JPH0251685B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] This invention relates to a method of bending a steel plate in an arc using bending rolls, and in particular, when setting the position of the rolls, it is possible to achieve high accuracy by taking into account mechanical strain data obtained by actual measurements in advance. It is designed to perform circular arc bending. [Prior art] A parallel upper bending roll is arranged above two parallel lower bending rolls arranged at the same height so as to be movable up and down, and the mutual positional relationship between these rolls is kept constant. A processing method in which a steel plate is passed between upper and lower rolls and bent in an arc while applying a constant load to the upper roll is known in the art. In addition, in order to eliminate the influence of mechanical distortion that occurs during processing, it is conventionally known to adjust the height of the upper roll, crown the upper roll, and attach a back-up roll to the lower roll. It is. [Problem to be solved by the invention] The degree of processing applied to a steel plate by bending rolls, that is, the size of the radius of curvature obtained by processing, is determined by considering the spring back of the plate depending on the size of the radius of curvature. It is determined by the mutual positional relationship between the rolls, which is calculated and determined geometrically, and the magnitude of the load, which is calculated based on the material, thickness, width, and winding diameter of the steel plate. However, calculation of the relative position of the rolls assumes that the machine is a rigid body, so
As the load increases and the mechanical strain (bending of the roll and elongation of the frame) increases, the difference from the calculated results increases and processing accuracy decreases. That is, the roundness due to the elongation of the frame and the cylindricity due to the deflection of the roll decrease. Therefore, in the former case, the correction is made by the amount of elevation of the upper roll, and in the latter case, the upper roll is crowned and the lower roll is provided with a back-up roll, as described above. However, since it has not been quantitatively determined how much mechanical strain occurs depending on the magnitude of the load, conventionally the positional relationship of the rolls and the position of the back-up roll have been adjusted by trial and error. This allowed us to obtain the optimum value. However, the reality is that this adjustment requires that even a skilled worker pass the steel plate 5 to 6 times and repeat the adjustment each time to reach the optimum value. On the other hand, theoretical calculations that quantitatively capture the influence of mechanical distortion are not easy, and although the inventor of this application actually attempted such calculations, the errors were large and the calculations were not practical. Therefore, this invention attempts to solve the above problems by actually measuring the influence of mechanical distortion in advance and setting the position of the upper roll and the back-up roll by taking the measured data into account. be. [Means for Solving the Problems] In order to solve the above problems, the present invention applies a load to the upper roll and presses both lower rolls so that the upper and lower rolls are brought into contact over their entire length. The size and the increment of the stroke of the upper roll at that time are measured in advance using the adjustment distance of the back-up roll with respect to the lower roll as a parameter, and when performing arc bending on the required steel plate, the increment of the stroke of the upper roll and the increment of the stroke of the back-up roll are measured. The adjustment distance for the lower roll is determined from the above measured data based on the required load for the steel plate. This will be explained in detail below. Actual data on mechanical strain of bending rolls is measured for each machine as follows. In Fig. 1, Y is the stroke of the upper roll 1, △Y is the stroke increment (mechanical strain amount) when the load F is applied to the upper roll 1, and △X is the back-up roll 3 and the lower roll 2. is the adjustment distance. However, when the back up roll 3 is in contact with the lower roll 2 with zero pushing up force (△X=0), the reference position is taken as the reference position, and the back up roll 3 is in contact with the lower roll 2
The distance from the reference position when the roller moves away from is indicated by a negative sign, and the distance moved from the reference position when the back up roll 3 pushes up the lower roll 2 is indicated by a positive sign. (1) As shown in FIG. 1, the back up roll 3 is separated from the lower roll 2 by a required adjustment distance (-ΔX ₁ ), and the upper roll 1 is lowered to contact the lower roll 2 without applying any load. Since the upper roll 1 is crowned (see FIG. 2), both the upper and lower rolls 1 and 2 come into contact only at the center, as shown in FIG. 3. At this time, measure the stroke _Y1 of the upper roll. Next, a load F ₁ is applied to the upper roll 1, and not only the center portion a of the upper roll 1 but also both end portions b and b' are brought into contact with the lower roll 2. At this time, the lower roll 2 is also slightly bent (see FIG. 4). Thereby, both the upper and lower rolls 1 and 2 are in line contact over the entire length. Measure the stroke increment △Y ₁ at this time. (2) As shown in Figure 5, △X=0 (reference position)
In this state, the upper roll 1 is brought into contact with the lower roll 2, and the stroke _Y2 is measured in the same manner as above. Next, apply a load F ₂ and move the upper roll 1 to the lower roll 2.
Make line contact over the entire length of. Measure the stroke increment ΔY ₂ at this time. (3) As shown in Figure 6, back-up roll 3
Push in from the reference position and measure the stroke _Y3 when the adjustment distance △X takes a positive value. next,
As shown in FIG. 7, a load _F3 is applied to bring the upper roll 1 into line contact with the lower roll 2 over the entire length in the same manner as in the previous case. (4) Using the above data as shown in Figure 8, use the adjustment distance △X as a parameter, plot the magnitude of the load F, and further plot the stroke increment △Y according to the load F, and then calculate the back-up plot. A graph A showing the relationship between the adjustment distance ΔX and the load F in No. 3, and a graph B showing the relationship between the stroke increment ΔY and the load F are obtained. The above measured data shows that once the magnitude of the load F to be applied to the upper roll 1 is determined, when the lower roll 2 is pressed with that magnitude of load, the upper roll 1 and the lower roll 2 will come into line contact over the entire length. It shows the adjustment distance ΔX of the back-up roll 3 that can be made, and also shows the increment ΔY that should be corrected in the increasing direction with respect to the geometrically determined stroke Y of the upper roll 1 at that time. Although the state of elongation of the frame when loads F ₁ to _{F 3} are applied is not shown, the elongation is the first
This can be determined by the increase in y shown in the figure. The above measured data is used as follows.
In other words, when actually bending a steel plate in an arc, the theoretically calculated load size according to the characteristics of the steel plate is
If F ₀ and the stroke of upper roll 1 are Y ₀ , then the adjustment distance △X ₀ of back up roll 3 can be found from graph A, and graph B
The stroke increment ΔY ₀ of the upper roll 1 can be found by . When the back-up roll 3 and the upper roll 1 are set as described above, and a load F ₀ is applied to the steel plate 4 as shown in FIG. 9, the upper and lower rolls 1,
Since the pressurized parts 2 are parallel over the entire length with the steel plate 4 in between (if the steel plate 4 does not exist, they will be in line contact over the entire length), the degree of processing of the steel plate 4 is constant over its entire length, and the roundness and cylindrical shape are constant. You can get a high quality product. [Example] Bending roll made by Kurimoto Iron Works Maximum load 100 tons Upper roll diameter 320mm Crowning 3mm Length 3100mm Lower roll diameter 165mm No crowning Length 3100mm Back-up roll diameter 160mm, length 900mm Actual measurement data for the above were as shown in Table 1.

