EP1769859B1 - Verfahren und Vorrichtung zur Herstellung einer hohlen Zahnstange - Google Patents

Verfahren und Vorrichtung zur Herstellung einer hohlen Zahnstange Download PDF

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Publication number
EP1769859B1
EP1769859B1 EP20050021222 EP05021222A EP1769859B1 EP 1769859 B1 EP1769859 B1 EP 1769859B1 EP 20050021222 EP20050021222 EP 20050021222 EP 05021222 A EP05021222 A EP 05021222A EP 1769859 B1 EP1769859 B1 EP 1769859B1
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EP
European Patent Office
Prior art keywords
shuttle
working
die
stocker
blank
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.)
Expired - Fee Related
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EP20050021222
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English (en)
French (fr)
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EP1769859A1 (de
Inventor
Seiji Shiokawa
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Shiokawa Hirohisa
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Shiokawa Hirohisa
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Publication date
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Priority to DE200560009196 priority Critical patent/DE602005009196D1/de
Priority to EP20050021222 priority patent/EP1769859B1/de
Publication of EP1769859A1 publication Critical patent/EP1769859A1/de
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Publication of EP1769859B1 publication Critical patent/EP1769859B1/de
Expired - Fee Related legal-status Critical Current
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21K—MAKING FORGED OR PRESSED METAL PRODUCTS, e.g. HORSE-SHOES, RIVETS, BOLTS OR WHEELS
    • B21K1/00—Making machine elements
    • B21K1/76—Making machine elements elements not mentioned in one of the preceding groups
    • B21K1/767—Toothed racks
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
    • B21C37/00—Manufacture of metal sheets, bars, wire, tubes or like semi-manufactured products, not otherwise provided for; Manufacture of tubes of special shape
    • B21C37/06—Manufacture of metal sheets, bars, wire, tubes or like semi-manufactured products, not otherwise provided for; Manufacture of tubes of special shape of tubes or metal hoses; Combined procedures for making tubes, e.g. for making multi-wall tubes
    • B21C37/15—Making tubes of special shape; Making tube fittings
    • B21C37/20—Making helical or similar guides in or on tubes without removing material, e.g. by drawing same over mandrels, by pushing same through dies ; Making tubes with angled walls, ribbed tubes and tubes with decorated walls
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21K—MAKING FORGED OR PRESSED METAL PRODUCTS, e.g. HORSE-SHOES, RIVETS, BOLTS OR WHEELS
    • B21K1/00—Making machine elements
    • B21K1/06—Making machine elements axles or shafts
    • B21K1/063—Making machine elements axles or shafts hollow

Definitions

  • the present invention relates to method and apparatus for producing a hollow rack bar.
  • a rack bar is for example used for a power steering device in an automobile.
  • a rack bar used for a power steering device in an automobile has conventionally been machined from a solid bar of a rounded cross-sectional shape.
  • a method has recently been proposed for producing a hollow rack bar from a pipe shaped blank by a forging process.
  • a power steering apparatus which is changed to an electrically operated type from a hydraulically operated type.
  • an attention is focused to a VGR (variable gear ratio) type of rack bar, wherein a pitch (spacing) and a pitch angle are non-uniform as compared with a standard type of rack bar wherein a pitch as well as pitch ration are fixed and unchanged.
  • a mandrel is inserted into a cavity of the pipe shaped blank under a pressure.
  • the mandrel is provided with an operating head portion of a taper shape, which is engaged with the flattened portion of the blank pipe, thereby generating an outwardly directed plastic flow of the material at the flattened portion toward the toothed portions of the die.
  • linear toothed portions the shape of which corresponds to those of the toothed portions of the die, are formed on the flattened portion of the pipe under a transferring principle, thereby obtaining a rack bar.
  • a stocker of vertical shift type or turret (rotating) type for mandrels of different operating heights is provided.
  • a shifting operation or rotating operation is done in the stocker, so that a consecutive selection of a mandrel of step-likely increased operating height, which is inserted to the pipe shaped blank, is obtained, in a manner that a progressive working is realized.
  • a hydraulic linear driving device is provided for obtaining linear reciprocating movement of a mandrel from the mandrel stockers.
  • the mandrel is of a highly elongated one, which is comprised of a working head and an integrated elongated rod integrally extended from the working head, which allows the working head to be inserted to the blank. This construction of the mandrel may cause it production cost to be high.
  • a periodical exchange due to the wear is essential, which causes the running cost to be also high.
  • a vertical or rotating shifting operation of mandrels of increased size as well as weight is required, which makes the shifting device to be of a large size, thereby enhancing the cost of the device itself.
  • German Patent application DE 199 18 230 A1 discloses a method for producing a cylinder liner blank which is to be incorporated in a cast light metal crank case.
