Method and apparatus for manufacturing a composite metal wire by using a two wheel type continuous extrusion apparatus

Abstract: A two wheel type continuous extrusion apparatus is provided with covering material inlet apertures (18a,18b) for communicating passage-ways to a covering chamber for extruding covering material (21a,21b) on a core metal wire (20) to manufacture a composite metal wire (22). The covering material inlet apertures (18a,18b) are inclined relatively to a line (L) connecting rotary axes of the rotary wheels (10a,10b), such that the covering chamber (19) is positioned on the side of supplying the covering material rods (21a,21b) relative to the line (L). Consequently, a constraining force for constraining a shoe block (25) becomes small.

Description: The invention relates to a method and an apparatus for manufacturing a composite metal wire by using a two wheel type continuous extrusion apparatus, and more particularly to the improvement in which the position of covering material inlet apertures is optimized. A conventional apparatus for manufacturing a composite metal wire by using a two wheel type continuous extrusion apparatus comprises two rotary wheels each having a groove on the outer periphery provided symmetrically relative to an extruding direction of the composite metal wire, a fixed shoe block having an arc-edge surface for closing partially the grooves of the rotary wheels to provide two passageways, a nipple having an aperture through which a core metal wire is supplied, two position-changeable abutments each pressed into the groove of a corresponding rotary wheel to close the passageway, and two adjusting bolts each adjusting a contact pressure of a corresponding abutment to the corresponding rotary wheel, wherein the shoe block is provided with a die which is positioned on the side of extruding the composite metal wire in a covering chamber which is defined between the die and the nipple and communicates with the two passageways. In operation, two aluminium rods are supplied into the two passageways, respectively, while the two rotary wheels are rotated to apply drag force to the two aluminium rods, so that the plasticized aluminium is interrupted by the abutments, so that a steel core wire supplied from the nipple is coated with the plasticized aluminium to be extruded from the die. Thus, a composite metal wire having the steel core wire coated with a covering layer of aluminium is manufactured by using the two wheel type continuous extrusion apparatus. In this two wheel type continuous extrusion apparatus, the covering chamber is connected via covering material inlet apertures to the passageways, wherein the covering material inlet apertures are provided vertical to the extrusion direction of the composite metal wire to be positioned on a line connecting the rotary axes of the rotary wheels. In another conventional apparatus for manufacturing a composite metal wire by using a two wheel type continuous extrusion apparatus, a covering chamber is provided on the opposite side of supplying covering material rods relative to a line connecting the rotary axes of the rotary wheels, such that the covering material inlet apertures are inclined relatively to the extrusion direction of the composite metal wire. In addition, the combination of abutments and a nipple is replaced by an abutment which is formed with a nipple in an integral manner. According to the former conventional apparatus for manufacturing a composite metal wire, however, there is a disadvantage in that the burr formation is difficult to avoid as it is increased due to the abrasion, the deformation, etc. of parts of the apparatus such as the rotary wheels, because the position change of the abutments is small which results in insufficient adjustment which cannot provide a predetermined seal effect between the grooves of the rotary wheels and the abutments. Consequently, the parts must be replaced sooner. This results in troublesome and more frequent disassembling operation of the fixed shoe block, the position-changeable abutments, etc. Further, there is a disadvantage in that the dimension precision of the parts which are required to manufacture a composite metal wire having a predetermined precision is determined by experiments, so that it takes a long time to adjust the apparatus appropriately. Still further, there is a disadvantage in that a pull-in force (a horizontal component force) of the fixed shoe block caused by the rotation of the rotary wheels is directly applied to the adjusting bolts and a support block for supporting the adjusting bolts, so that the mechanical strength of the support block must be large. On the other hand, the latter conventional apparatus for manufacturing a composite metal wire by using a two wheel type continuous extrusion apparatus is more practical than the former conventional one, because the sealing contact pressure is easily adjusted therein, for the reason that the two separate abutments are largely changed in position, and because the dimension precision of the parts is relieved to some extent. However, there is a disadvantage in that a force for sustaining the abutments must be large, because the covering material inlet apertures are inclined on the opposite side of the covering material supplying rods relatively to the rotary axis connecting line of the rotary wheels. Further there is a disadvantage in that the apparatus cost becomes high, because the total configuration of the