CN-121989485-A - Method for forming tread rubber

Abstract

The invention provides a tread rubber forming method capable of forming tread rubber with high precision by a non-conductive and conductive rubber belt. The tread rubber forming method includes a 1 st step (S1) of forming a non-conductive layer by winding a 1 st rubber band in a plurality of turns around a cylindrical body, a 2 nd step of forming a conductive layer by winding a 2 nd rubber band around the cylindrical body in parallel with the circumferential direction of the cylindrical body, and a 3 rd step (S3) of forming a non-conductive layer by winding a 1 st rubber band in a plurality of turns around the cylindrical body after the 2 nd step (S2). The 1 st step (S1) and the 3 rd step (S3) include, for each of the plurality of turns, a circumferential winding step of winding the 1 st rubber tape 3/4 th turn or more in parallel with the circumferential direction of the cylindrical body to form a circumferential portion, and a slant winding step of inclining the 1 st rubber tape with respect to the circumferential direction of the cylindrical body and winding the remaining portion to form an inclined portion.

Inventors

• HASHIMOTO HIROTO
• Sakamoto Yachi
• S. Y. Tivtikoy
• T. Saki

Assignees

• 住友橡胶工业株式会社

Dates

Publication Date

20260508

Application Date

20250822

Priority Date

20241108

Claims (10)

1. 1. A method for forming a tread rubber, in which a ring-shaped tread rubber is formed, The tread rubber forming method comprises the following steps: A step 1 of winding a plurality of turns of a1 st rubber tape, which is in a belt shape and is nonconductive, around a cylindrical body to thereby form a nonconductive layer; A step 2 of winding a2 nd rubber tape, which is electrically conductive and is in a strip shape, on the cylindrical body in at least 1 turn in parallel with the circumferential direction of the cylindrical body so as to overlap a part of the 1 st rubber tape, after the step 1, thereby forming an electrically conductive layer, and A 3 rd step of winding the 1 st rubber tape around the cylindrical body in a manner overlapping a part of the 2 nd rubber tape after the 2 nd step, thereby forming a non-conductive layer, The 1 st step and the 3 rd step include the following steps in each of the plurality of turns: A circumferential winding step of winding the 1 st rubber band in parallel with the circumferential direction of the cylindrical body by 3/4 or more turns to form a circumferential portion, and And a tilt winding step of forming a tilt portion by tilting the 1 st rubber tape with respect to the circumferential direction of the cylindrical body and winding the remaining portion.
2. 2. The tread rubber forming method as recited in claim 1, wherein, In 1 turn, the circumferential winding step is performed for 7/8 or more turns of the cylindrical body.
3. 3. The tread rubber forming method as recited in claim 1, wherein, The circumferential portion wound in the 1 st step and the circumferential portion wound in the 3 rd step are arranged in the same phase in the rotation direction of the cylindrical body.
4. 4. The tread rubber forming method as recited in claim 3, wherein, The inclined portion wound in the 1 st step and the inclined portion wound in the 3 rd step are inclined in opposite directions to each other.
5. 5. The tread rubber forming method as recited in claim 3, wherein, The inclined portion wound in the 1 st step and the inclined portion wound in the 3 rd step are inclined in the same direction as each other.
6. 6. The tread rubber forming method as recited in claim 1, wherein, The winding start position or the winding end position of the 1 st rubber belt and the circumferential end edge of the inclined portion are arranged in the same phase in the rotation direction of the cylinder.
7. 7. The tread rubber forming method according to any one of claims 1 to 6, wherein, The non-conductive layer contains a base layer in which the proportion of carbon in the rubber reinforcing agent is 10 mass% or less.
8. 8. The tread rubber forming method as recited in claim 7, wherein, The non-conductive layer comprises a top layer that is wound overlapping radially outward of the base layer.
9. 9. The tread rubber forming method as recited in claim 8, wherein, The circumferential portion of the base layer and the circumferential portion of the top layer are arranged in the same phase in the rotation direction of the cylinder.
10. 10. The tread rubber forming method as recited in claim 9, wherein, The inclined portion of the base layer and the inclined portion of the top layer are inclined in opposite directions to each other.

