JP2020055190A - Method of heating rubber material for tire - Google Patents

Abstract

To provide a heating method capable of making a temperature of a rubber material for a tire uniform.SOLUTION: In the heating method, a tire rubber material 10 is kneaded between a roll 14 and a roll 16. The method includes: a temperature measuring step for measuring a temperature of a rubber sheet 12; and a rotation ratio adjusting step for adjusting a rotation ratio between the roll 14 and the roll 16 based on the temperature of the rubber sheet 12. Preferably, in the rotation ratio adjusting step, a distance C between the roll 14 and the roll 16 is adjusted.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for warming a rubber material for a tire.

  A rubber material used for a member forming each part of the tire (hereinafter, also referred to as a tire member) is heated. This heating improves the plasticity of the rubber material. The heated rubber material is formed into the shape of a tire member. This insufficiently heated rubber material reduces the molding accuracy of the tire member. On the other hand, excessive heating causes so-called burn (partial vulcanization) in this rubber material. The burnt rubber material cannot be used as a tire member.

  JP-A-2017-109309 discloses a method for warming a rubber material. In this heating method, a rubber material is passed between a pair of rolls, and the rubber material is kneaded. The surface temperature of the rubber material is measured. In this heating method, the temperature of the rubber material is adjusted by a pair of temperature-adjusted rolls. Thereby, the temperature of the warming is optimized.

JP 2017-109309 A

  In the heating method disclosed in JP-A-2017-109309, the surface of the rubber material that is in contact with the roll is heated. In this method, it takes time to raise the temperature inside the rubber material. If the temperature is raised in a short time, a temperature difference between the surface and the inside tends to occur. This temperature difference can cause a bagging phenomenon in which the rubber material peels off the roll. Furthermore, if the temperature is raised for a short time, insufficient heating may occur, or burns may occur. This method of warming the rubber material has room for improvement in terms of making the entire temperature uniform.

  An object of the present invention is to provide a warming method capable of equalizing the temperature of a rubber material for a tire.

  The rubber material warming method according to the present invention is a method of kneading and warming a rubber material for a tire member between a pair of rolls to form a rubber sheet. This warming method includes a temperature measuring step of measuring the temperature of the rubber sheet, and a rotation ratio adjusting step of adjusting the rotation ratio of the pair of rolls based on the temperature of the rubber sheet.

  Preferably, in the rotation ratio adjusting step, an interval between the pair of rolls is adjusted.

  The pair of rolls includes a front roll around which the rubber material is wound, and a back roll for kneading the rubber material between the front roll. Preferably, in the rotation ratio adjustment step, the rotation ratio is adjusted by increasing or decreasing the rotation speed of the back roll.

  The rubber material warming apparatus according to the present invention is an apparatus for warming a rubber material used for a tire member to form a rubber sheet. This device includes a pair of rolls for kneading the rubber material therebetween, a temperature sensor for measuring the temperature of the rubber sheet, and a control device. The control device has a function of receiving temperature data of the rubber sheet from the temperature sensor, and a function of adjusting a rotation ratio of the pair of rolls based on the temperature data.

  Preferably, the control device has a function of adjusting an interval between the pair of rolls.

  Preferably, the pair of rolls include a front roll around which the rubber material is wound, and a back roll that heats the rubber material between the front roll. The control device has a function of adjusting the rotation ratio by increasing or decreasing the rotation speed of the back roll.

  In the method for producing a rubber material according to the present invention, the shearing force acting on the rubber material is adjusted by adjusting the rotation ratio of the pair of rolls. Thereby, the temperature inside the rubber material can also be adjusted. This method can adjust the temperature of the rubber material more uniformly.

FIG. 1 is a conceptual diagram illustrating a warming device according to an embodiment of the present invention.

  Hereinafter, the present invention will be described in detail based on preferred embodiments with reference to the drawings as appropriate.

  The warming device 2 shown in FIG. 1 includes a warming roll 4 as a pair of rolls, a temperature sensor 6, and a control device 8. FIG. 1 shows a rubber material 10 and a rubber sheet 12 formed from the rubber material 10 together with the warming device 2. The rubber material 10 and the rubber sheet 12 are made of unvulcanized rubber.

  The heating roll 4 includes a front roll 14 and a back roll 16. The front roll 14 has a cylindrical shape. The front roll 14 is supported by a support table (not shown). The front roll 14 is rotatably supported with its axis as a rotation axis. The rotation speed of the front roll 14 is measured on the outer peripheral surface 14a of the front roll 14.

