be rejuvenated" and Either the d * th train surface height 44, which can enter the opposite Druokoteer surface 47 ", must be for this reason Among other things, in essentially free tone apannun-increasing surface defects and this condition must be The rolling process can be sustained · You can either at the formation of the taper, as already stated, at the Tensile surface or on the compression surface of the leaf spring «

909825/0816

Like fig. 3 shows, the warm blank is placed in a die 58, which is arranged on a carrier 60 4 «r masohine 56. Binding roller 69» a. Axis is mounted transversely to the length of the blank 40 wire is is then in Längeriohtung length dea blanks abgt ^*! circulated namely auegehend of dea Mittelabsohiiittj dea Sohlinga and dieae roller is moved zuerat to a bathroom "and then on the other end. As in the above stated, the leaf spring on both Bnden in Abaoh & itte of uniform thickness so that attachment eyes can be made. If a fold 62 is used, the taper is formed on one half of the blank 40. The position of the hollow 40 is then reversed end to end and the other half of the blank 40 is tapered or conically shaped, in a double-equipped machine it is not necessary to turn the blank kt, which hangs above the die 58 and which is mounted in such a way that this guide surface can move in the longitudinal direction of the blank. If the guide surface 64 is shown in Pig. 3 moved to reohta, the surface presses the roller 62 against the blank 40, which is held against a movement. The roller 6g is therefore moved forward over the surface 44 of the blank through the frictional engagement between the roller 62 and the blank 40 and between the guide surface 64 and not shown guide surface close rollers, these rollers being on each 809826/0516.

ORIGINAL INSPECTED

des lüde der Valze 6 $ are arranged and old diee ^ r a 3anies form «

ITa the öensuigkeii of the Konieohen Torah or the Rejuvenation It is very important that there are no ridges or splinters or other so-mutes contacting surfaces of the Valze 69 and the blanks 40 Or the guide surface 64 and the Jühruagjirollen arrive "IkLe contour of the guide surface 64 is such" that dieee eioh against the Valze 62 and these goalkeepers moves1 whereby the roller 62 rolls the blank 40 onto the desired eioh youngster torrn. Daduroh becomes one Eioh rejuvenating leaf spring produced «which in the Pig · 3 and 5 denoted by 63 and the conical surface 66 has "If it is desired that the leaf spring has a constant width and is only in the Tapered strength, 'the die 98 with an in Elongated hollow space formed, which prevents the metal from spreading sideways

Ia ineohltti to this rolling process for the production of In the tapering torch, the half-finished, tapering leaf spring 65 is led to a heating furnace 68 (Tig. 8), and there the teder is brought to the temperature of the desert heated and the «let a preliminary stage for the subsequent Torming the arch. Like in Tig. 9 shown, the bend or curl is produced daduroh that the so, i 908625/0516

heated

ORIGINAL INSPECTED

■>} made leaf spring two bent keapleiientar · * i \ ΟΐβΓ · * are paired with lower joints 72 and 74. With regard to the right curvature of the finished leaf spring, changes in the height of the curvature in particular | thr # nt Torepannene are possible · The Yorriohtungi $ .ie fte • enkhalterungen 72 and H, where the <0 «where this part is clamped, we * a · period of time immersed in oil, the auereiöli ^, dfcö • Ine oart» "Iitohe transformation in the GröffMordnuJMC ^ O * 95? T or more achieved" song "driving the tJuwanftluni eta.ttiindet, the semi-finished leaf spring 65 under the yard ^ Binapanndruolc rwiaohen the aiienkhalterungen 72 and 74" receive "among other things a condition or Rejection eu

Then the leaf spring, € 5 also learn KühlBX | e & 4j | $ | ^, \ ₍ iet, this is removed from the die holders 72 and 74f? and is usually tempered in a tea furnace 76 sdifcY; conveyor device (Pig »10) to relieve tension which can be introduced into the> ed »r during de · fötnung · - KühlTorgangee» - < ^! Π>