  • the method comprises mechanical roughening of the cast material-contacting outside surface of the blank, by radial embossing using one or more embossing tools which bear the requisite roughness profile as a negative embossing structure.
  • An object of the present invention aims to combat the above mentioned difficulties in the prior art and, more particularly, to obtain an increased cost reduction not only in a view point of a part exchange cost but also in a view point of an equipment cost.
  • a method for producing a hollow rack bar comprising the steps of:
  • an apparatus for producing a hollow rack bar comprising:
  • the separate construction in the present invention makes it possible that a single presser member is commonly used between a plurality of short-sized working member (shuttles) for different working stages, resulting in a reduced cost for a rack bar formation, when compared with the prior art where a plurality of long sized mandrel for different working stages are employed. Namely, in the rack bar formation, a large force is generated, which make a part to be subjected to abrasion, resulting in the part to be changed. In the present invention, only exchange in the short sized working member of a relatively reduced cost is enough. Contrary to this, in the prior art, an occurrence of a abrasion makes it to be needed that an entire mandrel of increased cost is exchanged.
  • the present invention using the shuttle type short-sized working member makes a running cost to be reduced over the prior art where a long sized mandrel is used.
  • the short sized working members (shuttles) are cooperated with a presser rod for executing a rack bar formation, thereby keeping a desired quality of the products over those obtained by the prior art where long sized mandrels are employed.
  • an advantage will be explained with reference to a case where the present is employed for production of a rack bar for a steering mechanism of an automobile.
  • a rack bar is typically produced from a blank pipe under left-handed six steps and right-handed six steps, i.e., totally twelve working stages (steps).
  • shuttles of a length can be reduced to those of a length of 60mm, although a left-handed and a left-handed commonly used two presser rods of a length of 900mm are needed.
  • a production cost will now be compared between the prior art and the present invention.
  • a cost of a working head portion of a length of 60mm is 40, 000yens and a cost of a presser rod portion of a length of 900mm is 200,000yens.
  • a service life of a working head part is estimated such that it can be used for a production of 100,000 parts.
  • the present invention can obtain one sixth reduction of the running cost over the prior art.
  • a blank pipe as a work piece has a circular cross-sectional shape.
  • the blank pipe is held between an upper die having inner toothed portions and a lower die having a semi-circular cross-sectional shape.
  • the portion of the blank pipe, on which toothed portions are formed, is subjected to a diameter reduction of a value about 1mm in comparison with the remaining portion of the pipe and is flattened in a manner that a substantial semi-circular shape is obtained.
  • a short-sized working member (shuttle) of substantially semi-circular cross-sectional shape and having stepped head portions is inserted to the inner diameter of the blank pipe.
  • the shuttle is, at the portion with no diameter reduction, freely rotatable. However, the free rotational movement of the shuttle allows the semi-circular cross-sectional shape of the shuttle to be finally aligned with that of the cavity of the work, thereby proceeding the working of the blank pipe by the toothed portions of the shuttle.
  • the long-sized presser rod is connected to the shuttle in a manner that a free rotating movement of the shuttle is prevented with respect to the presser rod.
  • an insertion of the shuttle member to the blank pipe is always done at a desired orientation of the shuttle.
  • any end-to-end contact is prevented from being occurred, when the shuttle is inserted to the portion of the blank pipe of the semi-circular cross-sectional shape, which allows the working (rack forging) to be smoothly executed.
  • a plurality of shuttles having progressively changed working heights are stored in stockers located on both sides of the die for holding a blank pipe.
  • the stocker is subjected to a shift movement, so that a shuttle of step-likely increased operating height is selected from the stocker and is inserted into a work piece (blank pipe), resulting in a step by step working of the work piece of desired number of working stages.
  • a selection of shuttle is done alternately between the stocker on one side of the die set and the stocker on the other side, thereby obtaining symmetrical flow of metal to the die, resulting in an increased precision of a rack bar as a product.
  • the stocker is constructed by holders for shuttles and springs for resiliently urging the shuttles in place in the respective holders.
  • the stocker of a reduced size as well as a reduce weight can be used due to the fact the shuttles stored in the stocker are of reduced length.
  • a reduced pitch and an increased speed of the vertical shifting movement of the stocker are obtained.
  • a rack bar production of an increased efficiency is obtained, while preventing any vibration problem from being occurred, which would occur if a long sized mandrel in the prior art as long as 950mm is used.
  • a mandrel for forging a rack bar from a blank pipe, a mandrel is constructed by a shuttle shaped (short length) working member and an elongated (long sized) presser member detachable from said short-sized working member but cooperating with the shuttle shaped working member.
