JPH02151330A - Coiling pin - Google Patents

Abstract

PURPOSE:To improve the wear resistance and to decrease roughness of the friction surface by forming the title coiling pin by a ceramics sintered body which a groove part with which a spring element wire is brought into slide- contact and in which at least the tip part has high strength and high hardness. CONSTITUTION:A spring use wire rod W passes through plural straightening rolls 1, passes through a guide through feed rolls 2, 2', bent to a prescribed curvature by coiling pins 4, 4'... and formed like a spring along a mandrel 5. The wire rod W is fed at a prescribed pitch by a claw 7, stops automatically at prescribed length, and cut by a cutting edge 6. The coiling pin 4 has a curved groove part 8 whose cross section is circular and the wire rod W is brought into slide-contact therewith. This tip part is formed by a ceramics sintered body, and especially, in an alumina compound composite ceramics sintered body, an alumina - zirconia - silicon carbide compound composite ceramics sintered body is desirable. In such a way, the wire rod is scarcely adhered and a surface state of the spring which is manufactured s always satisfactory, and a service lift of the coiling pin can also be extended.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a coiling bin for a coiling machine that forms piano wire, hard steel wire, oil tempered wire, stainless steel wire, phosphor bronze wire, brass wire, etc. into springs. In particular, the present invention relates to a coiling pin that eliminates problems such as adhesion of spring material.

[Issues to be solved by conventional techniques and inventions] Currently,
The majority of springs used in various applications are continuously produced using the cold-open molding method using automatic coiling machines.

In this automatic coiling machine, the spring wire rubs against the guide and coiling pin groove, so the material and finish of the guide and coiling pin have a large effect on the surface condition of the spring.

By the way, because conventional coiling pins are made of tool steel or die steel, adhesion tends to occur between them and the wire rod, resulting in damage to the coiling pin and a significant deterioration in the quality of the spring. There's a problem. In particular, with spring materials coated with various anti-corrosion coatings, such as hot-dip galvanized piano wire (5WP-B material, etc.), adhesion is likely to occur between the coiling pin and the wire, reducing the quality of the spring. , productivity decreases.

Therefore, a coiling pin using a material made of highly hard cemented carbide was also proposed. According to this method, adhesion and roughness of the friction surface are improved to some extent, but it cannot be said to be sufficient.

As mentioned above, among the conventional coiling pins, none of them satisfactorily solved the problems of adhesion with the spring wire and roughness of the friction surface.

Therefore, an object of the present invention is to provide a coiling pin that has high hardness, has low affinity with spring materials, particularly metal-plated spring materials, and hardly causes adhesion.

[Failure to solve the problem]

As a result of intensive research into the above-mentioned problem, the present inventor has developed a material with high strength and high hardness that is less likely to cause adhesion and has excellent wear resistance due to its low affinity with spring materials. They discovered that ceramics were suitable and came up with the present invention.

That is, the coiling pin of the present invention is characterized in that at least the tip portion including the groove in which the spring wire slides is made of a high-strength, high-hardness ceramic sintered body. By using an alumina sintered body or an alumina-based composite ceramic sintered body as a high-hardness ceramic sintered body, higher wear resistance and
It has &1 attachability and can be made into a more suitable coiling pin.

[Examples and effects]

The present invention will be described in detail with reference to the accompanying drawings.

A coiling machine typically has a structure shown in FIG. 1, as disclosed in "Spring" Revised 2nd Edition Spring Technology Association M (Maruzen).

The spring wire W is straightened through a plurality of correction rollers 1, sent by a pair of feed rollers 2.2', and after passing through a guide 3, is held in a predetermined position by a plurality of coiling pins 4.4... It is bent to a curvature of , and formed into a spring shape along the reception area 5. At the same time, the wire W is bent into a coil shape.
is fed at a predetermined pitch by the claws 7, and when a certain length of spring is fed out, it automatically stops and is cut by the cutting blade 6, completing the forming of the spring.

