JP2021176685A - Tire manufacturing apparatus and method - Google Patents

Abstract

To provide an apparatus and method for manufacturing a tire that can further improve uniformity without applying extra external force to the tire during a PCI process.SOLUTION: A green tire G is vulcanized by a vulcanizer 2 to obtain a vulcanized tire T. In a PCI process performed on the tire T immediately after vulcanization, a shape sensor 7 detects an outer shape of the tire T held by a PCI machine 3. Based on the comparison between target shape data Dg which is set in advance for the tire T, and detected shape data Dm by the shape sensor 7, a cooling range Ac to be cooled on an outer surface of the tire T is determined, and a control unit 10 controls a cooler 9 to cool the cooling range Ac, thereby bringing the detected shape data Dm closer to the target shape data Dg.SELECTED DRAWING: Figure 6

Description

The present invention relates to a tire manufacturing apparatus and method, and more particularly to a tire manufacturing apparatus and method capable of further improving uniformity without applying an extra external force to the tire during a PCI process. be.

For tires with specifications in which the buried reinforcing fibers heat shrink, a PCI (post-cure inflation) process is performed to cool the tire in an inflated state in order to prevent deformation of the tire immediately after vulcanization. There is. The tire is completed through this PCI process.

Conventionally, various methods for improving tire uniformity have been proposed during the PCI process (see, for example, Patent Documents 1 and 2). Patent Document 1 proposes that by expanding a tire in a mold having a target shape, the tire is slowly cooled in a state of being molded into the target shape by the mold. Patent Document 2 proposes that the distance between the bead portions of a tire is changed and held in the tire circumferential direction. In these proposed methods, a corresponding external force is applied to the tire, so that the load on the tire is increased. In addition, these methods may not be able to sufficiently improve uniformity. Therefore, there is room for improvement in improving uniformity without applying extra external force to the tire during the PCI process.

Japanese Unexamined Patent Publication No. 62-249715 Japanese Unexamined Patent Publication No. 11-77848

An object of the present invention is to provide a tire manufacturing apparatus and method capable of further improving uniformity without applying an extra external force to the tire during the PCI process.

In order to achieve the above object, the tire manufacturing apparatus of the present invention includes a smelter for smelting a green tire and a PCI machine for inflating and holding the tire immediately after the green tire has been smelted. In the tire manufacturing apparatus, a shape sensor that detects the outer shape of the tire held by the PCI machine, a cooler that cools the outer surface of the tire, and a control unit that inputs the detected shape data by the shape sensor. In preparation, the cooling range of the outer surface of the tire is determined based on the comparison between the detected shape data and the target shape data preset for the tire, and the detected shape data becomes the target shape data. The cooler is controlled by the control unit so as to approach the cooling range, and the cooling range is cooled.

The tire manufacturing method of the present invention is a method for manufacturing a tire having a vulcanization step for a green tire and a PCI step for a tire immediately after being vulcanized in the vulcanization step.
In the PCI step, the outer shape of the tire held by the PCI machine is detected by the shape sensor, and the target shape data preset for the tire is compared with the detected shape data by the shape sensor. The feature is that the detected shape data is brought closer to the target shape data by determining the cooling range of the outer surface of the tire and controlling the cooler by the control unit to cool the cooling range.

According to the present invention, the outer shape state of a tire can be grasped by acquiring the detected shape data of the tire immediately after vulcanization using the outer shape sensor. Then, the difference between the two can be found by comparing the detected shape data with the target shape data, and the cooling range to be cooled on the outer surface of the tire can be determined based on the magnitude of the difference between the two. Therefore, by controlling the cooler by the control unit so as to eliminate the difference between the two and cooling the determined cooling range, the detected shape data can be accurately approached to the target shape data. Therefore, it is possible to further improve the uniformity without applying an extra external force to the tire during the PCI process.

