JP3305093B2 - Method and apparatus for forming annular member - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for forming an annular member using an extruder.

[0002]

2. Description of the Related Art As a conventional method for forming an annular member, for example, a method described in Japanese Patent Application Laid-Open No. 4-226741 is known. In this method, a lower mold having a plurality of divided receiving surfaces is rotated around a rotation axis perpendicular to the receiving surface, and the extruded material is extruded from the die of an extruder while being adhered to the receiving surface, and is pushed onto the receiving surface. Forming the extruded material bent in an arc shape, cutting the arc-shaped extruded material along substantially the dividing position of the lower mold, removing and transferring the lower mold segment to which the extruded material is adhered, The method includes a step of restoring a lower mold by assembling a plurality of mold segments, and a step of joining both ends of an extruded material adhered to each lower mold segment to form an endless annular member.

[0003]

However, in such a conventional method for forming an annular member, the arc-shaped extruded material extruded onto the lower die segment is once cut and then transferred to another gathering position. However, since the extruded material is joined at the gathering position to form the annular member by joining both ends, there is a problem that the molding operation is complicated and the molding cost is high.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method and an apparatus for forming an annular member in which the molding operation is simple and the molding cost can be reduced.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to form a ring-shaped groove on a receiving surface while rotating a lower die around a central axis of the ring-shaped groove while extruding an extruded material from the extruder. Extruding into the groove to fill the ring-shaped groove with the extruded material one after another, and the starting end of the extruded material filling the ring-shaped groove approached the die of the extruder by rotation of the lower die and reached the stop position. When the operation of the extruder is stopped, the extruded material is extruded from the extruder by the residual pressure to fill the remaining ring-shaped groove with the extruded material, and the starting end of the extruded material filling the ring-shaped groove is a lower mold. A step of cutting the extruded material by means of a shutter and closing the extrusion port of the extruder when the rotation reaches the closed position near the mouthpiece of the extruder by further rotation; and By rotating the end portion of the extruded material by pressing the end portion of the extruded material with a die while pressing the end portion of the extruded material into the ring-shaped groove while pressing the end portion of the extruded material, thereby forming an annular member. Also,
A lower die having a ring-shaped groove formed on a receiving surface, rotating means for rotating the lower die around a center axis of the ring-shaped groove, and a ring-shaped groove of the lower die rotating the extruded material. An extruder that extrudes and fills the ring-shaped groove with the extruded material one after another; a shutter that is provided near a die of the extruder and that cuts the extruded material when activated and closes an extruder of the extruder; When the starting end of the extruded material filling the groove approaches the die of the extruder by the rotation of the lower die and reaches the stop position, the extruded material is extruded from the extruder by residual pressure by stopping the operation of the extruder and remaining. When the starting end of the extruded material filling the ring-shaped groove reaches the closed position near the mouthpiece of the extruder due to the rotation of the lower mold, the shutter is actuated and the extruded material is filled. Cutting and closing the extrusion port of the extruder, further rotating the lower mold by a predetermined angle from the closing of the extrusion port, rubbing the end of the extruded material to the starting end of the extruded material with a die and pressing it into a ring shape Control means for pressing the annular member into the concave groove,
This can be achieved by an annular member forming apparatus provided with:

[0006]

Now, it is assumed that the lower die having the ring-shaped groove formed on the receiving surface is rotated around the center axis of the ring-shaped groove by the rotating means. At this time, the extruded material is extruded from the extruder into the ring-shaped groove, whereby the ring-shaped groove is successively filled with the extruded material. Next, when the lower end of the extruder further rotates and the starting end of the extruded material filling the ring-shaped groove approaches the die of the extruder and reaches the stop position, the operation of the extruder is stopped by the control means. Since the residual pressure remains in the extruder even after this stop, the extruded material is extruded from the extrusion port of the extruder due to the residual pressure. At this time, the lower die is still rotating. Fills the remaining ring-shaped groove. Next, when the lower die further rotates and the starting end of the extruded material filling the ring-shaped groove reaches the closed position near the die of the extruder, the control means operates the shutter, and is extruded by the shutter at the residual pressure. Cut the extruded material and close the extrusion opening of the extruder. At this time, since the internal pressure of the extruder is low, the next shutter opening operation becomes easy. After the extrusion port is closed, the lower die is further rotated by a predetermined angle. As a result, the end of the extruded material is pressed into the ring-shaped groove while being rubbed and pressed against the starting end of the extruded material by the die, thereby forming an annular member. Then, when the lower die rotates by a predetermined angle from the closing of the extrusion opening, the rotation of the lower die is stopped by the control means. By simply controlling the rotation of the lower die, the operation of the extruder, and the operation of the shutter by the control means, a high-quality endless annular member can be easily formed, and the molding cost can be reduced.