  • the shuttle shaped working members of a number corresponding to that of working stages are needed.
  • a presser member is commonly used between the shuttle shaped working members, resulting in a reduction in the part cost as well as a running cost.
  • Figs 1A to 1G illustrate, schematically, a series of processes of a rack bar production according to the present invention.
  • a reference numeral 1 denotes a steel pipe as a hollow blank, which is arranged between split dies 2 and 3 constructing a die set.
  • the lower die 3 functioning as a clamping die is, at its transverse cross-section, a inner surface 3A of a semi-circular shape, on which the pipe 1 is rested.
  • the upper die 2 functions as a clamping die as well as an embedded type holder for toothed portions and has toothed portions 2A (tooth profile) spaced along the length of the die 2.
  • a linear toothed shape corresponding to that of the toothed shape of the upper die 2 is formed on or transferred to an upper side of the pipe 1, resulting in a production of a rack bar.
  • the upper and lower dies 2 and 3 are combined with each other, so that the pipe 1 is contacted with the toothed portions 2A at the inner surface of the upper die 2.
  • the pipe 1 is, at its portion contacting with the upper die 2, collapsed in a manner that slightly inwardly recessed flattened upper surface 1A is obtained.
  • a shuttle member as a short-sized operating head 6L or 6R ( Figs.
  • the blank pipe 1 is subjected to a tooth shape formation under transferal forging principle at a portion of a length, for example, of about 250mm from the left-handed end of the pipe 1 in Figs. 1A to 1G .
  • the pipe 1 is at a portion of a length, for example, of about 500mm rightward from the toothed portion forms a completely rounded cross-sectional shape.
  • the portion of the rounded cross-sectional shape is, as shown in Figs. 1A to 1G , partly and freely protruded from the right hand end of the dies 2 and 3 for a length, for example, of about 300mm.
  • the shuttles 6L and 6R have a length of roughly about 60mm and are provided with a plurality of operating heads, as will be described later.
  • the presser rods 5L and 5R have, simply, a circular cross-sectional shape of a fixed diameter, which is smaller than the dimension of the shuttles 6L and 6R, so that any slippage does not occur even under the effect of pressing force as generated by the execution of an expanding forming operation.
  • These shuttles 6L and 6R of varied operating sizes are stored in a left-handed and right-handed outside stockers 7L and 7R, respectively, in such a manner that a vertical or rotary shifting of the shuttles 6L and 6R is occurred in the stockers 7L and 7R, respectively.
  • a pair of the presser rods 5L and 5R is arranged at positions outwardly from the respective stockers 7L and 7R.
  • Fig. 3 illustrates a shuttle 6L 1 , which is inserted into a blank pipe 1 in the right-handed direction as shown in Fig. 1A just after the completion of the flattening of the pipe 1 by a die clamping.
  • the shuttle 6L 1 in the direction of the insertion, has a right-handed end 6-1, where an introduction of the shuttle 6L 1 to the blank pipe is started and a left-handed end 6-2, where a withdrawal of the shuttle 6L 1 from the blank pipe is started.
  • the shuttle 6L 1 is formed with a recess 60, to which a leading end 5L-1 of the left-handed presser rod 5L is engaged, so that an insertion under a pressure of the shuttle 6L 1 into a cavity of a blank pipe is executed.
  • the shuttle 6L 1 is longitudinally reciprocated in the cavity of the blank pipe 1, while the shuttle 6L 1 keeps, at its bottom surface 6-3, a close contacted with the rounded inner surface of the blank pipe, as shown in Fig. 4 .
  • the shuttle has a pair of opposed flat surfaces 6-4, which are slightly spaced from the opposed rounded inner surface of the blank pipe 1.
  • the shuttle has top flat surfaces, which construct tri-stepped operating head portions 6-5, 6-6 and 6-7 of values of height h 1 , h 2 and h 3 , respectively. Forwardly from the operating head portions 6-5, 6-6 and 6-7 in the direction of the insertion of the shuttle to the blank pipe as shown by an arrow a in Fig. 3 , the shuttle is formed with tapered guiding portions 6-5A, 6-6A and 6-7A, respectively, so that a smooth movement of the shuttle is obtained irrespective of the flow resistance of the material during the execution of the rack formation.
  • the shuttle forms slightly recessed portions for storage of lubricant fed during the forged formation of rack under press insertion, thereby providing a desired lubricity to the shuttle.
  • the upper surface 1A of the pipe is flattened while being centrally recessed, i.e., the pipe is formed to a quasi-semicircular cross-sectional shape, as already explained with reference to Fig. 2A .
  • an introduction of the shuttle 6L 1 , to the blank pipe 1 is commenced. Namely, the shuttle 6L 1 is, from its leading end 6-1, introduced into the cavity of the blank pipe 1.
