JP7395947B2 - Rubber strip manufacturing equipment - Google Patents

Description

The present invention relates to a rubber strip manufacturing apparatus.

For example, as a method for forming rubber moldings for tire treads and sidewalls, the strip winding method is used, in which tape-shaped rubber strips are wound spirally around a forming drum to form a rubber molding having a desired shape. Are known. In this method, the rubber strip is formed using a rubber strip manufacturing device.

The rubber strip manufacturing device includes an extruder and a pair of calender rolls. This rubber strip manufacturing apparatus forms a rubber strip by rolling unvulcanized rubber extruded from an extruder between calendar rolls. An example of this rubber strip manufacturing apparatus is disclosed in Patent Document 1 below.

Japanese Patent Application Publication No. 2016-129976

In a rubber strip manufacturing apparatus, a pair of calender rolls rolls rubber while rotating. Therefore, the shape of the rubber strip in the longitudinal direction reflects the surface shape of one calender roll and the surface shape of the other calender roll. As mentioned above, in the strip wind method, a rubber molded body is formed by spirally winding rubber strips on a drum. Since the rubber strip is wound along the circumferential direction of the tire, there is a concern that this rubber strip may affect the uniformity of the tire depending on the relationship between the rotational phase of one calender roll and the rotational phase of the other calender roll. Ru. In order to improve tire uniformity, there is a need to establish a technology that can manufacture strips while taking into account the effect on uniformity.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a rubber strip manufacturing apparatus that can manufacture a rubber strip with suppressed influence on tire uniformity.

A rubber strip manufacturing apparatus according to one aspect of the present invention is an apparatus for manufacturing a rubber strip that is spirally wound around a forming drum to form a rubber molded body. This rubber strip manufacturing apparatus includes a first calender roll and a second calender roll that roll rubber while rotating to form a rubber strip, a prime mover that rotates the first calender roll, and a power source for the first calender roll. and a transmission means for transmitting the information to the second calender roll. The transmission means includes a first gear and a second gear having multiple teeth that mesh with each other. The first gear rotates together with the first calender roll, the second gear is rotated by the first gear, and the second calender roll rotates together with the second gear. The outer diameter of the first calender roll is different from the outer diameter of the second calender roll.

Preferably, in this rubber strip manufacturing apparatus, the outer diameter of the second calender roll is larger than the outer diameter of the first calender roll.

Preferably, in this rubber strip manufacturing apparatus, the ratio of the outer diameter of the second calender roll to the outer diameter of the first calender roll is 103% or more and 112% or less.

Preferably, in this rubber strip manufacturing apparatus, the number of rotations of the first calender roll from when the rotation of the first calender roll synchronizes with the rotation of the second calender roll until the rotation of the first calender roll is synchronized, and the first calender roll. The product with the circumference of the calender roll is larger than the circumference of the forming drum.

According to the rubber strip manufacturing apparatus of the present invention, a rubber strip can be manufactured with less influence on tire uniformity. This rubber strip manufacturing device can contribute to improving tire uniformity.

FIG. 1 is a side view showing the main parts of a rubber strip manufacturing apparatus according to an embodiment of the present invention. FIG. 2 is a front view showing the main parts of the rolling unit.

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

1 and 2 show an example of a rubber strip manufacturing apparatus 2 according to an embodiment of the present invention. This rubber strip manufacturing apparatus 2 (hereinafter referred to as manufacturing apparatus 2) is an apparatus for manufacturing a rubber strip GS used in a strip winding method as a method of forming a rubber molded body.

The rubber strip GS is a band-shaped molded body made of unvulcanized rubber and has a uniform shape. Although not shown, in the strip wind method, the rubber strip GS is spirally wound around a forming drum. As a result, a rubber molded body having a desired shape is formed. The outer diameter of the forming drum around which the rubber strip GS is wound is appropriately determined depending on the size of the tire to be manufactured, and is set within a range of 400 mm or more and 800 mm or less.

Examples of the rubber molded body formed from the rubber strip GS include tire constituent members such as treads and sidewalls.

The unvulcanized rubber is a rubber composition obtained by mixing a base rubber and a chemical using a kneading machine such as a Banbury mixer. This base rubber includes natural rubber (NR), butadiene rubber (BR), styrene butadiene rubber (SBR), isoprene rubber (IR), ethylene propylene rubber (EPDM), chloroprene rubber (CR), and acrylonitrile butadiene rubber (NBR). ) and butyl rubber (IIR). Chemicals include reinforcing agents such as carbon black and silica, plasticizers such as aromatic oils, fillers such as zinc oxide, lubricants such as stearic acid, anti-aging agents, processing aids, sulfur and Examples include vulcanization accelerators. The selection of the base rubber and chemicals, the content of the selected chemicals, etc. are determined as appropriate depending on the specifications of the component to which the rubber is applied.