Further, according to the present invention, the starting end of the extruded material can be securely pressed into the lower ring-shaped groove. Further, according to the third aspect, the resistance from the extruded material when the shutter is opened next time can be reliably reduced, and the shutter opening operation becomes easy.

[0008]

An embodiment of the present invention will be described below with reference to the drawings. 1 and 2, reference numeral 11 denotes a base provided on a floor surface 12, and a horizontal disk-shaped turret table 13 is rotatably supported on the base 11. And
The turret table 13 is intermittently rotated by 180 degrees around a vertical axis by a drive mechanism (not shown) built in the base 11. The turret table 13 rotatably supports a pair of supports 16.
Are arranged equidistant from the rotation axis of the turret table 13 and 180 degrees apart in the circumferential direction of the turret table 13. Each support 16 has a flat receiving surface 18 on the upper surface.
A disk-shaped horizontal lower mold 19 having a ring-shaped concave groove 23 whose cross-sectional shape is the same as the cross-sectional shape of the annular member to be formed is formed on the receiving surface 18 of each of these lower dies 19. ing. The turret table 13 is provided with a pair of motors 17 as rotating means, and these motors 17 apply a driving force to the corresponding support base 16 and the lower mold 19, respectively.
The support 16 and the lower mold 19 are rotated around the central axis of the ring-shaped groove 23. Also, these motors 17 have encoders
Each of the encoders 20 constantly detects the amount of rotation of the motor 17, that is, the amount of rotation of the support base 16 and the lower mold 19, and outputs the detection result to control means described later.
Numerals 21 are cylinders mounted on the support bases 16 and extending as a vertically extending mechanism. The ends of the piston rods 22 of these cylinders 21 are connected to the lower mold 19.
As a result, when the cylinder 21 operates, the lower molds 19 individually move up and down.

Reference numeral 31 denotes an extruder. Inside the extruder 31, there is formed a passage 32 through which an extruded material G, here high-temperature and soft raw rubber, passes. Screw 34 is housed. Then, when the screw 34 is driven and rotated by the drive unit 33, the extruded material G is transported in the passage 32 toward the extrusion port 35. Reference numeral 36 denotes a die provided at the end of the extruder 31. The die 36 defines the cross-sectional shape of the extruded material G extruded from the extruder 31 to be the same as the cross-sectional shape of the ring-shaped groove 23. The rotation of the turret table 13 and the operation of the cylinder 21 cause the lower mold 19 to receive its receiving surface.
18 is almost in contact with the lower end of the base 36, and the extrusion port 35 is transferred to a position overlapping the ring-shaped groove 23. At this time, the position of the lower mold 19 is the extrusion position A. When the mold 19 is present, the extruded material G is extruded from the extruder 31 into the ring-shaped groove 23. Here, one lower mold 19
Is in the extruding position A, the other lower mold 19 is located in the exchanging position B separated from the extruder 31. The extruder
At the bottom of the base 36, a pressure sensor as shown in FIG.
The pressure sensor 37 detects the pressure inside the extruder 31, that is, the pressure in the passage 32. Reference numeral 38 denotes a cylinder attached to the extruder 31, and a shutter 40 located near the base 36 is attached to a tip of a piston rod 39 of the cylinder 38. And this shutter
When the piston rod 39 of the cylinder 38 protrudes, the cylinder 40 moves until it comes into contact with the base 36 to cut the extruded material G being extruded from the extrusion port 35, and closes the extrusion port 35 of the extruder 31. Reference numeral 41 denotes control means such as a microcomputer, and the control means 41 includes an encoder.
The detection result is input from the pressure sensor 20 and the pressure sensor 37, and a control signal is output to the drive mechanism, the motor 17, the cylinder 21, the drive unit 33, and the cylinder 38 in the base 11 to control the operation thereof.

