JPH0114342Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a fin pass roll for pipe forming.

[Prior art] When forming a rectangular metal tube, a rectangular blank tube with corner bends is introduced into a fin pass roll.
A method of forming a square tube side into a desired circular arc cross section and preforming it into a shape in which each side has an outwardly convex circular arc is as follows:
For example, it is disclosed in Japanese Patent Application Laid-Open No. 57-50212.

[Problem to be solved by the invention] By the way, when forming a product with a curvature on the side of the product in the fine pass roll region, the curvature reduces the range of common use of the roll, and therefore it is difficult to produce products of many different sizes. In this case, the number of required sets of rolls increases, and the number of roll changes increases, leading to increased equipment costs and lower operating rates.

The present invention proposes a split lower roll of a fine pass roll that solves these problems.

[Means for Solving the Problems] The present invention fixes the center roll on the center line of the lower roll in the lower roll of the fin pass roll of a rectangular blank pipe with curvature on the product side, and installs side rolls on both sides of the center roll. The center roll and each side roll are provided to be slidable in the roll axis direction, and the roll profile of the center roll and each side roll is a straight line, the roll width of the center roll is smaller than the width of each side roll, and the roll surface of each side roll is the same as the roll surface of the center roll. This split fin pass lower roll is given an elevation angle θ and is characterized in that the center roll and each side roll are arranged so as to make point contact with the bottom side of a product of a rectangular blank pipe.

Hereinafter, the present invention will be explained in detail with reference to the drawings.

FIG. 1 is a partial explanatory cross-sectional view of the present invention. In the figure, 10 and 11 are fine pass rolls, and 1
0 indicates a roll arrangement in which the divided lower roll 4 is used in a divided state, and 11 indicates a roll arrangement in which the divided lower roll 4 is used in an undivided state. The center roll 4a of the divided lower rolls 4 is fixed on the roll center line (product center line) C, and the roll profile is a horizontal straight line R ₁
It is. Side roll 4 of divided lower roll 4
b and 4c are provided so as to be slidable in the direction of the roll axis L, and the divided side rolls 4b are set with spacers 5 forming a desired interval. In addition,
Reference numeral 1 indicates a rectangular blank tube (also referred to as a product in the description) formed by the fine pass roll, which has curvature on each side.

The divided lower roll 4 in the present invention is divided into three parts, and the side rolls 4b, 4 of the divided lower roll 4 are divided into three parts.
The roll profile of c is straight lines R ₂ and R ₃ ,
The roll surface of the center roll 4a and the elevation angle θ are given. In this way, a roll profile having a shape (hereinafter referred to as an inverted trapezoid) is formed by the center roll 4a and the left and right side rolls 4b, 4c. In addition, role profile is
It refers to the contour formed by the roll outer circumferential line on the forming material side in a cross-sectional view of the roll as shown in FIG. 1, that is, the shape of the roll hole. However, in the above case, we are talking about a part of the roll hole type, so
They are simply straight line parts R ₁ , R ₂ , and R ₃ .

In the present invention, the product side of the rectangular blank pipe is introduced into the fin pass roll in a state of curvature, so the elevation angle θ is arranged such that the roll surface of the side roll makes point contact with the bottom side of the product.

As mentioned above, the roll surfaces of the center roll and side rolls are straight, so the lower roll comes into contact with the bottom of the product at three points.

The roll width of the center roll 4a is designed to be 20% of the total width of the lower roll, but as shown in FIG. 1, it is smaller than the roll width of each side roll.

Further, a notch 6 is formed in the corner of the side roll of the divided lower roll on the center roll side. This is to prevent scratches on the product when it is compression molded with the fine pass roll, and also to prevent the center roll and side rolls (the state on the left in Figure 1) from being in close contact with each other. When separating the parts, a tool or the like can be inserted into the notch 6 to facilitate the separation.

Further, the vertical roll 2 of the fin pass roll can be moved in the direction of the product center line as shown by the arrow depending on the configuration of the lower divided roll 4, but the roll profile may be either arcuate or dogleg-shaped.

In the present invention, the fin pass roll includes the above-mentioned divided lower roll 4, vertical roll 2, and upper roll 3.
are arranged and used in a known manner.

The configuration of the present invention is as described above, but according to the divided lower roll 4 of the present invention, the bottom of the product and the three divided lower rolls 4 form point contact with each other in the fin pass area, resulting in three-point contact. . In other words, when a straight line touches an arc, it is always a point contact, but 3
The roll profile of the entire divided lower roll 4 is a combination of three straight lines: the straight line R ₁ of the center roll 4a and the straight lines R ₂ and R ₃ of the left and right side rolls 4b and 4c, and has the above-mentioned inverted trapezoidal roll profile. The contact between this shape and the bottom of the product, which is an arc, is a three-point contact (however, it is natural that the bottom of the product should be set so that it touches the center roll and the left and right side rolls due to the dimensions and shape). is necessary). Therefore, the bottom of the product is molded with three points in contact with the lower roll divided into three parts, and a stable shape and dimensional accuracy can be obtained without unnecessary deformation of the bottom of the product, which has curvature. The above-mentioned three points of contact are shown as A, B, and C in FIG.
Note that in reality, contact does not occur at a perfect point but in a certain area, and such contact is usually referred to as three-point contact.

