RU2752113C1 - Tire tread and cure plate to form 3d sipe in tire tread block - Google Patents

Abstract

FIELD: automotive industry.

SUBSTANCE: invention relates to the automotive industry, in particular to the design of the tread of pneumatic tires, preferably winter tires with 3D sipes located on the blocks of the tread band of the tire. The tire contains a tread band, which, in turn, is provided with a plurality of grooves, blocks and 3D sipes in the tread blocks. The shape of the slots is defined by two facing surfaces of block parts formed by a lamella of complex shape, which have a similar configuration, so that the recess formed in the second surface corresponds to the protrusion provided on the first surface, and, conversely, the protrusion provided on the second surface, corresponds to the recess provided in the first surface, wherein, the surface has the form of a periodically repeating sinusoidal element in the direction of the tangent plane, and in the radial direction it has the form of a periodically repeating sinusoidal element introduced in the direction of the radial plane, is interrupted in the radial direction at a certain interval and is replaced by a sinusoidal surface formed from the same periodically repeating element shifted by 1/2 period, forming 3D slit-like slots, the angles of which with the radial plane are 55±10°, wherein the sinusoids have the same wavelength from 4 to 8 mm, depending on the configuration of the lamella of a complex shape, and the number of alternating protrusions and recesses that form block sequences can vary in accordance with the longitudinal length of the lamella of a complex shape. The suitably designed vulcanization plate forms, during the molding process, narrow sipes of the desired shape and quantity in the tread blocks on the tread portion of the basic invention.

EFFECT: invention improves tire performance on dry, wet and snowy road surfaces.

6 cl, 5 dwg, 1 tbl

Description

The present inventions relate to the tread design of pneumatic tires, preferably winter tires, in particular to the design of 3D sipes (sipes) located on the blocks of the tread band of the tire and to the design of a device for its formation, namely the design of a vulcanization mold for manufacturing tires, preferably winter tires , in which the plate during the molding process forms narrow sipes of the required shape and in the required amount in the tread blocks on the tread area.

The purpose of the sipes is to provide additional gripping edges on a snow-covered surface and to retain a predetermined amount of snow present on the road surface. However, the presence of sipes in the tread band blocks equally reduces the tire's performance values if the road surface is not covered with snow, but is dry or wet.

It is believed that this decrease in performance values can be explained by the fact that the various parts of the block, separated by lamellas, the advantage of which may be the relative freedom of mutual movement, in particular in the radial direction, cannot provide sufficient resistance to tangential loads (or "shear stress"), communicated to the tread band during acceleration phases, cornering phases or braking phases, resulting in block deformation and a decrease in the contact surface with the road surface.

Many tire manufacturers are trying to optimize the tread design and create tires that are suitable for all of the road surface conditions mentioned above and that balance the design requirements.

This need is even more obvious in those countries where winters are characterized by sporadic or even rare snowfalls. In this case, it is recommended to use winter tires instead of summer tires, because the composition of the polymer materials that make up the tread band is more suitable for harsh winter temperatures, but most of the travel time is spent on roads that are not covered with snow, but, on the contrary, are simply dry or wet.

Known technical solutions for pneumatic passenger tires with metal cord and textile layers in the belt: RU patent No. 2381109 for the invention "Pneumatic tire" publ. 02/10/2010, patent RU No. 142966 for a useful model "Winter tire" publ. 10.07.2014, patent RU No. 2589531 for the invention "Pneumatic tire protector" publ. 10.07.2016.

Recently, various manufacturers are beginning to use profiled sipes to achieve increased rigidity in all directions and uniform distribution of deformation in the tread block. This leads to at least minimal deformation during the transfer of force, an increase in the speed of reaction to the driver's initiative and an increase in the safety of traffic on the roads. The following embodiments of lockable sipes are known.

