CN112368088A

CN112368088A - Pressure die and insert for a pressure die

Info

Publication number: CN112368088A
Application number: CN201980026952.1A
Authority: CN
Inventors: L·巴戈; E·巴戈
Original assignee: Pan Chemicals SpA
Current assignee: Pan Chemicals SpA
Priority date: 2018-03-28
Filing date: 2019-03-27
Publication date: 2021-02-12
Also published as: WO2019186421A1; IT201800004031A1; EP3774102C0; ES2963456T3; EP3774102B1; EP3774102A1; MX2020010095A

Abstract

The present invention describes a pressure die (1) comprising a die housing (10), a single pressure insert (30), a single drawing insert (40) and a locking ring (20) configured to lock the pressure insert (30) with respect to the die housing (10), wherein the die housing (10) comprises a tapered longitudinal through hole having a taper angle; and wherein the pressure insert (30) and the drawing insert (40) are tapered with a cone angle complementary to the cone angle of the tapered longitudinal through hole, the dimensions of which are such that, when inserted in the tapered longitudinal through hole, they do not contact each other and define a pressure chamber (50) for pumping lubricant. The invention also relates to a kit comprising a pressure insert and a drawing insert.

Description

Pressure die and insert for a pressure die

Technical Field

The present invention relates to the field of cold drawing of rods, metal wires or more generally long metal objects. More particularly, the present invention relates to a pressure die for cold drawing a rod or wire. The invention also relates to a pair of pressure and drawing inserts configured for use with such a pressure die.

Background

It is known that a method of drawing a metal wire or rod comprises introducing the metal wire or rod into a tool that reduces its diameter. Typically, the rod or wire is progressively reduced in diameter as it passes through a die having a smaller and smaller draw diameter.

During the drawing process, it is known to use lubricants. Typically, the lubricant is in solid form, such as powder or flake form. However, the drawing lubricant may also be in liquid form.

In order to press the lubricant into the die, it is known for the pressure die to perform, before the actual drawing step, a step whose task is to increase the pressure of the lubricant so that it is conveyed with the rod or wire during drawing.

IT1269433(Tecnovo, llc) describes a tool for drawing metal wires and rods, comprising: a support member traversed by the channel; and a drawing member made of a material having a high hardness, and accommodated inside the support member and having a hole that is aligned with the passage. The support member is made of at least two parts which can be combined with each other in a removable manner in order to fix the drawing member in position inside the support member.

IT1295286(Tecnovo, llc) describes a die for drawing rods or metal wires which allows the rapid replacement and recovery of the drawing core in ITs entirety, comprising a reinforcement with a through hole in which are removably housed an upper member and a drawing core, separated from each other and aligned with the hole, wherein the bottom profile of the upper member is such as to perfectly engage the inlet of the drawing core located below IT.

EP0679112(Paramount Die limited) describes a Die assembly for metal wire.

US2008/0173063a1 describes a drawing system in which the drawing heat is distributed over two or more drawing inserts.

Disclosure of Invention

The invention may be applied to any long metal element, including tubes, but typically rods or wires. For simplicity, the present description will be provided with reference to a rod only. However, in the present description and claims, the term "rod" should be understood to include any long metal element, such as a tube, a rod or a metal wire.

The applicant has noted that the known pressure dies comprise two inserts separated by a metal spacer, for example made of steel or copper or another metal, which is arranged between the two inserts to prevent contact between them (which would lead to breakage) and to prevent lubricant leakage (which would lead to pressure losses, thus reducing efficiency).

The drawing system described in US2008/0173063a1 includes two or more drawing inserts 300, 400 and a pressure insert 200. The pressure insert 200 remains in contact with the draw insert 300. According to the applicant, such a configuration leads to premature failure of the pressure insert and/or of the drawing insert in direct contact with the pressure insert. This occurs because the pressure insert is in direct contact with the first of the two drawing inserts and the pressures involved subject the inserts to high mechanical stresses.

Further, the pressure insert is retained by a bore inside the male fixation member 110 that is configured to engage threads inside the female mold member 120. Therefore, the male and female closure members must be machined separately: the male member must be machined to form a bore for the pressure insert and the female body must be machined to form a tapered bore for the mold inserts 300 and 400. The machining operations carried out on two separate components must be very precise and therefore costly.

