JPS5924283B2 - Single facer pressure roll - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION In recent years, with the decline in the quality of liner paper, problems such as step cracking (a phenomenon in which both the liner and the core paper break) and bonding occur when core paper 1 and liner 2 are bonded together using a single facer, as shown in FIG. Problems such as poor fitting are occurring.

There is a contradictory relationship between step cracking and poor lamination. That is, when step cracks occur, the vibration amplitude is large, so the pressure Calor 3
Displacement may be restricted (by a stopper). If the control is carried out, step cracks will not occur, but since the roll is deflected and vibrates, poor lamination will occur near both ends of the paper. In addition, step cracks and poor bonding often occur when the machine resonates, so countermeasures from the perspective of vibration have been desired. Figure 2 shows the structure of a conventional general pressure roll 3a, with a roll thickness of 4
a is formed uniformly, and the outer diameter portion 5a is often crowned on the outer diameter of the roll in consideration of deflection due to nip pressure and its own weight, but this crowning is for the purpose of correcting the deflection. The technical idea is different from the present invention (changing the wall thickness of the roll) described in detail below.

The following points can be considered as countermeasures against the above-mentioned step cracks and poor bonding.

(a) Reduce vibration amplitude and vibration acceleration during resonance.

(b) Decrease the resonance speed.

(c) The impact load at the time of resonance is distributed over the entire width of the roll.

By the way, with the structure of the conventional pressure calor, the above-mentioned (a) (
b) It was difficult to satisfy all the measures for (c) for the following reasons.

That is, if the thickness of the pressure calor is increased by making it uniform,
Conditions (a) and (b) above are satisfied, but condition (c) is not satisfied. Also, if the thickness of the pressure calor is reduced by making it uniform,
This is because the condition (c) above is not satisfied. The present invention was proposed in order to solve the above-mentioned conventional drawbacks, and the hollow roll is made thinner at the center and thickest at both ends, thereby preventing step cracks and poor lamination. It is intended to provide a pressure roll for phasers.

The present invention will be described below with reference to the embodiments shown in the drawings. As shown in Figure T, the pressure roll 3b showing the embodiment of the present invention has the thinnest wall thickness 6b at the center of the hollow roll, and the wall thickness Tb at both ends.
is the thickest, and is used in the position of the general single facer pressure roll 3 shown in FIG.

In addition, in Fig. □, 5b is the outer diameter portion of the roll, 14b is the inner diameter portion of the roll, and 15 is a bearing. Next, referring to FIG. 1, which shows a general single facer, the lower roll 8 and pressure roll 3 vibrate relative to each other during resonance, and both rolls 8 and 3 vibrate through the core paper 1 and liner 2. However, since the roll is deflecting and vibrating, the center of the roll hits hard at first.

However, when the pressure roll 3b of the present invention is used, since the wall thickness 6b of the central part is the thinnest, the roll deforms in cross-section, and the length of the surface that collides with the lower roll 8 gradually increases, reducing the impact load. The impact load is distributed over the entire length of the roll and can reduce the impact load applied to the core paper 1 and liner 2 per unit length. Also, since the wall thickness of the pressure roll 3b is made such that the wall thickness 7b at both ends is the thickest, the mass increases and the bending spring constant of the roll increases compared to a pressure roll with a uniform wall thickness equal to the wall thickness at the center of the roll. However, the mass effect is larger and the resonance speed decreases. In addition, 9 in FIG. 1 is an upper roll, 10 is a pasting roll, 11 and 12 are guide rolls, and 13 is a bonded single-sided corrugated board. Here, the core paper 1 is the upper and lower rolls 9,
8 are interlocked to form a step shape, and the liner 2 is pasted with a pasting roll 10 and pressed onto the liner 2 with a pressure roll 3. Figure 3 shows the relationship between pressure roll wall thickness and resonance frequency (surface length 2200mm, outer diameter 300φ, pressure roll, outer diameter 300mm).
φ×60t upper roll, outer diameter 300φ×40t lower roll).

Figures 4, 5, and 6 show model diagrams of the concave state of the pressure roll when the core paper and liner are bonded together.
The figure shows the case where the pressure roll 3a has a thick wall thickness (uniform), FIG. 5 shows the case where the pressure roll 3a has a thin wall thickness (uniform), and FIG. (core paper and liner), δ1, δ2, and δ3 indicate the concave state of the pressure roll surface in FIGS. 4, 5, and 6, respectively. Figure 8 shows the relationship between line speed and vibration amplitude (3rd
FIG. 2 is a diagram showing the same conditions as in the figure (pressure roll dimensions are as follows). A is the actual measurement value when the pressure roll has a uniform wall thickness of 20t. B is the actual measurement value when the pressure roll has a uniform thickness of 60t. C is the actual measurement value for the pressure roll according to the present invention. Figure 9 shows the relationship between line speed and vibration acceleration. 3 is a diagram showing the relationship (same conditions as in FIG. 3, dimensions of the pressure roll are as follows); FIG.