fixed shoe block and the abutments becomes large in an integral block, and is therefore divided to be assembled in two sections. Thus a considerable amount of skilled labour is required to assemble and disassemble the apparatus Accordingly, an object of the invention is to provide a method and an apparatus for manufacturing a composite metal wire by using a two wheel type continuous extrusion apparatus in which a seal contact pressure is easily adjusted between each groove of the rotary wheels and each pressure surface of the abutment portions. US-A-5000025 discloses a method for manufacturing a composite metal wire by using a two wheel type continuous extrusion apparatus, comprising the steps of: providing two rotary wheels each having an endless groove on an outer periphery thereof; providing a fixed shoe block having two portions facing the grooves of the two rotary wheels to define two passageways and a die for extruding the composite metal wire; providing an abutment block having two portions for closing said two passageways and a nipple for supplying a core metal wire; defining two covering material inlet apertures, inclined at a predetermined angle relative to a line connecting rotary axes of the two rotary wheels and communicating with the two passageways and a covering chamber including the die and the nipple and being communicated with the two covering material inlet apertures between the fixed shoe block and the abutment block; rotating the two rotary wheels in opposite directions; supplying a covering material rods to each passageway to be plasticized therein by a pressure increase and the core metal wire through the nipple to the covering chamber to extrude the composite metal wire from the die, the composite metal wire comprising the core metal wire and a covering material layer extruded on the core metal wire in accordance with the plasticized deformation of the covering material rods; and generating a pull-in force (F 1 ), of the fixed shoe block and a reaction force (F 2 ) resulted from a power of the two rotary wheels equivalent to an extrusion pressure by the rotating of the two rotary wheels; and according to a first aspect of the present invention, such a method is characterised in that the predetermined angle is such that a horizontal component of the pull-in force (F 1 ) is opposite in direction and substantially equal in magnitude to a horizontal component of the reaction force (F 2 ) so that a resultant constraining force (F 0 ) is substantially zero. US-A-5000025 discloses an apparatus for manufacturing a composite metal wire the apparatus comprising two rotary wheels each having an endless groove on an outer periphery provided symmetrically relative to a direction of extruding the composite metal wire; a fixed shoe block having two portions each facing a groove of a respective rotary wheel to define respective passageways and a die for extruding composite metal wire, a covering material rod being supplied, in use, to each passageway; an abutment block having two portions each for closing a respective passageway and a nipple for supplying the core metal wire; and two covering material inlet apertures defined between the fixed shoe block and the abutment block to communicate two passageways to a covering chamber including the nipple and the die; wherein the two covering material inlet apertures are inclined relatively to a line connecting rotary axes of the two rotary wheels by a predetermined angle, so that the covering chamber is positioned on side of the line from which the composite metal wire is withdrawn; and according to a second aspect of the present invention, such an apparatus is characterised in that the covering material inlet apertures are inclined at such an angle that a horizontal component of a pull-in force (F 1 ) of the shoe block is opposite in direction and substantially equal in magnitude to a horizontal component of a reaction force (F 2 ) of the rotary wheels so that a resultant constraining force (F 0 ) is substantially zero. In the accompanying drawings: Fig.1 is a cross sectional view showing a first conventional apparatus for manufacturing a composite metal wire by using a two wheel type continuous extrusion apparatus; Fig.2 is a cross sectional view showing a second conventional apparatus for manufacturing a composite metal wire by using a two wheel type continuous extrusion apparatus; Fig.3 is a cross-sectional view showing an apparatus for manufacturing a composite metal wire by using a two wheel type continuous extrusion apparatus of a preferred embodiment according to the invention; Fig. 4 is a cross sectional view showing an enlarged main portion of the preferred apparatus for manufacturing a composite metal wire by using a two wheel type continuous extrusion apparatus; Figs. 5A to 5D are vector diagrams showing each force acting in the preferred apparatus for manufacturing a composite metal wire by using a two wheel type continuous extrusion apparatus; and Fig. 6 is a graph explaining a relation between an angle of covering material inlet apertures and each acting force in the preferred apparatus for manufacturing a composite metal wire by using a two wheel type continuous extrusion apparatus. Before explaining an apparatus for manufacturing a composite metal wire by using a two wheel type continuous extrusion apparatus of a preferred embodiment according to the invention, the aforementioned conventional apparatus for manufacturing a composite metal wire by