  Although not shown, a cooling pipe and a heating pipe are provided inside the front roll 14. The cooling pipe has a function of cooling the outer peripheral surface 14a of the front roll 14 by flowing a cooling medium, for example, cooling water. The heating pipe has a function of heating the outer peripheral surface 14a of the front roll 14 by flowing a heating medium, for example, steam. With the cooling pipe and the heating pipe, the temperature of the outer peripheral surface 14a of the front roll 14 can be adjusted.

  The back roll 16 has a cylindrical shape. The back roll 16 is supported by a support (not shown). The back roll 16 is rotatably supported around its axis as a rotation axis. The rotation speed of the back roll 16 is measured on the outer peripheral surface 16a of the back roll 16. Although not shown, cooling pipes and heating pipes are provided inside the back roll 16, similarly to the front roll 14. The temperature of the outer peripheral surface 16a of the back roll 16 can be adjusted by the cooling pipe and the heating pipe.

  A double arrow C in FIG. 1 indicates an interval (nip gauge) formed between the front roll 14 and the back roll 16. The front roll 14 and the back roll 16 are arranged with an interval C therebetween. This interval C is measured as the shortest distance between the outer peripheral surface 14a of the front roll 14 and the outer peripheral surface 16a of the back roll 16. The support supports the front roll 14 and the back roll 16 such that the distance C can be changed.

  The temperature sensor 6 has a function of measuring the temperature of the rubber sheet 12. The temperature sensor 6 has a function of transmitting temperature data obtained by measurement to the control device 8. The temperature sensor 6 is disposed at a position where the temperature of the rubber sheet 12 formed by the heating roll 4 is measured. Here, a non-contact type temperature sensor will be described as an example of the temperature sensor 6, but it is sufficient that the temperature of the rubber sheet 12 can be measured. As the temperature sensor 6, a contact-type temperature sensor may be used.

  The control device 8 stores in advance the range of the set temperature of the rubber sheet 12, for example, the upper limit temperature and the lower limit temperature. The control device 8 has a function of controlling the flow rates of the cooling water and the steam to adjust the temperature of the outer peripheral surface 14 a of the front roll 14 and the function of adjusting the temperature of the outer peripheral surface 16 a of the back roll 16. The control device 8 has a function of receiving temperature data from the temperature sensor 6. The control device 8 has a function of controlling the driving device of the front roll 14 to adjust the rotation speed of the front roll 14. The control device 8 has a function of controlling the driving device of the back roll 16 to adjust the rotation speed of the back roll 16. The control device 8 has a function of adjusting the rotation speed of the front roll 14 and the rotation speed of the back roll 16 and adjusting the rotation ratio of both. The control device 8 has a function of controlling the support table and adjusting the distance C between the front roll 14 and the back roll 16.

  The control device 8 has a function of determining whether or not the temperature data received from the stored set temperature is appropriate. The controller 8 has a function of adjusting the rotation speed of the front roll 14 and the rotation speed of the back roll 16 in order to make the temperature data appropriate. The control device 8 has a function of adjusting the interval C between the front roll 14 and the back roll 16 based on the rotation speed of the front roll 14 and the rotation speed of the back roll 16. Thus, the control device 8 has a function of adjusting the heating condition of the rubber material 10.

  A method of manufacturing a tire member formed from the rubber material 10 using the warming device 2 will be described. The manufacturing method includes a preparation step, a heating step, and an extrusion step. The heating step described in this manufacturing method is an example of the heating method according to the present invention.

  In the preparation step, the rubber material 10 is prepared. The control device 8 stores a plurality of rubber materials including the rubber material 10 in which the blending information is specified, in advance. The operator selects the rubber material 10 from the plurality of rubber materials and inputs the selected rubber material 10 to the control device 8. The control device 8 stores the initial heating condition of the rubber material 10. The controller 8 adjusts the outer peripheral surface 14a of the front roll 14 and the outer peripheral surface 16a of the back roll 16 to a predetermined temperature in accordance with the initial heating condition. The control device 8 adjusts the rotation ratio and the gap C of the heating roll 4 according to predetermined conditions.