FIG. 2 shows an example of a coiling pin 4 used in such a coiling machine.

Each coiling pin 4 has at its tip a curved groove 8 with a circular cross section that is machined to a size that matches the diameter of the spring wire W.
The wire rod W comes into sliding contact with this groove portion 8 .

The wear surface of this coiling pin 4 is the groove 8 at the tip.
3, it is not necessary to make the entire bottle wear-resistant, and only the tip 10 may be made of a ceramic material as shown in FIG.

The groove portion 8 at the tip of the coiling pin 4 serves as a wear surface for the spring wire W, so in order to reduce adhesion of the wire W, it is necessary to have a low affinity with the spring material, especially a metal-plated spring material. Furthermore, it is necessary that the wear of the groove portion 8 due to the adhered metal be as small as possible.

In order to meet such requirements, the coiling pin 4 of the present invention is characterized in that at least the tip portion is formed of a high-strength, high-hardness ceramic sintered body.

High strength that can be used for the coiling pin of the present invention,
As the high-hardness ceramic sintered body, an alumina sintered body and an alumina-based composite ceramic sintered body are preferred, and an alumina-zirconia-silicon carbide composite ceramic sintered body is particularly preferred as the alumina-based composite ceramic sintered body.

The alumina sintered body may be formed by a conventional method, and is generally made of alumina powder having an average particle size of about 40 μm or less and optionally containing SiL, Cab, ! It is possible to use one which is sintered under normal pressure or under pressure at 1400 to 1700°C with the addition of a sintering aid such as AgO.

In addition, the alumina-zirconia-silicon carbide composite ceramic sintered body contains 5 to 50% by volume of partially stabilized zirconia,
(3 to 40% by volume of silicon carbide whiskers, but not more than 55% by volume in total), and the remainder substantially consists of alumina. This composite ceramic sintered body generally consists of alumina powder with an average particle size of 1.0 μm or less, partially stabilized zirconia powder with an average particle size of 0.1 to 1.0 μm, a diameter of 1 μm or less, and an aspect ratio of 3 to 200. After mixing with silicon carbide whiskers in the above ratio and press-molding into the shape of a coiling pin or its tip,
It can be manufactured by sintering by normal pressure sintering, pressure sintering, IIIP, etc. at 00°C.

In addition, in such an alumina-zirconia-silicon carbide composite ceramic sintered body, if the particle size of the partially stabilized zirconia powder is less than 0.1 μm, it becomes too stable, and if it exceeds 1.0 μm, it becomes unstable. Both of them do not contribute sufficiently to strength improvement. Further, if the content is less than 5% by volume, the effect of increasing toughness is not significant, and if it exceeds 50% by volume, hardness decreases.

If the aspect ratio of silicon carbide whiskers is less than 3, the effect of increasing toughness is insufficient, and if it exceeds 200, the effect of increasing toughness decreases. Moreover, when the diameter exceeds 1 μm, the strength of the sintered body is rather reduced.

If the content is less than 3% by volume, no effect can be expected from the addition of silicon carbide whiskers, and if it exceeds 40% by volume, the strength will actually decrease.

Furthermore, if the total amount of partially stabilized zirconia and silicon carbide whiskers exceeds 55% by volume, too much whisker or zirconia will be added, and the toughness or hardness of the sintered body will decrease.

The alumina-zirconia-silicon carbide composite ceramic sintered body has high toughness and is excellent in wear resistance and adhesion resistance. Therefore, it can be used as a coiling pin for a long period of time without breaking.

In the coiling pin of the present invention in which at least the tip portion is formed of the above-mentioned high-strength, high-hardness ceramic sintered body, the groove portion has low reactivity with metal, so adhesion is unlikely to occur, and adhesion does not occur. However, since there is almost no chemical bonding with the friction surface of the groove, the finished surface of the coiling pin in the groove will hardly become rough.

