JPH07276532A - Continuous generation preventive method of defective coating of coating rubber of bead wire - Google Patents

Abstract

PURPOSE:To dissolve defectiveness in the case where a defective coating of rubber is generated and stabilize swiftly dispersion in weights of products, gauges and widths. CONSTITUTION:Rubber is heated by an increase of inner pressure of a head of an extruding device 32. In this case, a pressure changing ratio is performed comparatively hastily in consideration of only swift dissolution of a defective coating. However, since responsing properties of a temperature of the rubber to a sudden pressure change is comparatively bad, though the defective coating is dissolved swiftly, hunting is generated. Then along with inner pressure of the extruding device 32, a preheating temperature of a bead wire are controlled. Since the bead wire 10 is made of a metal, it responds sensitively. Therefore, since the temperature of the rubber is controlled roughly and fine adjustment is performed by the preheating temperature of the bead wire 10, swift dissolution of defective coating and controlling which stabilizes swiftly by preventing the hunting become possible.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling continuous occurrence of coating failure of a bead wire coating rubber for preventing continuous coating failure of a rubber in which a part of a bead wire is exposed or close to exposure. Regarding

[0002]

2. Description of the Related Art Conventionally, when a bead wire is preheated and then conveyed to a rubber extruding device to coat the rubber around the bead wire, a part of the bead wire may be generated due to fluctuations in the rubber extruding pressure, temperature unevenness of the bead wire, etc. May be exposed, or the rubber coating thickness may be smaller than the prescribed value, resulting in defective coating. The main causes are the above, but in addition, the temperature of the head of the rubber extrusion device, the line speed, changes in the environment (temperature, humidity), and the like can be cited as the causes of the defective coating. In particular, the line speed may be intentionally changed in order to improve productivity, and thus it is difficult to completely eliminate defective coatings, and swift countermeasures after occurrence can improve yield. Will play an important role in.

Therefore, a detector for detecting this coating defect is installed on the downstream side of the rubber extrusion device, and an alarm is activated when the coating defect is detected. By the operation of this alarm, the operator can be notified in a relatively short time from the occurrence of the defect, and prompt measures such as adjusting the temperature of the rubber output from the rubber extrusion device (internal pressure of the extrusion head) can be taken.

It is also conceivable that an alarm is activated when a defect occurs, and a coating defect detector is used as a trigger to automatically raise the internal pressure of the rubber extrusion device when the defect is detected to eliminate the coating defect. There is.

[0005]

However, if the line speed sharply increases intentionally or for some reason, defective coating is likely to occur. Also, immediately after the occurrence of defects, adjust (raise) the rubber extrusion pressure of the rubber extrusion device.
However, it is difficult to stabilize quickly due to hunting or the like. As a result, variations in product weight, gauge, and width occur, resulting in poor yield.

In consideration of the above facts, the present invention provides a bead wire-coated rubber capable of eliminating a defective rubber coating and quickly stabilizing variations in product weight, gauge and width. It is an object to obtain a control method for preventing continuous occurrence of coating defects.

[0007]

According to a first aspect of the present invention, a bead wire preheated to a predetermined temperature by a preheating device is fed to a rubber extruding device and covered with rubber extruded at a predetermined pressure so that the bead wire is aerated. In the step of forming a bead portion of a tire, a method for preventing continuous occurrence of coating failure of a bead wire-coated rubber for preventing continuous coating failure of rubber in a state where a part of the bead wire is exposed or close to exposure In the case where the coating defect is detected on the downstream side of the rubber extrusion device, the adjustment of the internal pressure by the rubber extrusion device and the adjustment of the preheating temperature of the bead wire by the preheating device are controlled in combination. It is characterized by doing.

According to a second aspect of the present invention, the rate of change of the pressure inside the device by the rubber extrusion device is increased to quickly eliminate the coating defect, and the preheating device adjusts the preheating temperature of the bead wire, whereby the responsiveness is improved. It is characterized by suppressing hunting due to fluctuations in rubber temperature.