The thread between the male and female closure members is on a smaller diameter and therefore the locking force must be limited.

The applicant has identified the object of providing a pressure die comprising only two inserts (a single pressure insert and a single drawing insert) axially separated from each other, so as to provide a pressure chamber. In particular, the applicant has determined the object of providing a pressure die in which the two inserts are always in a configuration such that they do not axially contact each other directly or through spacers without direct contact.

The applicant has also defined the object of providing a pressure die of the aforementioned type in which the insert can be assembled in a simple and quick manner.

The applicant has determined the object of providing a pressure die of the aforementioned type in which the inserts, in particular the drawing inserts, can be replaced in a simple and quick manner. In fact, the drawing inserts are subject to rapid wear and must be replaced at a certain frequency.

These objects, among others, are achieved by a pressure die according to the invention in that the pressure insert and the drawing insert each have a nipple-tapered shape and the taper angles are the same. The inserts are configured such that they can be inserted into tapered bores of a mold housing having a taper angle complementary to the taper angle of the inserts. The two inserts are dimensioned so as to leave a distance between them in the axial direction, thus forming a pressure chamber and preventing the possibility of the two inserts coming into contact during use of the mould or due to incorrect (or inaccurate) assembly of the components. A ring nut is preferably provided to hold the pressure insert in place relative to the body.

According to a first aspect, the invention relates to a pressure die comprising a die housing, a single pressure insert, a single draw insert and a locking ring configured to lock the pressure insert relative to the die housing,

wherein the die housing includes a tapered longitudinal through bore having a single taper angle from a first larger diameter inlet end to a second smaller diameter outlet end;

wherein the pressure insert is inserted into the tapered longitudinal through hole and positioned near the inlet end, wherein the drawing insert is inserted into the tapered longitudinal through hole and positioned near the outlet end, and

wherein the pressure insert and the drawing insert are tapered with a cone angle complementary to the cone angle of the tapered longitudinal through hole and are dimensioned such that they do not contact each other and define a pressure chamber for pumping lubricant.

Unlike the solution described in US2008/0173063a1, it has a single drawing insert. According to the invention, the drawing insert is never in contact with the pressure insert. Further, in the present invention, both the drawing insert and the pressure insert are inserted into the tapered hole formed in the die body. A single tapered bore in the die body has significant advantages in both the tolerances available and the tooling costs during its formation.

The taper angle of the longitudinal through hole is preferably between 1 ° and 10 °, more preferably between 1 ° and 6 °, even more preferably between 1 ° and 4 °.

According to a preferred embodiment, the taper angle of the longitudinal through hole is 3 °.

According to one embodiment, the mold housing is a male member and the locking ring is a threaded female member configured to engage threads of the mold housing. This aspect is very advantageous. In fact, in the die housing according to the invention, tapered through holes are formed for a single pressure insert and a single drawing insert. The (female) locking ring engages with the threads on the outer surface of the mould shell. Thus, the thread between the die housing and the locking ring extends over a surface having a diameter larger than the diameter of the solution described in US2008/0173063a 1. Thus, in the present invention, the locking action is stronger and more reliable. Furthermore, the hexagon formed at the top has a larger diameter and this improves the ability to secure the locking ring relative to the mould housing.

The smaller diameter of the pressure insert is preferably larger than the larger diameter of the draw insert.

According to a second aspect, the invention relates to a pair of inserts, namely a kit, comprising a pressure insert and a drawing insert for a pressure die comprising: a mold housing and a locking ring configured to lock the pressure insert relative to the mold housing,

wherein the die housing includes a tapered longitudinal through bore having a taper angle from a first larger diameter inlet end to a second smaller diameter outlet end;

wherein the pressure insert is configured to be inserted into the tapered longitudinal through hole and positioned proximate to an inlet end, wherein the draw insert is configured to be inserted into the tapered longitudinal through hole and positioned proximate to an outlet end,

wherein the pressure insert and the drawing insert are tapered with a cone angle complementary to the cone angle of the tapered longitudinal through hole, and

wherein the smaller diameter of the pressure insert is larger than the larger diameter of the drawing insert, such that when inserted into the tapered longitudinal through hole, the pressure insert and the drawing insert do not contact each other and define a pressure chamber for pumping lubricant.