Known patents EP 3573849 (A1), publ. 04.12.2019, EP 1223054 A1, publ. 01/12/2001, EP 0131246 from Continental, publ. 01/16/1985, W0 9948707 by Goodyear, publ. 09/30/1999, patent RU No. 2388620 for the invention "Tire tread and plate for fixing in a vulcanization mold to form a slotted slot in the tire tread block" publ. 05/10/2010, patent RU No. 2388619 for the invention "Tire tread and plate for fixing in a vulcanization mold to form a slotted slot in the tire tread block" publ. 05/10/2010, with three-dimensional slits and devices for vulcanizing molds for their formation.

The closest analogue to the developed solution is a technical solution according to patent No. 2388619 "Tire tread and plate for fixing in a vulcanization mold to form a slotted slot in the tire tread block", publ. 05/10/2010, including a tire tread containing at least one row of blocks located in the circumferential direction of the tire. In this case, at least one of the blocks is provided with one or more profiled three-dimensional sipes in the radial direction. Moreover, the profiled three-dimensional slot-like slot is limited by mutually matching profiled surfaces formed by the plate during vulcanization. The sipe is in the form of a periodically repeating element introduced into the surface in the direction of the radial plane, and this surface is interrupted at least once in the radial direction at a certain interval and is replaced by a surface formed from the same periodically repeating element displaced by 1/2 period. The periodically repeating element consists of lateral sides connected by arcs, which, when inserted into the surface, will form parts of the lateral surface of the cylinder. The surfaces formed at the interruptions form angles with the radial plane of the sipe which range from 75 to 90 °. As a result, the contact efficiency of the tire with the road surface is improved.

The second invention under the patent RU No. 2388619 is a plate for fixing in a vulcanization mold to form a sipe in the tread block, which forms a sipe in the tire tread block. The plate is formed by introducing a periodically repeating element into the surface, while the specified element consists of 2 pairs of lateral sides connected by two arcs oriented opposite each other and offset relative to each other on the axis through which the radial plane passes, and in the radial direction the surface is at least at least once it is interrupted at a certain interval and is replaced by a surface formed by the same periodically repeating element, displaced by 1/2 period, and the surfaces formed at the points of interruption form angles α2 with the radial plane of the sipe, which range from 75 to 90 ° ...

The disadvantage of these solutions is the insufficient resistance to tangential loads (or "shear stress") imparted to the tread band during acceleration phases, cornering phases or braking phases. These patents do not disclose all variants of the designs of the sipes (sipes) located on the blocks of the tread band of the tire, and the designs of the device for its formation.

The lamellas in the tire tread blocks are formed by plates located and firmly fixed in the tread part of the vulcanization mold cavity. Plates are made by forming sheet metal with the required properties (corrosion resistance, strength, etc.), possibly using 3D printing technologies. They are oriented radially relative to the axis of rotation of the tire. The plates correspond to the depth of the tread grooves, depending on the requirements for the tread. When viewed in the radial direction, the shape of the plate can consist of known lines (arcs, straight line, parabola, etc.) and form a specific pattern (for example, sinusoid, zigzag, etc.). The size and shape of the vulcanized plates and thus also the sipes in the tread of the tires formed by them are determined by the design and size of the tread blocks.

It was found that the presence of complex shaped sipes on the blocks increases their rigidity and resistance to tangential loads, increasing the values of the tire performance on dry and wet surfaces as during the acceleration phases, cornering phases or braking phases. In this case, the rigidity of the block increases with an increase in the interfering effect between the parts of the block due to the increase in the size and number of protrusions made respectively on the surfaces. It should be noted that when using sipes of complex shape for the formation of 3D sipes in the tire tread block, which provide a high level of interfering effect between adjacent parts of the block, it leads to an increase in production difficulties, since the difficulty of removing the tire from the mold increases, as well as the appearance of part breaks. blocks in the area of the protrusions.

The objective of the first invention is to develop a tread structure for pneumatic tires, preferably winter tires, in particular the design of 3D sipes (sipes) located on the blocks of the tread band of the tire, which is suitable for the use of tires in all conditions of the road surface (snowy, dry, wet), and in which the requirements for the design are balanced, the sipes on the blocks of the tread bracelet are optimized in accordance with the needs of operation, the technological characteristics when removing tires from the molds are improved, the arsenal of technical means is expanded.

