JPS603884B2 - Extrusion device with multiple movable wheels - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in an extrusion device using a movable wheel that is capable of continuous extrusion without any limitation on the length of the material, and in particular to an extrusion device that uses a plurality of movable wheels to achieve high efficiency. The present invention also relates to an extrusion device that can stably extrude materials.

A device for extruding material using a single movable wheel having an endless groove is disclosed, for example, in Tokukan Sho 47-31859.
This method is already known as disclosed in Japanese Patent No. 49-65369 or Tokusekki No. 49-65369.

First, the mechanism for extruding material using such a movable wheel will be explained.

Since this mechanism itself is the same whether it is a single wheel or a plurality of wheels, in order to make the following explanation easier to understand, FIG. 1, which is an embodiment of the present invention, will be referred to, and FIG. This will be explained with reference to FIGS. 5 and 6. The movable wheel 10 used in this type of extrusion system has an endless groove 11 with a substantially U-shaped cross section formed on its outer circumferential surface, and a shoe lock 13 is interlocked with the endless groove. A transport passage 16 is formed by the endless groove 11 and the shoe lock 13, and the material 15 for extrusion is forcibly fed into the transport passage 16. FIG. 5 is a partial sectional view showing the vicinity of the transport passage 16 in this case, and as can be seen from the figure, in the transport passage 16 the material 15 is in contact with the shoe block 13 on one side, whereas , is in contact with the endless groove 11 on three sides. Therefore, the traverse friction resistance on each contact surface is three times greater on the endless groove 11 side than on the shoe block 13 side. In this state, with the contact pressure P of each contact surface, Shuprock 1
3 is fixed and the movable wheel 10 is rotated. For example, if we consider the case where the wheel 10 is rotated toward the back of the figure, the contact friction resistance between the material 15 and the wheel 10 is much larger, so the material 15 is continuously rotated toward the back of the figure from the wheel 10'. sent. On the other hand, a fixing block 20 is tightly fitted in the endless groove 11, as shown in a partial sectional view in FIG. movement is prevented. Since the material 15 is still forcibly fed into the transport passage 16 in a state where the movement of the leading end of the material 15 is prevented, an internal pressure is generated in the material 15 due to the forced feeding force. The internal pressure becomes the extrusion pressure, and by providing a die deep within the extrusion pressure, an extruded product of infinite length can be obtained from the die. However, in the above extrusion method, since the source of the extrusion pressure is dependent on the contact friction resistance between the material 15 and the endless groove 11, there are some problems not seen in the conventional ram extrusion method. do.

The first of these is a problem originating from the structure.

That is, when internal pressure is generated in the material 15 as described above in FIG. 5, a force acts on the shoe lock 13 which is iron-coupled to the endless groove 11 to separate the shoe lock 13 from the endless groove 11. Therefore,
If the shoe lock 13 is not restrained with a restraining force Fn sufficient to resist this separation force, the shoe lock 1
3 and the endless groove 11, the material 15 not only becomes burrs and overflows from the transport passage, but also causes a decrease in extrusion pressure. Moreover, the internal pressure generated in this case is enormous, and it is technically quite difficult to completely hold down the shoe lock 13 rigidly against this internal pressure. The reality is that this holding structure has become extremely exaggerated and complicated. Second, there is the following major problem, which can be said to be fatal to the movable wheel system.

That is, as mentioned above, the pressure generation mechanism is made to depend on the contact frictional resistance between the material and the groove surface, but the adhesion between the material and the groove surface is not always perfect and uniform on all contact surfaces during extrusion work. changing over time or location,
So-called dry slip occurs.

When this slippage occurs, the pressure generated on the material naturally fluctuates, which causes fluctuations in the extrusion pressure and creates an imbalance in the flow of the material extruded from the die.
There is a risk of destabilizing the quality of the product.
As a result of various experiments and plastic mechanics analysis related to movable wheel type extrusion, the inventors found that the above-mentioned problems associated with movable wheel type extrusion can be solved by combining multiple wheels instead of using a single wheel. We found that significant improvements can be made by using The already proposed hakama face No. 50-132736 (Samurai Seki Sho 52-5706)
No. 8) is one of the results, and the present invention relates to its improvement. The following will first explain why the problems associated with the movable wheel system can be solved by using a plurality of wheels.

As we have already seen, the extrusion pressure for material extrusion in the movable wheel method depends on the contact friction resistance between the material and the groove surface of the wheel, so the pressure distribution of the material in the transportation passage is naturally dependent on the pressure distribution at the entrance of the passage. It's small and big in the back.

FIG. 7 is a diagram showing the actual pressure distribution situation,
An example is shown in which the arc angle Jo of the contacting portion of the material is 90o, where 0 on the horizontal axis scale means the entrance of the passage, and 90 means the innermost part of the passage. P(0) on the vertical axis is the pressure value at the angular coordinate ◇ degrees from the inlet. o is the yield stress of the material, and the vertical scale indicates how many times the pressure at that point is the yield stress. From FIG. 7, it can be seen that the pressure at the entrance of the passage is 4.0 mm, and the pressure increases rapidly at the back of the passage. The existence of a pressure distribution as shown in Figure 7 means that a corresponding separation force is also acting on the shoe block. Consider suppressing it from the outside.

