JP3392195B2 - Pipe making equipment - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pipe manufacturing apparatus for manufacturing a synthetic resin pipe such as a pipe with a rib. 2. Description of the Related Art Generally, a mandrel is surrounded by a plurality of mold blocks connected in a belt shape, and a resin material is extruded into a cavity formed between the mold block and the mandrel. 2. Description of the Related Art There is known a synthetic resin pipe forming apparatus in which blocks are sequentially sent out and circulated to form a pipe body. Conventionally, in this tube making apparatus, a displacement sensor is provided on a substrate that supports a mold block, and the displacement of the distance between the substrates is fed back to the feed speed of the mold block, so that a composite with a stable mold clamping pressure is obtained. A method for manufacturing a resin tube has been proposed (for example, see Japanese Unexamined Patent Publication No.
No. 3515222). [0004] However, in the case of the above-mentioned conventional pipe making apparatus, it is possible to detect only a change in the mold clamping pressure enough to move the substrate supporting the entire mold block. That is, a change in the mold clamping pressure can be detected only when nearly half of the mold blocks forming the cavity space are displaced.
However, in reality, in the initial position of the mold block clamping, that is, in the plastic deformation region of the resin material, the displacement of the mold block due to the fluctuation of the clamping pressure occurs. Cannot follow the fluctuation of the mold clamping pressure. As a result, when a product with a higher degree of perfection is required, a highly accurate product cannot be provided. The present invention has been made in view of the above circumstances, and provides a pipe manufacturing apparatus which can prevent the occurrence of a product defect and a failure of the pipe manufacturing apparatus and can manufacture a product having excellent product accuracy. It is intended to be. [0006] In order to solve the above-mentioned problems, a pipe producing apparatus according to the present invention surrounds a mandrel around a plurality of mold blocks connected in a belt shape. The resin material is extruded into a cavity space formed between the mold block and the mold block is sequentially sent out and circulated to form a tube body of a synthetic resin tube. A positioning unit provided, a displacement sensor provided at an initial position of the mold block for clamping the mold block, and detecting a displacement of the positioning unit; and a circulation of the mold block based on the displacement detected over time by the displacement sensor. Control means for controlling the speed. According to the present invention, a change in the mold clamping pressure is detected from the displacement of the mold block in the plastic deformation region before the resin material is hardened, and the circulation of the mold block is performed based on the detected pressure. The speed can be controlled. An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 and FIG. 2 show a main part of a pipe producing apparatus 1 for producing a ribbed pipe 2, and FIG. 3 shows a production line using the same. That is, a pipe-making apparatus 1 for this ribbed pipe 2
Is formed by surrounding a mandrel 4 with a plurality of mold blocks 3 connected in a belt shape, extruding a resin material 23 into a cavity space 20 formed between the mold block 3 and the mandrel 4, and Are sequentially sent and circulated to form the ribbed tube 2. The protrusions 30 are provided on each mold block 3, and the displacement sensor 5 is provided on the mold block 3 at the initial position of the mold clamping. Things. The displacement sensor 5 detects the mold clamping pressure of the mold block 3 that changes with the supply pressure of the resin material 23 over time, and based on the detected displacement, the controller (not shown) uses the mold block 3. To control the circulation speed. The mold block 3 includes a tube body forming portion 31 for forming a portion corresponding to the tube body 21 of the ribbed tube 2 and a rib for forming a portion corresponding to the rib 22 of the ribbed tube 2. A forming part 32 is formed. In addition, a protrusion 30 is formed on one side surface of the mold block 3 so as to be parallel to the feeding direction of the mold block 3. A plurality of such mold blocks 3 are connected in a belt shape, and two split mold groups 33 and 34 are provided.
