JPS5814003Y2 - Roll shaft damage prevention structure - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a structure for preventing damage to a roll shaft that supports rolling rolls in a pipe making machine or the like.

As shown in FIG. 1, a conventional roll shaft 1 that supports rolling rolls of a pipe making machine, etc. has a large-diameter body 2 formed at the center with a width dimension A, and a large-diameter body 2 on both sides of the large-diameter body 2. It consists of a fitting shaft part 5 of a bearing 4 which is connected to the rolling mill and rotatably supports the rolling roll 3, and a shaft holding part 6 which is connected to the end of this fitting shaft part 5. It is supported by the casing via a fixing part 7.

In the roll shaft 1 as described above, a corner radius 8 is formed from the fitting shaft portion 5 toward the large-diameter body portion 2 .

This corner radius 8 is formed to have a small diameter that matches the radius of the bearing 4 because a commercially available bearing 4 is used.

Incidentally, since an unbalanced load acts on the roll shaft 1 during rolling, if the corner radius 8 has a small diameter, stress will be concentrated on this portion, causing a problem that breakage will occur from the corner radius portion.

It is also possible to disperse the stress concentration by increasing the diameter of the corner radius, but this is not actually implemented due to economic reasons, as it would require changes to the shape of the bearing, etc.

In view of the above points, this idea allows the conventional bearing to be used as is, and also allows the corner radius to be formed into a curved surface with a sufficiently large radius, providing sufficient strength against stress concentration and durability. The purpose of this invention is to provide a breakage prevention structure for a roll shaft that is excellent in performance and economically advantageous.Hereinafter, an embodiment of this invention will be described with reference to FIGS. 2 and 3.

As shown in the figure, the roll shaft 11 includes a large-diameter body portion 12 at the center, and a shaft portion 1 for fitting bearings 13 provided at both ends of the body portion 12.
4, and a shaft holding portion 1 connected to the end of the fitting shaft portion 14.
It consists of 5.

The corner radius 16 provided from the fitting shaft portion 14 toward the large-diameter body portion 12 is formed into a curved surface with a radius sufficient to disperse stress concentration as shown in FIG. A spacer ring 18 is inserted into the corner radius 16.

The spacer ring 18 has an inner circumferential surface at the end on the large-diameter body 12 side formed into a radius that matches the corner radius 16 .

Furthermore, the large-diameter body 12 is narrower than the large-diameter body 2 of the conventional roll shaft 1 shown in FIG. 1 due to the formation of the corner radius 16 with a large curved surface. The dimension A between the outer ends of the conventional large-diameter body 2
It is equal to the width dimension A of.

Therefore, the dimension from the end of the fitting shaft 14 to the end surface of the spacer ring 18 is equal to the length of the fitting shaft 5 of the conventional roll shaft 1, and the bearing 13 is the same as the conventional bearing without any processing. You can use it as is without any trouble.

The outer diameters of the large-diameter body 12 and the spacer ring 18 are equal, and a gap is formed between the large-diameter body 12 and the inner peripheral surface of a rolling roll 19 rotatably supported by a bearing 13.

This invention has the above-mentioned structure, in which a roll shaft 11 with a fixed part 20 rotatably supported by a casing in a pipe making machine etc. rotatably supports a rolling roll 19 via a bearing 13. .

Further, the corner radius 16 formed from the fitting shaft portion 14 to the large diameter body portion 12 is formed into a curved surface with a sufficiently large radius,
Since the spacer ring 18 is inserted into the corner radius 16, it is possible to disperse stress concentration on the corner radius of the roll shaft, prevent breakage due to stress concentration, and greatly improve durability. Can be done.

In addition, due to the spacer ring inserted into the corner radius, the length of the mating shaft of the bearing remains the same as before, so there is no need to change the shape of the bearing, and conventional products can be used as is, making it economical. It is also advantageous.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional plan view showing the structure of a conventional roll shaft, FIG. 2 is a cross-sectional plan view showing the structure of the roll shaft of this invention, and FIG. 3 is an enlarged view of the main parts of the same. 11 is a roll shaft, 12 is a large-diameter body, 13 is a bare tongue, 14 is a fitting shaft, 15 is a shaft holding portion, 16 is a corner radius, 18 is a spacer ring, and 19 is a rolling roll.

Claims (1)

[Scope of utility model registration request] In a roll shaft in which bearing fitting shafts are formed on both sides of a large-diameter body, the corner radius from the fitting shaft toward the large-diameter body is formed into a curved surface with a sufficiently large radius to disperse stress concentration. A breakage prevention structure for a roll shaft, characterized in that a spacer ring is inserted, the inner circumference of which matches the corner radius of the fitting shaft portion, and which provides a required width dimension to the large diameter body portion.