[0009]

According to the first aspect of the invention, when the coating defect is detected on the downstream side of the rubber extrusion device, the internal pressure of the rubber extrusion device is adjusted (increased). As a result, the temperature of the rubber can be constantly increased, and the defective coating is eliminated.
However, since the temperature characteristics of rubber have a relatively poor response, hunting causes variations in weight, etc. in terms of quality,
As a result, the yield may be deteriorated. Therefore, not only the rubber extrusion device but also the adjustment of the bead wire preheating temperature by the bead wire preheating device is used together. Since the bead wire is made of metal, it has good responsiveness due to temperature characteristics,
Fine adjustment of temperature is possible. Therefore, by increasing the preheating temperature, so-called rubber sticking can be improved and the rise in the rubber temperature can be reduced accordingly. Therefore, it is possible to reduce variations in weight and the like, and it is possible to quickly stabilize the coating after the defective coating is eliminated.

According to the second aspect of the present invention, the rate of change of the internal pressure of the rubber extrusion device is increased to quickly eliminate the coating defect, and the preheating temperature of the bead wire is adjusted by the preheating device (preheating temperature). By lowering (), the coating defect can be resolved quickly, and hunting due to the rapid fluctuation of the extrusion pressure is suppressed, so that the time until stabilization can be shortened.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a conveying line for a rubber coating process.

The bead wire 10 has an elongated shape and is wound around a wire reel 12 and accommodated therein. A heating unit 14 is arranged on the downstream side of the wire reel 12. As shown in FIG. 2, the heating unit 14 includes a ceramic cylindrical body 16, and the outermost peripheral end of the bead wire 10 pulled out from the wire reel 12 linearly passes through the inner passage of the cylindrical body 16. It is like this.

The electric wire 1 is coiled around the outer circumference of the cylindrical body 16.
8 is wound, and both ends of this electric wire 18 are connected to a high frequency inverter 20.

As shown in FIG. 1, the high frequency inverter 2
0 is connected to the control device 24 via the converter 22, and the output can be changed to 0 to 5 kw based on the voltage (0 to 10 v) output from the converter 22. The converter 22 has a role of converting the control voltage (1 to 5 v) output from the control device 24 into a voltage suitable for the high frequency inverter 20.

When a high frequency current flows through the electric wire 18 by the high frequency inverter 20, the bead wire 1 is passed through the inside of the cylindrical body 16.
When 0 passes, an eddy current is generated, and the bead wire 10 can be induction-heated by the action of Joule heat due to this eddy current.

The most downstream side of the heating section 14, that is,
In the vicinity of the discharge side of the bead wire 10 from the cylindrical body 16,
A radiation temperature sensor 26 (hereinafter, simply referred to as temperature sensor 26) is provided. The temperature sensor 26 can detect the temperature of the bead wire 10 in a non-contact state with the bead wire 10. The temperature sensor 26 is connected to the control device 24 via a temperature controller 28 and a converter 30.

The controller 28 converts the detected temperature into a voltage (0 to 1v), and the converter 30 converts it into a voltage (1 to 5v) suitable for the control device. The appropriate temperature of the bead wire 10 is 70 ° C to 80 ° C.
The temperature sensor 2 is used as the temperature sensor 2 in the controller 24.
The high frequency inverter 20 is controlled based on the temperature detected by 6 to control the heating temperature in the heating unit 14.

An extruding device 32 is arranged on the downstream side of the heating section 14, and the preheated bead wire 10 is fed into the extruding device 32 and is coated with rubber to form the bead 3.
4 is formed. A pressure sensor 60 that detects the pressure inside the extrusion device 32 is attached to the extrusion device 32. The pressure sensor 60 is connected to the control device 24 via a converter 62.

On the downstream side of the extrusion device 32, a pull roll section 36 which constitutes a part of the conveying means is arranged. The pull roll portion 36 is composed of a plurality of rollers 38, and the rubber-coated bead 34 is spirally wound several times.