This manufacturing device 2 includes an extruder 4 and a calender head 6. The extruder 4 forms the unvulcanized rubber G into a belt shape. A calender head 6 is provided at the tip of the extruder 4. This calendar head 6 rolls the rubber G formed into a band shape in the extruder 4 to adjust its shape. In FIG. 1, the rubber G moves from the right side to the left side of the page. In FIG. 1, the right side of the page is the upstream side of the manufacturing apparatus 2, and the left side of the page is the downstream side of the manufacturing apparatus 2.

Extruder 4 has a well-known structure. This extruder 4 includes an extruder main body 8 and an extrusion head 10. The extruder main body 8 includes a screw 12. The extrusion head 10 is attached to the tip of the extruder main body 8. This extrusion head 10 has a die 14 .

In this extruder 4, rubber G is introduced into the extruder main body 8 through a hopper (not shown). By rotating the screw 12, the rubber G is moved toward the base 14. The rubber G that has reached the cap 14 is discharged from a discharge port 16 provided in the cap 14. Thereby, the rubber G is formed into a band shape.

Calendar head 6 includes a pair of calender rolls 18. Each of the pair of calender rolls 18 includes a roll body 20 and a rotating shaft 22. In this calender head 6, a rotating shaft 22 of a calender roll 18 is rotatably supported by side plates 24 arranged on both sides of a roll body 20. Calendar roll 18 rotates around rotating shaft 22 .

In this calender head 6, a pair of calender rolls 18 are arranged in parallel in the vertical direction. Calendar roll 18 located on the lower side (hereinafter referred to as first calender roll 26) and calender roll 18 located on the upper side (hereinafter referred to as second calender roll 28) are parallel to each other.

This calendar head 6 includes a prime mover 30. In this calender head 6, the rotating shaft 22 of the first calender roll 26 and the drive shaft 32 of the prime mover 30 are connected by a transmission means (hereinafter referred to as the first transmission means 34). This first transmission means 34 includes a pair of pulleys 36 and a belt 38 that spans both pulleys 36.

In this calendar head 6, as shown in FIG. 2, a pulley 36 is attached to the rotating shaft 22 of the first calender roll 26 and the drive shaft 32 of the prime mover 30. are connected by a belt 38. Thereby, when the prime mover 30 is driven to rotate the drive shaft 32, the first calender roll 26 is rotated. This prime mover 30 rotates the first calender roll 26.

In this calender head 6, the power of the first calender roll 26 is transmitted to the second calender roll 28 by the transmission means. In other words, this calender head 6 includes a transmission means (hereinafter referred to as second transmission means 40) that transmits the power of the first calender roll 26 to the second calender roll 28.

In this calendar head 6, the second transmission means 40 includes a first gear 42 and a second gear 44. The first gear 42 and the second gear 44 are spur gears. Although not shown, the first gear 42 and the second gear 44 include a large number of teeth that mesh with each other. The first gear 42 is attached to the rotating shaft 22 of the first calender roll 26 , and the second gear 44 is attached to the rotating shaft 22 of the second calender roll 28 . The first gear 42 and the second gear 44 are set on the calendar head 6 so that their respective teeth mesh with each other. The number of teeth provided on the first gear 42 is appropriately set according to the outer diameter of the first calender roll 26 that rotates together with the first gear 42. The number of teeth provided on the second gear 44 is appropriately set according to the outer diameter of the second calender roll 28 that rotates together with the second gear 44.

In this calender head 6, when the first calender roll 26 rotates, the first gear 42 rotates together with the first calender roll 26. The rotation of the first gear 42 causes the second gear 44 to rotate, and the second calender roll 28 rotates together with the second gear 44.

In this calender head 6, a prime mover 30 rotates a first calender roll 26, and this first calender roll 26 rotates a second calender roll 28. In the calender head 6, the first calender roll 26 is a driving roll, and the second calender roll 28 is a passive roll.

Although not shown, in this calender head 6, a gap is provided between the first calender roll 26 and the second calender roll 28. The rubber G extruded from the extruder 4 described above passes through this gap.

Although not shown, the calender head 6 includes position adjusting means for finely adjusting the vertical position of the second calender roll 28 with respect to the first calender roll 26. In this calender head 6, the position adjustment means finely adjusts the position of the second calender roll with respect to the first calender roll 26, so that the size of the gap between the first calender roll 26 and the second calender roll 28 is finely adjusted. be adjusted.

