JP2006123381A - Rubber member molding equipment and rubber member molding method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide rubber member molding equipment which, in twisting a rubber strip around a rotating support, can neither too much nor too less deliver the rubber strip at the start of the molding, and also to provide a rubber member molding method. <P>SOLUTION: The equipment is equipped with a molding drum 7 around which the rubber strip S extruded through a molding mouthpiece 4 is twisted, a gear pump 3 which sends out the rubber material supplied from an extruder 2 to the molding mouthpiece 4, and a pressure sensor 11 which detects the outlet side pressure in the gear pump 3. A controlling device 8 performs the control so that the rotation of the molding drum 7 may be started after the gear pump 3 is driven for a predetermined time based on a point of time when the pressure, which the pressure sensor 11 detects after the start of the driving of the gear pump 3, has become a predetermined pressure or higher. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a rubber member molding facility and a rubber member molding method for forming a rubber member having a desired cross-sectional shape by winding a rubber strip around a rotary support.

  Conventionally, a so-called strip build method is known in which a rubber member is formed by winding a ribbon-shaped rubber strip in the circumferential direction (see, for example, Patent Documents 1 to 3 below). According to such a strip build method, a rubber member having a desired cross-sectional shape can be formed by winding a rubber strip around a rotating support such as a forming drum and sequentially laminating it. Such a rubber member is used, for example, as a rubber member constituting a sidewall portion of a pneumatic tire.

  The rubber strip is continuously molded by extruding a rubber material kneaded by a screw of an extruder through a molding die having a predetermined cross-sectional shape. In this regard, there is known an extrusion apparatus configured to supply a rubber material to a molding die using a gear pump for the purpose of suppressing variation in the discharge amount of the rubber strip (see Patent Document 4 below).

  FIGS. 3A to 3D are schematic views showing a state at the start of molding of a rubber member by the strip build method. First, the extrusion device 1 is brought close to the molding drum 7, and an interval of about several millimeters is provided between the molding die 4 and the outer peripheral surface of the molding drum 7. Next, the screw of the extruder 2 is rotated to knead the rubber material, and the gear pump 3 is driven to discharge the rubber strip S. When a certain amount of the rubber strip S is discharged and adhered to the outer peripheral surface of the molding drum 7, the molding drum 7 is rotated in the R direction and the rubber strip S is wound along the circumferential direction. Then, after the extrusion device 1 is slightly retracted, the molding drum 7 is reciprocated in the axial direction so as to obtain a desired cross-sectional shape, thereby molding a rubber member.

  As described above, when the rotation of the forming drum is started, the rubber strip needs to be attached to the outer peripheral surface thereof. Conventionally, the sticking state of the rubber strip has been secured by controlling the discharge time of the rubber strip. That is, for example, when the set time is set to 5 seconds, the rubber strip discharged is attached to the outer peripheral surface of the molding drum when the gear pump is driven for 5 seconds after starting to discharge the rubber strip. It was controlled to start the drum rotation.

  However, according to the control described above, when the type of rubber material, kneading conditions, and the like change, the rubber strip has a constant discharge time due to changes in rubber properties such as temperature and viscosity. The amount of discharge sometimes fluctuated. Further, when the rubber material is not sufficiently filled in the gear pump, the discharge amount of the rubber strip may be insufficient. Furthermore, in order to avoid such a shortage of discharge amount, if the discharge time of the rubber strip is set to be long, the discharge amount of the rubber strip may be excessive. For these reasons, when the discharge amount of the rubber strip is insufficient, the rubber strip may not stick to the outer peripheral surface of the molding drum. As shown in FIG. There was a problem of not winding. On the other hand, when the discharge amount of the rubber strip is excessive, as shown in FIG. 5, the rubber strip S at the start of discharge becomes a lump, which may deteriorate the uniformity and weight balance of the rubber member.

In addition, the following Patent Document 4 discloses a configuration in which the pressure on the inlet side of the gear pump is detected by a pressure sensor, and the screw rotation speed of the extruder is controlled based on the detection result. This is to stabilize the supply amount of the rubber material by the extruder, and cannot solve the problem that the discharge amount of the rubber strip fluctuates at the start of molding.
JP-A-9-29858 JP 2002-178415 A JP 2002-205512 A JP 2003-266523 A

  Accordingly, an object of the present invention is to provide a rubber member molding facility and a rubber member molding method capable of discharging a rubber strip at the start of molding without excess or deficiency when molding a rubber member by winding the rubber strip around a rotating support. Is to provide.