  • the first operating or enlarging head 6-5 of an operating height of h 1 is engaged with the flattened portion 1A of the pipe 1, which causes the material of the pipe to be expanded or displaced (plastically flown) toward the toothed portion 2A at the inner surface of the upper die 2.
  • a metal flow by the second operating head 6-6 of the height of h 2 and after guided by the tapered surfaces 6-7A a metal flow by the third operating head 6-7 of the height of h 3 are sequentially operated. As a result, a smooth step-like progress of the forging operation is obtained.
  • Fig. 5 illustrates a construction of a shuttle 6R 1 , which is inserted into a blank pipe 1 in the left-handed direction as shown by an arrow b for the second stage processing when a withdrawal of the shuttle 6L 1 in the left-handed direction is done due to the completion of the first stage working by the shuttle 6L 1 .
  • the shuttle 6R 1 in the direction of the insertion, has a left-handed end 6'-1, where an introduction of the shuttle 6R 1 to the blank pipe is started and a right-handed end 6'-2, where a withdrawal of the shuttle 6R 1 from the blank pipe is started.
  • the shuttle 6R 1 is formed with a recess 60', to which a leading end 5R-1 of the right-handed presser rod 5R is engaged, so that an insertion under a pressure of the shuttle 6R 1 into a cavity of a blank pipe is executed.
  • the shuttle 6R 1 in Fig. 5 is formed with three step working heads 6'-5, 6' -6 and 6' -7, of which heights are step-likely increased as illustrated by h 4 , h 5 and h 6 , respectively, in the direction of the insertion of the shuttle 6R 1 as shown by the arrow b .
  • the height h 4 of the first operating (enlarging) head 6'-5 of the shuttle 6R 1 in the direction of the insertion as shown by the arrow b is decided in accordance with the height h 3 of the third working head 6-7 of the shuttle 6R 1 , i.e., the highest value of the working head height during the preceding working stage in the opposite insertion direction. Namely, after the withdrawal of the inserted shuttle 6L 1 , some degree of a spring back (shrinkage of the worked portion) is occurred in the blank 1.
  • the height of height h 4 of the first operating head 6'-5 of the shuttle 6R 1 is such that a desired expansion amount is obtained irrespective of inevitable occurrence of the spring back as generated after the completion of the preceding working in the opposite insertion direction.
  • the blank is sequentially engaged with heads 6'-5, 6'-6 and 6'-7, so that a smooth, further plastic flow of the material of the blank 1 toward the toothed portions 2A of the die is obtained.
  • a shuttle used for the following third stage working is, as similar to that shown in Fig. 3 , inserted in the right-handed direction. But, the values of the heights of its working heads are such that a further increased expansion is done when compared with that obtained at the preceding second stage working.
  • a shuttle having further increased heights of operating heads is used and is inserted in the left-handed direction as similar to the shuttle for the second stage shown in Fig. 5 .
  • a desired number of total working stages such as twelve working stages are obtained, resulting in a final completion of the rack forming process.
  • Fig. 2B schematically illustrates a positional relationship of a shuttle 6" for the final working stage to the blank pipe 1.
  • the shuttle 6" has a height, which is enough for causing the material to be fully expanded or flown to the toothed portions 2A of the die, so that a forging of toothed portions corresponding to those 2A of the die on the upper portion of the pipe 1, i.e., a transfer type rack formation is completed.
  • the recesses 60 and 60' formed in the shuttles for preventing any free rotating movement between the shuttles and the respective presser rods 5L and 5R are effective for obtaining a smooth movement of the shuttles.
  • the shuttles effect mere end-to-end contact with the presser rods 5L and 5R, which allows a relative free angular relative movement to be generated between contacted parts.
  • a situation may be arisen where an introduction of a shuttle to a portion the blank pipe of rounded cross-sectional shape is done while the shuttle is an angularly displaced from a desired angular position and a continued insertion of the shuttle may cause the latter to be blocked when the shuttle is engaged with the portion of the blank pipe of the semicircular cross-sectional shape.
  • a certain mechanism is essential for obtaining a corrective, relative angular movement in a manner that the operating head portions of the shuttle is finally engaged with the flattened portion 1A of the blank pipe, thereby obtaining a desired forged operation.
  • a process for forming a rack according to the present invention wherein shuttles are reciprocated in the cavity of a blank pipe 1 held between the dies 2 and 3.
  • the stockers 7L and 7R are arranged on the respective sides of a blank pipe 1 as a work piece.
  • Arranged in the stockers 7L and 7R are shuttles of step-likely increased values of operating height.
  • the shuttles on the left-handed side are designated by 6L followed by shift numbers and the shuttles on the right-handed side are designated by reference number 6R followed by shift numbers in a similar way.
