JP3945637B2 - Strip material winding control method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a strip material winding control method suitable for forming a pneumatic tire by winding a strip material around a forming drum, and more specifically, uniformizing the weight distribution of the strip material in the drum circumferential direction. The present invention relates to a method for controlling the winding of a strip material.
[0002]
[Prior art]
As a method for forming a pneumatic tire, it has been proposed to form a green tire having a predetermined cross-sectional shape by continuously winding a strip material of a rubber composition around a forming drum.
[0003]
Among them, a rubber composition for molding a part for one tire is filled in a pot of a plunger type injection device, a strip material is injected using the measured rubber composition, and this is used as a molding drum. When it is made to wind around the periphery of the tire, there is an advantage that the weight of the entire tire can be managed with high accuracy.
[0004]
However, since the number of windings of the strip material varies depending on the capacity of the rubber composition to be filled, the start end and the end end of the strip material are not always at the same position in the drum circumferential direction. Therefore, when the start end and the end end of the strip material do not coincide with each other, there is a problem that weight imbalance occurs in the tire circumferential direction even if the weight accuracy of the entire tire is high.
[0005]
Further, when the strip material is wound, the surface speed of the forming drum is controlled based on the piston speed of the injection device. Therefore, the winding end position varies depending on the injection state and winding state of the strip material. It was necessary to make it smaller. Further, the difference in the state due to the type of rubber compound and the change with time has also caused variations in the winding end position of the strip material.
[0006]
[Problems to be solved by the invention]
An object of the present invention is suitable for forming a pneumatic tire by winding a strip material around a forming drum, and makes it possible to make the weight distribution of the strip material uniform in the drum circumferential direction. It is to provide a winding control method.
[0007]
[Means for Solving the Problems]
The strip material winding control method according to the present invention for solving the above-described object is achieved by injecting the strip material around the molding drum while injecting the strip material from the plunger-type injection device. In a method for controlling the piston speed and the surface speed of the molding drum with time,
In the winding adjustment period set between the initial winding period and the final winding period, the surface speed of the molding drum is set to an arbitrary ratio with respect to the supply speed of the strip material converted from the piston speed of the injection device. Then, based on the speed ratio, the start and end of the strip material are arranged at the same position in the drum circumferential direction.
[0008]
More specifically, the strip material winding control method is more specifically determined from the drum surface movement amount consisting of the time integral value of the surface speed of the forming drum and the drum outer circumference length, and the strip material winding number N1 at the initial winding stage. The number of turns N2 is set so that the sum of the number of turns N2 of the strip material in the winding adjustment period and the number of turns N3 of the strip material in the end of winding is an integer, and the supply length and the number of turns of the strip material in the winding adjustment period Based on the ratio of the drum surface movement amount corresponding to N2, the ratio of the strip material supply speed and the surface speed of the forming drum in the winding adjustment period is calculated.
[0009]
Thus, the winding adjustment period is set between the initial winding period and the final winding period, and the surface of the forming drum is compared with the supply speed of the strip material converted from the piston speed of the injection device in the winding adjustment period. Since the speed is set to an arbitrary ratio and the start and end of the strip material are made coincident based on the speed ratio, the weight distribution of the strip material can be made uniform in the drum circumferential direction. Therefore, when a pneumatic tire is formed by winding a strip material around a forming drum, it is possible to make the weight distribution uniform in the tire circumferential direction and improve the weight balance of the tire.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.
[0011]
FIG. 1 shows a tire forming apparatus according to an embodiment of the present invention. In FIG. 1, 1 is a plunger type injection device, 2 is a molding drum, and 3 is a control unit. The injection device 1 is a device in which a plunger sliding in a pot is driven by a piston, and a rubber composition filled in the pot is extruded from a die 4 to form a strip material S. The strip material S injected from the injection device 1 is guided to the outer peripheral surface of the forming drum 2 via the guide roller 5.
[0012]
The injection device 1 and the molding drum 2 are driven under the control of the control unit 3, and the surface speed of the molding drum 2 is controlled based on the piston speed of the injection device 1. The injection device 1 is provided with a capacity measuring unit 6 that measures the filling capacity and the discharge capacity of the rubber composition based on the piston position. A slack detection sensor 7 is disposed between the injection device 1 and the molding drum 2. The slack detection sensor 7 detects slack of the strip material S, that is, detects the start of discharge of the strip material S. The measurement results of the capacity measurement unit 6 and the slack detection sensor 7 are supplied to the control unit 3, respectively.
[0013]
In the tire molding apparatus, when the strip material S is wound around the molding drum 2 while injecting the strip material S from the plunger type injection device 1, the piston speed of the injection device 1 and the surface of the molding drum 2 are increased. The strip material S is wound by controlling the speed with time. As a result, as shown in FIG. 2, the strip material S is wound around the forming drum 2 to form tire parts such as sidewalls and treads.