  The above object can be achieved by the present invention as described below. That is, the rubber member molding facility according to the present invention includes an extruder for kneading and feeding a rubber material, a gear pump for feeding the rubber material supplied from the extruder to a molding die, and an extrusion through the molding die. A rotating support member around which the rubber strip is wound, a first driving device for driving the gear pump, a second driving device for rotating the rotating support member, and the control of the first driving device and the second driving device. A pressure sensor that detects an outlet side pressure in the gear pump, and the control device detects a pressure detected by the pressure sensor after the start of driving of the gear pump. Control is performed so that the rotation of the rotating support is started after the gear pump is driven for a predetermined time on the basis of the above point. .

  According to the above configuration, first, by providing the pressure sensor for detecting the outlet side pressure in the gear pump, it is possible to confirm the filling condition of the rubber material on the outlet side of the gear pump. Then, the control device controls so that the rotation of the rotary support is started after the gear pump is driven for a predetermined time with reference to the time when the pressure detected by the pressure sensor becomes equal to or higher than the predetermined pressure after the drive of the gear pump is started. By doing so, the rotation of the rotating support can be started after discharging a certain amount of rubber strip with reference to the time when the gear pump is filled with the rubber material. At this time, since control is performed based on the pressure in the gear pump, even if the rubber properties such as temperature and viscosity change, a certain amount of rubber strip can be discharged. As a result, the rubber strip is discharged without excess or deficiency at the start of molding of the rubber member, and the state where the rubber strip at the start of discharge is stuck to the outer peripheral side of the rotating support is ensured without becoming a lump.

  In this specification, the expression “wrapping the rubber strip around the rotating support” is not limited to the case where the rubber strip is directly wound around the outer peripheral surface of the rotating support, and the rubber strip is already wound around the outer peripheral surface of the rotating support. In such a case, it is also included that the wrapping is performed from the outer peripheral side.

  The rubber member molding method according to the present invention includes a rubber member molding method in which a rubber member is molded by winding a rubber strip extruded through a molding die around a rotating support, and the rubber material is kneaded by an extruder. A step of supplying to the gear pump; a step of sending the rubber material supplied to the gear pump toward the outlet of the gear pump toward the outlet of the molding; a step of detecting an outlet side pressure in the gear pump; And starting the rotation of the rotating support after the gear pump is driven for a predetermined time with reference to the time when the pressure becomes equal to or higher than the predetermined pressure.

  According to the said structure, the filling condition of the rubber material in the exit side of a gear pump can be confirmed first by providing the process of detecting the exit side pressure in a gear pump. The gear pump is filled with a rubber material by providing a step of starting the rotation of the rotary support body after driving the gear pump for a predetermined time on the basis of the time when the detected pressure becomes equal to or higher than the predetermined pressure. The rotation support can be started after a certain amount of rubber strip has been discharged on the basis of the point in time when the rotation support is reached. At this time, even if the rubber properties change, a certain amount of rubber strip is discharged, and the state where the rubber strip at the start of discharge is stuck to the outer peripheral side of the rotating support is secured without becoming a lump. This is as described above.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<Configuration of rubber member molding equipment>
FIG. 1 is a schematic view showing an example of the configuration of a rubber member molding facility according to the present invention. The rubber member molding facility shown in FIG. 1 includes an extrusion device 1, a molding drum 7 (corresponding to the rotary support), and a control device 8.

  The extrusion apparatus 1 includes an extruder 2, a gear pump 3 connected to the front end side in the extrusion direction of the extruder 2, and a molding base 4 connected to the front end side thereof. The extruder 2 includes a cylindrical barrel 2a, a hopper 2b connected to the supply port of the barrel 2a, a screw 2c for kneading a rubber material and feeding it to the tip side, and a first drive device as a drive device for rotationally driving the screw 2c. 3 servo motors 2d. The rotation speed of the third servo motor 2d is controlled by third servo motor control means 15 included in the control device 8.

  The gear pump 3 has a pair of gears 5 and has a function of feeding a rubber material toward the outlet toward the molding die 4. Each of the gears 5 is rotationally driven by a first servo motor 6 (corresponding to the first driving device), and the number of rotations thereof is controlled by a first servo motor control means 13 included in the control device 8. For convenience of illustration, the pair of gears 5 are arranged in the vertical direction in FIG. 1, but are actually arranged in the plane direction (the direction in which the rotation axis of the gear 5 is up and down in FIG. 1).

  A pressure sensor 11 is provided on the outlet side of the gear pump 3, and detects the outlet side pressure in the gear pump 3, that is, the pressure when the gear pump 3 sends out the rubber material. Further, a pressure sensor 12 is provided on the inlet side of the gear pump 3, and detects an inlet side pressure in the gear pump 3, that is, a pressure when a rubber material is supplied from the extruder 2 to the gear pump 3.