A coating defect detecting sensor 64 is arranged on the conveying path of the rubber-coated bead 34 between the extrusion device 32 and the pull roll portion 36.

As shown in FIG. 3, the coating defect detecting sensor 64 has a main body 64A surrounding the bead 34 in an annular shape.
And a plurality of detection elements 64B evenly arranged around the bead 34 on the inner peripheral surface of the main body 64A. The detection element 64B is provided with a light projecting section 64C and a light receiving section 64D as a pair, and the light emitted from the light projecting section 64C reaches the peripheral surface of the bead 34. here,
When the rubber is surely covered, this light is scattered and does not reach the light receiving portion 64D. However, when the rubber is not completely covered and the bead wire 10 is exposed or in a state close to the exposure, the light emitted from the light projecting portion 64C is reflected by the metal bead wire 10 and received. Part 6
It is designed to reach 4D. That is, the light receiving unit 6
When light is detected by 4D, it can be recognized that the coating is defective. The signal lines (harnesses) of these light receiving elements 64B are connected to the control device 24 via the converter 66.

One rotation axis (upper side) of the roller 38 is
The drive shaft of the servo motor 40 is connected, and the drive force of the servo motor 40 can be sent to the next process while winding the bead 34.

The drive of the servo motor 40 is controlled by a servo amplifier 42. In this embodiment, a pulse generator 44 connected to the servo amplifier 42 can select two rotation speeds. Has become.

The servo amplifier 42 is connected to the control device 24 via a converter 46, and the converter 46 is adapted to output a voltage (0 to 10 v) according to the rotation speed. The converter 46 has a role of converting the voltage from the servo amplifier 42 into a voltage (1 to 5v) suitable for the control device 24.

Here, the bead wire 10 (bead 34)
Since the amount of heat given by the heating unit 14 changes depending on the carrying speed, the control device 24 uses this carrying speed together with the temperature detected by the temperature sensor 26 as one element of the temperature control of the heating unit 14.

The output signal of the converter 30 to which the signal from the controller 28 is input is sent to the PID control unit 50 via the delay circuit unit (LAG) 48 forming a part of the control device 24.
It is designed to be input to. The LAG 48 has an integrating circuit for suppressing variations in the detected temperature due to minute plating unevenness on the wire surface, and thereby an appropriate converted voltage value is input to the PID control unit 50.

In the PID controller 50, the detected temperature and the preset preheating temperature of the bead wire 10 are compared and controlled (proportional control, integral control, differential control), and the heating unit 14 is operated.
The voltage value (1 to 5v) corresponding to the heating temperature in 1 is calculated.

The calculation result in the PID control unit 50 is the adder 5
It is designed to be input to 2. A signal from a feedforward (FF) control unit 54 is also input to the adder 52, and the PI from the signal from the FF control unit 54 is input.
The output signal of the D control unit 50 is corrected.

That is, the signal from the converter 46 is
It corresponds to the transport speed (linear velocity) of the bead wire 10, and this transport speed greatly affects the amount of heat applied to the bead wire 10. Therefore, it is necessary to adjust the preheating temperature set in advance at a predetermined transport speed, and this is performed by the adder 52. Therefore, the output signal of the adder 52 has a value in which both the transport speed of the bead wire 10 and the detected temperature are taken into consideration, and this signal (voltage value 1 to 5 v) is converted by the converter 22 into a voltage value suitable for the high frequency inverter 20 ( 0 to 10 v) and is sent to the high frequency inverter 20.

On the other hand, the extrusion device 32 is controlled based on the signal output from the FF control unit 54 via the converter 55, and in the steady state, the bead wire 1 is used.
As long as the transportation speed of 0 is constant, the internal pressure of the device is kept constant.