The present invention will be explained in more detail by the following specific examples.

Example 1 Alumina powder with an average particle size of 0.7 μm 1 and a purity of 99% or more 7
0% by volume and 2% by mole (3.5% by weight) (D Y2
15% by volume of partially stabilized zirconia powder with an average particle size of 062 μm containing ．． 8μm, length 20
15% by volume of β-crystalline silicon carbide whiskers having a diameter of ~200 μm and an aspect ratio of 20 to 200 were placed in an alumina ball mill containing alumina balls, and mixed for 24 hours using ethyl alcohol as a medium.

Next, the mixed powder was press-molded and then sintered using a hot press method in an argon gas atmosphere at a compacting pressure of 300 kg/cut and a temperature of 1500° C. for 60 minutes to obtain a sintered body.

The obtained sintered body was subjected to a baking (adhesion) test on a hot-dip galvanized coil wire material (5IIIP-B material).

The test device is schematically shown in FIG. 4 and FIG. 5, which is a side view taken along line A-A in FIG. , has a disc-shaped stator 12 with a polished finish of 10 mm in thickness, and a rotor 13. A predetermined pressing force P is applied to the stator holder 11 toward the right in the figure by a hydraulic system (not shown).

A rotor 14 is disposed opposite to the disc stator 12, and is configured to rotate at a predetermined speed by a drive device (not shown). A test piece holder 14a is attached to the rotor 14, and the test piece holder 14a has a test piece (with a square end face or a spherical end with a radius of 2.25 mm as a sliding surface).
Ceramic sintered bodies or coil wires) 15 are fixed concentrically at equal intervals. Each test piece is slidably pressed against the stator 12.

In such an apparatus, a predetermined pressing force P is applied to the stator holder 11, and the rotor 14 is rotated while the disc-shaped stator 12 and the test piece 15 are brought into pressure contact with each other with a predetermined surface pressure. According to the rotation of the rotor 14, the stator holder 11 is
Torque (torque generated by 'PIl friction force) T is applied to the load cell 17 via the spindle 16, and its change is read by the dynamic strain meter 18 and recorded on the recorder 19.

In this example, the stator 12 was formed from the above-mentioned composite ceramic sintered body, and the test piece 15 was formed from hot-dip galvanized piano wire (5WP-8 material). The tip of the test piece 15 had a spherical end (FIG. 6) with a radius R2 of 25 mm.

The test conditions were as shown below.

Test conditions 1 Rotor tip shape Hemispherical with diameter on both sides of 2.25 mm (Figure 6) Stator side material: Alumina zirconia silicon carbide composite ceramic sintered body Rotor side material: Hot-dip galvanized piano wire (
Friction speed: 20rn/min Friction pressure: 10kg f/cd Friction time
: 15 minutes As a result of this test, an adhesive layer of hot-dip galvanizing with a width of about 1.5 mm was observed on the stator J- made of alumina-zirconia-gayric carbide composite ceramic sintered body, but the thickness It was confirmed that the amount of ms was extremely small.

On the other hand, when an adhesion test was conducted under the same conditions except that a currently used cemented carbide V5 material was used as the test piece, an adhesion layer with a width of approximately 1.5 mm was similarly formed. ,
It was confirmed that the adhesion layer was very thick and the amount of adhesion of hot-dip galvanizing was large.

Try again! i′! i! The frictional force just before the end is the cemented carbide ν5
2.5 kgf for the material, 1.5 kgf for the alumina-zirconia-silicon carbide composite ceramic sintered body. It was Okgf. i!
! Torque increases when adhesion occurs, so this difference also corresponds to the amount of adhesion, and hot-dip galvanization is less likely to adhere to alumina-based composite ceramic sintered bodies than to cemented carbide V5 materials. Recognize.