  In the present embodiment, the detection result by the pressure sensor 12 is sent to the pressure adjusting means 16 of the control device 8. The pressure adjusting means 16 gives a command to the third servo motor control means 15 so that the pressure value detected by the pressure sensor 12 matches a preset pressure value (first set value). The first set value can be appropriately set via an input unit (not shown). The pressure adjusting means 16 has, for example, a pressure support controller that outputs an analog voltage value in response to a signal received from the pressure sensor 12, and sends a speed command corresponding to the voltage value to the third servo motor control means 15. It may be configured to send to the third servo motor 2d via That is, the third servo motor control means 15 controls the rotational speed of the third servo motor 2d that drives the screw 2c in accordance with the inlet side pressure in the gear pump 3. Thereby, the inlet side pressure in the gear pump 3 is kept constant, and the supply amount of the rubber material by the extruder 2 is stabilized.

  The molding die 4 has a predetermined cross-sectional shape, and the rubber material supplied from the gear pump 3 to the molding die 4 is continuously extruded in the form of a rubber strip S having a predetermined cross-sectional shape. The rubber strip S has a small ribbon width and a small thickness, and various sizes can be adopted depending on the type of tire. Further, the cross-sectional shape of the rubber strip S is not limited to a specific one, and various and preferable shapes can be adopted according to the finished cross-sectional shape such as a triangle, a crescent shape, a circle, and a rectangle.

  The forming drum 7 is configured to be rotatable in the R direction by a second servomotor 9 (corresponding to a second driving device). The rotation speed of the second servo motor 9 is controlled by the second servo motor control means 14 included in the control device 8. The rubber strip S extruded through the molding die 4 is directly supplied to the molding drum 7, and the rubber strip S is rotated by rotating the molding drum 7 in the R direction with the rubber strip S adhered. Can be wound along the circumferential direction. The pressure roller 10 has a function of pressure bonding the rubber strip S supplied to the molding drum 7.

  The detection result by the pressure sensor 11 provided in the gear pump 3 is sent to the pressure comparison means 17 of the control device 8. The pressure comparison means 17 compares the pressure value detected by the pressure sensor 11 with the preset pressure value (second set value) after the gear pump 3 starts to drive, and the detected pressure value is the first value. A command for starting the rotation of the forming drum 7 is given to the second servo motor control means 14 after a predetermined time has elapsed with reference to the time when the value becomes equal to or greater than 2 set values. That is, the molding drum 7 starts rotating after the gear pump 3 is driven for a predetermined time with reference to the time when the outlet side pressure in the gear pump 3 becomes equal to or higher than the predetermined pressure. The predetermined pressure (second set value) and the predetermined time can be appropriately set via an input unit (not shown).

  The forming drum 7 is configured to reciprocate in an axial direction (a direction perpendicular to the paper surface in FIG. 1) by a driving device (not shown), and the reciprocating movement is controlled by the control device 8. By moving the rotating forming drum 7 relative to the extrusion device 1 in the axial direction, the rubber strip S can be spirally wound along the circumferential direction to form a rubber member having a desired cross-sectional shape. . On the other hand, the extrusion device 1 is configured to be movable in the forward and backward directions in the extrusion direction by a drive device (not shown), and such movement is also controlled by the control device 8.

<Rubber member molding method>
Next, a method for molding a rubber member using the above rubber member molding equipment will be described. FIG. 2 is a flowchart showing an example of a procedure for molding a rubber member.

  First, the extrusion device 1 moves forward (# 1) and is brought close to the forming drum 7 as shown in FIG. At this time, a predetermined interval is provided between the molding die 4 and the outer peripheral surface of the molding drum 7. The timing at which the extrusion device 1 is brought close to the molding drum 7 is not particularly limited as long as the predetermined interval is provided before the rubber strip S is discharged.

  Next, the rubber material adjusted in the previous step is put into the hopper 2b of the extruder 2. Here, the rubber material is not particularly limited. For example, the rubber material is a general-purpose rubber raw material such as natural rubber, styrene-butadiene rubber (SBR), butadiene rubber (BR), isoprene rubber (IR), etc. And prepared by kneading and heat crosslinking. Moreover, there is no restriction | limiting in particular as a shape of the rubber material thrown in, For example, shapes, such as a ribbon shape, a sheet form, a pellet form, are mentioned. The charged rubber material is kneaded by the screw 2c of the extruder 2, sent to the front end side in the extrusion direction, and supplied to the gear pump 3 (# 2, 3). Then, the rubber material supplied to the gear pump 3 is sent to the outlet side toward the molding die 4 by a pair of rotating gears 5 (# 4).

