JPH0243522Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a forming roller for forming a steel strip into a spiral shape in a spiral steel pipe manufacturing facility.

The manufacturing line for spiral steel pipes is equipped with forming rollers for forming the steel strip into a spiral shape, and the forming rollers consist of a pair of front and rear forming support rollers and a forming pressure roller provided between them.
The steel strip is fed diagonally to the roller axis and formed into a spiral shape. The present invention relates to forming rollers, particularly elongated forming support rollers (hereinafter simply referred to as forming rollers).

As shown in Figure 1, conventional forming rollers are made entirely of the same material (SUJ-2, SNCM-8 or SCM
The body 1 is hardened to a hardness depth of 8 to 10 mm and a hardness of Hs 80 to 90 in order to improve the wear resistance of its surface. The friction coefficient of the body surface was about 0.25, and the hardness of the bearing part 2 was Hs40-50.
In terms of shape, this forming roller 3 has a body length L=2400
It is an elongated roller with L/D of 8 or more, such as mm, body diameter D = 280 mm, etc.

As shown in FIG. 2, when the body 1 of the forming roller 3 is worn out, the body 1 cannot be modified and re-quenched for use, and the entire roller has been discarded. Therefore, the cost of the roller increases, which is economically disadvantageous.

Therefore, an assembly roller can be considered in which only the body surface layer can be rearranged when it wears out. This assembly roller shrink-fits the sleeve to the arbor.

However, in the shrink fitting operation, the heated sleeve must be fitted to the arbor in a short period of time, and this fitting operation is extremely difficult in the case of the long forming roller. Moreover, after shrink fitting, the sleeve contracts in its radial and axial directions, generating residual stress, but if it is a long sleeve, the shrinkage allowance in the axial direction will be large, and the residual stress will be strong. Due to this, there was a problem in that it was easy to cause breakage accidents.

Therefore, the present invention has been devised in view of the above-mentioned problems, and an object of the present invention is to provide a forming roller that facilitates shrink-fitting work, regardless of whether it is a shrink-fit assembly type roller. Therefore, its characteristic feature is that it is a roller for feeding the steel strip from an angle to the roller axis direction and forming it into a spiral shape, and the ratio of the body length L to the body diameter D is L/D≧8. In forming rollers for manufacturing elongated spiral steel pipes, the surface layer of the body of the roller is divided into two or more sleeves in the longitudinal direction and is shrink-fitted to the arbor. A slip prevention protrusion is provided at the axial end to prevent relative movement of the sleeve in the axial direction, and a chamfer is formed on the outer periphery of the adjacent end of the sleeve.

Hereinafter, embodiments of the present invention will be described in detail based on the drawings. As shown in FIGS. 3 to 7, the forming roller 10 according to the present invention has a body diameter D with respect to a body length L of the forming roller 10.
It is an elongated roller with D≧8. This forming roller 1
0 is an assembly type roller in which a sleeve 12 is shrink-fitted to an arbor 11.

The sleeve 12 and the arbor 11 are made of different materials, the sleeve 12 forming a surface layer of the body 13,
The arbor 11 forms a core portion of the body portion 13 and a bearing portion 14 .

The sleeve 12 is divided into two in the longitudinal direction and shrink-fitted to the arbor 11, and one of the sleeves 12 is
As shown in FIG. 7, the outer end of the arbor 11 is locked by a slip prevention protrusion 15 provided at the axial end of the core of the arbor 11 on the steel strip feeding direction side.
Incidentally, it is sufficient to form the projection 15 at the axial end of the core portion on the steel strip feeding direction side. In this type of forming roller for manufacturing spiral steel pipes, the steel strip is fed in from a diagonal direction with respect to the axial direction of the roller, so during forming, a thrust load is applied only to the axial direction of the roller in the feeding direction of the steel strip. This is because it works.

In addition, as shown in an enlarged view in FIG. 6, the sleeve 12 has a structure in which the outer circumferential edges of the ends of the sleeves that are in contact with each other are brought into contact with each other on the concave side of the deflection due to the deflection of the roller that occurs during molding. A chamfered portion is formed to prevent this.