Thus, the temperature of the bead wire 10 is feedback-controlled (PID control in this embodiment),
Since the feed speed of the bead wire is feedforward controlled, the bead wire 10 immediately after passing through the cylindrical body 16 is controlled.
The temperature of can be kept constant.

Here, when the coating failure is detected by the signal from the coating failure detection sensor 64, the control device 24 interrupts the control for keeping the bead wire 10 at a constant temperature to eliminate the coating failure and to quickly perform the beading. In order to stabilize variations in the weight of the rubber 34, the rubber extrusion device 32 and the heating unit 14
To control.

That is, in this embodiment, the rubber extrusion device 3
The increase in the internal pressure of the head 2 heats the rubber and controls the adhesion rate to the bead wire 10 to be improved. In this case, the rate of pressure change is relatively rapid, taking into consideration only the rapid elimination of the coating defect.

However, since the temperature of the rubber has relatively poor responsiveness to this rapid pressure change, the coating defect can be quickly resolved, but variations in weight, width, etc. occur due to the change in coating thickness. It will happen (occurrence of hunting). Therefore, the preheating temperature of the bead wire 10 is controlled. Since the bead wire 10 is made of metal, it responds sensitively. Therefore, by roughly controlling the temperature of the rubber and finely adjusting it by the preheating temperature of the bead wire 10, it is possible to quickly eliminate defective coating and prevent hunting to stabilize quickly.

The operation of this embodiment will be described below. When the servo motor 40 starts driving at the set rotation speed, the roller 38 starts rotating. As a result, the bead wire 10 is pulled out from the wire reel 12, and first reaches the heating unit 14. In the heating part 14, the bead wire 10 linearly passes through the inside of the cylindrical body 16. Here, the cylindrical body 1
A coil-shaped electric wire 18 is wound around the outer circumference of 6, and a high-frequency current set by the high-frequency inverter 20 flows, so that an eddy current is generated as the bead wire 10 is transported. The bead wire 10 is heated by the Joule heat at this time.

That is, since no current is directly applied to the bead wire 10, non-uniform heating does not occur due to a change in contact resistance, and it is not necessary to wind the drum on a drum or the like.
There is no habit.

The bead wire 10 that has passed through the cylindrical body 16 of the heating section 14 is sent to the extrusion device 32 after the temperature is detected by the temperature sensor 26 and is coated with rubber to form the bead 34. In this case, the bead wire 10
Since the preheating temperature is constant, there is no peeling of the rubber and the rubber is firmly adhered.

The bead 34 is spirally wound around the roller 38 and then sent out to the subsequent step. (Bead Wire Preheating Temperature Control in Steady State) Here, the signal detected by the temperature sensor 26 is sent to the control device 24, compared with a preset preheating temperature (70 ° C. to 80 ° C.), and Control output. In addition, a signal from the servo amplifier 42 is also input to the control device 24, and the correction is also performed by the change in the transport speed. The temperature control will be described below with reference to the flowchart (main routine) of FIG.

In step 100, the temperature of the bead wire 10 detected by the temperature sensor 26 is detected.
That is, when the temperature is detected by the temperature sensor 26, a voltage (0 to 1 v) corresponding to the temperature (0 to 100 ° C.) is sent to the converter 30, and the converter 30 controls the input voltage by this voltage. After being converted into a voltage (1 to 5v) suitable for 24, it is input to the LAG 48.

In the next step 102, an appropriate conversion voltage value is input to the PID control unit 50 by the integrating circuit for suppressing the variation in the detected temperature due to the minute plating unevenness on the wire surface. In the PID control, proportional control and integral control are performed by comparing a preset preheating temperature with the detected temperature. By this PID control, the output voltage to the high frequency inverter 20 is calculated.

Here, the preset preheating temperature is
It can be applied only when the bead wire 10 is conveyed at a predetermined conveying speed, and if the conveying speed is different, it is necessary to correct the change in speed. That is, the amount of heat applied to the bead wire 10 per unit time decreases as the conveying speed increases, and the amount of heat increases as the conveying speed decreases.

