EP0404674A1 - Verfahren und Vorrichtung zur Verbesserung der Dauerfestigkeit einer zusammengedrückten Schraubenfeder und durch dieses Verfahren hergestellte Feder - Google Patents

Verfahren und Vorrichtung zur Verbesserung der Dauerfestigkeit einer zusammengedrückten Schraubenfeder und durch dieses Verfahren hergestellte Feder Download PDF

Info

Publication number
EP0404674A1
EP0404674A1 EP90401744A EP90401744A EP0404674A1 EP 0404674 A1 EP0404674 A1 EP 0404674A1 EP 90401744 A EP90401744 A EP 90401744A EP 90401744 A EP90401744 A EP 90401744A EP 0404674 A1 EP0404674 A1 EP 0404674A1
Authority
EP
European Patent Office
Prior art keywords
spring
shot
rotor
blasting
internal surfaces
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP90401744A
Other languages
English (en)
French (fr)
Inventor
Michel Duchemin
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Allevard Industries SA
Original Assignee
Allevard Industries SA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Allevard Industries SA filed Critical Allevard Industries SA
Publication of EP0404674A1 publication Critical patent/EP0404674A1/de
Withdrawn legal-status Critical Current

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D7/00—Modifying the physical properties of iron or steel by deformation
    • C21D7/02—Modifying the physical properties of iron or steel by deformation by cold working
    • C21D7/04—Modifying the physical properties of iron or steel by deformation by cold working of the surface
    • C21D7/06—Modifying the physical properties of iron or steel by deformation by cold working of the surface by shot-peening or the like
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24C—ABRASIVE OR RELATED BLASTING WITH PARTICULATE MATERIAL
    • B24C1/00—Methods for use of abrasive blasting for producing particular effects; Use of auxiliary equipment in connection with such methods
    • B24C1/10—Methods for use of abrasive blasting for producing particular effects; Use of auxiliary equipment in connection with such methods for compacting surfaces, e.g. shot-peening
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24C—ABRASIVE OR RELATED BLASTING WITH PARTICULATE MATERIAL
    • B24C3/00—Abrasive blasting machines or devices; Plants
    • B24C3/32—Abrasive blasting machines or devices; Plants designed for abrasive blasting of particular work, e.g. the internal surfaces of cylinder blocks