using a two wheel type continuous extrusion apparatus will be explained in Figs. 1 and 2. Fig. 1 shows the first conventional apparatus for manufacturing a composite metal wire by using a two wheel type continuous extrusion apparatus which comprises rotary wheels 10a and 10b having grooves 11a and 11b on the outer peripheries, a fixed shoe block 12 having a die 13 provided to define passage-ways along portions of the grooves 11a and 11b of the rotary wheels 10a and 10b, abutments 14a and 14b for closing the passage-ways in accordance with the pressure contact to the rotary wheel grooves 11a and 11b, a nipple 15 through which a core metal wire 20 is supplied, a support block 17 for constraining the abutments 14a and 14b, and bolts 16a and 16b for adjusting the position of the abutments 16a and 16b. In this apparatus, covering material inlet apertures 18a and 18b and a covering chamber 19 are defined between the fixed shoe block 12 and the nipple 15, such that they are positioned on a line L which connects rotary axes of the rotary wheels 10a and 10b. In manufacturing a composite metal wire 22, covering material rods (for instance, aluminium) 21a and 21b are supplied along the rotary wheel grooves 11a and 11b via the passage-ways and the covering material inlet aperures 18a and 18b to the covering chamber 19, in which the plasticized covering material applies pressure on the outer surface of the core metal wire (for instance, steel) 20, so that a composite metal wire 22 is extruded from the die 18. In this apparatus, the seal contact pressure of the abutments 14a and 14b on the inner surfaces of the rotary wheel grooves 11a and 11b is adjusted in accordance with the position shift of the abutments 14a and 14b carried out in the extrusion direction and the reverse direction thereof by the bolts 16a and 16b. Fig.2 shows the second conventional apparatus for manufacturing a composite metal wire by using a two wheel type continuous extrusion apparatus, wherein like parts are indicated by like reference numerals as used in Fig. 1. In this apparatus, covering material inlet apertures 18a and 18b are inclined relatively to a line L connecting the rotary axes of the wheels 10a and 10b by an angle , such that a covering chamber 19 is positioned on the opposite side of the supply of the covering material rods 21a and 21b relative to the connecting line L. In addition, a nipple 15 is defined by an abutment 23, such that the horizontal position shift of the abutment 23 may be different in amount to adjust not only a horizontal pressure but also a vertical pressure. In accordance with the first and second conventional apparatus for manufacturing a composite metal wire by using a two wheel type continuous extrusion apparatus, however, the aforementioned disadvantages result. Next, an apparatus for manufacturing a composite metal wire by using a two wheel type continuous extrusion apparatus of a preferred embodiment according to the invention will be explained in Fig. 3, wherein like parts are indicated by like reference numerals as used in Figs. 1 and 2. In this preferred apparatus, covering material inlet apertures 18a and 18b are inclined relatively to a line L connecting the rotary axes of the wheels 10a and 10b in the opposite direction to that in Fig. 2 by an angle , such that the covering chamber 19 is positioned on the side of supply of the covering material rods 21a and 21b relative to the connecting line L. In addition, the support block 17 is provided to adjust the position of fixed shoe block 25 by using bolts 16a and 16b, and heat proof alloy ring members 26a and 26b are provided on the inner surface of the covering material inlet apertures 18a and 18b. The shoe block 25 and the abutment block 24 are preferably one integral block. Next, various forces acting on parts of the apparatus for manufacturing the composite metal wire 22 by using a two wheel type continuous extrusion apparatus will be explained. In Fig. 4, a pull-in force F 1 for pulling the fixed shoe block 25 into the vector direction in accordance with the rotation of the rotary wheel 10a, and a reaction force F 2 caused by a power (extrusion force) of the rotary wheel 10a are shown. The relation of the forces F 1 and F 2 and a constraining force F 0 for constraining the fixed shoe block 25 will be explained in Figs. 5A to 5D, wherein each vector is shown to be positive in the direction opposite to the extrusion direction and negative in the extrusion direction. The constraining force F 0 has the same magnitude as a combined force of a vertical component f 1 of the pull-in force F 1 and that of the reaction force F 2 , and a reversely directional vector relative to the direction of the combined force. If it is assumed that the pull-in force F 1 end the reaction force F 2 have vectors as shown in Figs. 5A and 5B, the constraining forces F 0 will be a negative value as shown in Fig. 5C or a positive value as shown in Fig. 5D. Fig.6 shows a force F acting in the horizontal direction relative to an angle  with which the covering material inlet aperture 18a is defined relatively to the connecting line L, wherein the force F is positive in the extrusion direction, and the angle  is positive in the counter-clockwise direction, so that the angle  is negative in the preferred embodiment. As understood from the curves represented in Fig. 6, the horizontal component f 1 of the pull-in force F 1 acts constantly in the positive direction regardless of the defined angle  of