[0014]
In FIG. 2, the positions of the start end S1 and the end S2 of the strip material S in the drum circumferential direction coincide with each other. Therefore, the weight distribution of the strip material S is uniform in the drum circumferential direction. On the other hand, in FIG. 3, the positions in the tire circumferential direction of the starting end S1 and the terminal end S2 of the strip material S do not coincide with each other, and the number of strip materials S arranged in the region W1 between the starting end S1 and the terminal end S2 Is less than other areas. On the other hand, in FIG. 4, the positions in the tire circumferential direction of the start end S1 and the end S2 of the strip material S do not coincide with each other, and the number of strips S arranged in the region W2 between the start end S1 and the end S2 is different. More than the area. 3 and 4, the weight distribution of the strip material S is not uniform in the drum circumferential direction.
[0015]
In the winding of the strip material S, the winding state as shown in FIG. 2 is ideal, but unless special control is performed, the number of windings of the strip material S varies depending on the capacity of the rubber composition to be filled, Further, it changes depending on the injection state and winding state of the strip material S, and as a result, the winding form as shown in FIGS. Therefore, in the present invention, control is performed so that the strip material S always approximates the winding state shown in FIG.
[0016]
FIG. 5 is a graph for explaining a strip material winding control method according to an embodiment of the present invention, in which the horizontal axis represents time (sec.) And the vertical axis represents speed (mm / sec.). In FIG. 5, the solid line X indicates the supply speed of the strip material converted from the piston speed of the injection device, and the alternate long and short dash line Y indicates the surface speed of the forming drum. The strip material supply speed converted from the piston speed is obtained by multiplying the piston speed by the ratio (A2 / A1) between the cross-sectional area A1 of the strip material (opening area of the die base) and the cross-sectional area A2 of the plunger. Is. The strip material supply speed converted from the piston speed is approximately the same as the actual supply speed in the stable supply state of the strip material, but at the beginning of winding, the strip material discharge start is delayed from the piston operation start, so the actual supply speed Does not match the speed.
[0017]
As shown in FIG. 5, the supply speed (X) of the strip material S converted from the piston speed of the injection device 1 gradually increases from the stopped state to the first speed, and after maintaining the first speed for a while, The speed gradually increases to the second speed, and the second speed is maintained for a while. Thereafter, the supply speed of the strip material S gradually decreases to the third speed, and after maintaining the third speed for a while, the strip material S reaches a stop state. On the other hand, the forming drum 2 starts rotating with a discharge start time t1 delayed from the start of the piston operation in response to the detection of the slackness of the strip material S by the slackness detection sensor 7. Then, the surface speed (Y) of the forming drum 2 gradually increases from the stopped state to an initial adjustment speed slower than the first speed, and after maintaining the initial adjustment speed for a while, gradually increases to the first speed, Maintain the first speed. Next, the surface speed of the forming drum 2 is gradually increased to the second speed, and the second speed is maintained for a while. Thereafter, the surface speed of the forming drum 2 gradually decreases to an end adjustment speed that is slower than the third speed, and after maintaining the end adjustment speed for a while, a stop state is reached.
[0018]
In the present invention, the winding adjustment period is between a winding initial period T1 from the start of rotation of the molding drum 2 to the start point of the second speed and a winding final period T3 from the end point of the second speed to the end of rotation of the molding drum 2. T2 is set, and in this winding adjustment period T2, the surface speed of the forming drum 2 is set to an arbitrary ratio with respect to the supply speed of the strip material S converted from the piston speed of the injection device 1, and the speed ratio is set to Based on this, the start end S1 and the end end S2 of the strip material S are arranged at the same position in the drum circumferential direction.
[0019]
The number of turns N1 of the strip material S in the winding initial period T1, the number of turns N2 of the strip material S in the winding adjustment period T2, and the number of turns N3 of the strip material S in the final winding period T3 are time integrals of the surface speed of the forming drum 2, respectively. It can be determined on the basis of the drum surface movement amount and the drum outer peripheral length. That is, the value obtained by dividing the drum surface movement amount by the drum circumferential length is the number of turns. Here, the number of turns N2 in the winding adjustment period T2 is adjusted so that the total number of turns N, which is the sum of the number of turns N1 to N3, becomes an integer.
[0020]
For example, the supply length of the strip material S obtained from the rubber filling capacity into the pot of the injection device 1 and the opening area of the die base corresponds to 25 turns, and the winding number N1 of the initial winding T1 is 3 turns. When the number of turns N3 of the turn final period T3 is 1, the number of turns N2 of the turn adjustment period T2 may be adjusted to 21 and the total number of turns N may be 25 (integer).
[0021]
Further, the supply length of the strip material S determined from the rubber filling capacity in the pot of the injection apparatus 1 and the opening area of the die base corresponds to 25 turns, and the number of turns N1 of the initial winding T1 is 2.8. When the winding number N3 of the winding final period T3 is one, the winding number N2 of the winding adjustment period T2 may be adjusted to 21.2, and the total number of windings N may be 25 (integer).
[0022]
Further, the supply length of the strip material S obtained from the rubber filling capacity in the pot of the injection device 1 and the opening area of the die base corresponds to 25.5 turns, and the number of turns N1 of the initial winding T1 is 3 turns. When the winding number N3 of the winding end period T3 is one, the winding number N2 of the winding adjustment period T2 may be adjusted to 22 and the total number of windings N may be 26 (integer).