Definitions

  • the present invention relates to a method and a device for improving, by shot peening, the fatigue resistance of helical springs and more particularly of compression helical springs.
  • Shot blasting is a surface treatment process which involves projecting shot against the surface to be treated.
  • the fatigue resistance of metal parts can be improved by this process, provided that the shot is well rounded, that it is thrown at high speed and that the impacts fully cover the stressed surfaces of the part to be treated.
  • Each impact of shot on the surface of the part produces a deformation which generates internal compression tensions, which hardens the metal and which attenuates the possible small irregularities. All these effects contribute to increasing the resistance to the weariness of the part, provided that no portion of the stressed surface is forgotten.
  • the internal tensions which will subsequently compensate for the constraints of use can be increased if the part is shot blasted, under tension, in a stress state similar to that which it will support in service. The increase is all the more noticeable as the tension of the metal during shot peening is higher.
  • the maximum efficiency of a coil spring is obtained by making its entire surface work at maximum stresses.
  • the internal shot blasting tensions make it possible to increase the value of the admissible stresses in service and therefore the efficiency of the spring, but the orientation in all directions of the surface of the helical spring makes it difficult to carry out shot blasting.
  • the most commonly used method which consists in displacing the spring under a conical jet of shot projected at high speed by a turbine does not allow reach all surfaces and in particular the internal surfaces of the spring only if the turns are sufficiently spaced. If it is a helical compression spring that is to be shot blasted under high tension, the covering of the internal surfaces by the impacts of shot is not sufficient to bring about a significant improvement.
  • the internal surfaces of the spring can be defined as those which constitute the internal wall of the spring when the latter has contiguous turns.
  • a method of shot blasting generally used for cleaning consists in entraining the shot in a jet of compressed air. This method is sometimes also used to improve resistance to fatigue, by reducing the diameter of the jet outlet nozzle so that its speed is substantially the same as that obtained with shot blasted by a turbine.
  • the angle at the top of the cone formed by the shot of shot becomes very sharp and the impact surface covered by the shot very narrow. As a result, it takes a long time to blast a coil spring.
  • a part of the surfaces being reached only by a tangential jet is not subjected to sufficiently strong internal tensions and constitutes a zone of weakness likely to be the seat of a subsequent rupture.
  • Japanese patent published under number 56-107880 gives an example of the application of this method.
  • two nozzles one inside and the other outside the spring, are driven in an alternating translational movement parallel to the axis of the spring by projecting shot against the compressed spring and rotated simultaneously.
  • shot is always projected in the same direction, it follows that not all surfaces receive the same intensity of shot; some being reached that tangentially are therefore only subject to low internal tensions and will be therefore the seat of breaking points.
  • DE 3,711,826 describes a device for peening cylindrical parts on their internal wall by means of a direct shot projection member, said member being movable in translation and / or in rotation inside the piece but without changing tilt, relative to the axis of the spring.
  • the shot should hit the spring at all points perpendicular to its surface and therefore the turns should be very far apart, which would exclude shot blasting under tension from a compression spring.
  • the spring In order for the spring to acquire the maximum internal tension, it should be shot peened in the highest possible stress state, i.e. be compressed with contiguous turns, but then the contact surfaces between turns would not be blasted and would constitute zones of weakness likely to constitute a starting point of rupture.
  • the object of the present invention is to produce high performance helical compression springs capable of withstanding without damage high stress amplitudes leading the spring to a state of almost contiguous turns.
  • the external surfaces of the spring which are less stressed in service than the internal surfaces, do not need to be blasted as much.
  • the spring is compressed with contiguous or almost contiguous turns during the shot blasting but it is however necessary to leave enough passage for the shot between the turns of the spring.
  • the internal surfaces of the spring acquire better resistance to fatigue when they are blasted with contiguous turns.
  • a device for improving the fatigue resistance of a helical compression spring by shot blasting of the surfaces comprising a shot distributor and a movable shot projection member disposed coaxially inside said spring and means for compressing said spring, characterized in that said movable shot projection member comprises a cylindrical rotor whose l the axis is substantially vertical during shot blasting and which is provided on its side wall with peripheral fins adapted to project the shot from the distributor against the internal surfaces of the spring as a function of the speed of rotation
  • the rotor is at variable speed.
  • said peripheral fins are divided into two series, one of which extends parallel to the vertical axis of said rotor and the other extends obliquely with respect to said vertical axis.
  • the shot dispenser comprises a substantially horizontal upper plate mounted above the rotor and comprising, at its lower part, a housing adapted to receive in support contact the end upper spring and at least one shot distribution duct.
  • Another object of the invention is a method of improving the fatigue resistance of a helical compression spring comprising in particular the blasting of the internal surfaces of the spring, characterized in that the blasting is carried out by shot deviated to inside the spring and projected in different directions by a rotor.
  • the shot peening is carried out inside the spring, so that the internal surfaces of the spring are struck at least directly and perpendicularly by said shot.
  • said spring is maintained at least partially in the compressed state.
  • said spring is gradually compressed during shot-blasting until the state of almost contiguous turns.
  • said spring is kept compressed during shot peening in the form of almost contiguous turns.
  • Yet another object of the invention is a helical compression spring having improved fatigue resistance and obtained by the method of the invention.
  • the internal surfaces of the spring are advantageously blasted by jets of shot differently oriented so that all the points of these surfaces are struck at least once during shot blasting from an effective angle.
  • the device of the invention as shown in Figure 1 comprises a shot dispenser 2 and a movable member 3 of shot projection disposed inside the spring 1 coaxially with respect to said spring.
  • the device of the invention also includes means for compressing the spring 1 so as to gradually make its contiguous or almost contiguous turns during the peening.
  • the mobile shot projection member 3 comprises a cylindrical rotor 5 with variable speed.
  • the common axis of the rotor and the spring is substantially vertical during the blasting.
  • the rotor 5 is provided on its side wall included inside the spring 1, with two series of peripheral fins 6, 7, one of which 6 extends parallel to the axis vertical of said rotor 5 and the other 7 extends obliquely relative to said vertical axis. These fins 6, 7 are adapted to deflect and project the shot from the distributor 2 in all directions against the internal surfaces of the spring 1 as a function of the speed of rotation.
  • the shot dispenser 2 comprises a substantially horizontal upper plate 8 mounted above the rotor 5 and comprising at its lower part a housing 9 adapted to receive in contact with support the upper end of the spring 1 and at least one conduit 10 of shot distribution.
  • the conduit 10 as shown in Figure 1 is formed in the mass of the upper plate 8 in the form of a frustoconical recess whose side faces are inclined to allow a gradual flow by gravity of the shot.
  • the compression means of the spring 1 are constituted by the upper plate 8 actuated in the vertical direction by a set of hydraulic cylinders 11 and by a lower plate 12 supporting and wedging the lower end of the spring 1.
  • the rotor 5 is preferably moved at variable speed by a motor 13 mounted coaxially on the upper plate 8.
  • the helical compression spring 1 is therefore compressed either gradually or in a single phase between the two plates 8 and 12 before or during the peening operation by means of the hydraulic cylinders 11 and the positioning of the spring 1 between the plates 8 , 12 is done prior to the introduction of the rotor 5 coaxially at the center of the spring 1.
  • the blasting is carried out, according to the method of the invention, inside the spring in all the angular directions, so that the internal surfaces are struck at least directly and perpendicularly by said shot, that is to say along the normal to each of these surfaces.
  • This operation is carried out by first supplying the distributor 2 with shot and by putting the rotor 5 in rotation by means of the motor 13.
  • the shot flows by gravity inside the conduits 10, falls inside the spring 1 where it is struck and deflected by the peripheral fins 6, 7 of the moving rotor 5.
  • the subsequent kinetics of the shot depend on the speed of the rotor and the type of fin with which the impact takes place.
  • the shot blasting of the external surfaces of the spring 1 is carried out in a known manner and independently of the shot blasting of the internal surfaces described above.
  • the shot peening process according to the invention applies not only to cylindrical springs in round wire but also to all coiled springs and in particular to conical springs or springs with variable winding diameter, to springs with variable pitch, to springs in wire conical or of variable wire diameter, with square, rectangular or any section wire springs and produces springs with resistance to exceptional fatigue.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Springs (AREA)
EP90401744A 1989-06-20 1990-06-20 Verfahren und Vorrichtung zur Verbesserung der Dauerfestigkeit einer zusammengedrückten Schraubenfeder und durch dieses Verfahren hergestellte Feder Withdrawn EP0404674A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8908222 1989-06-20
FR8908222A FR2648380B1 (de) 1989-06-20 1989-06-20