It is explanatory drawing which illustrates the tire manufacturing apparatus of this invention in a side view with a part in a vertical cross section. It is explanatory drawing which illustrates the PCI machine of FIG. 1 and its ancillary equipment in a side view with a part in a vertical cross section. It is explanatory drawing which illustrates the PCI machine of FIG. 2 and its ancillary equipment in a plan view. It is a graph which illustrates the detected shape data and the target shape data of a tire. It is a graph which illustrates the temperature distribution data of the outer surface of a tire. It is explanatory drawing which illustrates the state which cooled the cooling range of the outer surface of a tire in a plan view. It is explanatory drawing which illustrates the state of FIG. 6 from the side view. It is a flow chart which illustrates the procedure of a PCI process.

Hereinafter, the tire manufacturing apparatus and method of the present invention will be described based on the embodiments shown in the drawings.

The tire manufacturing apparatus 1 of the embodiment illustrated in FIG. 1 includes a vulcanizer 2 and a PCI machine 3. The vulcanizer 2 vulcanizes the green tire G. A vulcanization mold 11 corresponding to each specification of the pneumatic tire T to be manufactured is attached to the vulcanizer 2. A vulcanizer 2 having various known specifications for vulcanizing the green tire G can be used. In this embodiment, a so-called sectional type vulcanization mold 11 composed of a large number of sector molds arranged in an annular shape and an annular upper side mold and a lower side mold is used. The vulcanization mold 11 is not limited to the sectional type, and a so-called halved mold can also be used.

The PCI machine 3 performs a PCI process on the tire T obtained by vulcanizing the green tire G by the vulcanizer 2, and the uniformity of the tire T (hereinafter referred to as UF) is improved during the PCI process. .. The PCI machine 3 has a holding portion 4a attached to the central shaft 3A to hold the tire T, and an inflating portion 4b for expanding the held tire T. PCI machines 3 having various known specifications can be used. For example, the holding portion 4a is a rim member that holds both bead portions of the tire T, and the inflating portion 4b is an injection source that injects air into the inside of the tire T. (High pressure air accommodating cylinder, etc.) is used.

The manufacturing apparatus 1 further includes a shape sensor 7 for detecting the outer shape of the tire T held by the PCI machine 3, a cooler 9 for cooling the outer surface of the tire T, and a control unit 10. In this embodiment, a temperature sensor 8 for detecting the outer surface temperature of the tire T held by the PCI machine 3 is further provided.

As illustrated in FIGS. 2 and 3, the central axis 3A of the PCI machine 3 can be rotated around the axis by the rotation mechanism 5. The two-dot chain line CL in the figure indicates the axis of the central axis 3A, and the tire axis of the tire T held by the PCI machine 3 substantially coincides with the axis CL.

The rotation mechanism 5 is composed of, for example, a drive motor and a transmission belt hung around the drive motor and the central shaft 3A. By operating the rotation mechanism 5, the tire T held by the holding portion 4a rotates around the central axis 3A. Therefore, the tire T rotates about the tire shaft by the rotation mechanism 5 with respect to the shape sensor 7. Since it is sufficient that the tire T can be rotated relative to the shape sensor 7 about the tire axis, the shape sensor 7 is rotated around the central axis 3A with the circumferential position of the tire T fixed. The mechanism 5 may be adopted.

As the shape sensor 7, a known non-contact type displacement sensor (distance sensor) that detects the distance to an object, such as a laser displacement sensor, is used. In this embodiment, the displacement sensor 7 can be moved in the width direction of the tire T held by the PCI machine 3 by the width direction moving mechanism 6. As the width direction moving mechanism 6, a fluid cylinder, a rod operated by a servomotor, a robot arm, or the like can be used.

The shape sensor 7 is not limited to a single shape sensor 7, and a plurality of shape sensors 7 may be provided, and a detection range in charge of each shape sensor 7 may be assigned and used. Since it is sufficient that the tire T can be moved relative to the shape sensor 7 in the tire width direction, the tire T is moved in the tire width direction while the position of the shape sensor 7 in the tire width direction is fixed. The mechanism 6 may be adopted.

Alternatively, as the shape sensor 7, a two-dimensional laser displacement meter or the like that detects a planar shape can be used. When such a two-dimensional laser displacement meter is adopted as the shape sensor 7, each shape sensor 7 is located on the outer peripheral side of the tire T so that the entire outer shape of the tire T can be detected by a plurality of shape sensors 7. It may be fixed at a predetermined installation position at intervals. In this case, it is possible to eliminate the need for a moving mechanism that moves the shape sensor 7 relative to the tire T.

