Winding tension controlling apparatus for a tire-constituting member

Abstract: A winding tension controlling apparatus controls tensile force to be applied to a tire constituting member (4) wound about a building drum. The apparatus comprises a memory device (22) for storing patterns of tensile forces, a detecting sensor (26) for always detecting winding positions of the tire member, and a processing unit (23) for obtaining a tensile force value from a pattern of tensile force received on the basis of the memory device and a detected result from the memory device and outputting the tensile force value as a control signal.

Description: This invention relates to a winding tension controlling apparatus for tire constituting members for controlling tensile forces exerted on a tire constituting member depending on winding positions of the member onto a building drum when the member being transferred in contact with a tension pulley for winding the member about the building drum. Recently, a pneumatic tire suitable for running at high speeds has been proposed. The tire is so constructed that a belt-like tire constituting member is spirally wound radially outwardly about a belt layer and tensile forces in a zone of the tire constituting member adjacent shoulders of the tire are larger than those in a zone adjacent an equatorial plane of the tire. Both the shoulders are thus strongly restrained to prevent radial enlargement of the shoulders due to a large mass of rubber. Such a tire constituting member capable of changing tensile forces therein as above described can be obtained, for example, by changing winding tensile forces depending on winding positions when the tire constituting member is being wound about a building drum. An apparatus capable of controlling tensile forces depending on winding positions in such a manner has been proposed in Japanese Patent Application No. 62-98,388 (filed on April 21, 1987 by the assignee of the present case). The proposed apparatus comprises a brake roller provided upstream of a building drum and in contact with a running tire constituting member, an electromagnetic brake connected with the brake roller and a program setting device having a program memorized therein for controlling the electromagnetic brake. Moreover, the apparatus further comprises a controller for feeding control signals to the electromagnetic brake through a regulator according to a program called from the program setting device when the tire constituting member arrives at a winding starting position so as to control braking force produced in the electromagnetic brake to give a tensile force depending on a winding position to the tire constituting member. The apparatus further comprises a tension detection sensor for detecting the tensile force given to the tire constituting member and feeding a signal corresponding to the detected tensile force as a feed-back signal to the regulator. However, as such a tensile force controlling apparatus includes the electromagnetic brake, durability against friction is low and the braking force can be variable only in a narrow range. Moreover, as the feed-back control is utilized, feed back delay will occur, when the tire constituting member is longer. Therefore, the apparatus has some capability for improving accuracy in control of winding tensile forces with respect to a predetermined tensile force pattern, accuracy in response and reliability. Moreover, since the controlled state of the apparatus when winding the member cannot always be confirmed, problems are only noticed after the elapse of a long time. The document EP-A-0 288 609 corresponds to the above-mentioned document JP-A-63-264332 and has a priority date of 21.04.87 and was published on 02.11.88, and therefore belongs to the state of the art under the meaning of Article 54(3). However, the document EP-A-0 288 609 is not state of the art according to Article 54(2) EPC, as it was only published after the priority date of the present application. EP-A-0 288 609 can be understood as disclosing: storing means (36) for storing patterns of tensile forces previously inputted for applying the tensile forces to the tire constituting means, detecting sensor (34) for always (see column 7, lines 1-3) detecting winding position of the tire constituting member being wound onto the building drum, and processing means (35) (see column 4, lines 34-35) for obtaining a tensile force value to be applied to the tire constituting member at a given instant on the basis of a pattern of tensile force received from the storing means and a detected result received from the detecting sensor and outputting the tensile force value as a control signal. The present invention aims to provide an improved tire constituting member winding tension controlling apparatus which eliminates all the disadvantages of the prior art and which has high accuracy in control of winding tensile forces, high accuracy in response and high reliability, and which is durable against friction and has a wide range of variable braking force and further enables any problems occuring therein to be rapidly discovered. The present invention provides a winding tension controlling apparatus for tire constituting members for controlling tensile force to be applied to a tire constituting member depending on a winding position of the tire constituting member whcih is spirally or helically wound about a building drum during running of the member in contact with a tension roller, comprising storing means for storing patterns of tensile forces previously inputted for applying the tensile forces to the tire constituting members, a detecting sensor for always detecting winding positions of the tire constituting member being wound onto the building drum, processing means for obtaining a tensile force value to be applied to a tire constituting member at a given instant on the basis of a pattern of tensile force received from the storing means and a