Is made up. That is, the split mold group 3
The reference numerals 3 and 34 are attached to the outer peripheral surfaces of the first slide substrate 6 and the second slide substrate 7 such that the respective molded portions 31 and 32 of the plurality of mold blocks 3 face outward. Then, a first split mold group 33 having a linear region 33a in a part and connected in an annular shape, and a second split mold group 34 having the same configuration as the first split mold group 33 are configured. The first and second split mold groups 33, 34
In each of the linear regions 33a and 34a, the respective mold blocks 3 and 3 are disposed so as to face each other, and the second split mold group 34 is moved in the mold clamping direction with respect to the first split mold group 33. Being energized. That is, the first slide substrate 6 of the first split mold group 33 is provided with a support member 81 erected from the apparatus main body 10.
Is fixed at a predetermined position in advance. The first slide substrate 6 is provided with an insertion hole 61 for a fastening bolt 82. A guide bar 83 is provided upright on the support member 81. On the other hand, the second slide substrate 7 of the second split mold group 34 has a guide hole 7 through which the guide bar 83 can be inserted.
1 is provided, and a tightening bolt 82 is screwed. Then, the guide hole 71 of the second slide substrate 7 is inserted into the guide bar 83, and the guide bar 83
The second slide substrate 7 is movable along the direction in the mold clamping direction or the counter mold clamping direction. The fastening bolt 82 screwed to the second slide board 7 is inserted into the insertion hole 61 of the first slide board 6, and a nut 85 is screwed to the insertion end side of the first slide board 6 via a disc spring washer 84. . That is,
By adjusting the degree of screwing between the nut 85 and the second slide substrate 7, the mold clamping state of the second split mold group 34 with respect to the first split mold group 33 is determined. The adjustment of the screwing degree is adjusted by rotating the fastening bolt 82 by a motor (not shown) or the like. However, when the second slide substrate 7 is urged against the first slide substrate 6 in this manner, the mold block 3 bears all the urging force, and the deformation of the mold block 3 and an increase in the driving load are performed. This causes inconveniences such as the following. Therefore, a spacer 86 is provided on the guide bar 83 so that the urging force applied to the mold block 3 is reduced. In the pipe making apparatus 1 having such a configuration, the first split mold group 33 and the second split mold group 34 are arranged in opposite directions at a predetermined speed, that is, in FIG. The second mold group 34 circulates in the clockwise direction and the second mold group 34 in the counterclockwise direction, so that each mold block 3, 3 of each group 33, 34 divides the cavity space 20 with the mandrel 4. In the formed state, it moves horizontally (to the right in the figure) in the same direction. The displacement sensor 5 is provided on the first slide substrate 6 and the second slide substrate 7 at the initial position of the mold block 3 at the time of clamping. The protrusion 30 provided on the mold block 3 at the initial position of the mold clamping.
Is detected. When the protrusion 30 of the mold block 3 is displaced due to a change in the mold clamping pressure, the control device (not shown) controls the circulation speed of the mold block 3. The resin material 23 extruded from the mandrel 4 into the cavity 20 is usually at a resin temperature of about 200 ° C., but is sent while being cooled by a cooling mandrel 41 provided at the tip of the mandrel 4. When it is released from the mold block 3, it is cooled to around 60 ° C. Therefore, the displacement of the mold block 3 due to a change in the mold clamping pressure is in the vicinity of the cooling mandrel 41 where the resin material 23 can be plastically deformed. That is, the displacement sensor 5
The initial position of the mold clamping at which the displacement of the mold block 3 can be detected by the resin material 23 may be a position near the cooling mandrel 41 where the resin material 23 can be plastically deformed. Is preferred for obtaining good sensitivity. As the displacement sensor 5, an electric dial gauge, a differential transformer, or the like can be used. In this embodiment, the mold block 3
The protrusions 30 are provided only on one side surface of the mold block 3, and the displacement of the protrusions 30 is detected by the displacement sensor 5. However, the protrusions 30 are provided on both side surfaces of the mold block 3, and the corresponding displacement sensors 5 are provided. May be provided on both sides of the mold block 3 to detect the displacement of the mold block 3. Further, as shown in the present embodiment, the protrusion 30 is not limited to a protrusion protruding in the feeding direction of the mold block 3, but as shown in FIGS. Positioning portions 35 such as lines (see FIG. 4) and grooves (see FIG. 5) drawn on the side surfaces of
May be detected by the displacement sensor 5. However, in this case, it is necessary to prevent the displacement sensor 5 from erroneously recognizing lines and grooves formed by the positioning section 35 as oil stains. Next, the tube with ribs 2 is
A method for controlling the circulation speed of the mold block 3 performed by a control device (not shown) when manufacturing the mold will be described. First, the first and second split mold groups 33, 34
Is circulated at a constant speed as described above, and the molten resin material 23 extruded from the extruder 9 through the extrusion die 91 is fed into the cavity space 20 formed between the mold block 3 and the mandrel 4. Normally, the mold block 3 in the mold-clamped state
The gap between them varies depending on the molding state and the like.