As the temperature sensor 8, various known non-contact type temperature sensors can be used, and thermography or the like can also be used. The number of temperature sensors 8 is not limited to one, and a plurality of temperature sensors 8 may be provided, and a detection range in charge of each temperature sensor 8 may be assigned and used.

The cooler 9 cools the tread portion, the shoulder portion, the side portion, and the like as the outer surface of the tire T. All parts of the tread part, the shoulder part, and the side part can be cooled, or at least one or two parts of these parts can be selectively cooled as the cooling range Ac. Cooling around the shoulder part is effective in improving the UF.

In this embodiment, the cooler 9 is formed in an annular shape and is arranged on the outer peripheral side of the tire T. A large number of nozzles 9a are formed on the inner peripheral surface of the annular cooler 9 at intervals in the circumferential direction. The cooler 9 is supported by a movable mechanism 9b that expands and contracts up and down. Therefore, the cooler 9 can move in the tire width direction with respect to the tire T. As the movable mechanism 9b, a fluid cylinder, a rod operated by a servomotor, a robot arm, or the like can be used. When the annular cooler 9 is used, it becomes easy to suppress variation in the circumferential direction of the facing distance between the nozzle 9a and the outer surface of the tire T.

The cooling medium a is supplied to the cooler 9 from the medium supply source, and the cooling medium a is injected from each nozzle 9a. As the cooling medium a, a gas such as air, a liquid such as water, powdery dry ice, or the like can be used. In this embodiment, the annular cooler 9 is divided into four areas 9A, 9B, 9C, and 9D in the circumferential direction, and each area has a structure in which the cooling medium a can be injected independently. The number of areas divided in the circumferential direction is not limited to four, and can be a desired number of two or more. The structure may be such that the cooling medium a can be injected independently for each nozzle 9a.

Further, a plurality of annular coolers 9 may be arranged vertically, and a cooling area in charge of each cooler 9 may be assigned in the tire width direction for use. Alternatively, instead of the annular cooler 9 and the movable mechanism 9b, a nozzle 9a for injecting the cooling medium a may be attached to the robot arm so that the cooling medium a can be injected at an arbitrary desired position.

The control unit 10 controls the operations of the PCI machine 3, the rotation mechanism 5, the width direction moving mechanism 6, the cooler 9, and the movable mechanism 9b. The shape data Dm detected by the shape sensor 7 and the temperature data Tm detected by the temperature sensor 8 are input to the control unit 10. A computer or the like is used for the control unit 10.

When the tire T is attached to the PCI machine 3 according to the reference, the vertical position and the circumferential rotation angle (circumferential position) of the tire T are always grasped by the control unit 10. The position of the shape sensor 7 and the position of the cooler 9 (nozzle 9a) are also constantly grasped by the control unit 10. Further, the target shape data Dg preset for the tire T is input to the control unit 10.

Hereinafter, a method of manufacturing the pneumatic tire T using this manufacturing apparatus 1 will be described.

First, as illustrated in FIG. 1, a vulcanization step is performed on a green tire G molded by a known method using a vulcanizer 2. A heat-shrinkable fiber cord is embedded in the green tire G as a reinforcing material (carcass material or the like). In the vulcanization step, the green tire G in a sideways state is vulcanized in the vulcanization mold 11 to obtain a vulcanized tire T.

Next, the PCI step is performed on the tire T immediately after vulcanization using the PCI machine 3. In the PCI step, as illustrated in FIGS. 2 and 3, air is injected into the tire T held by the holding portion 4a to maintain the tire T in an appropriately inflated state. Since this inflating is performed to counter the heat shrinkage of the fiber cord embedded in the tire T, the internal pressure applied by the inflating causes the tire T to slightly expand and deform with time.