the covering material inlet aperture 18a, and is the maximum value in the vicinity of the angle (=0°), and the horizontal component f 2 of the reaction force F 2 is approximately negative in the region where the angle  is negative, and positive in the region where the angle  is positive, wherein the absolute value thereof is proportional to the absolute value of the angle . The constraining force F 0 which is the combined force of the horizontal forces f 1 and f 2 becomes zero at a predetermined negative angle  c , while it becomes a negative value on the negative side of the angle  c , and a positive value on the positive side thereof. Even worse, the constraining force F 0 becomes large as the angle  is increased in the positive direction. For this reason, the angle  is set to be approximately the angle  c , so that the constraining force F 0 becomes zero or a relatively small value to make the position shift of the fixed shoe block 25 possible by a small external force. As a matter of course, a minute position adjustment can be also made easily. When the angle  is on the negative side of the angle  c , the combined force is negative, while the constraining force F 0 is positive, so that the position adjustment of the fixed shoe block 25 can be carried by an external force applied in the direction opposite to the extrusion direction. In manufacturing the composite metal wire 22 in which the steel core wire 20 is covered with the aluminium covering layer 21, it is assumed in a first instance that the angle  is -25°, that is, the covering material inlet apertures 18a and 18b are inclined on the side of supplying the covering material rods 21a and 21b relative to the connecting line L by 25°. In this instance, the constraining force F 0 is measured to be approximately 5 tons. On the other hand, the constraining force F 0 is 40 tons in the conventional apparatus as shown in Fig.1, wherein each 20 tons are required for the abutments 14a and 14b. As apparent from the comparison of these measured constraining forces F 0 , the constraining force F 0 is much decreased in the apparatus according to the invention. When the negative angle  becomes larger in absolute value than the above specified angle, a horizontal component f 1 of the pull-in force F 1 is always smaller than a horizontal component f 2 of the reaction force F 2 , so that a required constraining force F 0 is always reverse to the extrusion direction. As a result, no constraining means is required on the side of supplying the core metal wire 20, and a support mechanism for constraining the fixed shoe block 25 (which may be integral with the abutment 24) is only provided on the side of extruding of the composite metal wire 22. Accordingly, the position adjustment of the fixed shoe block 25, and the pressure adjustment of the abutment 24 on the grooves 11a and 11b of the rotary wheels 10a and 10b becomes extremely easy. In this preferred embodiment, the heat-proof alloy rings 26a and 26b are provided on the inner surfaces of the covering material inlet apertures 18a and 18b, so that they are protected thereby from abrasion and deterioration caused by high temperature which is generated by abrasion with the covering material rods 21a and 21b in the passage-ways defined between the rotary wheels 10a and 10b and the fixed shoe block 25. The heat-proof alloy rings 26a and 26b may made of, for instance, Inconel (Trademark) which is one of nickel based heat-proof alloys. In the invention, a composite metal wire may be modified in material and construction. For instance, a core metal wire may be in construction of a metal wire having an axial bore, a stranded wire, a wire having gaps, a wire insulated by a continuous insulation, or a non-continuous insulation, etc. In a second instance of the preferred embodiment, the angle  may be set to be -15° for the covering material inlet apertures 18a and 18b, through which aluminium is supplied to the covering chamber 19 to manufacture the composite metal wire 22 having a steel wire 20 and an aluminium covering layer 21. In this instance, the following parameters are adopted. PARAMETER EXAMPLE1 EXAMPLE2 ROTARY WHEEL OUTER DIAMETER ⊘ 440mm ⊘ 440mm ALUMINIUM COVERING MATERIAL ROD DIAMETER ⊘ 9.5mm ⊘ 9.5mm STEEL CORE WIRE DIAMETER ⊘ 6.6mm ⊘ 2.1mm ALUMINIUM COVERED COMPOSITE WIRE DIAMETER ⊘ 7.6mm ⊘ 3.4mm ALUMINIUM COVERING LAYER THICKNESS 0.5mm 0.65mm ROTARY WHEEL REVOLUTION NUMBER 7.3rpm 5.5rpm STEEL CORE WIRE PRE-HEAT TEMPERATURE 400°C 400°C STEEL CORE WIRE FRONT TENSION 2,000kg 350kg YIELD OF ALUMINIUM COVERING MATERIAL 95% 93% As apparent from the above table, the steel core wire 20 is pre-heated prior to the supply to the covering chamber 19, and is applied with a front tension which is generated, for instance , by a winding drum which is installed at a stage following the two wheel type continuous extrusion apparatus. Consequently, the yield of the aluminium covering material is 95% in the Example 1, and 93% in the Example 2. This means that the yield is largely improved in the invention as compared to the conventional apparatus as shown in Fig.1 in which the yield is approximately 80 to 85%. In the modification of the apparatus as shown in Fig.3, the abutment block 24 may have a die, and the shoe block may have a nipple, so that the extrusion direction becomes reverse. The horizontal force components f 1 and f 2 referred to herein are the components of F 1 and F 2 parallel to the direction of wire feed and extrusion direction.