Next, the operation of the embodiment of the present invention will be described. Now, the rotation of the turret table 13 is stopped, and one lower die 19 is located immediately below the extrusion position A, and the other lower die
19 is located at the exchange position B. Next, the control means
The piston rod 22 of one cylinder 21 is protruded by the control signal from 41, and the lower mold 19 is raised to the pushing position A as shown in FIG. At this time, the receiving surface 18 of the lower mold 19 and the lower end of the base 36 are almost in contact with each other. As a result, the entire ring-shaped groove 23 between the lower end of the base 36 and the inner wall of the ring-shaped groove 23 is pushed out. It becomes a space through which the material G can pass.

Next, a control signal is output from the control means 41 to the cylinder 38 to retract the piston rod 39, and the shutter 40 is separated from the base 36 as shown in FIG. 4 (c). As a result, the extrusion port 35 is opened as shown in FIG. 5, and the extruded material G can be extruded. Such an extrusion port 35
Immediately after the opening of the extruder, a control signal is output from the control means 41 to the drive section 33, and the extruder is driven by the drive section 33 as shown in FIG.
The rotation of the screw 34 is started. As a result, the passage
The extruded material G in 32 is pushed by the screw 34 and extruded from the extruding port 35 into the ring-shaped groove 23 of one lower mold 19. At this time, as shown in FIGS. 4 (a) and 4 (d), since the lower mold 19 has stopped rotating, the internal pressure in the passage 32 of the extruder 31 gradually increases with time, and as a result, Groove
The starting end portion G1 of the extruded material G extruded into the inside 23 is pressed (pressed) against the inner wall of the ring-shaped groove 23 and securely adhered (pressed) without being turned up.

When the internal pressure of the extruder 31 rises above the set pressure, the control means 41 outputs a control signal to one of the motors 17 based on the detection result from the pressure sensor 37. As a result, the motor 17 operates, and the support base 16 and the lower mold 19 are moved to the position shown in FIG.
As shown in (d), the ring-shaped groove 23 is integrally rotated around the central axis. Also at this time, since the extruder 31 is continuously operating, the extruded material G is sequentially extruded from the extruding port 35 into the ring-shaped groove 23, and the ring-shaped groove 23 is extruded by the extruded material G. It is filled one after another. At this time, since the lower end of the base 36 is almost in contact with the receiving surface 18 of the lower mold 19, the extruded material G is a fixed contour determined by the lower end of the base 36 and the inner wall of the ring-shaped groove 23, in this case, a ring. It is formed in the same shape as the cross-sectional shape of the groove 23.

In this state, the lower die 19 rotates nearly one turn, and the starting end of the extruded material G filling the ring-shaped groove 23 approaches the base 36 of the extruder 31 as shown in FIG. Upon reaching, the control means 41 based on the output from the encoder 20
Outputs a control signal to the drive unit 33 of the extruder 31. As a result, the drive unit 33 of the extruder 31 stops operating, whereby the rotation of the screw 34 stops as shown in FIG. 4 (a). Here, since the internal pressure of the extruder 31 is considerably high (about 25 kgf / cm ² ) at the time of extrusion, the extruded material G is sloshly formed by the residual pressure remaining in the extruder 31 even after the rotation of the screw 34 is stopped. It is extruded into the ring-shaped groove 23 from the extrusion port 35 of 31. At this time, the lower die 19 is continuously rotated by the motor 17, so that the extruded material G fills the remaining ring-shaped groove 23.