Following the orphan in the sioh ver ^ üncende fornij 4n the bending and tempering, the leaf spring & 5 is geatrahli; or hammered under tension, at least on the grounded traction surfaces 44 and also on the deep. '* · On the longitudinally ground side parts d **'01># ^ * M surfaces 41 and 43 > f '

BATH ORIGINAL

I "T V

of the usual construction, and one or more jet wheels can be provided. Two jet wheels are shown at 77 and 78 in FIG. The tension surface 44 is bombarded from the wheels 77 and 78, while the leaf spring is held in a tensioned state by a suitable clamping device, the spring being bent, for example, in the longitudinal direction. The sole rudder wheels can be arranged at an angle in order to simultaneously irradiate the edge surfaces which are adjacent to the traction surface 44, or additional wheels can be provided for this purpose. If the ball irradiation is to be carried out under tension in a special way, it should be carried out with a tensile stress that is very close to the yield point of the steel. The leaf spring 65 ', which is bent under tension before the shot peening, is preferably clamped in an essentially flat position by suitable means. It should be noted that other conventional shot peening devices can be used, such as air nozzles. The shot peening treatment removes harmful residual tensile stresses which could be present in the surface layer and compressive stresses are advantageously introduced. Following the shot peening under tension, the leaf spring is preferably input into the presetting device 86, which is shown in FIG. The device 86 has a fixed bracket 88 which has a curved upper surface and surface über.diese 909,825 / 0S16 is

is the curved leaf spring in the opposite direction to Operating direction bent by bumpers 90 or other suitable means. The leaf spring will go some distance deflected the predetermined maximum operating deflection and the yield point of the material exceeds «By this adjustment treatment, the bent leaf spring is made its curved unloaded shape and is passed through a flat shape and is then in bent into an inversely curved shape as shown in FIG. This setting treatment represents the normal Height of curvature decreases again and reduces the possibility of "that a permanent adjustment in the leaf spring during of operation occurs and residual compressive stresses continue introduced in the traction surface layer in addition to those introduced by the shot peening became. When the leaf spring is removed from the mold, it returns to a curved shape, which is somewhat relaxed compared to the curved shape shown in Fig. 9 *

after the initial grinding treatment and before taper rolling can at least the ground tension surface 44 and parts of the adjacent edge surfaces 41 and 43 of the blank 40 are treated so that these Eläohen one Get resistance to the formation of burrs and oxides, especially if the blank is conical is rolled. This can be done in an effective manner, for example, that the ground blank with

909825/0516 _T4 . _{v4 Λ φ} i

Lithium vapor :

BATH ORIGINAL

IittiiiiFidaipi - '.. ι Berutenmg brought:;. "... during the raw IiUg -in ^ f © r -: φ erliitcS mrd. The J ;. ^: / i} - .:«. U;:.: -of adheres to ~?: -: ^ L · / ·: /; CiTiCi ": .-: ■ -jviliioLtiit cLsaen with jinei ^ J-ll ...... der zu-3a5sl ^ jii ui, ::: . _; da3, LUco: ^ äie iusDÜdimg from Ira ^ - ^ n. and Splitisr: ■: /..-: ■: ■ Oxyden ^ ss ⁵ ! iind.eri5 _? s / uoh as Sohmierüiittel "at the ¥ alE3-i v.drkt.

la Ansolil'ifi: ■■ - eilest S ^ i: .. ■ - ..: / eiaa: iäIi: ^ g and before the hot rolling ecler Yiaoh, learn Wa ^ iüvia.i.rion harüi: l3 some cases of Eohling AO with öffn-xigrai for Bs ^ osLLgungalaolzen or Zentriertoigseiiix'Luh-'Tüigs;} '/-?rsei>.en yar ^ i.;., »V / ie it is shown in Pig _u 4» Aus Gi-rfruden, d: le iidgIi are set out, preference is given to the anoring of an opening for the fastening bolt. 2 :: - ': ■; i? ^: 3n and instead the leaf spring is provided with press-fit '-. Mgeii or pegs or projections, preferably on the neutral axis of the edge sides of each or on the compression side, in order to be able to arrange and center the spring and to exclude or to exclude the effects of increasing tension reduce, which are caused by the hole in the fastening area, as shown and explained in particular in US patent application Serial Ho. 411 285 of November 16, 1964,