Note that if the roll profile of the side roll is only a straight line and there is no elevation angle θ (in other words, if the entire bottom roll is just a flat roll (cylindrical roll)), the bottom of the product will be at the center roll 4.
A is in contact only at one point (one point in the center of the bottom of the product), causing deformation of the bottom of the product and making production impossible.However, in this invention, as described above, the bottom of the product is not unnecessarily deformed. Can be molded.

When the product size changes, the left and right side rolls are moved in the roll width direction (roll axis direction) in accordance with the product size, so that the lower roll divided into three parts can be used for the product. Adjust so that three points touch the bottom. In Fig. 1, the left side roll is placed closest to the product center line in response to the small product size.
The right side roll has a spacer 5 inserted and moved outward in the roll width direction in order to accommodate a large product size. In this way, the roll profile of the lower roll divided into three parts is all straight, and the lower roll divided into three parts contacts the bottom of the product at three points, so even if the product size changes, the roll profile remains the same. This can be accommodated using the lower roll (without having to rearrange it into another roll).

In addition, the side rolls 4b, 4 of the divided lower roll 4
The value of the elevation angle θ of c is appropriately determined in consideration of the product size range to which the divided lower roll is applied (i.e., the dual-use range of the roll) (however, it is not strictly determined as described below). in this case,
There are two aspects to the dual use range of a roll: the product size and the combined size width.A specific example of the elevation angle θ that is appropriate for the product size and the combined size width is as follows. That's right. In addition, in the following, for example, □50 indicates that the product size is a pipe with a square cross-sectional angle of 50 mm in both length and width.

□When the range of 50 to □75 is the common range: The range of θ is 10° to 15° □When the range of 50 to □100 is the common range: The range of θ is 8° to 12° □150 to □ When the range of 200 is the common range: The range of θ is 6° to 10° □When the range of 200 to 300 is the common range: The range of θ is 4° to 8° As in the example above, the product size It is more appropriate to decrease the value of the elevation angle θ as the value increases. The reason for this is that the curvature of the product sides of large-sized products is usually larger than the curvature of the product sides of small-sized products. From a geometrical relationship, it is appropriate that the elevation angle θ when the product size is large (when the curvature of the product side is large) is smaller than the elevation angle θ when the product size is small (when the curvature of the product side is small). however,
This relationship is not strict and changes depending on various conditions. For example, what dimensions should be taken for the width of the center roll or the width of the side rolls (the effective width of the part that can contact the side of the product), and the difference in the outer diameter of the side rolls between the product center line side and the outside diameter? How much (head difference) can you actually take?
Furthermore, the appropriate value of the elevation angle θ changes depending on the width of the product size to be applied. Therefore, the elevation angle θ is not particularly numerically limited. Further, the correspondence between the product size and the curvature of the product side does not necessarily have to match as described above.

[Effect of the invention] In this invention, the roll surfaces of the center roll and side rolls are given an angle θ with respect to the roll surface of the center roll, so the bottom of the product of the square blank pipe and the lower roll surface are in point contact, and the product is divided into three parts. The lower roll has three points of contact, resulting in stable shape and dimensional accuracy.

In addition, according to the present invention, the upper roll is used as a dedicated roll for product sizes and can be selected and rearranged according to the product size, but the lower roll can be divided, so by adjusting the movement of the side rolls in the roll width direction, various products can be manufactured. It can be adjusted to any size, eliminates the need for dedicated rolls, and eliminates roll recombination, improving operating efficiency.

Furthermore, if the entire corner of the side rolls on the center roll side is cut out, there is no risk of the product being scratched by the rolls during molding.

[Brief explanation of the drawing]

FIG. 1 is a partial cross-sectional view of the present invention. 1: Square raw pipe (product), 4: Lower divided roll, 4
a: center roll, 4b, 4c: side roll.

Claims (1)

[Scope of utility model registration request] In the lower roll of a fine pass roll made of a square blank pipe with a curvature on the product side, the center roll is fixed on the center line of the lower roll, and side rolls are provided on both sides of the center roll so as to be slidable in the roll axis direction. The roll profile of each side roll is a straight line, the roll width of the center roll is smaller than the width of each side roll, and the roll surface of each side roll is given an elevation angle θ with respect to the roll surface of the center roll. is a split fin pass lower roll that is arranged so as to make point contact with the bottom of the product of a square blank pipe.