When the lower end 19 further rotates in this state, and the starting end of the extruded material G filling the ring-shaped groove 23 reaches the closed position H near the base 36 of the extruder 31, as shown in FIG. Based on the output from 20, the control means 41 outputs a control signal to the cylinder 38 to cause the piston rod 39 to protrude. As a result, the shutter 40 moves toward the base 36 as shown in FIG. 4 (c), and cuts the extruded material G extruded from the extrusion port 35 at the extrusion port 35, and at the same time the extrusion port of the extruder 31. Stop 35. As a result, the extruded material G is confined in the extruder 31, but as described above, the extruded material G is extruded from the extruder 31 by the residual pressure even after the rotation of the screw 34 is stopped. , The internal pressure of the extruder 31 becomes equal to or lower than a predetermined low pressure. Therefore, the resistance from the extruded material G when the shutter 40 is opened next time can be greatly reduced, and the opening work of the shutter 40 becomes easy. At this time, the control means 41 controls the pressure sensor 37 so that the shutter 40 does not close the extrusion port 35 when the internal pressure of the extruder 31 is higher than a predetermined low pressure, that is, the extruder 31 is closed when the extrusion port 35 is closed. The internal pressure is monitored so as to be kept below a predetermined low pressure. The shutter 40
In order to further reduce the internal pressure of the extruder 31 at the time of closing the extrusion port 35 due to the above, the screw 34 of the extruder 31 is slightly reversed just before the closing of the extrusion port 35 by the shutter 40 to further facilitate the opening operation of the shutter 40. You may make it rotate. When the extruded material G is cut by the shutter 40 as described above, the extruded material G extruded into the ring-shaped groove 23 is separated from the extruded material G in the extruder 31 to form an end.

The extrusion port 35 by the shutter 40 as described above.
The rotation of the lower mold 19 is continued even after the closing of. As a result, the end portion G2 of the extruded material G is
And pressed into the ring-shaped groove 23 while being rubbed against the starting end G1. Here, at the start of the rubbing / compression bonding, if the end G2 of the extruded material G is slightly raised from the ring-shaped groove 23, the starting end G1 of the extruded material G can be obtained.
The crimping of the end portion G2 becomes good, and the raised portion is widely dispersed and disappears by the above-mentioned rubbing, so that a high-quality annular member is formed.

When the lower mold 19 rotates by a predetermined angle from the time when the extrusion port 35 is closed, the control means 41 outputs a control signal to one of the motors 17 based on the output from the encoder 20, and the rotation of the motor 17 is controlled. Stop. This allows one lower mold
The rotation of 19 is stopped as shown in FIG. At the same time when the rotation of the motor 17 is stopped, the control means 41
A control signal is output to 21 and the piston rod 22 is retracted to lower the lower mold 19 on which the annular member is formed as shown in FIG. 4 (e). When one of the lower dies 19 is lowered to the lower limit, the control means 41 outputs a control signal to the drive mechanism to rotate the turret table 13 by 180 degrees, and the ring-shaped groove 23 is filled with the extruded material G. The other lower mold 19 is directly under the extrusion position A, and the other lower mold 19 in which the annular member is formed in the ring-shaped groove 23 is replaced with the replacement position B.
Transfer to Then, as described above, the other lower mold 19
The extruded material G is extruded into the ring-shaped groove 23 to form an annular member. At this time, the annular member is taken out from the lower mold 19 located at the exchange position B and is transported to the next step. As described above, in this embodiment, in order to form the annular member, it is not necessary to perform the operations of cutting, transferring, gathering, and joining the arc-shaped extruded materials.
Only by controlling the operation of the (drive unit 33) and the operation of the shutter 40 (cylinder 38) by the control means 41, a high-quality endless annular member can be easily formed, and the molding cost can be reduced.

In the above embodiment, the control means 41 controls the rotation of the lower mold 19 based on the output from the encoder 20.
Although the timing of the operation of the extruder 31 and the timing of the operation of the shutter 40 are determined, in the present invention, these timings may be determined using a timer or the like. In the above-described embodiment, the two lower dies 19 are supported on the turret table 13, and the turret table 13 is intermittently rotated by 180 degrees so that the lower die 19 can be pushed out of the extruding position A and the exchanging position B. However, in the present invention, the four lower dies are supported on the turret table, and the turret table is rotated intermittently by 90 degrees to push out the lower die. It may be arranged to stop one after another at the four stations of the correction position, the replacement position, and the cleaning position. Further, in the above-described embodiment, the ring-shaped groove is formed by one rotation of the lower mold 19.
23, the whole is filled with the extruded material G to form a single-layered annular member. However, in the present invention, the lower half of the ring-shaped groove is filled with the extruded material in the first rotation of the lower mold, and the second rotation is performed in the second rotation. By filling the upper half of the ring-shaped groove with an extruded material, an annular member having a multilayer (two-layer) structure may be formed.