  In the warming step, the rubber material 10 is charged into the warming roll 4. The rubber material 10 is wound around the outer peripheral surface 14a of the front roll 14. The rubber material 10 is sent toward the discharge port by the front roll 14. The rubber material 10 wound around the outer peripheral surface 14a is passed through a gap C formed by the front roll 14 and the back roll 16. By passing through the gap C, the rubber material 10 is kneaded by the front roll 14 and the back roll 16. By being kneaded, a shear force acts on the rubber material 10. By this shearing force, the rubber material 10 is heated including its inside. The rubber material 10 is heated or cooled by the outer peripheral surface 14a and the outer peripheral surface 16a. The rubber sheet 12 formed by heating the rubber material 10 is discharged from an outlet of the heating roll 4.

  The warming step includes a temperature measuring step of measuring the temperature of the rubber sheet 12, and a rotation ratio adjusting step of adjusting the rotation ratio of the heating roll 4 based on the temperature of the rubber sheet 12.

  In this temperature measurement step, the temperature sensor 6 measures the temperature of the rubber sheet 12 discharged from the heating roll 4. The measured temperature data is transmitted from the temperature sensor 6 to the control device 8. The control device 8 receives temperature data from the temperature sensor 6.

  In this rotation ratio adjustment step, the control device 8 determines whether or not the received temperature data is within the set temperature range of the rubber sheet 12. When the temperature data is in the range of the set temperature of the rubber sheet 12, the control device 8 determines the rotation speed of the front roll 14, the temperature of the outer peripheral surface 14a, the rotation speed of the back roll 16, and the temperature of the outer peripheral surface 16a. , As it is.

  In this rotation ratio adjustment step, the control device 8 increases or decreases the rotation speed of the back roll 16 when the temperature data is not within the range of the set temperature of the rubber sheet 12. Thereby, the rotation ratio between the front roll 14 and the back roll 16 is changed. By changing the rotation ratio, the shearing force that the rubber material 10 receives from the heating roll 4 is adjusted. By adjusting the shearing force, the temperature of the rubber sheet 12 is increased or decreased. Thus, the temperature of the rubber sheet 12 is adjusted.

  In this rotation ratio adjustment step, the control device 8 adjusts the interval C between the front roll 14 and the back roll 16. For example, when the rotation speed of the back roll 16 is increased, the interval C is reduced. When the rotation speed of the back roll 16 is reduced, the interval C is increased. Thus, when the rotation ratio between the front roll 14 and the back roll 16 is changed, the interval C is adjusted. Thereby, the discharge amount of the rubber sheet 12 per unit time is stabilized.

  In the extrusion step, the rubber sheet 12 is put into an extruder (not shown). The injected rubber sheet 12 is extruded into a predetermined shape. The rubber sheet 12 is formed into a shape of a tire member. The rubber sheet 12 is formed into, for example, a tread member forming a tread, a sidewall member forming a sidewall, and the like. This rubber sheet 12 may be formed into a tire member by a roll instead of an extruder.

  This heating step includes a temperature measurement step and a rotation ratio adjustment step. The temperature is adjusted including the inside of the rubber material 10. This heating step can make the temperature of the rubber material 10 more uniform.

  In the rotation ratio adjusting step of the heating method, the rotation ratio between the front roll 14 and the back roll 16 is adjusted and the interval C is adjusted, but the interval C is not necessarily adjusted. In this warming method, the temperature of the rubber material can be made more uniform by adjusting the rotation ratio described above.

  In this method, the front roll 14 adjusts the temperature of the rubber material 10. By adjusting the temperature by heating or cooling the front roll 14 in addition to the temperature adjustment by adjusting the rotation ratio described above, the temperature can be adjusted in a short time. Further, by adjusting the temperature of the rubber material 10 by heating or cooling the back roll 16, the temperature can be adjusted in a shorter time.

  In this rotation ratio adjustment step, the interval C between the heating rolls 4 is adjusted. Thereby, the discharge amount of the rubber sheet 12, which changes with the adjustment of the rotation ratio, is adjusted. In this method, not only the temperature but also the discharge amount of the rubber material 10 is made uniform.