Publications (1)

Publication Number Publication Date
EP0404674A1 true EP0404674A1 (de) 1990-12-27

Family

ID=9382954

Family Applications (1)

Application Number Title Priority Date Filing Date
EP90401744A Withdrawn EP0404674A1 (de) 1989-06-20 1990-06-20 Verfahren und Vorrichtung zur Verbesserung der Dauerfestigkeit einer zusammengedrückten Schraubenfeder und durch dieses Verfahren hergestellte Feder

Country Status (2)

Country Link
EP (1) EP0404674A1 (de)
FR (1) FR2648380B1 (de)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0672501A1 (de) * 1994-03-15 1995-09-20 Fried. Krupp AG Hoesch-Krupp Kugelstrahlanlage für Schraubendruckfedern
EP2644714A1 (de) * 2012-03-30 2013-10-02 Allevard Rejna Autosuspensions Kontrolierte Sperrvorrichtung einer Feder und Verfahren zu deren.

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2249677A (en) * 1940-07-11 1941-07-15 Eaton Mfg Co Apparatus for treating coil springs
DE2616894A1 (de) * 1975-04-19 1976-10-28 Riichi Maeda Zentrifugalschleudervorrichtung
JPS56107880A (en) * 1981-01-23 1981-08-27 High Frequency Heattreat Co Ltd Stress shot peening device for coil spring
JPS58192754A (ja) * 1982-04-30 1983-11-10 Kato Hatsujo Kaisha Ltd 疲労強度向上処理ばね及びその処理方法
DE3711826A1 (de) * 1987-04-08 1988-10-27 Meuwsen & Brockhausen Verfahren zur reparatur von hydraulikzylindern
DE3800679A1 (de) * 1987-07-11 1989-01-19 Teves Gmbh Alfred Dichtring fuer eine kolben-zylinder-einheit
JPS6471666A (en) * 1987-09-07 1989-03-16 Taiyo Chuki Kk Shot blast material shooting device

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2249677A (en) * 1940-07-11 1941-07-15 Eaton Mfg Co Apparatus for treating coil springs
DE2616894A1 (de) * 1975-04-19 1976-10-28 Riichi Maeda Zentrifugalschleudervorrichtung
JPS56107880A (en) * 1981-01-23 1981-08-27 High Frequency Heattreat Co Ltd Stress shot peening device for coil spring
JPS58192754A (ja) * 1982-04-30 1983-11-10 Kato Hatsujo Kaisha Ltd 疲労強度向上処理ばね及びその処理方法
DE3711826A1 (de) * 1987-04-08 1988-10-27 Meuwsen & Brockhausen Verfahren zur reparatur von hydraulikzylindern
DE3800679A1 (de) * 1987-07-11 1989-01-19 Teves Gmbh Alfred Dichtring fuer eine kolben-zylinder-einheit
JPS6471666A (en) * 1987-09-07 1989-03-16 Taiyo Chuki Kk Shot blast material shooting device