〔effect〕

As described above, the present invention obtains in advance the adjustment distance △X of the back-up roll and the increment △Y of the load and stroke corresponding to the load that allows the upper and lower rolls to make line contact over their entire length as actual measurement data of the machine. By doing so, the above △X and △Y can be known based on the load obtained from the logic value.
Therefore, according to the present invention, the back-up roll position and the stroke size of the upper roll can be set with one adjustment, taking into account the influence of mechanical distortion. Further, depending on the settings, a product with good roundness and cylindricity can be obtained with only one pass.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram of actual mechanical strain measurement, Figure 2 is a side view of Figure 1, Figures 3 and 4 are sectional views of the contact part in Figure 1, and Figures 5 to 7 are mechanical FIG. 8 is a graph showing an example of actual measurement data, and FIG. 9 is an explanatory diagram of a steel plate bending state. 1... Upper roll, 2... Lower roll, 3... Backup roll, 4... Steel plate.

Claims (1)

[Claims] 1. A crowned upper roll is placed on top of two parallel lower rolls placed at the same height so that it can be raised and lowered, and a back-up roll is pressed against the lower roll, and while applying a load to the upper roll, the upper roll is moved between the upper and lower rolls. In an arc bending method using bending rolls that passes through a steel plate and bends it, the magnitude of the load when a load is applied to the upper roll and pressed against both lower rolls so that the upper and lower rolls are in contact over their entire length, At that time, the increment of the stroke of the upper roll and the adjustment distance of the back-up roll with respect to the lower roll are measured in advance, and when performing arc bending on the required steel plate, the increment of the stroke of the upper roll and the lower part of the back-up roll are measured. A circular arc bending method using bending rolls, characterized in that an adjustment distance for the rolls is determined from the above-mentioned actual measurement data based on the required load for the steel plate.