The cone angle is preferably between 1 ° and 10 °. According to a preferred embodiment, the cone angle is 3 °.

Drawings

A detailed description of the invention will now be provided, by way of non-limiting example, with reference to the accompanying drawings, in which:

fig. 1 and 2 are two longitudinal sectional views of a pressure die according to an embodiment of the invention, differing by the machining tolerances of the inserts;

fig. 3.1 and 3.2 show a front view and a longitudinal section of the mold shell;

figures 4.1 and 4.2 show front and longitudinal cross-sectional views of the locking ring of the mould housing;

fig. 5.1 and 5.2 show a pressure insert;

FIG. 5.3 shows another pressure insert according to the present invention; and

fig. 6.1 and 6.2 show a drawing insert according to the invention.

Detailed Description

A pressure die according to an embodiment of the invention is schematically shown in fig. 1 and 2. In particular, fig. 1 and 2 are two longitudinal sections showing the same pressure die according to the invention. However, depending on the machining tolerances, the two inserts may be arranged in different positions and form pressure chambers having different dimensions. In other words, their relative positions may be different.

The press die is generally indicated by the numeral 1. It comprises a mold shell 10, a closing or locking ring 20, a first insert 30 and a second insert 40. The first insert 30 is a pressure insert and the second insert 40 is a draw insert.

The pressure die 1 (and therefore also the single component) can have different dimensions depending on the diameter of the body to be drawn and/or the reduction in diameter to be obtained. By way of non-limiting example only, in the present description below, a die for drawing a rod having an initial diameter of 5.5mm will be described, so as to obtain a final diameter of 4.7mm, thus a reduction of about 27%. The die according to the invention can be made for larger or smaller diameters and various reduction percentages of the diameter.

An embodiment of the mold shell 10 is also shown in fig. 3.1 and 3.2. According to the embodiment shown, the die housing 10 comprises a substantially cylindrical male body, the outer surface of which is provided with a thread 11. According to one embodiment, the outer diameter is about 28mm and includes an outer surface M27x1.5. Obviously, this is an example and the mould shell 10 may have a different diameter and/or have a different thread.

The outer surface of the mould housing preferably also comprises at least one groove 12 for an elastic sealing ring (O-ring).

The outer surface of the mould shell preferably also comprises hexagonal sections 13.

The die housing 10 includes a longitudinal through bore 14. The longitudinal through hole 14 is a tapered hole. The cone angle 15 (measured with respect to the longitudinal axis X-X of the housing) of the longitudinal through hole 14 may be between 1 ° and 10 °, preferably between 1 ° and 6 °, even more preferably between 1 ° and 4 °. According to a preferred embodiment, the cone angle 15 is 3 °. Still referring to the specific example, the larger diameter of the longitudinal through hole may be about 14 mm.

The taper angle 15 remains constant over the entire length of the tapered longitudinal through bore from the first (larger diameter) inlet end 141 to the second (smaller diameter) outlet end 142.

The die housing 10 is preferably made of a metallic material, such as steel, in particular stainless steel.

The female locking ring 20 is configured to engage the male mold housing 10 and lock the insert 30 within the longitudinal through bore 14. More specifically, the locking ring 20 includes a generally cylindrical body having a threaded bore 21 configured to engage the external threads 11 of the die housing 20. The head of the locking ring 20 comprises a longitudinal through hole 24. When the die housing 10 and the locking ring 20 are brought together (by means of the external thread 11 of the die housing 10 and the internal thread 21 of the locking ring 20), the axis X-X of the longitudinal through hole 14 of the die body 10 preferably coincides with the axis Y-Y of the longitudinal through hole 24 of the head of the locking ring 20. The longitudinal through bore 24 of the head of the locking ring 20 is preferably open, tapering outwardly like a funnel, as indicated by numeral 27 in figure 4.2.

Preferably, the locking ring 20 further comprises a shaped hexagonal section 23.

The outer surface of the locking ring 20 also preferably includes a seat 22 for an elastic sealing ring (O-ring).

The locking ring 20 is preferably made of a metallic material, such as steel, in particular stainless steel.

Referring now to fig. 5.1 and 5.2, a pressure insert 30 adapted to be mounted inside the pressure die 1 according to fig. 1 and 2 will be described.