  • a shuttle of the first shift position is designated by 6L 1
  • a shuttle for the second shift position by 6L 2 is designated by 6L 3
  • a shuttle for the third shift position by 6L 3 is designated by 6R 1
  • a shuttle for the second shift position by 6R 2 is designated by 6R 3 .
  • Fig. 1A illustrates a preparatory condition, where a blank pipe 1 is held by the dies 2 and 3.
  • the left-handed presser rod 5L is opposed to the shuttle 6L 1 ( Fig. 3 ) for the first stage working and the right-handed presser rod 5R is opposed to the shuttle 6R 1 ( Fig. 3 ) for the second stage working.
  • a movement of the left-handed presser rod 5L in the right-handed direction is started, which causes its leading end 5L-1 ( Fig. 3 ) to be engaged with the recess 60 of the shuttle 6L 1 .
  • the continued movement of the presser rod 5L in the right-handed direction in Fig. 1A is continued, so that the shuttle 6L 1 is, first, moved out from the stocker 7L and, then, is inserted into the cavity of the blank pipe 1. Due to the insertion of the into the cavity of the blank pipe 1, the first stage working by the operating heads 6-5, 6-6 and 6-7 of successively increased values of height is done as already explained with reference to Fig. 3 .
  • the shuttle 6L 1 As the end of the right-handed stroke of the left-handed presser rod 5L, the shuttle 6L 1 is completely passed the toothed portions 2A of the upper die 2 as shown in Fig. 1B and is stopped at a position in the pipe 1, which is a preparatory position for the following second stage working.
  • the second stage working is started by a movement of the right-handed presser rod 5R in the left-handed direction in Fig. 1B .
  • the presser rod 5R is, first, at its leading end 5R-1, engaged with the recess 60' as shown in Fig. 5 .
  • the shuttle 6R 1 is moved out from the right-handed stocker 7R and, then, the shuttle 6R 1 is inserted into the cavity of the blank pipe 1 from its right-handed end. Then, the shuttle 6R 1 is made end-to-end contact with the shuttle 6L 1 .
  • the shuttle 6L 1 is moved in the left-handed direction, due to the fact that the left-handed presser rod 5L is in a retracted position as shown Fig. 1C .
  • the second stage working of the blank pipe 1 is done by the shuttle 6R 1 , which has the operating heads 6'-5, 6'-6 and 6'-7 as shown in Fig. 5 .
  • the metal is further plastically flown toward the toothed portions 2A of the die.
  • the shuttle 6L 1 which is still under an end-to-end contact with the right-handed shuttle 6R 1 , is stored in the stocker 7L while the shuttle 6R 1 is engaged out of the toothed portions 2A of the die, i.e., the second stage working of the blank pipe 1 by the shuttle 6R 1 is finished.
  • one step upward shift of the left-handed stocker 7L is obtained in a manner that the second step shuttle 6L 2 is aligned with the left-handed presser rod 5L as shown in Fig. 1D .
  • the presser rod 5L is moved in the right-handed direction, so that a third stage working of the blank pipe 1 by means of the working heads of the shuttle 6L 2 is executed.
  • the shuttle 6R 1 executed the preceding second stage working is entrained by the shuttle 6L 2 and is moved back in the right-handed direction toward the stocker 7R.
  • the left-handed movement of the right-handed presser rod 5R i.e., the entrained movement of the shuttle 6R 2 is ceased when a condition as shown in Fig. 1G is obtained, where the shuttle 6L 2 is stored in the designated position in the left-handed stocker 7L.
  • an alternate insertion is done between the shuttles 6L 1 , 6L 2 , 6L 3 , — and 6L n in the left-handed stocker 7L and the shuttles 6R 1 , 6R 2 , 6R 3 , ising and 6R n in the right-handed stocker 7R.
  • a selection of a shuttle for working from the respective stocker is such that the operating height is progressively or gradually increased.
  • the stocker 7L and 7R are subjected to an upward step-by-step shift movement.
  • a shuttle used at the preceding working stage is entrained by the movement of the shuttle effecting the instant working stage and returned to a designated position of the respective stocker. In this way, a desired number of working stages, such as 12 is obtained, resulting in a reliable and highly qualified formation of a rack bar under a transfer forging basis.
  • Figs. 6 to 8 schematically illustrates a schematic construction of a stocker 7.
  • the stocker 7 corresponds to the right-handed stocker 7R shown in Fig. 1 .
  • the stocker 7 is formed with a pair of upright stands 9 having opposed guide grooves 9A, to which the stocker 7 is vertically slidably mounted.