The sleeve 12 has a surface portion 16 with high hardness (approximately Hs80) made of chilled steel material, nickel grain material, etc., and an inner surface portion 17 with toughness made of graphite steel, ductile cast iron material, etc. This is a composite sleeve that is welded into one piece.

According to the roller 10 according to the present invention, the sleeve 12 is divided even though it is long, so the shrink fitting operation becomes extremely easy. Moreover, the amount of axial shrinkage after shrink fitting is smaller than that of a one-piece long sleeve because it is divided into parts.
Residual stress generated in the sleeve 12 is also reduced, and breakage accidents can be prevented.

In addition, as shown in FIG.
Since the sleeve 12 is received by the projection 15 provided on the arbor 11, there is no risk that the sleeve 12 will move relative to each other in the axial direction, and therefore, the shrink fit stress does not need to be increased too much. This prevents the sleeve 12 from breaking.

In addition, since the sleeve 12 has a chamfered portion formed on the outer peripheral edge of the ends of the sleeves that adjoin each other, the roller is deflected during forming the steel strip, and as it rotates in this state, the concave side of the deflection occurs. It is possible to prevent defects caused by contact between the outer circumferential edges of the sleeves, and therefore it is possible to prevent irregular patterns that occur at the ends of the sleeves due to defects from being transferred to the steel strip during molding. Product yield can be improved. As mentioned above, since a thrust load is always applied to the sleeve 12 on the steel strip feeding direction side in the axial direction of the roller, it is difficult to form a gap between the end surfaces of the adjacent sleeves, and the forming roller Since it is slender and tends to bend easily, the above-mentioned defects will inevitably occur if a chamfered portion is not formed.

Further, as shown in FIG. 9, when the roller body 13 is worn out, only the sleeve 12 can be replaced without discarding the entire roller body, and the arbor 11 can be used again, which is economical.

Furthermore, since the sleeve 12 is a composite sleeve and its surface portion 16 is made of a material with a low friction coefficient, the conventional friction coefficient of 0.25 can be reduced to 0.15 to 0.2, and the thrust load P can be reduced.

The present invention is not limited to the above-mentioned embodiment, but may be one in which a sleeve 12 divided into three parts is shrink-fitted as shown in FIG. 10, and the number of divisions of the sleeve 12 can be freely determined. can be selected.

According to the present invention, since the body surface layer is formed of a plurality of sleeves and these are shrink-fitted to the arbor,
Even if the body is elongated, shrink fitting is easy, and residual stress is reduced, resulting in good cracking resistance.

Further, since a slip prevention protrusion is provided at the axial end of the arbor on the steel strip feeding direction side of the core portion of the arbor, relative movement of the sleeve in the axial direction can be reliably prevented.

Furthermore, since a chamfer is formed on the outer circumferential edge of the end of the contact sleeve, the elongated forming roller according to the present invention has a bending that inevitably occurs during forming, which is caused by contact between the outer circumferential edges of the sleeves. It is possible to reliably prevent defects, and it is possible to prevent irregular patterns that occur at the end of the sleeve due to defects from being transferred to the steel strip, contributing to an improvement in product yield.

[Brief explanation of the drawing]

Figure 1 is a front view showing a conventional integrated roller;
FIG. 3 is a front view showing the forming roller according to the present invention, FIG. 4 is a sectional view of the same, and FIGS. 5 to 7 are the same as those in FIG.
8 is an explanatory diagram of the thrust load P, FIG. 9 is a sectional view showing the state of wear, and FIG. 10 is a front view of a forming roller showing another embodiment of the present invention. 10... Forming roller, 11... Arbor, 12...
...sleeve, 13...body, 15...protrusion.

Claims (1)

[Claims for Utility Model Registration] A roller for forming a steel strip into a spiral shape by feeding it from a direction oblique to the axial direction of the roller, which is an elongated spiral with a ratio L/D≧8 of body length L and body diameter D. In forming rollers for manufacturing steel pipes, the surface layer of the body of the roller is divided into two or more sleeves in the longitudinal direction and is shrink-fitted to the arbor. A forming roller for manufacturing a spiral steel pipe, characterized in that the roller is provided with a slip prevention protrusion for preventing relative movement of the sleeve in the axial direction, and a chamfer is formed on the outer peripheral edge of the adjacent end of the sleeve.