Example 2 Using alumina powder with an average particle size of 0.7 μm and a purity of 99% or more, it was wet-pulverized under the same conditions as Example 1, then press-formed and sintered at 7.1600°C for 2 hours under pressure. A sintered body for a test piece was obtained 3. A test piece made of the obtained sintered body was placed in a holder 14a, and a stator made of hot-dip galvanized steel (S45C) was used. , mW test was conducted.

The test equipment used was the same as that used in Example 1, and the test conditions were as follows.

Test conditions 2 0-Rota tip shape: 5mm x 5mm square (Figure 7) Stator side material: Hot-dip galvanized (base material 545C steel) Rotor side material: Alumina sintered body ↑ Friction speed: 20m/min Friction pressure: 20kg f / cffl Friction time: 2 minutes During this test, the friction force was about 4 to 5 kgF. Further, an adhesion layer having a width of about 1 to 5 mm was formed on the alumina test piece 15, but the amount of adhesion was small.

Further, the same tests were conducted under the same conditions using test pieces made of an alumina-zirconia-silicon carbide composite ceramic sintered body having the same composition as in Example 1 and a cemented carbide V5 material. As a result, the friction force was approximately 4 to 5 kgf in both cases, and a coagulated M layer having a width of approximately 1 to 1.5 mm was similarly formed.

However, in the case of the test piece made of the alumina-zirconia-silicon carbide composite ceramic sintered body, the amount of adhesion of the hot-dip galvanizing was very small, whereas in the case of the cemented carbide V5 material, it was very large.

Example 3 The surface roughness before and after the adhesion test of Example 2 was determined for each test piece made of the alumina sintered body, the alumina-zirconia-silicon carbide composite ceramic sintered body, and the cemented carbide V5 material used in Example 2. compared.

The surface roughness after the test was measured after removing the hot-dip galvanized layer adhered to each test piece with hydrochloric acid. Further, as surface roughness, both average surface roughness and maximum surface roughness were measured using a Tokyo Precision Roughness Measuring Instrument. The results are shown in Table 1.

As can be seen from Table 1, the cemented carbide V5 material showed significant surface roughness (increase in surface roughness) due to friction, but it is composed of alumina sintered body and alumina-zirconia-silicon carbide composite ceramic sintered body. In the case of the test pieces, even if adhesion occurred, the surface roughness was very slight within the measurement error range.

〔Effect of the invention〕

As is clear from the above description, the bottle of the present invention is made of high-strength, high-hardness ceramic material at least first.
Since it is used in the spring wire, it not only has good wear resistance on the abrasion surface with the spring wire but also has very little chance of adhesion of the wire and roughening of the friction surface due to adhesion. Therefore, the surface condition of springs manufactured using the coiling pin of the present invention is always good, and the coiling pin of the present invention also has a long service life.

By using the coiling pin of the present invention, the productivity of springs is significantly improved.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing an example of a coiling pin using the coiling pin of the present invention, Fig. 2 is a sectional view showing an example of the coiling pin, and Fig. 3 is a schematic diagram showing another example of the coiling pin. FIG. 4 is a partial sectional view showing the main parts of the test apparatus used for the adhesion friction test; FIG. 15 is a side view taken along line A-A in FIG. 4; 6 is a sectional view and a front view showing an example of the shape of the rotor tip, and FIG. 7 is a sectional view and a front view showing another example of the shape of the rotor tip. 1...Correcting roller 2.2'...Feed roller 3...Guide 4...Coiling pin 5...Reception 6...Cutting blade 7...・Claws 11・ 12・ 14・ 4a 15・ ・Stator holder ・Disc-shaped stator ・Rotor ・Test specimen holder ・Test specimen applicant

Claims (2)

[Claims] (1) A coiling pin for a coiling machine, characterized in that at least the tip portion including the groove in which the spring wire slides is made of a high-strength, high-hardness ceramic sintered body. (2) The coiling pin according to claim 1, wherein the ceramic sintered body is an alumina sintered body or an alumina-based composite ceramic sintered body.