  • two pipes 1 as work pieces are simultaneously worked. Namely, as shown in Figs. 6 and 7 , two pipes 1 are, under a parallel condition, held between the upper and lower dies 2 and 3 and two presser rods 5 insert simultaneously two shuttles 6 to respective pipes 1 via a stocker 7.
  • the shuttles 6 for working the respective pipes are stored in respective shuttle holders 10.
  • a plurality of vertically spaced pairs of horizontally spaced holders 10 for left-handed and right-handed shuttles are provided, the number of which pair corresponds to the number of shift (six in the embodiment in Fig. 8 ).
  • the pair of horizontally spaced presser rods 5 are, at their ends spaced from the corresponding stocker 7, held by a holder 11, which is carried by a cross frame 13 moved or operated by a hydraulic cylinder 14.
  • the hydraulic cylinder 14 has a piston rod 14-1 having an end connected to the cross bar 13 unit is cylinder frame 13.
  • a well-known mechanism is provided for controlling a direction of flow of pressure liquid to the cylinder 14 in a manner that a desired movement of the presser rods 5 is obtained.
  • a drive mechanism such as a hydraulic mechanism is provided for obtaining a vertical shift movement of the stocker 7.
  • a working is started from the shuttles 6 located at the top of the stocker 7 by causing the respective shuttle holders 10 to be aligned with the pipe 1 as a work piece.
  • the presser rod 5 is operated so that the shuttle 10 is moved out of the respective holder 10 in the stocker 7 and is inserted to the inner cavity of the pipe 1.
  • An upward shift (selection) movement of the stocker followed by a working by released shuttles from respective holders for the working is done under a step-by step basis.
  • the stocker 7 is in a vertically shifted position where a shuttle 6A in the fourth position from the top is aligned with the blank pipe 1 as a work piece as well as the presser rod 5.
  • a forward movement of the presser rod 5 in the left-handed direction as shown by an arrow f causes the shuttle 6A to be released from the respective holder 10A and to be inserted to the blank pipe 1.
  • Figs. 9 and 10 illustrate a construction for holding a shuttle 6 by a shuttle holder 10 in a stocker 7.
  • the shuttle holder 10 forms a sleeve shape, which is inserted to a tubular cavity 7A of the stocker 7 and is locked in a predetermined position in the stocker 7 by means of a ball shaped notch member 17.
  • the shuttle holder 10 forms a semi-spherical recess 10A, with which the ball shaped notch member 17 is engaged under a preset load as obtained by a spring 18 stored in a bore 7B in the stocker 7.
  • a set screw 19 is screwed to the bore 7B, which allows the spring load by the spring 18 to be adjusted.
  • Fig. 9 and 10 illustrate a construction for holding a shuttle 6 by a shuttle holder 10 in a stocker 7.
  • the shuttle holder 10 forms a sleeve shape, which is inserted to a tubular cavity 7A of the stocker 7 and is locked in a predetermined position in the
  • the shuttle holder 10 is formed with an axially extending tubular cavity 22 therethrough, which has a cross-sectional shape, which corresponds to that of the shuttle 6 as shown in Fig. 10 .
  • the shuttle 6 is, at its curved bottom surface 6-3 and the flat side surfaces 6-4, closely and slidably engaged with the opposed surface of the shuttle cavity 22.
  • the shuttle 6 is, at its operating head portion 6-7A of the maximum height, closely and slidably engaged with the opposed upper flat surface of the shuttle cavity 22.
  • a stopper plate 24 is fixed to an end surface of the stocker 7 by any suitable means and has a bottom end extending slightly out of an inner edge of the bore 22.
  • the shuttle holder 10 is formed with a vertical bore 26 extending radially therethrough, in which a ball shaped locking member 28 is stored.
  • the ball shaped locking member 28 is, as shown in Fig. 8 , engaged with a tapered guiding surface 6-7A of the shuttle 6 adjacent the operating head 6-7 under the set force as obtained by the spring 30, so that the shuttle 6 is held in a predetermined position in the corresponding shuttle holder 10 under a preset spring load.
  • a set screw 32 is in contact with the spring 30, so that a desired adjustment of the spring force (load) as generated by the spring 30 is made possible.
  • the shuttle holder 10 is further formed with a hole 34 for feeding lubricating oil.
  • Fig. 9 the presser rod 5 is moved forwardly as shown by an arrow for starting the rack bar formation.
  • a continued movement causes the leading end 5-1 of the presser rod 5 to be fitted with the recess 60 of a shuttle 60.
  • the shuttle 60 is moved in the same direction (left-handed direction in Fig. 9 ), while the ball 28 engaged with the tapered surface 6-7A of the shuttle 60 is displaced upwardly against the force of the set spring 30.