Therefore, in the next step 106, speed correction is performed. That is, the signal (voltage 0 to 10v) from the servo amplifier 42 is converted into a voltage (1 to 5v) suitable for the control device 24 by the converter 46, is sent to the FF control unit 54, and is supplied to the PID control unit 50. The difference from the conveying speed when the set preheating temperature is determined is calculated and added by the adder 52 to the output signal from the PID control unit 50. This allows the PID
The control temperature calculated by the control unit 50 is corrected, and the converter 2
2 (step 108). That is, the converter 2
2, the input voltage (1 to 5v) is high frequency inverter 20
Is converted into a voltage (0 to 10 V) for controlling the temperature, and a high-frequency current corresponding to this voltage flows through the coil-shaped electric wire 18 wound around the cylindrical body 16 to heat the bead wire 10.

In the next step 110, the bead wire 1
It is determined whether or not the transport of 0 has been completed, and if the determination is negative, the process returns to step 100 and the above routine is repeated.

As described above, the temperature of the bead wire 10 immediately after passing through the cylindrical body 16 is detected, and the heating state in the heating section 14 is controlled in accordance with the feedback control (PID control in this embodiment) and the conveying speed of the bead wire 10. Since it is controlled, the bead wire 10 can be controlled within an appropriate temperature range (70 ° C to 80 ° C). (Temperature control when coating failure occurs) When the preheating temperature control of the bead wire 10 is performed as described above, the rubber coating is steadily (the change rate of the line speed is relatively small and the influence of environmental temperature, humidity, etc. is small). Although there is no variation in the weight of the bead 34 formed, if the line speed changes abruptly (whether intentionally or for some reason) and the environmental temperature and humidity change abruptly, the preheating temperature of the bead wire 10 is controlled. However, the bead wire 10 inside the bead 34 may be exposed or a state close to the exposure to a part of the bead 34, resulting in defective coating.

The control from the occurrence of a coating defect to the elimination of this defect will be described below with reference to the flowchart of FIG.

At step 150, it is judged whether or not the coating defect is detected by the coating defect detection sensor 64, and if the determination is negative, the process returns to the main routine (FIG. 4) to perform the normal preheating temperature control of the bead wire 10. Be seen. If an affirmative determination is made, the process proceeds to step 152 in order to eliminate this defective coating.

At step 152, a predetermined internal pressure increase rate R is taken in, and the routine proceeds to step 154, where the internal pressure of the extruder 32 is increased based on the taken internal pressure increase rate R. Due to this increase in internal pressure, the temperature of the rubber rises, and the adhesion to the bead wire 10 tends to improve. Therefore, the higher the rate of increase of the internal pressure, the higher the rate of increase of the temperature of the rubber, and it is possible to eliminate the defective coating quickly. However, due to the poor temperature response of the rubber, if the temperature is rapidly raised to the optimum temperature, hunting occurs and it becomes difficult to stabilize the temperature. Therefore, the internal pressure increase rate is set to some extent, and pressurization is performed based on the determined increase rate.

By the way, hunting occurs even at a predetermined rate of increase R. Therefore, step 156
At, the preheating temperature of the bead wire 10 is calculated based on the rubber type and the signal (current internal pressure) from the pressure sensor 60. In the present embodiment, the internal pressure of the extrusion device 32 is controlled by rapidly increasing it, and the preheating temperature is controlled to be low in order to reduce the hunting accompanying this.

In step 158, PID control is executed with the calculated preheating temperature as a reference, and in step 16
Move to 0. In step 160, it is determined whether or not the covering defect has been resolved, and in the case of a negative determination, step 15
6, the internal pressure continued to rise, and the bead wire 1
The setting of the preheating temperature of 0 and the PID control are repeated. Further, when it is determined in step 160 that the coating defect has been eliminated (when an affirmative determination is made), the process proceeds to step 162, the increase of the internal pressure is stopped, and the current preheating temperature of the bead wire 10 is stopped in step 164. It is determined whether the set value is within the proper range, and if it is proper, the process returns to the main routine. If it is determined to be improper, step 166 is performed.
After that, the preheating temperature is reset to the nearest preset value range within the proper range, and the internal pressure of the extruder 32 is set based on the reset preheating temperature. Then, the internal pressure set in step 168 is adjusted, and the process returns to the main routine.