detected result received from the detecting sensor and outputting the tensile force value as a control signal, regenerative control means for controlling a DC motor connected to the tension roller to cause the tension roller to rotate at a speed slower by a predetermined value than a running speed of the tire constituting member wound about the building drum, and display means for displaying various information concerning winding of the tire constituting member, whereby said tire constituting member causes said tension roller to accelerate until its circumferential speed becomes substantially equal to the running speed of the tire constituting member wound about the building drum so that current generated in the DC motor is regenerated on a side of a power source by means of said regenerative control means to give the DC motor braking force, thereby causing a tensile force in the tire constituting member substantially equal to said tensile force value to be applied to the tire constituting member. It is assumed that after the tire constituting member was brought into contact with the tension roller and fed to the building drum, the tire constituting member has been spirally (helically) wound about the building drum. At this moment, a detected result of the winding position of the tire constituting member onto the drum is fed from the detecting means to the processing means. Moreover, one of the patterns of tensile forces previously inputted in the storing means is fed from the storing means into the processing means. The processing means obtains a tensile force value to be applied to the tire constituting member at the instant with the aid of the detected result and the pattern of tensile force and thereafter the processing means sends the tensile force value as a control signal to the regenerative control means. As a result, the regenerative control means controls the rotation of the DC motor so that the tension roller connected to the DC motor is caused to rotate at a circumferential speed slower by a predetermined value than the running speed of the tire constituting member wound on the building drum. In this case, since the tension roller and the tire constituting member do not slide with respect to each other, the tension roller is forced to accelerate by the tire constituting member until the circumferential speed of the tension roller becomes equal to the running speed of the tire constituting member. Such an acceleration causes a tensile force in the tire constituting member substantially equal to the tensile force value above described. In other words, the increase in speed of the tension roller causes the DC motor to generate current which is then regenerated onto the side of the power source so that braking force is applied onto the DC motor. In this manner, by regeneratively controlling the DC motor and in doing so by obtaining the tensile force value at that instant, the tensile force is given to the tire constituting member. In this case, as the generated current is regenerated onto the power source, it is possible to improve accuracy in control of winding tensile forces, accuracy in response to actuation, reliability in use and durability against wear. Moreover, the apparatus has a wide range of variable braking forces. Furthermore, as the display means always indicates the winding state every moment, any problems can be discovered early by an operator. The invention will be further described, by way of example only, with reference to the accompanying drawings, in which: Fig. 1 is a front view partially including a block diagram illustrating one embodiment of the invention; Fig. 2 is a view illustrating the building drum and the screw shaft viewed in directions shown by arrows II in Fig. 1; Fig. 3 is a graph illustrating one example of tension patterns used in the invention; and Figs. 4a and 4b are graphs for explaining the arithmetic operation for obtaining tensile forces to be applied to the tire constituting member. Referring to Figs. 1 and 2, a building drum 1 for forming a tire is cylindrical and rotatively driven by a motor (not shown). On a rear side of the building drum 1 is arranged a pay-off unit 2 having a roll 3 from which a narrow tire constituting member 4 is paid out so as to be supplied to the building drum 1. Between the building drum 1 and the pay-off unit 2 there are provided a rotatable support roller 8 and a tension roller 9 above the support roller 8, between which the tire constituting member 4 passes. As a result, the tire constituting member 4 is always in contact with the tension roller 9 without sliding therebetween. Moreover, the tire constituting member 4 runs about and in contact with guide rollers 10 and 11. The guide roller 11 as a dancer roller takes up slack in the member 4 by gravity. A loop of the member 4 extending about the guide roller 11 serves as a surplus length of the member 4 providing for any problems in running of the member 4. Between the tensile roller 9 and the building drum 1 is provided a screw shaft 16 which is in parallel with an axis of the building drum 1 and formed on its outer surface with screw threads 17 (Fig. 2). A winding guide 18 is threadedly engaged with the threads of the screw shaft 16 for guiding the tire constituting member 4 in a manner that the tire constituting member 4 is spirally (helically) wound about the building drum 1 when the winding guide 18 moves along the screw shaft 16. Inputting means 21 is provided for inputting process numbers and contents of the processes (patterns of tensile forces to be applied to the tire constituting member 4). The "process numbers" herein are numbers given to tires to be formed. One number is given to one kind of tire. On the other hand, the "patterns of tensile forces or tension patterns" are predetermined according to the process numbers. The tension pattern does mean polygonal lines in a graph for example in Fig. 3 whose abscissa indicates winding positions (moved distances of the winding guide in an axial direction of the screw shaft 16) and ordinate indicates tensile forces. Signals inputted from the inputting means 21 as tension patterns are coordinates of respective inflection points in a graph (angular points of polygonal lines, for example, points D1, D2 ... D18). In the case that a tension pattern is line-symmetrical with respect to a center of winding positions as shown in Fig. 3, the inputting above described is performed from a winding starting position to the winding center position, for example, D0 to D9 and inputting thereafter is omitted. In this case, x coordinates of inflection points of the later half, or points D10 to D18 are automatically set by the inputting means using equations shown in Fig. 3. Referring again to Fig. 1, storing means 22 is provided for storing the process numbers and the tension patterns inputted from the inputting means 21. In forming tires of a predetermined kind, when one process number corresponding to the tire now being formed is called, a tension pattern associated with the process number or coordinates of inflection points in the storing means are called which are fed to processing means 23. On the other hand, the screw shaft 16 is provided with a pulse generator 24 secured thereto, which generates pulses corresponding to rotating amounts of the screw shaft 16. The pulses from the pulse generator 24 are fed to a counter 25 which counts the pulses to detect an axial position of the winding guide 18 or a winding position of the tire constituting member 4 at the moment. The pulse generator 24 and the counter 25 form a detecting sensor 26 as a whole for always detecting winding positions of the tire constituting member 4 onto the building drum 1. The detected results by the detecting sensor 26 are fed to the processing means 23 in the same manner as the coordinates of the inflection points from the storing means 22. The processing means determines a position between inflection points at which the tire constituting member 4 is being wound with the aid of the coordinates of inflection points and the detected results. At the same time, the processing means 23 momentarily performs arithmetic operation to obtain a tensile force value to be applied to the tire constituting member 4 at the moment (at the present winding position). As shown in Figs. 4a and 4b, arithmetic equations are different in the cases that the tensile force is increasing as shown between the inflection points D2 and D3 and that the tensile force is decreasing as shown between the inflection points D4 and D5, respectively. The tensile force value to be applied to the tire constituting member 4 detected in the processing means 23 is converted into a tension signal (torque signal) by means of an AD converter 27 as shown in Fig. 1 and fed to regenerative control means 28. As a result, a DC motor 29 regenerates a regenerative current onto a side of a power source with the aid of the regenerative control means 28 to produce braking force. The DC motor 29 is connected to the tension roller 9. Therefore, when the DC motor 29 is rotated at a speed corresponding to the tension signal, the tension roller 9 is also rotatively driven at a circumferential speed slower by a predetermined value than a speed of the tire constituting member 4 wound on the building drum 1. On the other hand, the tire constituting member 4 and the tension roller 9 do not slide relative to each other as above described. Therefore, the tire constituting member 4 causes the tension roller 9 to accelerate until its circumferential speed becomes equal to the running speed of the tire constituting member 4. As a result, the DC motor 29 is also forced to accelerate so that the DC motor 29 generates a current commensurate with its acceleration. On the other hand, a tensile force is produced in the tire constituting member 4 owing to a resistance caused in the DC motor 29 when it is accelerated as above described. The tensile force produced in the tire constituting member 4 is substantially equal to the tensile force value detected in the processing means 23. In other words, the direct current generated in the DC motor 29 is regenerated to the side of the power source through the renegerative control means 28 to produce the braking force in this manner. Display means 30 having, for example, a plurality of LED (light-emitting diode) elements is provided for displaying inputted information, for example, process numbers and coordinates of inflection points during inputting such information or by reading from the storing means 22. Moreover, the display means 30 displays a wound state of the tire constituting member 4, for example, a winding position and a tensile force acting upon the tire constituting member 4 at that instant by reading the regenerative current. The operation of the apparatus of the embodiment according to the invention as above described will be explained. It is now assumed that after a tire constituting member 4 paid out of the roll 3 by means of the pay-off unit 2 was supplied onto the rotating building drum 1 while being in contact with the tension roller 9, the tire constituting member 4 has been wound about the building drum 1. In this case, the winding guide 18 for guiding the tire constituting member 4 is moved in the axial direction of the building drum 1 by the rotating screw shaft 16 so that the tire constituting member 4 is spirally wound about the building drum 1. During such an operation, pulses corresponding to rotated amounts of the screw shaft 16 are fed from the pulse generator 24 to the counter 25 so that the counter 25 counts the pulses to detect an axial position of the winding guide 18 or a winding position of the constituting member 4 at the moment. The detected results are fed from the counter 25 to the processing means 23. On the other hand, the processing means 23 receives information as tension pattern signals, for example, coordinates