Just as there is a center of gravity that can support static gravity at one point, even in the pressure distribution state shown in Figure 7, when trying to support something from the outside, there is a point that can support it from the outside, like the fulcrum of a balance. There is a point of concentration of balanced stress.
Let us now assume that the angular coordinates of such a concentration point are gm. When holding down the shoe block, the restraining force Fn is this J
It goes without saying that it is most effective to concentrate on m. This Jm is influenced not only by the internal pressure of the material but also by the rotational moment due to the rotation of the wheel, and also changes depending on the size of the contact angle 0. Figure 3 shows the relationship between the contact angle gu and 0 m. This is a diagram obtained as a solution to a theoretical formula for m (the details of the theoretical formula are omitted). In the figure, 8 is a value of 2mmRw/Ri, and s is the coefficient of friction between the workpiece and the shoe lock. The effective coefficient of friction of the striped workpiece, Ri is the radius of the workpiece before extrusion, and Rw is the radius of the wheel. The value of o here can be selected as appropriate, but since the contact angle ◇o commonly used industrially is about 90o, in such an extrusion device (as shown in Fig. 1), the stress concentration point is As can be seen from Figure 3, the point 0m is
Almost like Jo.

If this point is suppressed by the restraining force Fn, the shoe lock can theoretically be supported most efficiently at this one point. Now, consider a situation in which two wheels 10a and 10b are arranged as shown in FIG. 4 (the arrangement shown in FIG. 1), and one shoe lock 13 is arranged between them as shown in the figure.

Since guo=900 in FIG. 4, gum in this case is also approximately 90o from FIG. 3, which corresponds to the position marked 0m in FIG. 4. This position Jm
The separation force on the shoe lock is concentrated at this position, and it can be seen that at this position, the separation force applied to the shoe lock directly acts as a restraining force Fn against the separation force from the opposite wheel. That is, the separation force from the wheel 10a directly acts as a restraining force Fn against the separation force from the wheel 10b, and conversely, the separation force from the wheel 10b directly acts as a restraining force Fn against the separation force from the wheel 10a. . In this way, the separation force acts on each other as a restraining force, and there is no need to add a special holding mechanism to the shoe block to restrain it. Compared to the case of a single wheel, which requires a complex and exaggerated structure for holding down the shoe block as described above, the benefits of using multiple wheels are obvious. Furthermore, the second problem with a single wheel, the instability of the pressure generated due to wheel slippage and the resulting uneven quality of the extruded product, is due to the fact that multiple wheels are used. This problem can be effectively solved by using multiple wheels.

As mentioned above, the problems seen in the case of a single wheel are:
Although the problem was solved by using a plurality of wheels, it was found that there were still problems as follows. The effect achieved by using the plurality of wheels described above can be said to be achieved when the material is fed smoothly in each wheel, and if this is not the case, it may not necessarily be said to be sufficient.

For example, in FIG. 4, consider a case where one wheel 10a is slipping and the other wheel 10b is not slipping. Naturally, the internal pressure on the 10a side where the slippage occurred will be low, and the internal pressure on the 10b side will be high, breaking the balance of Fn, and there is a risk that an unexpected abnormal force will be applied to the shoe block. Moreover, when the internal pressure on one side of the wheel is high and the other side is low, there is an imbalance in the extrusion pressure itself, which causes uneven material flow near the die entrance, resulting in poor quality of the extruded product. It may cause. The present invention has been made in view of the above-mentioned circumstances, and even if pressure fluctuations occur due to the above-mentioned idle slip in an extrusion device using a plurality of movable wheels, the device itself automatically corrects the pressure fluctuation. The purpose of the present invention is to provide an extrusion device that can always achieve stable extrusion by correcting imbalance, and its gist is to provide a plurality of movable wheels having endless grooves on their outer peripheries, and A shoe lock is fitted with each of the endless grooves to form a transport passage for material extrusion, and a fixed block is disposed opposite to the shoe lock and is tightly fitted with each of the endless grooves. In an extrusion device, the space between the shoe lock and the fixed block facing each other is formed in a collecting chamber having a die for extruding the material, and the transport passage is passed through the collecting chamber, The shoe lock is provided in an extrusion device using a plurality of movable wheels that are configured to be able to move slightly in accordance with the difference in extrusion pressure that occurs within each transport path of each of the movable wheels.

The present invention will be specifically explained below with reference to two embodiments shown in the accompanying drawings. Figure 1 shows two movable wheels 1
FIG. 2 is an explanatory cross-sectional view showing an embodiment of an extrusion device according to the present invention using 0,10.