In this calender head 6, the rubber G extruded from the extruder 4 is passed through a gap between a rotating first calender roll 26 and a second calender roll 28, and is rolled. Thereby, the shape of the rubber G formed into a belt shape in the extruder 4 is adjusted, and a rubber strip GS is obtained. In this manufacturing apparatus 2, the first calender roll 26 and the second calender roll 28 rotate while rolling the rubber G formed into a belt shape in the extruder 4 to form a rubber strip GS.

In FIG. 1, a double-headed arrow D1 indicates the outer diameter of the first calender roll 26. The double-headed arrow D2 is the outer diameter of the second calender roll 28. The outer diameter D1 of the first calender roll 26 and the outer diameter D2 of the second calender roll 28 are specified at a position through which the rubber G formed into a band shape passes in the extruder 4. In this calender head 6, the outer diameter D1 of the first calender roll 26 matches the reference circular diameter of the first gear 42. The outer diameter D2 of the second calender roll 28 matches the reference circle diameter of the second gear 44.

In this manufacturing apparatus 2, a first gear 42 rotates together with a first calender roll 26 which is a driving roll, a second gear 44 is rotated by this first gear 42, and a second gear 44 which is a passive roll together with this second gear 44 rotates. Two calendar rolls 28 rotate. In particular, in this manufacturing apparatus 2, the outer diameter D2 of the second calender roll 28, which is a passive roll, is different from the outer diameter D1 of the first calender roll 26, which is a driving roll.

In this manufacturing apparatus 2, the second calender roll 28 rotates once before the first calender roll 26, or the first calender roll 26 rotates once before the second calender roll 28. Since the time from when the rotation of the first calender roll 26 and the rotation of the second calender roll 28 are synchronized until the next synchronization can be secured, the rotation of the first calender roll 26 and the rotation of the second calender roll 28 can be A rubber strip GS is obtained in which the spacing between the synchronization points is longer than the spacing between the synchronization points in a conventional manufacturing device configured such that the first calender roll 26 and the second calender roll 28 have the same outer diameter. According to the rubber strip GS manufactured by this manufacturing apparatus 2, the uniformity of the tire due to the synchronization of the rotation of the first calender roll 26 and the rotation of the second calender roll 28, specifically, the fluctuation of the radial dimension can be improved. The influence on the index radial runout (RRO) is suppressed. This rubber strip manufacturing device 2 can contribute to improving tire uniformity.

In this manufacturing apparatus 2, it is preferable that the outer diameter D2 of the second calender roll 28 is larger than the outer diameter D1 of the first calender roll 26. Since the second calender roll 28, which is a passive roll, rotates behind the first calender roll 26, which is a driving roll, the rubber G passing through the gap between the first calender roll 26 and the second calender roll 28 has an appropriate rotation speed. Shear force acts. With this manufacturing apparatus 2, a rubber strip GS that not only has a long interval between the synchronization points of the rotation of the first calender roll 26 and the rotation of the second calender roll 28 but also has excellent shape stability is obtained. According to the rubber strip GS manufactured by this manufacturing apparatus 2, the influence on tire uniformity can be effectively suppressed. From this point of view, in this manufacturing apparatus 2, the ratio of the outer diameter D2 of the second calender roll 28 to the outer diameter D1 of the first calender roll 26 is more preferably 103% or more. This ratio is more preferably 112% or less, and even more preferably 108% or less.

As described above, the rubber strip GS manufactured by this manufacturing apparatus 2 is wound around a forming drum to form a rubber molded body. In this manufacturing apparatus 2, the number of times the first calender roll 26 rotates from when the rotation of the first calender roll 26 is synchronized with the rotation of the second calender roll 28 until the rotation is next synchronized, and It is preferable that the product of . As a result, the interval between the rotation of the first calender roll 26 synchronizing with the rotation of the second calender roll 28 and the next synchronization increases, and the rotation of the first calender roll 26 and the rotation of the second calender roll 28 increases. A rubber strip GS is obtained that does not contain synchronization points. This rubber strip GS contributes to improving tire uniformity.

In this manufacturing apparatus 2, the outer diameter D1 of the first calender roll 26, which is a driving roll, is the reference outer diameter of the calender roll 18. From the viewpoint of effectively manufacturing a rubber strip GS that can contribute to improving tire uniformity, the outer diameter D1 of the first calender roll 26 is preferably 75 mm or more, and preferably 95 mm or less.

As mentioned above, each of the first gear 42 and the second gear 44 is provided with a large number of teeth. In this manufacturing apparatus 2, the ratio of the number of teeth provided on the second gear 44 to the number of teeth provided on the first gear 42 is determined from the viewpoint of effectively manufacturing the rubber strip GS that can contribute to improving tire uniformity. is preferably 1.03 or more. This ratio is preferably 1.12 or less, more preferably 1.08 or less.

As explained above, according to the present invention, a rubber strip manufacturing apparatus 2 is obtained that can manufacture a rubber strip GS with suppressed influence on tire uniformity.