Claims: A method for manufacturing a composite metal wire by using a two wheel type continuous extrusion apparatus, comprising the steps of: providing two rotary wheels (10a,10b) each having an endless groove (11a,11b) on an outer periphery thereof; providing a fixed shoe block (25) having two portions facing the grooves of the two rotary wheels to define two passageways and a die (13) for extruding the composite metal wire; providing an abutment block (24) having two portions for closing said two passageways and a nipple (15) for supplying a core metal wire (20); defining two covering material inlet apertures (18a,18b), inclined at a predetermined angle relative to a line (L) connecting rotary axes of the two rotary wheels (10a,10b) and communicating with the two passageways and a covering chamber (19) including the die and the nipple and being communicated with the two covering material inlet apertures between the fixed shoe block and the abutment block; rotating the two rotary wheels (10a,10b) in opposite directions; supplying a covering material rod (21a,21b) to each passageway to be plasticized therein by a pressure increase and the core metal wire (20) through the nipple (15) to the covering chamber (19) to extrude the composite metal wire from the die (13), the composite metal wire comprising the core metal wire and a covering material layer extruded on the core metal wire in accordance with the plasticized deformation of the covering material rods; and generating a pull-in force (F 1 ) of the fixed shoe block (12) and a reaction force (F 2 ) resulted from a power of the two rotary wheels (10a,10b) equivalent to an extrusion pressure by the rotating of the two rotary wheels; characterised in that the predetermined angle () is such that a horizontal component of the pull-in force (F 1 ) is opposite in direction and substantially equal in magnitude to a horizontal component of the reaction force (F 2 ) so that a resultant constraining force (F 0 ) is substantially zero. An apparatus for manufacturing a composite metal wire the apparatus comprising two rotary wheels (10a,10b) each having an endless groove (11a,11b) on an outer periphery provided symmetrically relative to a direction of extruding the composite metal wire; a fixed shoe block (25) having two portions each facing a groove of a respective rotary wheel to define respective passageways and a die (13) for extruding composite metal wire, a covering material rod being supplied, in use, to each passageway; an abutment block (24) having two portions each for closing a respective passageway and a nipple (15) for supplying the core metal wire (20); and two covering material inlet apertures (18a,18b) defined between the fixed shoe block and the abutment block to communicate two passageways to a covering chamber (19) including the nipple and the die; wherein the two covering material inlet apertures (18a,18b) are inclined relatively to a line (L) connecting rotary axes of the two rotary wheels by a predetermined angle, so that the covering chamber is positioned on side of the line from which the composite metal wire is withdrawn; characterised in that the covering material inlet apertures are inclined at such an angle that a horizontal component of a pull-in force (F 1 ) of the shoe block (25) is opposite in direction and substantially equal in magnitude to a horizontal component of a reaction force (F 2 ) of the rotary wheels so that a resultant constraining force (F 0 ) is substantially zero. An apparatus according to claim 3, further comprising a support block (17) for constraining the fixed shoe block (12) against the constraining force. An apparatus according to claim 3, wherein the predetermined angle () of the two covering material inlet apertures (18a,18b) is determined to generate the constraining force (F 0 ) acting in a direction of extrusion of the composite metal wire, and the support block (17) is provided on the side from which the composite metal wire is withdrawn. An apparatus according to any one of claims 2 to 4, wherein the predetermined angle (6) is from 10° to 40°. An apparatus according to any one of claims 2 to 5, wherein the fixed shoe block (25) is integral with the abutment block (24). An apparatus according to any one of claims 2 to 6, wherein the covering material inlet apertures (18a,18b) are covered on inner surfaces with super heat-proof alloy layers (26a,26b).

Inventors: ABE KAZUO, MIYAKE YASUHIKO, NAGAI MASAHIRO, NIREKI TADASHI, YAMAGISHI HISANOBU, ABE, KAZUO, MIYAKE, YASUHIKO, NAGAI, MASAHIRO, NIREKI, TADASHI, YAMAGISHI, HISANOBU
Applicants: HITACHI CABLE, HITACHI CABLE, LTD.
Application year: 1992
Main classification: B21C23
IPC codes: B21C23