[0023]
In order to adjust the number of turns N2 in the winding adjustment period T2 as described above, the supply length L1 of the strip material S in the winding adjustment period T2 and the drum surface movement amount L2 corresponding to the number of turns N2 are obtained. In the adjustment period T2, the ratio (Y / X) of the surface speed (Y) of the forming drum 2 to the supply speed (X) of the strip material S may be set to L2 / L1.
[0024]
For example, when the supply length L1 of the strip material S in the winding adjustment period T2 is 23.5 m and the drum surface movement amount L2 corresponding to the winding number N2 is 23.9 m, that is, L2 / L1 = 1.016. In this case, the surface speed (Y) of the forming drum 2 in the winding adjustment period T2 may be set to 101.7% of the supply speed (X) of the strip material S. Even if this length adjustment is performed, the strip material S is not broken, and the physical properties of the molded body are not adversely affected.
[0025]
As a result, the total number of turns N of the strip material S can be set to an integer, and the start end S1 and the end S2 of the strip material S can be arranged at the same position in the drum circumferential direction. Uniform in the direction. As a result, when forming the pneumatic tire by winding the strip material S around the forming drum 2, the weight distribution can be made uniform in the tire circumferential direction, and the weight balance of the tire can be improved.
[0026]
When performing the above calculation, as a detection variable, it is possible to use a rubber filling capacity into the pot of the injection apparatus, a discharge start time of the strip material, a discharge capacity during the injection, and the like. The rubber filling capacity into the pot of the injection device is used for calculating the supply length of the strip material. The discharge start time of the strip material is used to calculate the number N1 of strip material windings at the initial winding time T1. As the discharge capacity during the injection, the discharge capacity at the end point of the first speed may be measured. That is, if the discharge capacity after the unstable time at the start of winding is known, the speed ratio of the winding adjustment period T2 can be calculated at the calculation time t2 (see FIG. 5) using the discharge capacity. .
[0027]
According to the strip material winding control method described above, the start end S1 and the end end of the strip material S are not only different in the case of different rubber filling capacities, but also in the case of different states due to the type of rubber compound and changes over time. S2 can be arranged at the same position in the drum circumferential direction.
[0028]
In the present invention, the target is to arrange the start end S1 and the end S2 of the strip material S at the same position in the drum circumferential direction. However, the positions of the two do not necessarily need to be completely matched. The interval in the drum circumferential direction may be 50 mm or less, more preferably 30 mm or less.
[0029]
【The invention's effect】
As described above, according to the present invention, when the strip material is wound around the molding drum while ejecting the strip material from the plunger type injection device, the piston speed of the injection device and the surface of the molding drum are In the method of controlling the speed with time, in the winding adjustment period set between the initial winding period and the final winding period, the forming drum is supplied with respect to the strip material supply speed converted from the piston speed of the injection device. The surface speed of the strip material is set to an arbitrary ratio, and the start and end of the strip material are arranged at the same position in the drum circumferential direction based on the speed ratio, so the weight distribution of the strip material is made uniform in the drum circumferential direction. be able to. Therefore, when a pneumatic tire is formed by winding the strip material around the forming drum, the weight distribution can be made uniform in the tire circumferential direction and the weight balance of the tire can be improved.
[Brief description of the drawings]
FIG. 1 shows a tire forming apparatus according to an embodiment of the present invention.
FIG. 2 is a perspective view illustrating a winding state of a strip material on a forming drum.
FIG. 3 is a perspective view illustrating a winding state of a strip material on a forming drum.
FIG. 4 is a perspective view illustrating a winding state of a strip material on a forming drum.
FIG. 5 is a graph for explaining a strip material winding control method according to an embodiment of the present invention;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Injection apparatus 2 Molding drum 3 Control part 4 Dies 5 Guide roller 6 Capacity measuring part 7 Looseness detection sensor S Strip material S1 Start end S2 End

Claims (2)

In the method of controlling the piston speed of the injection device and the surface speed of the molding drum with time when the strip material is wound around the molding drum while injecting the strip material from the plunger type injection device,
In the winding adjustment period set between the initial winding period and the final winding period, the surface speed of the molding drum is set to an arbitrary ratio with respect to the supply speed of the strip material converted from the piston speed of the injection device. And a strip material winding control method in which the start and end of the strip material are arranged at the same position in the drum circumferential direction based on the speed ratio. The number of turns N1 of the strip material in the initial stage of winding, the number of turns N2 of the strip material in the winding adjustment period, which is obtained from the amount of movement of the drum surface consisting of the time integral value of the surface speed of the forming drum and the outer peripheral length of the drum. The number of turns N2 is set so that the sum of the number of turns N3 of the strip material in the final stage becomes an integer, and based on the ratio between the supply length of the strip material in the winding adjustment period and the amount of movement of the drum surface corresponding to the number of turns N2, The strip material winding control method according to claim 1, wherein a ratio between the strip material supply speed and the surface speed of the forming drum in the winding adjustment period is calculated.

Images