Haeh dem Konisohwalzen can the partially finished Leaf spring 65 optionally a further sole treatment be subjected to all surface imperfections to remove that occurred during the Konisohv / alzens

909825 / 05TS

testifies

BATH ORIGINAL

were witnessed, especially on the train surface 44 and on the adjacent edge surfaces 41 and 45 The leaf spring 65 can then be sent to a test station (Fig. 15) are brought and there is the contour of the leaf spring taper Checked as the exact thickness dimensions are very important along the tapered file *

"Before bending, spring fastening eyes can, if desired, as shown in FIGS. 6 and 7, produced by first the leaf spring 65 heating is carried out in right and left double ovens 100 shown in FIG Has conveyor, and where .this furnace has two opposite Has heating devices 102 and 104 arranged on either side of a conveyor 105. The leaf spring 65 is led across between the furnace 102 and 104 durohge, to heat the spring end pieces 106 · TJm to simplify the manufacture of the fastening eyes the end portions 106 preferably have uniform thicknesses. Ovens 102 and 104 can be any suitable have the usual structure and preferably these ovens are gas-heated in order to generate intense heat. Direct After heating, the leaf spring end sections are simultaneously formed into fastening eyes 108, as shown in FIG. The eyes can be made with any common automatic molding machine, which can process both ends at the same time,

I " 909825/0616 ^ S *

E. ORIQINALiNSPECTED

- C \ J - '

and the standard rollers 110 shown in FIG are·

Bach, the setting is the finished leaf spring, which in Pig, 14 "is shown at 112, preferably coated with a corrosion-resistant coating, namely, that the leaf spring is immersed in a suitable solution 113 contained in a container 114 is.

Ba is preferred, the access surface 44 and the adjacent ones Edge surfaces 41 and 43 prior to rolling in to grind the aioh tapered shape. The surfaces can, however, alternatively be ground into the shape shown in FIG. 5 after rolling and before Blasting treatment under tension.

Reference is made to FIG. The grinding of the opposite side edge surfaces 41 and 43 extends from the rounded edges 45, at which the side edges cut the traction surface 44, to an atreoke that is little about 35 $> the strength of the leaf spring.

909825/0 516

Claims (1)

Patent application 1. Procedure for dividing a rejuvenating leaf spring, in which a blank is rolled conically, heat treated and then peened on the side under tension which is the tension side of the finished spring is characterized by the fact that the tension surface and the adjacent longitudinal side edges before shot peening be ground under tension in such a way that a surface layer of minimal depth is removed that decarburization inclusions and subsurface inclusions and other stress-increasing inclusions Media are removed 2. The method according to Anapruoh 1, daduroh characterized in that the grinding is carried out in such a way that an upper * Shallow layer of at least 0.02 µm in depth will. 3. The method according to one of claims 1 or 2, daduroh! marked that the sole grinding before the Koniaoa rolling of the blank. 909825/051 $ -oil / B. ■ 4 _# Method according to one of Claims 1 or 2, characterized in that the grinding takes place after the conical rolling and is carried out before the heat treatment of the blank. 5. The method according to any one of the preceding claims, characterized in that the blank is in an inert Protective steam is heated immediately before the conical rolling. 6. The method according to Anspruoh 1, characterized in that the unfinished leaf spring for shot peening is pretensioned in such a way that this preload is dioht at the yield point, but in such a way Distance from this so that permanent deformation is prevented. 7 · The method according to claim 3 »characterized in that the peder blank is heated to a temperature of 1200 ° 3? heated up to 2250 ° ϊ ¹ before conical rolling. 8. The method according to Anspruoh 5, characterized in that the conically rolled before the shot peening under tension ! The spring is heated to the austenite temperature and in this heated state is so bent to achieve the desired arching, and that the spring while it is clamped in this way, cooled will" , 909825/0516 1% 9. The method according to claim. 8, daduroh marked that the! feder daduroh gate is set so that it is reversed is bent to deflect during operation, beyond the yield point of the steel. 90.9825 / 0516