A is the actual measurement value when the pressure roll has a uniform wall thickness of 20t.B is the actual measurement value when the pressure roll has a uniform thickness of 60t.C is the actual measurement value for the pressure roll according to the present invention. A (uniform wall thickness 20t), B (uniform wall thickness 60t)
From the comparison, it is clear that the thicker the wall thickness, the better in order to take the above-mentioned measure (4).

Also, regarding the above-mentioned (b), it can be seen that the thicker the wall, the better, as shown in FIG. Next, in order to achieve the effect (c), as shown in the models of Figures 4 and 5,
Since a thick roll is almost a rigid body, it has little ability to distribute the impact load during resonance through cross-sectional deformation, and the impact load concentrates near the center, which is the biggest cause of step cracking (Figure 4).

The thin-walled roll shown in FIG. 5 is easily deformed in cross section and has an even load distribution, so the impact load applied to the paper per unit length is reduced, which helps prevent step cracking. As described above, the wall thickness of the pressure roll has advantages and disadvantages in terms of countermeasures. In the present invention, the center part of the roll, where the local load is most likely to be applied, has the thinnest wall thickness to distribute the load around the periphery, while the wall thickness at both ends is the thickest in order to reduce the vibration amplitude, vibration acceleration, and reduce the resonance speed. It was made so that it would become so.

According to the pressure roll of the present invention, no local load occurs as shown in Fig. 6, and the magnitude of the vibration amplitude and vibration acceleration as shown in C of Figs. It's not much different. The acceleration roll dimensions of C are 20t in the center and 60t in the roll end (surface length 2000mm), 12,520mm.
It is set as R. The wall thickness may be designed to have a tapered shape, a circular shape, etc., but it is expected that the same effect will be obtained in either case.

For example, in the case of a circular shape, the radius R is determined geometrically using the following formula. However, x: Thickness y at the center of the roll
: Thickness of the end of the roll l: Length of the surface The practical wall thickness of a pressure roll is approximately 15t to 80t, but local loads are considered to be applied to rolls of 45t or more, and below that, the roll gradually collapses. The distribution progresses around the center and becomes a distributed load below 25t.

As explained above, in the pressure roll of the present invention, the wall thickness of the hollow roll is made thinnest at the central part, so the mouth roll is deformed in cross section, and the length of the impact contact surface with the lower roll gradually increases, and the impact load is distributed over the entire length of the roll and can reduce the impact load applied to the paper per unit length.

Therefore, it is possible to avoid concentration of the impact load in the center, which occurs when the pressure roll has a large uniform wall thickness, and thus it is possible to prevent step cracks, poor bonding, etc. at the time of resonance.
In addition, in the present invention, the wall thickness of the hollow roll is made thickest at both ends, so the mass increases and the bending spring constant of the roll increases compared to a pressure roll with a thin and uniform wall thickness equal to the wall thickness at the center of the roll. However, the mass effect is larger and the resonance speed decreases.

As the resonance speed decreases, the inertia of the roll decreases, so
The absolute values of vibration amplitude and vibration acceleration are reduced, and impact force and impact energy during lamination can be reduced. Therefore, in addition to the effect of making the thickness of the central portion the thinnest, step cracks and bonding defects at the time of resonance can be avoided.

[Brief explanation of drawings]

Figure 1 is a side view of a typical single facer, Figure 2 is a partial cross-sectional front view of a pressure roll in a conventional single facer, and Figure 3 shows the relationship between pressure roll wall thickness and resonance frequency. The diagrams, FIGS. 4, 5 and 6 are model diagrams of the concave state of the pressure roll when the core paper and liner are bonded together in the case of the conventional method and the present invention, respectively, and FIG. FIG. 8 is a diagram showing the relationship between line speed and vibration amplitude; FIG. 9 is a diagram showing the relationship between line speed and vibration acceleration. Explanation of the main parts of the figure, 3b...pressure roll, 6
b...Central part, 7b...Both ends.

Claims (1)

[Claims] 1. A single facer pressure roll characterized by the hollow roll being thinnest at the center and thickest at both ends.