The pressure insert 30 is a generally frustoconical body having a larger base 31 corresponding to the inlet mouth of the stem (not shown) and a smaller base 32 corresponding to the outlet of the stem. The advancing direction of the rod is indicated by arrows IN and OUT.

The cone angle 35 of the drawing insert 40 corresponds (is complementary) to the cone angle 15 of the longitudinal through hole 14 of the die housing 10. According to the invention, the cone angle 35 (excluding the first section 33' near the larger base, if required) is between 1 ° and 10 °, preferably between 1 ° and 6 °, even more preferably between 1 ° and 4 °. According to a preferred embodiment, the cone angle 35 is 3 °.

As shown in fig. 5.1, the pressure insert 30 comprises a suitably shaped longitudinal through hole 34. The longitudinal through hole 34 of the pressure insert 30 comprises a more open first section 341, defining an inlet bell, a second conical section 342, a third substantially cylindrical section 343 and an outlet bell 344 open towards the pressure chamber 50.

According to an embodiment, the length of the pressure insert 30 is about 10-20mm, preferably 10-15mm, even more preferably 10-12 mm.

According to an embodiment, the diameter D30 of the larger base portion 41 of the pressure insert 30 is about 10-20mm, preferably 10-15mm, even more preferably 14-15 mm.

According to an embodiment, the length of the third substantially cylindrical section 343 is 1-7mm, for example 2 mm.

The inlet bell may have an angle alpha of 80 deg. and the outlet bell may have an angle beta of 60 deg..

Preferably, the pressure insert 30 is made of a hard material, such as sintered tungsten carbide, which is optionally cobalt-based.

Depending on the machining tolerances, the pressure insert may be in the position shown in fig. 1 (maximum tolerance), in the position shown in fig. 2 (minimum tolerance), or in any intermediate position.

Fig. 5.3 shows a variant of the pressure insert 30 in which no drawing is performed. The main difference is that the second section 342 is also cylindrical, having the same diameter as the third section 343. The diameter of the cylindrical section substantially corresponds to the diameter of the rod passing through it.

Referring now to fig. 6.1 and 6.2, a drawing insert 40 suitable for mounting inside the pressure die 1 according to fig. 1 and 2 is described.

The drawing insert 30 is a substantially frustoconical body having a larger base 41 corresponding to the inlet mouth of the rod (not shown) and a smaller base 42 corresponding to the outlet of the rod undergoing drawing.

The cone angle 45 of the drawing insert 40 corresponds (is complementary) to the cone angle 15 of the longitudinal through hole 14 of the die housing 10. According to the invention, the cone angle 45 (excluding the first section 43' near the larger base, if required) is between 1 ° and 10 °, preferably between 1 ° and 6 °, even more preferably between 1 ° and 4 °. According to a preferred embodiment, the cone angle 45 is 3 °.

As shown in fig. 6.1, the drawing insert 40 comprises a suitably shaped longitudinal through hole 44. The longitudinal through hole 44 of the drawing insert 40 comprises a more open first section 441 defining an inlet bell, a second tapered section 442 defining a surface for reducing the diameter of the rod, a third substantially cylindrical portion 443 inside which the diameter of the rod is consolidated, and an outlet bell 444 for discharging the drawn rod. Typically, drawing occurs in the final portion 442' of the second section 442.

According to an embodiment, the angle formed by the reduced surface 442 of the drawing insert 40 is between 4 ° and 30 °, for example 16 °.

According to an embodiment, the third substantially cylindrical section 443 has a length of 1-7mm, e.g. 2mm, and a diameter 444 of about 4-5mm, e.g. 4.6 mm.

The outlet bell may have an angle beta of 60 deg..

Preferably, the drawing insert 40 is made of a hard material, such as sintered tungsten carbide, which is optionally cobalt-based.

The diameter D30 of the smaller base 31 of the pressure insert 30 is greater than the diameter D40 of the larger base 41 of the draw insert 40.