  • a continuation of such a movement of the shuttle 60 in the left-handed direction of Fig. 9 finally causes the shuttle 60 to be released from the shuttle holder 10 and is inserted to a cavity of a blank pipe as a work piece as already described in detail with reference to Figs. 1A to 1G and Figs. 6 to 8 .

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  • Mechanical Engineering (AREA)
  • Forging (AREA)

Claims (6)

  1. Verfahren zur Herstellung einer hohlen Zahnstange, umfassend die Schritte:
    Bereitstellen eines Gesenks (2) mit darin gebildeten gezahnten Bereichen (2A);
    Bereitstellen eines schiffchenförmigen Bearbeitungsorgans (6L, 6R) und eines länglichen Drückerorgans (5L, 5R) gesondert von dem Bearbeitungsorgan (6L, 6R);
    Schließen des Gesenks (2), so dass ein hohler Rohling (1) durch das Gesenk (2) gehalten wird; und
    Einführen des Bearbeitungsorgans (6L, 6R) in einen Hohlraum des hohlen Rohlings (1) unter Druck, wobei das Bearbeitungsorgan (6L, 6R) und das längliche Drückerorgan (5L, 5R) zusammenwirken, so dass ein auswärts gerichtetes plastisches Fließen des Materials des Rohlings (1) in Richtung der gezahnten Bereiche (2A) des Gesenks (2) erhalten wird, wodurch eine Zahnstange geformt wird.
  2. Verfahren zur Herstellung einer hohlen Zahnstange, umfassend die Schritte:
    Bereitstellen eines Gesenks (2) mit darin gebildeten gezahnten Bereichen (2A);
    Bereitstellen einer Mehrzahl von schiffchenförmigen Bearbeitungsorganen (6L, 6R) mit stufenartig variierten Werten der Bearbeitungshöhe und eines länglichen Drückerorgans (5L, 5R) gesondert von dem Bearbeitungsorgan (6L, 6R);
    Schließen des Gesenks (2), so dass ein hohler Rohling (1) durch das Gesenk (2) gehalten wird;
    Auswählen eines schiffchenförmigen Bearbeitungsorgans (6L, 6R) aus der Mehrzahl von schiffchenförmigen Bearbeitungsorganen (6L, 6R) derart, dass das Bearbeitungsorgan von graduell erhöhter Bearbeitungshöhe ausgewählt wird;
    Einführen des ausgewählten schiffchenförmigen Bearbeitungsorgans (6L, 6R) in einen Hohlraum des hohlen Rohlings (1) unter Druck, wobei das Bearbeitungsorgan (6L, 6R) und das längliche Drückerorgan (5L, 5R) zusammenwirken, so dass ein auswärts gerichtetes plastisches Fließen des Materials des Rohlings (1) in Richtung des gezahnten Bereichs (2A) des Gesenks (2) erhalten wird; und
    Wiederholen der Auswahl- und Einführungsschritte bis eine Bearbeitung durch das abschließend gewählte schiffchenförmige Bearbeitungsorgan (6L, 6R) abgeschlossen ist, wodurch ein mehrstufiges Formen einer Zahnstange vollendet wird.
  3. Vorrichtung zur Herstellung einer hohlen Zahnstange, umfassend:
    ein Gesenk (2) mit darin gebildeten gezahnten Bereichen (2A) zum Halten eines rohrförmigen Rohlings (1);
    einen Satz von schiffchenförmigen Bearbeitungsorganen (6L, 6R) mit stufenartig variierten Bearbeitungshöhen;
    eine Aufnahmevorrichtung (7L, 7R) auf mindestens einer Seite des Gesenks (2) zum Speichern des Satzes von schiffchenförmigen Bearbeitungsorganen (6L, 6R) derart, dass ein gewünschtes aus den Bearbeitungsorganen (6L, 6R) ausgewählt wird; und
    ein längliches Drückerorgan (5L, 5R), lokalisiert auf einer von dem Gesenk (2) entfernten Seite der Aufnahmevorrichtung (7L, 7R), wobei das längliche Drückerorgan (5L, 5R) und das ausgewählte Bearbeitungsorgan (6L, 6R) derart zusammenwirken, dass Letzteres in den Hohlraum des Rohlings (1) eingeführt wird, so dass ein auswärts gerichtetes Fließen des Materials des Rohlings in Richtung des gezahnten Bereichs (2A) des Gesenks (2) erhalten wird, wodurch eine Zahnstange geformt wird.
  4. Vorrichtung nach Anspruch 3, wobei die Aufnahmevorrichtung (7L, 7R) eine Mehrzahl von entsprechenden Haltern (10) für die Bearbeitungsorgane (6L, 6R) mit stufenartig variierten Bearbeitungshöhen aufweist und Federorgane (18, 30) zum elastischen Drücken der Bearbeitungsorgane (6L, 6R) derart, dass die Bearbeitungsorgane (6L, 6R) an gewünschten Positionen in den entsprechenden Haltern (10) elastisch gehalten werden.