[0018]

As described above, according to the present invention, the molding operation can be simplified and the molding cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a partially cutaway front view showing an embodiment of the present invention.

FIG. 2 is a similar plan view.

FIG. 3 is a front sectional view near a shutter.

FIG. 4 is a time chart showing the operation timing of each part, (a) is the rotation speed of the screw of the extruder, (b) is the internal pressure of the extruder, (c) is the open / closed state of the shutter, and (d) is The number of rotations of the lower die, (e), shows the lower die ascending and descending.

FIG. 5 is a front sectional view similar to FIG. 3, illustrating the operation of the present invention.

FIG. 6 is a front sectional view similar to FIG. 3, illustrating the operation of the present invention.

FIG. 7 is a front sectional view similar to FIG. 3, illustrating the operation of the present invention.

[Explanation of symbols]

 17 ... rotating means 18 ... receiving surface 19 ... lower mold 23 ... ring-shaped concave groove 31 ... extruder 35 ... extrusion port 36 ... base 37 ... pressure sensor 40 ... shutter 41 ... control means G ... extrusion material T ... stop position H ... Closing position

Claims (4)

(57) [Claims] 1. An extruder extrudes an extruded material into a ring-shaped groove while rotating a lower mold having a ring-shaped groove formed on a receiving surface about a central axis of the ring-shaped groove. A step of filling the grooves one after another with the extruded material, and when the starting end of the extruded material filling the ring-shaped groove reaches the stop of the extruder by rotating the lower die, stops the operation of the extruder, Extruding the extruded material from the extruder by residual pressure and filling the remaining ring-shaped groove with the extruded material; closing the extruded material filling the ring-shaped groove near the mouthpiece of the extruder by further rotating the lower die When reaching the position, cutting the extruded material by a shutter and closing the extrusion opening of the extruder;
The lower mold is further rotated by a predetermined angle from the closing of the extrusion opening, and the end of the extruded material is pressed into the ring-shaped groove while being rubbed and pressed against the starting end of the extruded material by a die to form an annular member. A method for forming an annular member, comprising: 2. A step of pressing the starting end of the extruded material extruded from the extruder into the ring-shaped concave groove of the lower mold in which the rotation is stopped and sticking the extruded material, and then starting the rotation of the lower mold. The method for forming an annular member according to claim 1, further comprising: 3. The molding of an annular member according to claim 1, wherein the internal pressure of the extruder is detected by a pressure sensor, and the internal pressure of the extruder when closing the extrusion opening of the extruder by a shutter is kept below a predetermined low pressure. Method. 4. A lower die having a ring-shaped groove formed on a receiving surface, rotating means for rotating the lower die around a center axis of the ring-shaped groove, and a ring of the lower die rotating an extruded material. An extruder for extruding the ring-shaped groove with the extruded material by extruding into the groove, and a shutter provided near the die of the extruder for cutting the extruded material and closing an extruder of the extruder when activated. When the starting end of the extruded material that fills the ring-shaped groove approaches the die of the extruder by rotation of the lower die and reaches the stop position, the operation of the extruder is stopped, and the extruded material is left from the extruder. Extrusion by pressure to fill the remaining ring-shaped groove, and when the starting end of the extruded material filling the ring-shaped groove reaches the closed position near the mouthpiece of the extruder by rotation of the lower mold, the shutter is operated. The extruded material is cut and the extrusion port of the extruder is closed, and the lower mold is further rotated by a predetermined angle from the closing of the extrusion port, and the end of the extruded material is rubbed and crimped to the starting end of the extruded material with a die. Control means for pushing the annular member into the annular groove while forming the annular member.