The movable wheels 10, 10' supported by mutually parallel shafts 19, 19 have endless grooves 11, 11 having a substantially U-shaped cross section formed on their outer peripheral surfaces. On the other hand, separately from these movable wheels 10, 10, the endless groove 11,
There is a shufrock 13 which is iron-coupled to the shaft 11, and the shufrock 13 is configured to be able to move slightly around a support shaft 19 in the direction of the arrow in the figure. Also, the endless grooves 11, 11 and the shoe lock 13 that is in sync with the endless grooves 11, 11.
Transport passages 16, 16 for moving the materials 15, 15 are formed by these transport passages 16, 1.
One end of 6 is configured as a closed opening into which materials 15, 15 can be inserted, as shown in the figure, and at the back of the transport passage there is a fixing member that completely seals the endless grooves 11, 11 and tightly intersects with them. There is a block 20, and the movement of the material 15, which has been fed to the fixed block 20 by the rotation of the wheel 10, is forcibly blocked by this fixed block 20'. Shuffle block 13 and fixed block 20
As shown in the figure, there is a gathering chamber 18 for the materials 15, and the backs of the transport passages 16, 16 are passed through this gathering chamber 18, and the material 15 is forcibly moved by the fixed block 20'. The blocked material 15 is configured to change direction at the back of the passage 16 and collect in the collection chamber 18. Reference numeral 17 denotes a die provided in the collecting chamber 18, and the material 15 collected in the collecting chamber 18 is extruded from this die 17 to form an extruded product 21.

Now, since the extrusion device according to the present invention is configured as described above, it can exhibit the following effects.

Now, in the extrusion apparatus shown in FIG. 1, it is assumed that slippage occurs in the wheel on the right side, and that the wheel on the left side is operating normally without such slippage.

There is a difference in the way the material is fed into the left and right passages depending on the presence or absence of idle slip, and naturally the internal pressure in the left passage where there is no idle slip is higher than that in the right passage where there is idle slip. higher than the internal pressure. That is, in FIG. 1, the relationship between the internal pressures RI and R2 is such that RI>R2, and since the shoe lock 13 itself is configured to be able to move slightly, it moves slightly due to the difference in internal pressure and moves to the right in the drawing. . As a result, the space of the left passage becomes wider, and the space of the right passage becomes narrower. The internal pressure decreases on the side where the space is wide, while the internal pressure increases on the side where the space is narrow. In that case, the internal pressure will conversely become RI<
The shoe lock 13 is pushed back to the left side as indicated by the arrow R in the figure. In this way, even if the internal pressure in the passages of both wheels changes due to slippage, the shoe lock itself moves slightly in response to the change in internal pressure, and the internal pressure in both wheels is always maintained at a constant level. Since it acts to maintain an equilibrium state, it is not only possible to always obtain stable extruded products of good quality, but also to accurately prevent abnormal forces from being applied to the support structure of the shoe flock. .

Next, FIG. 2 shows another embodiment of the present invention, in which the same reference numerals as in FIG. 1 indicate the same configurations. That is, in Fig. 2, the shoe lock fine movement mechanism is
The operation and effect of the system is the same as in Figure 1, except that instead of the support shaft 19' shown in the figure, it relies on the rolling of rollers 30, 30 arranged in large numbers on the bottom of the shoe lock, allowing for more horizontal movement. There is no difference. As described above,
According to the extrusion device according to the present invention, since the shoe lock is configured to be able to move slightly according to the difference in internal pressure that occurs in the transport passage of each movable wheel, the extrusion pressure can be balanced without making the device particularly large-scale. It was able to completely solve the problems that remained when multiple movable wheels were used by automatically holding the Not only was it possible to extrude high-quality products, but it was also possible to extrude with a high degree of stability compared to those using multiple wheels with fixed shoe locks, and its industrial significance is obvious. There's something big.

[Brief explanation of drawings]

FIG. 1 is an explanatory cross-sectional view showing one embodiment of an extrusion device according to the present invention, FIG. Diagram showing the relationship with the best support point. Figure 4 is an explanatory diagram showing the stress relationship applied to the shoe lock when two wheels are used. Figure 5 is a partial cross-section showing the configuration near the transportation path. Figure 6 is a partial sectional view showing the state of the fixed block, and Figure 7 is a diagram showing the pressure distribution of the material in the transportation passage. 10: Movable wheel, 11: Endless groove, I3: Shoe block, 15; Material, 16: Transport passage, 17; Die, 18: Gathering chamber, 19, 19': Shaft, 20; Fixed block, 21; Extruded product, 30; Roller. Kotobuki 1 and 2 figures Figure 3 Figure 4 Ryo S diagram Hishi et al. younger brother Ryo diagram

Claims (1)

[Claims] 1. A plurality of movable wheels having endless grooves on the outer periphery, a shoe block that fits into the respective endless grooves of each of these movable wheels to form a transport passage for material extrusion, and a shoe block facing the shoe block. A fixing block is provided which is disposed and tightly fits into each of the endless grooves, and a space between the shove blocks and the fixing block facing each other is formed into one collecting chamber having a die for extruding the material. In the extrusion device in which the transportation passage is communicated with the collection chamber, the shove block has a plurality of movable wheels configured to be able to move slightly according to the difference in extrusion pressure generated within each transportation passage of each of the movable wheels. Extrusion device using wheels.