Non-Patent Citations (4)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 13, no. 274 (M-841)(3622) 23 juin 1989, & JP-A-1 71666 (TAIYO CHUKI K.K.) 03 mars 1989, *
PATENT ABSTRACTS OF JAPAN vol. 5, no. 187 (M-98)(859) 26 novembre 1981, & JP-A-56 107880 (KOUSHIYUUHA NETSUREN K.K.) 27 août 1981, *
PATENT ABSTRACTS OF JAPAN vol. 8, no. 35 (M-276)(1472) 15 février 1984, & JP-A-58 192754 (KATOU HATSUJIYOU K.K.) 10 novembre 1983, *
WIRE INDUSTRY. vol. 55, no. 654, juin 1988, OXTED GB Sommer: "Shot blast descaling and shot peening" *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0672501A1 (de) * 1994-03-15 1995-09-20 Fried. Krupp AG Hoesch-Krupp Kugelstrahlanlage für Schraubendruckfedern
EP2644714A1 (de) * 2012-03-30 2013-10-02 Allevard Rejna Autosuspensions Kontrolierte Sperrvorrichtung einer Feder und Verfahren zu deren.

Also Published As

Publication number Publication date
FR2648380A1 (de) 1990-12-21
FR2648380B1 (de) 1994-10-07

Similar Documents

Publication Publication Date Title
EP1208942B1 (de) Kugelstrahlen von gekühlten Laufschaufelspitzen
CA2363276C (fr) Procede et installation de grenaillage par ultrasons des alveoles annulaires d'attache d'aubes sur un rotor
CA2363306C (fr) Procede pour augmenter la duree de vie des attaches d'aubes sur un rotor
CA2363313C (fr) Procede et dispositif de grenaillage par ultrasons des alveoles "axiales" d'attache des aubes sur un rotor
WO2001036692A1 (fr) Procede de grenaillage par ultrasons de surfaces annulaires de grandes dimensions sur des pieces minces
FR2903173A1 (fr) Dispositif d'injection d'un melange d'air et de carburant, chambre de combustion et turbomachine munies d'un tel dispositif
EP2726211B1 (de) Sprühdüse zum zerstäuben von trockeneis, insbesondere trockeneis aus kohlendioxid
FR2512374A1 (fr) Appareil et procede de grenaillage
EP0659523B1 (de) Vorrichtung zum Sandstrahlen von Flächen, die von einer geraden Sandstrahlkanalisation nicht zugänglich sind
EP0505285A1 (de) Pistole zum Schneiden von Blechplättchen
EP0404674A1 (de) Verfahren und Vorrichtung zur Verbesserung der Dauerfestigkeit einer zusammengedrückten Schraubenfeder und durch dieses Verfahren hergestellte Feder
FR2905290A1 (fr) Dispositif de traitement pour le grenaillage de la surface interieure d'une piece tubulaire
WO2013038084A1 (fr) Dispositif de projection de glace sèche, notamment de glace carbonique, et buse pour un tel dispositif
EP1616041A1 (de) Flammenbeschichtungsverfahren und entsprechende vorrichtung
FR2521712A1 (fr) Procede et appareil pour refroidir brusquement un objet
FR2815280A1 (fr) Machine et procede de grenaillage
WO2005065887A1 (fr) Turbine de grenaillage a hautes performances equipee de palettes reversibles
WO2002030619A1 (fr) Procede de grenaillage et machine pour la mise en oeuvre d'un tel procede
FR3102385A1 (fr) Dispositif pour l’expansion a froid d’un perçage debouchant
FR2876599A1 (fr) Dispositif pour creer un jet fluide orbital pur ou charge de particules notamment abrasives
FR1459926A (fr) Perfectionnements au dépoussiérage des gaz
FR2912072A1 (fr) Procede de refroidissement et de nettoyage de revetement en cours de depot par projection thermique
FR3085855A1 (fr) Lance a incendie comportant deux rangees de dents intercalees sur la face avant de sa bague de tete
FR2721536A1 (fr) Procédé et dispositif de pulvérisation de liquide.
BE546728A (de)

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AT BE CH DE DK ES FR GB GR IT LI LU NL SE

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 19910628