of inflection points of a process number corresponding to a tire now being formed among information such as process numbers and coordinates of inflection points of respective processes previously stored in the storing means 22. The processing means 23 having received such detected signals and tension pattern signals determines inflection points between which the winding is effected at that instant and performs arithmetic operation by substituting the winding position at that instant in an equation shown in Fig. 4a or 4b to obtain a tensile force value to be applied to the tire constituting member 4. The tensile force value obtained in the processing means 23 is converted in the AD converter 27 and fed into the regenerative control means 28. As a result, the tension signal is fed from the regenerative control means 28 to the DC motor 29 to control its rotating speed such that the tension roller 9 is rotatively driven at a speed slower by a predetermined speed than the speed of the tire constituting member 4 wound about the building drum 1. In this case, as there is no slip between the tire constituting member 4 and the tension roller 9, the tire constituting member 4 forces the tension roller 9 to accelerate until its circumferential speed becomes equal to the running speed of the tire constituting member 4. As a result, the DC motor 29 is also forced to accelerate so that the DC motor 29 generates electric current commensurate with the increased speed. On the other hand, a tensile force substantially equal to the tension force value acts in the tire constituting member 4 owing to a resistance caused when the DC motor 29 is accelerated. In other words, the current generated in the DC motor 29 is regenerated onto the side of the power source to give the DC motor 29 a braking force. By detecting the tensile force value to be applied to the tire constituting member 4 at that instant and at the same time regeneratively controlling the DC motor 29, the tensile force is given to the tire constituting member 4. By regenerating the regenerative current generated in the process onto the side of the power source by means of the regenerative control means 28, accuracy of the tensile force controlled in response to the tension pattern can be improved. Moreover, the display means 30 always indicates the winding state of the tire constituting member every moment, for example, the winding position of the member and the tensile force value to be applied to the tire constituting member 4. Therefore, any problems can be discovered early. As can be seen from the above description, the invention provides a tire constituting member winding tension controlling apparatus which has improved accuracy in control of winding tensile forces, accuracy in response to actuation, reliability in use and durability against wear. Moreover, the apparatus according to the invention has a wide range of variable braking forces and any problems which occur can be discovered early.

Claims: A winding tension controlling apparatus for tire constituting members for controlling tensile force to be applied to a tire constituting member (4) depending on a winding position of the tire constituting member which is spirally or helically wound about a building drum (1) during running of the member in contact with a tension roller (9), comprising storing means (22) for storing patterns of tensile forces previously inputted for applying the tensile forces to the tire constituting members, a detecting sensor (26) for always detecting winding positions of the tire constituting member being wound onto the building drum, processing means (23) for obtaining a tensile force value to be applied to a tire constituting member at a given instant on the basis of a pattern of tensile force received from the storing means and a detected result received from the detecting sensor and outputting the tensile force value as a control signal, regenerative control means (28) for controlling a DC motor (29) connected to the tension roller to cause the tension roller to rotate at a speed slower by a predetermined value than a running speed of the tire constituting member wound about the building drum, and display means (30) for displaying various information concerning winding of the tire constituting member, whereby said tire constituting member causes said tension roller to accelerate until its circumferential speed becomes substantially equal to the running speed of the tire constituting member wound about the building drum so that current generated in the DC motor is regenerated on a side of a power source by means of said regenerative control means to give the DC motor braking force, thereby causing a tensile force in the tire constituting member substantially equal to said tensile force value to be applied to the tire constituting member. A winding tension controlling apparatus as claimed in claim 1, characterized in that said storing means (22) comprises inputting means (21) for inputting said patterns of tensile forces into the storing means. A winding tension controlling apparatus as claimed in claim 1 or 2, characterized in that said detecting means (26) comprises a pulse generator (24) secured to a screw shaft (16) for generating pulses corresponding to rotating amounts of said screw shaft with which is threadedly engaged a winding guide (18) for guiding the tire constituting member, and a counter (25) for counting the pulses from the pulse generator and detecting axial positions of said winding guide as the winding positions of the tire constituting member. A winding tension controlling apparatus as claimed in any of claims 1 to3, characterized in that said processing means (23) comprises an AD converter for converting tensile force values into torque signals.

Inventors: HIRAI TAKAYUKI, HIRAI, TAKAYUKI
Applicants: BRIDGESTONE CORP, BRIDGESTONE CORPORATION
Application year: 1989
Main classification: B29D30
IPC codes: B65H23, B29D30, B29C53