  5. Vorrichtung nach Anspruch 4, wobei die Halter (10) linear beabstandet sind und wobei die Aufnahmevorrichtung (7L, 7R) eine Linearbewegung erfährt, derart, dass ein Bearbeitungsorgan (6L, 6R) von gewünschter Bearbeitungshöhe ausgewählt und mit dem Drückerorgan (5L, 5R) zusammenwirkt, gemäß dem Fortschritt der Zahnstangen-Formungsstufe.
  6. Vorrichtung zur Herstellung einer hohlen Zahnstange, umfassend:
    ein Gesenk (2) mit darin gebildeten gezahnten Bereichen (2A) zum Halten eines rohrförmigen Rohlings (1);
    einen ersten Satz von schiffchenförmigen Bearbeitungsorganen (6L) mit stufenartig variierten Bearbeitungshöhen;
    einen zweiten Satz von schiffchenförmigen Bearbeitungsorganen (6R) mit stufenartig variierten Bearbeitungshöhen;
    eine erste Aufnahmevorrichtung (7L) auf einer Seite des Gesenks (2) zum Speichern des ersten Satzes von schiffchenförmigen Bearbeitungsorganen (6L) derart, dass ein gewünschtes aus den Bearbeitungsorganen (6L) in der ersten Aufnahmevorrichtung (7L) ausgewählt wird;
    eine zweite Aufnahmevorrichtung (7R) auf der anderen Seite des Gesenks (2) zum Speichern des zweiten Satzes von schiffchenförmigen Bearbeitungsorganen (6R) derart, dass ein gewünschtes aus den Bearbeitungsorganen (6R) in der zweiten Aufnahmevorrichtung (7R) ausgewählt wird;
    ein erstes längliches Drückerorgan (5L), lokalisiert auf einer von dem Gesenk (2) entfernten Seite der ersten Aufnahmevorrichtung (7L); und
    ein zweites längliches Drückerorgan (5R), lokalisiert auf einer von dem Gesenk (2) entfernten Seite der zweiten Aufnahmevorrichtung (7R), wobei das erste und das zweite längliche Drückerorgan (5L, 5R) mit dem ausgewählten der Bearbeitungsorgane (6L, 6R) in der ersten bzw. zweiten Aufnahmevorrichtung (7L, 7R) derart zusammenwirkt, dass die ausgewählten Bearbeitungsorgane (6L, 6R) wechselweise in den Hohlraum des Rohlings (1) eingeführt werden, so dass ein auswärts gerichtetes Fließen des Materials des Rohlings (1) in Richtung des gezahnten Bereichs (2A) des Gesenks (2) erhalten wird, wodurch eine Zahnstange geformt wird.
EP20050021222 2005-09-29 2005-09-29 Verfahren und Vorrichtung zur Herstellung einer hohlen Zahnstange Expired - Fee Related EP1769859B1 (de)

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ATE530267T1 (de) 2007-03-20 2011-11-15 Neturen Co Ltd Herstellungsverfahren einer hohlen zahnstange und vorrichtung zum herstellen einer hohlen zahnstange
WO2008138033A1 (en) * 2007-05-09 2008-11-20 Bishop Innovation Limited Hollow steering rack

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US4133221A (en) * 1977-06-23 1979-01-09 Trw, Inc. Rack gear and method of making the same
DE2758134C2 (de) * 1977-12-27 1980-02-28 Metallgesellschaft Ag, 6000 Frankfurt Verfahren zur Herstellung von Wärmetauscherrohre!) mit inneren und äußeren Längsrippen
JPH09141354A (ja) * 1995-11-20 1997-06-03 Aisin Seiki Co Ltd 中空シャフトの高歯たけスプライン製造方法および高歯たけスプラインを備えた中空シャフト
DE19918230C2 (de) * 1999-04-22 2001-06-28 Daimler Chrysler Ag Verfahren zum Herstellen eines aus einer übereutektischen Aluminium-Silizium-Legierung bestehenden, rohrförmigen Rohlings einer Zylinderlaufbüchse
US6575009B2 (en) * 2000-02-14 2003-06-10 Kabushiki Gaisha Koshingiken Mandrel insertion type metal forming of rack bar
JP3901551B2 (ja) * 2001-05-28 2007-04-04 株式会社ショーワ パイプラック成形方法及び装置
JP4077236B2 (ja) * 2002-04-22 2008-04-16 松岡 美奈子 中空ラック部材の製造方法

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