As described above, in order to eliminate the coating defect, the internal pressure of the extrusion device 32 and the adjustment of the preheating temperature of the bead wire 10 are used together to promptly eliminate the coating defect and to reduce the internal pressure. Hunting of the rubber temperature due to the rise can be reduced by controlling the preheating temperature of the bead wire 10, and the process can be stabilized quickly.
Further, it is possible to prevent continuous occurrence of coating defects.

In this embodiment, the main control (increase) of the internal pressure of the extrusion device 32 and the sub control (fine adjustment) of the preheating temperature of the bead wire 10 are adjusted so that the preheating temperature is lowered. The rate of increase in the internal pressure of the device 32 may be reduced and the preheating temperature of the bead wire 10 may be increased.

Further, as the coating defect detecting sensor 64, the structure in which the detecting element 64B is arranged on the inner circumference of the annular main body 64A is applied, but as shown in FIG.
By rotating the sensor array 65 in which 4B is arranged parallel to the axis of the bead 34 around the bead 34 (see the solid line in FIG. 6), the bead 34 is moved in the axial direction to move relatively in a spiral shape (see FIG. 6). (See the imaginary line), and the entire bead 34 can be covered.

Further, the bead 34 may be captured as an image using a CCD sensor or the like, and the operator may monitor it. These are all non-contact type sensors,
If there is no danger of scratching the peripheral surface of the bead 34,
It is also possible to use a contact type sensor.

[0054]

As described above, the control method for preventing continuous occurrence of defective coating of the bead wire-coated rubber according to the present invention eliminates the defective coating of the rubber when the defective coating of the rubber occurs, and the product weight, gauge and width. It has an excellent effect that the variation of can be stabilized quickly.

[Brief description of drawings]

FIG. 1 is a schematic and preheat control block diagram of a bead wire transfer line according to the present embodiment.

FIG. 2 is an enlarged view of a heating unit.

FIG. 3 is a front view of a coating defect detection sensor.

FIG. 4 is a flowchart showing a temperature control routine.

FIG. 5 is a flowchart showing a control routine for preventing continuous occurrence of coating defects.

FIG. 6 is a side view showing a modified example of the coating defect detection sensor.

[Explanation of symbols]

 10 Bead Wire 14 Heating Section 24 Control Device 26 Temperature Sensor 32 Extrusion Device 34 Bead 40 Servo Motor 60 Pressure Sensor 62 Coating Failure Detection Sensor

Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display area B29L 30:00

Claims (2)

[Claims] 1. A step of forming a bead portion of a pneumatic tire by feeding a bead wire, which has been preheated to a predetermined temperature by a preheating device, to a rubber extrusion device, and covering the bead wire with rubber extruded at a predetermined pressure to form a bead portion of a pneumatic tire. A method for preventing continuous occurrence of defective coating of a bead wire-coated rubber for preventing a continuous coating failure of a partially exposed or near-exposed rubber, wherein the method is provided downstream of the rubber extrusion device. When a coating defect is detected, adjustment of the pressure inside the device by the rubber extrusion device and adjustment of the preheating temperature of the bead wire by the preheating device are controlled in combination, and the coating defect of the bead wire coated rubber is continuous. Prevention control method. 2. The rubber extruding device increases the rate of change of the internal pressure to quickly eliminate the coating defect, and the preheating device adjusts the preheating temperature of the bead wire, thereby varying the rubber temperature with poor responsiveness. The method for preventing continuous occurrence of coating failure of a bead wire-coated rubber according to claim 1, wherein hunting is suppressed.