If the degree of decrease in temperature (cooling condition) of the tire T in the PCI process is uniform as a whole, the degree of diameter expansion and deformation of the tire T in the PCI process over time is unlikely to vary in the circumferential direction and the width direction. .. However, the inventor of the present application has confirmed that since the cooling condition varies in the conventional PCI process, it greatly affects the uniformity of the tire T after the PCI process (hereinafter referred to as UF).

The present invention has been created by paying attention to the variation in the cooling condition in the PCI process. The part where the temperature of the tire T is relatively low (the part where the cooling condition is strong) tends to increase the degree of diameter expansion and deformation of the tire T over time, and the part where the temperature is relatively high (the part where the cooling condition is weak). It was found that the degree of diameter expansion and deformation of the tire T with time tends to be suppressed. Further, depending on the tire specifications, there are some tires T whose diameters are deformed in a portion where the temperature is relatively low. As described above, since the temperature of the outer surface of the tire T during the PCI process affects the tire shape, in the present invention, the tire shape is appropriately shaped by controlling the temperature of the outer surface of the tire T during the PCI process. Improve UF by modifying and maintaining.

Specifically, the shape sensor 7 detects the outer shape of the tire T held by the PCI machine 3. By operating the rotating mechanism 5 and the movable mechanism 6, the outer surface of the tire T and the shape sensor 7 are relatively moved, and the distance between the outer surface of the tire T (almost the entire range) and the shape sensor 7 is adjusted. Upon detection, data (detection shape data Dm) indicating the outer shape of the tire T illustrated in FIG. 4 is acquired. In this embodiment, the temperature sensor 8 also detects the temperature of the outer surface (almost the entire range) of the tire T illustrated in FIG. 5 to acquire the detected temperature data Tm.

The control unit 10 compares the detection shape data Dm described by the broken line in FIG. 4 with the preset target shape data Dg described by the solid line. FIG. 4 shows data at one widthwise position of the tire T. At this width direction position, the target shape data Dg is that the radius of the tire T is a predetermined constant value. On the other hand, in the detected shape data Dm, the radius of the tire T in the circumferential direction of approximately 60 ° to 240 ° is larger than that of the other ranges with respect to the target shape data Dg. If this condition remains, even if the tire T expands and deforms over time during the PCI process, the variation in radius at the circumferential position indicated by the broken line is not eliminated.

Therefore, the control unit 10 determines the circumferential position (range) in which the difference between the target shape data Dg and the detected shape data Dm is relatively large as the cooling range Ac of the outer surface of the tire T. do. For example, an allowable range is set for the maximum value and the average value of the detected shape data Dm, and the range where the radius is small outside the allowable range is determined as the cooling range Ac. In this embodiment, the range where the circumferential position is 0 to 60 ° and 240 to 360 ° is determined as the cooling range Ac. The cooling range Ac is also determined at a plurality of width direction positions of the tire T spaced apart from each other in the width direction in the same manner as described above. In this way, the cooling range Ac is determined with the entire width of the tire T as the subject of consideration.

In this embodiment, the control unit 10 calculates the temperature distribution of the outer surface (almost the entire range) of the tire T using the detection temperature data Tm illustrated in FIG. FIG. 5 shows the detected temperature data Tm at a certain width direction position of the tire T. The larger the difference in the surface temperature of the tire T, the easier it is to change the degree of diameter expansion and deformation of the tire T. Therefore, the cooling range Ac can be determined in consideration of the calculated temperature distribution on the outer surface of the tire T. For example, in the cooling range Ac determined based on the comparison between the target shape data Dg and the detected shape data Dm, the cooling range is set centering on the range where the temperature is relatively high.

Next, the cooler 9 and the movable mechanism 9b are controlled by the control unit 10, and the determined cooling range Ac is cooled by the cooler 9. In this embodiment, as illustrated in FIGS. 6 and 7, the cooling medium a is injected only through the nozzle 9a at the position corresponding to the determined cooling range Ac to cool the cooling range Ac. The cooling medium a is not ejected from the nozzle 9a at a position that does not correspond to the cooling range Ac. By this cooling, the outer surface of the tire T is cooled to about 90 ° C.