  In this rotation ratio adjustment, the rotation ratio is adjusted by increasing or decreasing the rotation speed of the back roll 16. The rotation speed of the front roll 14 around which the rubber material 10 is wound is kept constant. This suppresses a large change in the discharge amount of the rubber sheet 12 due to the adjustment of the rotation ratio. Along with the adjustment of the interval C, the discharge amount of the rubber sheet 12 is made uniform. Here, the rotation ratio is adjusted by increasing or decreasing the rotation speed of the back roll 16 while keeping the rotation speed of the front roll 14 constant, but is not limited to this. In adjusting the rotation ratio, the rotation speed of the front roll 14 and the rotation speed of the back roll 16 may both be increased or decreased, or the rotation speed of the front roll 14 may be increased or decreased to keep the rotation speed of the back roll 16 constant. Is also good.

  In this heating method, the temperature of the rubber material 10 is adjusted by adjusting the rotation ratio between the front roll 14 and the back roll 16. This heating step can reduce the temperature difference between the surface and the inside of the rubber sheet 12 as compared with the conventional heating step. Since the temperature difference between the surface and the inside of the rubber sheet 12 is small in this heating step, the temperature of the rubber sheet 12 can be grasped with high accuracy by measuring the temperature of the surface of the rubber sheet 12.

  In this heating method, heating is performed by one heating device 2, but heating may be performed by a plurality of heating devices 2. For example, the rubber material 10 may be heated through three heating devices 2.

  Hereinafter, the effects of the present invention will be clarified by examples, but the present invention should not be construed as being limited based on the description of the examples.

[Example 1]
Rubber material was prepared. The rubber material was heated by the manufacturing method according to the present invention using the heating device 2 of FIG. Using the rubber sheet formed from this rubber material, 200 rubber members for tire were extruded.

[Comparative Example 1]
Conventionally, a rubber material was heated by a heating method. In this method, the rotation speed of the heating roll was kept constant. The temperature of the outer peripheral surfaces of the pair of rolls was adjusted, and the rubber material was heated. Using the rubber sheet formed from this rubber material, 200 rubber members for tire were extruded.

[Example 2]
The rubber material was heated in the same manner as in Example 1 except that the interval C was fixed. Using the rubber sheet formed from this rubber material, 200 rubber members for tire were extruded.

[Weight evaluation]
About the rubber member for tires of Example 1, Example 2, and Comparative Example 1, the average mass and the standard deviation of the mass were obtained. The results are shown in Table 1.

[Formability evaluation]
With respect to the rubber members for tires of Example 1, Example 2, and Comparative Example 1, the ease of molding and the quality of molding accuracy were evaluated. The result is shown in Table 1 as an index. This index is evaluated in five steps using Comparative Example 3 as a reference value 3. The larger the index, the better the moldability. The larger the index, the better.

  As shown in Table 1, the manufacturing method of the example has a higher evaluation than the manufacturing method of the comparative example. From the evaluation results, the superiority of the present invention is clear.

  The method described above can be widely applied to warming of rubber members for tires.

2 Heating device 4 Heating roll (a pair of rolls)
6 ... Temperature sensor 8 ... Control device 10 ... Rubber material 12 ... Rubber sheet 14 ... Front roll 16 ... Back roll

Claims (6)

A warming method of forming a rubber sheet by kneading and warming a rubber material for a tire member between a pair of rolls,
A temperature measuring step of measuring the temperature of the rubber sheet,
A rotation ratio adjusting step of adjusting a rotation ratio of the pair of rolls based on a temperature of the rubber sheet.   2. The method according to claim 1, wherein in the rotation ratio adjusting step, an interval between the pair of rolls is adjusted. 3. The pair of rolls, a front roll around which the rubber material is wound, and a back roll kneading the rubber material between the front roll,
3. The method according to claim 1, wherein in the rotation ratio adjusting step, the rotation ratio is adjusted by increasing or decreasing the rotation speed of the back roll. 4. An apparatus for forming a rubber sheet by heating a rubber material used for a tire member,
A pair of rolls between which the rubber material is kneaded,
A temperature sensor for measuring the temperature of the rubber sheet,
And a control device,
The control device,
A function of receiving temperature data of the rubber sheet from the temperature sensor,
A rubber material warming device, comprising: a function of adjusting a rotation ratio of the pair of rolls based on the temperature data.   The warming device according to claim 4, wherein the control device has a function of adjusting an interval between the pair of rolls. The pair of rolls, a front roll around which the rubber material is wound, and a back roll that heats the rubber material between the front roll,
The control device,
The heating device according to claim 4 or 5, further comprising a function of adjusting the rotation ratio by increasing or decreasing the rotation speed of the back roll.

Images