It is around 03mm. That is, usually, the displacement sensor 5
From the distance between the mold block 3 and the protrusion 30, it is detected that the gap between the mold blocks 3 is about 0.03 mm. Then, the protrusion 30 of the mold block 3 is displaced, and the gap between the mold blocks 3 is reduced to 0.0.
If it exceeds 3 mm, the circulation speed of the mold block 11 is increased. Then, this causes the cavity space 20
At the same time, a sudden increase in the supply pressure of the resin material 23 to the driving portion is prevented, and a rise in the load on the driving portion is also prevented. When the gap is smaller than 0.03 mm, the circulation speed of the mold block 11 is reduced. Then, this causes the resin material 2 to enter the cavity space 20.
3 will be prevented from being insufficiently filled. It is preferable that the change in the speed at which the circulation speed is increased or decreased be controlled in accordance with a program set in accordance with the change in the gap, the resin material 23 and the molding conditions. However, once the circulation speed is changed, the next speed control is not performed until the mold block 3 moves 0.6 to 1 m. In this embodiment, the displacement of the mold block 3 of each of the first and second split mold groups 33 and 34 is detected by the displacement sensor 5.
Since the split mold group 33 is fixed via the first slide substrate 6 and it can be assumed that there is no displacement of the mold block 3, only the displacement of the mold block 3 of the second split mold group 34 is detected. The above-described speed control may be performed. Thereafter, the ribbed pipe 2 produced by the pipe producing apparatus 1 is cooled by a cooling machine 9 located at a later stage of the pipe producing apparatus 1.
2 for complete cooling. After cooling, the ribbed pipe 2 is cut into a suitable length at a substantially central position of the pipe main body 21 by a cutting device (not shown). As described above, according to the present invention, a change in the mold clamping pressure of the mold block in the plastic deformation region before the resin material is commercialized is detected, and the detected pressure is applied to the detected pressure. Since the circulation speed of the mold block can be controlled based on the amount of resin material supplied, it is possible to control the mold clamping pressure with high sensitivity in accordance with the supply amount of the resin material. Can be prevented,
High-precision products can be manufactured.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partially broken side view schematically showing a main part of a pipe producing apparatus. FIG. 2 is a sectional view taken along line AA of FIG. FIG. 3 is a schematic view showing a production line using a pipe producing apparatus. FIG. 4 is a side view and a front view showing another embodiment of the mold block. FIG. 5 is a side view and a front view showing still another embodiment of the mold block. [Description of Signs] 1 Pipe-making apparatus 2 Pipe with ribs (synthetic resin pipe) 20 Cavity space 23 Resin material 3 Mold block 30 Projection (positioning section) 35 Positioning section 4 Mandrel 5 Displacement sensor

Claims (1)

(57) [Claim 1] A mandrel is surrounded by a plurality of mold blocks connected in a belt shape, and a resin material is filled in a cavity space formed between the mold block and the mandrel. Extruding, a molding device for a synthetic resin tube made to sequentially send and circulate the mold block to form a tube body, a positioning portion provided on the side surface of each mold block,
A displacement sensor provided at an initial position of the mold block for clamping the mold block and detecting displacement of the positioning portion;
Control means for controlling a circulation speed of the mold block based on a displacement detected over time by the displacement sensor.