As illustrated in FIG. 8, the series of operations described above in the PCI step is repeatedly performed at predetermined time intervals so that the detected shape data Dm falls within an allowable range with respect to the target shape data Dg. As a result, the detected shape data Dm approaches the target shape data Dg during the PCI process, and the UF of the tire T is improved.

More specifically, the radial force variation (RFV) is set within the appropriate range by reducing the variation in the circumferential direction of the cooling degree of the tire T so that the detected shape data Dm falls within the allowable range with respect to the target shape data Dg. It will be easier. Further, by reducing the variation in the width direction of the cooling degree of the tire T, it becomes easy to set the Lateral Force Variation (LFV) and Conicity (CON) in the appropriate range.

In the present invention, since the detection shape data Dm of the tire T immediately after vulcanization is acquired by using the outer shape sensor 7, the outer shape state of the tire T can be accurately grasped. Then, since the difference between the two is found by comparing the detected shape data Dm and the target shape data Dg, the cooling range Ac to be cooled can be quickly determined based on the magnitude of the difference between the two.

Therefore, by cooling the determined cooling range using the cooler 9 so as to eliminate the difference between the detected shape data Dm and the target shape data Dg, the detected shape data Dm can be accurately approached to the target shape data Dg. Can be done. Since no extra external force is applied to the tire T during the PCI process, the tire T is not damaged unnecessarily. In the PCI process, it is possible to further improve the UF of the tire T only by controlling the cooling condition in the circumferential direction and the width direction of the tire T.

Also, since the UF is improved during the existing PCI process, the additional time required to improve the UF can be reduced. Along with this, it also contributes to the improvement of the productivity of the tire T.

1 Manufacturing equipment 2 Vulcanizer 3 PCI machine 3A Central axis 4a Holding part 4b Inflator part 5 Rotation mechanism 6 Width direction movement mechanism 7 Shape sensor 8 Temperature sensor 9 Cooler 9a Nozzle 9b Movable mechanism 10 Control part 11 Vulcanization mold G Green tire T Vulcanized tire

Claims (6)

In a tire manufacturing apparatus including a vulcanizer for vulcanizing a green tire and a PCI machine for inflating and holding the tire immediately after the green tire has been vulcanized.
The detected shape includes a shape sensor that detects the outer shape of the tire held by the PCI machine, a cooler that cools the outer surface of the tire, and a control unit that inputs the detected shape data by the shape sensor. The control so that the cooling range of the outer surface of the tire is determined based on the comparison between the data and the target shape data preset for the tire, and the detected shape data approaches the target shape data. A tire manufacturing apparatus characterized in that the cooler is controlled by a unit to cool the cooling range. It has a temperature sensor that detects the outer surface temperature of the tire, the temperature data detected by the temperature sensor is input to the control unit, and the temperature distribution data of the outer surface of the tire calculated using the detected temperature data is used. The tire manufacturing apparatus according to claim 1, wherein the cooling range is determined based on the above. A claim having a rotation mechanism for rotating the tire held by the PCI machine relative to the shape sensor with respect to the tire axis, and a width direction moving mechanism for moving the tire relative to the tire width direction. The tire manufacturing apparatus according to 1 or 2. According to claim 1 or 2, the shape sensor is a two-dimensional laser displacement meter, and a plurality of the shape sensors are fixed at a predetermined installation position on the outer peripheral side of the tire held by the PCI machine at intervals. The described tire manufacturing device. Any of claims 1 to 4, wherein the cooler has a nozzle formed in an annular shape and ejects a cooling medium on the inner peripheral surface at intervals in the circumferential direction, and is arranged on the outer peripheral side of the tire. The tire manufacturing apparatus described in. In a tire manufacturing method having a vulcanization step for a green tire and a PCI step for a tire immediately after being vulcanized in the vulcanization step.
In the PCI step, the outer shape of the tire held by the PCI machine is detected by the shape sensor, and the target shape data preset for the tire is compared with the detected shape data by the shape sensor. A method for manufacturing a tire, characterized in that the detection shape data is brought closer to the target shape data by determining the cooling range of the outer surface of the tire and controlling the cooler by a control unit to cool the cooling range. ..

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