The embodiments disclosed herein are illustrative in all respects and are not restrictive. The technical scope of the present invention is not limited to the above-described embodiments, and this technical scope includes all modifications within the range of equivalents to the configurations described in the claims.

Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples.

[Example 1]
A rubber strip for a tread is manufactured using a rubber strip manufacturing apparatus having the basic configuration shown in FIGS. 1 and 2 and the specifications shown in Table 1 below. The outer diameter D1 of the first calender roll is set to 81 mm, and the outer diameter D2 of the second calender roll is set to 84 mm. In this case, the ratio (D2/D1) of the outer diameter D2 of the second calender roll to the outer diameter D1 of the first calender roll is 104%. Note that the tooth profiles of the teeth provided on the first gear and the second gear are regular teeth, and the pressure angles of the first gear and the second gear are 20 degrees. Further, the number of teeth of the first gear is 27, and the number of teeth of the second gear is 28.

In this Example 1, the number of times the first calendar roll rotates from when the rotation of the first calendar roll synchronizes with the rotation of the second calendar roll until the next synchronization, and the circumference of the first calendar roll. The product is 6867 mm, which is shown in the "Synchronization Interval" column of Table 1 below.

[Example 2-3 and Comparative Example 1]
The same rubber strip manufacturing apparatus as in Example 1 was used, except that the outer diameter D2 of the second calender roll and the number of teeth of the second gear were changed, and the ratio (D2/D1) was set as shown in Table 1 below. In this way, rubber strips of Examples 2-3 and Comparative Example 1 are manufactured. The synchronization intervals of Example 2-3 and Comparative Example 1 are as shown in Table 1. The number of teeth of the second gear in Example 2 is 29, the number of teeth of the second gear in Example 3 is 30, and the number of teeth of the second gear in Comparative Example 1 is 27. Comparative Example 1 is a conventional rubber strip manufacturing device.

[Uniformity evaluation]
Regarding tires (size = 195/65R15) whose tread is a rubber molded body formed by winding the rubber strips of Example 1-3 and Comparative Example 1 around a molding drum (outer diameter = 750 mm), JASO C607:2000 " The radial runout (RRO) was measured in accordance with the test conditions of ``Uniformity Test Method for Automotive Tires''. The results are shown in Table 1 below as an index with Comparative Example 1 as 100. It is preferable that the smaller this value is, the smaller the RRO is.

As shown in Table 1, it was expected that the RRO would be lower in the Examples than in the Comparative Examples. From this evaluation result, the superiority of the present invention is clear.

The technique for manufacturing a rubber strip described above can be applied to molding rubber using a pair of calender rolls.

2... Rubber strip manufacturing device 4... Extruder 6... Calender head 8... Extruder main body 10... Extrusion head 12... Screw 14... Mouthpiece 16... Discharge port 18 ... Calendar roll 20... Roll body 22... Rotating shaft 26... First calender roll 28... Second calender roll 30... Prime mover 32... Drive shaft 34... First Transmission means 36... Pulley 38... Belt 40... Second transmission means 42... First gear 44... Second gear

Claims (5)

An apparatus for producing a rubber strip that is spirally wound around a forming drum to form a rubber molded body, the apparatus comprising:
a first calendar roll and a second calendar roll that roll rubber while rotating to form a rubber strip;
a prime mover that rotates the first calender roll;
A transmission means for transmitting the power of the first calender roll to the second calender roll,
The transmission means includes a first gear and a second gear having a large number of teeth that mesh with each other,
The first gear rotates together with the first calender roll, the second gear is rotated by the first gear, and the second calender roll rotates together with the second gear,
The outer diameter of the first calender roll is different from the outer diameter of the second calender roll,
A rubber strip manufacturing apparatus , wherein the outer diameter of the second calender roll is larger than the outer diameter of the first calender roll . The rubber strip manufacturing apparatus according to claim 1 , wherein the ratio of the outer diameter of the second calender roll to the outer diameter of the first calender roll is 103% or more and 112% or less. The product of the number of times the first calendar roll rotates from when the rotation of the first calendar roll synchronizes with the rotation of the second calendar roll until the next synchronization and the circumference of the first calendar roll is: The rubber strip manufacturing apparatus according to claim 3 , wherein the circumferential length of the forming drum is larger than the circumferential length of the forming drum. The rubber strip manufacturing apparatus according to any one of claims 1 to 3, wherein the first calender roll has an outer diameter of 75 mm or more and 95 mm or less. The rubber according to any one of claims 1 to 4, wherein the ratio of the number of teeth provided on the second gear to the number of teeth provided on the first gear is 1.03 or more and 1.12 or less. Strip manufacturing equipment.

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