Description

Method for forming tread rubber Technical Field The present invention relates to a method of forming an annular tread rubber. Background Conventionally, a method of forming a tread rubber by winding a nonconductive rubber belt and a conductive rubber belt around a cylindrical body is known (for example, refer to patent document 1). Patent document 1 Japanese patent application laid-open No. 2021-130222 In the tread rubber forming method of patent document 1, the nonconductive rubber belt is formed into a nonconductive layer by being wound in a spiral shape, that is, obliquely with respect to the circumferential direction of the cylindrical body. Tread rubber is typically designed with a profile that varies in thickness in the axial direction of the tire, in conformity with the distribution of the rubber volume of the finished tire. The tread rubber having such a profile is formed by adjusting the moving speed (feed amount) of the rubber belt with respect to the axial direction of the rotating cylinder. However, it is generally difficult to lap-wind the rubber belt with high accuracy in order to fit the design profile of the tread rubber, and it is necessary to conduct researches such as (1) rotating the cylindrical body at a low speed and (2) bringing the applicator of the rubber belt as close as possible to the cylindrical body. In addition, a conductive rubber called a ground contact pen for discharging static electricity (electric charge) charged in the vehicle is partially formed in the tread rubber. In the case where the conductive rubber belt is wound so as to fit the design profile of the tread rubber in addition to the nonconductive rubber belt, the elements to be studied are increased and control is complicated. On the other hand, in order to perform sufficient discharge, it is necessary to expose the ground pen on the tread surface. Therefore, the winding position of the conductive rubber is set so that the exposed portion of the ground contact pen on the tread surface does not coincide with the position of the circumferential groove. However, in the method described in patent document 1, since the grounding pen is formed obliquely to the circumferential direction in a relationship in which the conductive rubber tape is wound in a spiral shape, it is difficult to adjust the positional relationship between the grounding pen and the circumferential groove. Disclosure of Invention The present invention has been made in view of the above circumstances, and a main object thereof is to provide a tread rubber forming method capable of forming a tread rubber with high accuracy from a nonconductive and conductive rubber belt. A method for forming a tread rubber having a ring shape, comprising a1 st step of winding a1 st rubber band which is a multi-turn band and is nonconductive, around a cylindrical body, thereby forming a nonconductive layer, a2 nd step of winding a2 nd rubber band which is a band-like band and is conductive, around the cylindrical body, in parallel with the circumferential direction of the cylindrical body, in such a manner as to overlap a part of the 1 st rubber band, after the 1 st step, thereby forming a conductive layer, and a3 rd step of winding a1 st rubber band, around the cylindrical body, in such a manner as to overlap a part of the 2 nd rubber band, thereby forming a nonconductive layer, wherein the 1 st step and the 3 rd steps comprise a circumferential winding step of winding the 1 st rubber band, in parallel with the circumferential direction of the cylindrical body, by 3/4 turns or more, thereby forming a circumferential portion, and a diagonal winding step of winding the 1 st rubber band, in such a manner as to overlap the remaining circumferential direction, thereby forming a diagonal portion. The tread rubber forming method of the present invention has the above-described structure, and therefore, the tread rubber can be formed with high accuracy from the nonconductive and conductive rubber belt. Drawings Fig. 1 is a cross-sectional view showing an example of tread rubber formed by the tread rubber forming method of the present invention. Fig. 2 is a schematic perspective view showing a tread rubber forming method according to an embodiment of the present invention. Fig. 3 is a flowchart showing steps of the tread rubber forming method of fig. 2. Fig. 4 is a perspective view showing the 1 st step of fig. 3. Fig. 5 is a perspective view showing the 2 nd step of fig. 3. Fig. 6 is a perspective view illustrating the 3 rd step of fig. 3. Fig. 7 is an expanded view schematically showing the tread rubber formed in step 1. Fig. 8 is an expanded view schematically showing the tread rubber formed in step 2 next to fig. 7. Fig. 9 is an expanded view schematically showing the tread rubber formed in step 3 next to fig. 8. Fig. 10 is an expanded view schematically showing a modification of the tread rubber of fig. 9. Fig. 11 is a cross-sectional view showing a modification of the tr