To assemble the press die 1 according to the invention, the drawing insert 40 is first inserted into the through-hole 14 of the die housing 10. The diameter of the larger base 41 is designed so that the drawing insert 40 is positioned close to the smaller diameter end 142 (fig. 1) of the hole. Then, the pressure insert is also inserted into the through-hole 14 of the mold housing and positioned close to the larger-diameter end 141 of the through-hole 14. The diameter of the smaller base 32 of the pressure insert 30 is always larger than the diameter of the larger base 41 of the draw insert 40. In this way, the two

inserts

30, 40 never contact each other and form the pressure chamber 50.

The locking ring 20 is then screwed onto the mould shell 10. By screwing the locking ring 20 onto the die housing 10 (advantageously by means of the hexagons 13 and 23), the pressure insert 30 is retained inside the die housing without the risk of being pushed out by the pressure of the lubricant generated during drawing of the rod.

The pressure chamber 50 is configured to collect lubricant (not shown) removed from the reservoir upstream of the die 1 and drawn along the stems by the stems during high speed movement of the stems within the pressure insert 30. The high pressure lubricant present in the pressure chamber 50 adheres to the surface of the rod before the rod enters the draw insert 40.

If the drawing insert 40 and/or the pressure insert 30 need to be replaced, the locking ring 20 is unscrewed and the two

inserts

30, 40 are pushed in the opposite direction to the insertion direction. Thus, both

inserts

30, 40 are released and can be withdrawn and replaced.

Advantageously, the through hole 14 is smooth and unthreaded. Also, the tapered outer surfaces of the two

inserts

30, 40 are smooth and unthreaded.

Claims

1. A pressure die (1) comprising a die housing (10), a single pressure insert (30), a single draw insert (40), and a locking ring (20) configured to lock the pressure insert (30) relative to the die housing (10),

wherein the die housing (10) comprises a tapered longitudinal through bore (14) having a single taper angle (15) from a first larger diameter inlet end (15) to a second smaller diameter outlet end (142);

wherein the pressure insert (30) is inserted into the tapered longitudinal through hole (14) and positioned proximate to the inlet end (141); wherein the drawing insert (40) is inserted into the tapered longitudinal through hole (14) and positioned close to the outlet end (142); and is

Wherein the pressure insert (30) and the drawing insert (40) are tapered with a cone angle (35, 45) complementary to the cone angle (15) of the tapered longitudinal through hole (14), and the dimensions of the pressure insert and the drawing insert are such that they do not contact each other and define a pressure chamber (50) for pumping lubricant.

2. Pressure die (1) according to claim 1, wherein the taper angle (15) of the longitudinal through hole (14) is between 1 ° and 10 °.

3. Pressure die (1) according to claim 2, wherein the taper angle (15) of the longitudinal through hole (14) is 3 °.

4. The pressure die (1) of claim 1, 2 or 3, wherein the die housing (10) is a male member and the locking ring (20) is a threaded female member configured to engage with threads (11) of the die housing (10).

5. Pressure die (1) according to any one of the preceding claims, wherein the smaller diameter (32) of the pressure insert (30) is larger than the larger diameter (41) of the drawing insert (40).

6. Kit (30, 40) comprising a pressure insert (30) and a draw insert (40) for a pressure die (1), the pressure die comprising a die housing (10) and a locking ring (20) configured to lock the pressure insert (30) relative to the die housing (10),

wherein the die housing (10) comprises a tapered longitudinal through bore (14) having a taper angle (15) from a first larger diameter inlet end (15) to a second smaller diameter outlet end (142);

wherein the pressure insert (30) is configured to be inserted into the tapered longitudinal through bore (14) and positioned proximate to the inlet end (141); wherein the drawing insert (40) is configured to be inserted into the tapered longitudinal through hole (14) and positioned near the outlet end (142),

wherein the pressure insert (30) and the drawing insert (40) are tapered with a taper angle (35, 45) complementary to the taper angle (15) of the tapered longitudinal through hole (14), and

wherein the smaller diameter (32) of the pressure insert (30) is larger than the larger diameter (41) of the drawing insert (40) such that, when inserted into the tapered longitudinal through hole (14), the pressure insert and the drawing insert are not in contact with each other and define a pressure chamber (50) for pumping a lubricant.

7. A kit (30, 40) according to claim 6, wherein the cone angle (15) is between 1 ° and 10 °.

8. A kit (30, 40) according to claim 7, wherein the cone angle (15) is 3 °.