  When the rubber material is fed to the outlet side of the gear pump 3, the pressure sensor 11 detects the outlet side pressure in the gear pump 3 (# 5). The detection result is sent to the control device 8 and compared with a preset pressure value (second set value) by the pressure comparison means 17. When the detected pressure value is equal to or greater than the second set value, a command is given to the second servo motor control means 14 after a predetermined time has elapsed from that point, and the rotation of the molding drum 7 is started. (# 6, 7).

  That is, the rotation of the forming drum 7 is started after the gear pump 3 is driven for a predetermined time with reference to the time point when the detected pressure value becomes equal to or higher than the predetermined pressure value. By driving the gear pump 3 for a predetermined time, a predetermined amount of the rubber strip S is discharged to the molding drum 7 as shown in FIG. Further, the rotation of the molding drum 7 is started thereafter, and as shown in FIG. 3C, the rubber strip S at the start of the discharge is not agglomerated but is secured to the molding drum 7. Is done.

  The extrusion apparatus 1 moves backward (# 8) after the molding drum 7 is rotated several times or before it is rotated once (# 8), and a predetermined interval is provided between the molding drum 7 and the extrusion apparatus 1. The molding drum 7 is reciprocated in the axial direction in accordance with the desired cross-sectional shape of the rubber member while being rotationally driven in the R direction (# 9). Thereby, the rubber strip S is wound spirally along the circumferential direction. The driving of the molding drum 7 and the extrusion device 1 is controlled by the control device 8, and a control program for that purpose is input to the control device 8 in advance.

  While the rubber strip S is continuously extruded, the pressure sensor 12 detects the inlet side pressure in the gear pump 3. The detection result is sent to the control device 8, and the pressure adjusting means 16 instructs the third servo motor control means 15 so that the detected pressure value matches the preset pressure value (first set value). And the number of rotations of the third servo motor is controlled. When the winding of the rubber strip S is completed, the driving of the extruder 2, the gear pump 3 and the molding drum 7 is stopped. Then, the rubber strip S spanned from the molding die 4 to the molding drum 7 is cut, and the molded rubber member is moved to the next process.

  When the next rubber member is continuously molded, the process returns to # 1, the extrusion device 1 is brought close to the molding drum 7, and the rubber member is molded according to the above-described procedure. In such a case, the exit side of the gear pump 3 is filled with a rubber material to some extent, but even in such a state, according to the rubber member molding method according to the present invention, at the start of molding of the rubber member. The rubber strip S can be discharged without excess or deficiency.

  As described above, the rubber member molding method of the present invention relates to the control for starting the rotation of the molding drum 7 by discharging the rubber strip S at the start of molding by the so-called strip build method. After starting the rotation of 7, the rubber member can be molded in the same manner as the conventional strip build method. Examples of the rubber member molded according to the present invention include, but are not limited to, a rubber member constituting a tread portion and a sidewall portion of a pneumatic tire, a solid tire, a pneumatic rubber roller, and the like. .

The schematic diagram which shows an example of a structure of the rubber member molding equipment which concerns on this invention Flow chart showing an example of a procedure for molding a rubber member Schematic showing the state at the start of molding of a rubber member by the strip build method The figure explaining the malfunction which arises when using the conventional rubber member molding equipment The figure explaining the malfunction which arises when using the conventional rubber member molding equipment

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Extruder 2 Extruder 2c Screw 2d 3rd servo motor 3 Gear pump 4 Molding die 5 Gear 6 1st servomotor 7 Molding drum 8 Control apparatus 9 2nd servomotor 11 Pressure sensor 12 Pressure sensor 16 Pressure adjustment means 17 Pressure comparison means

Claims (2)

An extruder for kneading and feeding the rubber material, a gear pump for feeding the rubber material supplied from the extruder to the molding die, and a rotating support body around which the rubber strip extruded through the molding die is wound, A rubber member molding facility comprising: a first drive device that drives the gear pump; a second drive device that rotationally drives the rotary support; and a control device that controls the first drive device and the second drive device. In
A pressure sensor for detecting an outlet side pressure in the gear pump;
The control device drives the gear pump for a predetermined time and starts to rotate the rotary support with reference to a time when the pressure detected by the pressure sensor becomes equal to or higher than a predetermined pressure after the gear pump starts driving. A rubber member molding facility that performs control. In a rubber member molding method for molding a rubber member by winding a rubber strip extruded through a molding die around a rotating support,
Kneading rubber material with an extruder and supplying it to a gear pump;
Sending the rubber material supplied to the gear pump toward the outlet of the gear pump toward the molding die;
Detecting an outlet side pressure in the gear pump;
And a step of starting the rotation of the rotary support after the gear pump is driven for a predetermined time with reference to the time when the detected pressure becomes equal to or higher than the predetermined pressure.

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