The objective of the second invention is to develop a device for its formation, namely the design of a vulcanization mold for the manufacture of tires, preferably winter tires, in which the plate during the molding process forms narrow sipes of the required shape and in the required amount in the tread blocks on the tread area, forming sipes in the blocks of the tread band of tires according to the first invention with improved technological characteristics when removing tires from molds, the arsenal of technical means has been expanded.

Thus, in order to increase the amount of interconnection between adjacent block parts without complicating the production step of removing the tire from the mold, it is necessary to improve the configuration of the protrusions and recesses, increasing their ability to withstand radial loads without increasing the interfering effect of the surface between the block parts.

To achieve this task, a tire tread has been developed containing at least one row of blocks located in the circumferential direction of the tire, while at least one of the blocks is equipped with one or more profiled three-dimensional sipes in the radial direction, and the profiled sipes the slot is bounded by two mutually matching profiled surfaces - the sides of the slot formed by the plate during vulcanization, characterized in that each side of the three-dimensional slot has the form of a periodically repeating sinusoidal element in the direction of the tangent plane, and in the direction of the radial plane has the form of a periodically repeating sinusoidal element introduced in the direction of the radial plane, is interrupted in the radial direction at a certain interval and is replaced by a sinusoidal surface formed from the same periodically repeating element displaced by 1/2 ne period, forming 3D slit slots, the angles of which with the radial plane are 55 ± 10 °, and the sinusoids have the same wavelength, in particular from 4 mm to 8 mm, depending on the configuration of the lamella of complex shape, and the number of alternating protrusions and depressions that form block sequences, depending on the longitudinal extent of the three-dimensional slits. In a particular case, at least one element of the three-dimensional sipe may have a flat lateral plane.

The presence of sinusoidal elements on the sides of the three-dimensional sipe, displaced in the three-dimensional sipe in the direction of the radial plane, increases the rigidity of the block elements, making it possible to limit the deformation of the tread blocks when they are subjected to tangential loads, for example, in the case of acceleration, braking or turns on dry or wet, but capable of providing optimum tire performance on snowy surfaces.

To implement the created invention of a tire tread with one or more profiled three-dimensional sipes (3D sipes), it was required to create a second invention - a plate for fixing in a vulcanization mold to form a 3D sipe in the tire tread block.

A plate has been developed for fixing in a vulcanization mold for the formation of a 3D sipe in the tire tread block, characterized in that it has the form of a periodically repeating sinusoidal element in the direction of the tangent plane, and in the direction of the radial plane it has the form of a periodically repeating sinusoidal element introduced in the direction of the radial plane , is interrupted in the radial direction at a certain interval and is replaced by a sinusoidal surface formed from the same periodically repeating element, displaced by 1/2 period, forming 3D slit-like slots, the angles of which with the radial plane are 55 ± 10 °, and the sinusoids have the same length waves, in particular from 4 mm to 8 mm, depending on the configuration of a lamella of complex shape, and the number of alternating protrusions and depressions that form block sequences depends on the longitudinal extent of the three-dimensional lamellae.

These inventions are linked by a single creative concept. The main invention for solving the technical problem is the design of the tread with 3D sipes, and the plate for fixing in the vulcanization mold to form a 3D sipe in the tire tread block is intended for manufacturing, obtaining the main invention.

A lamella of complex shape 1, forming 3D sipes in the tread block 2 (Fig. 1), which, in turn, allow limiting the deformation of the tread blocks when they are subjected to tangential loads, as in the case of acceleration, braking or turns on a dry or wet surface but capable of providing optimum performance on snowy surfaces. Thus, the two facing surfaces 3 of the block parts defined by a lamella of complex shape have a similar configuration, so that the recess formed in the second surface corresponds to the protrusion provided on the first surface, and vice versa, the protrusion provided on the second surface, corresponds to the recess provided in the first surface, wherein the surface 4 has the form of a periodically repeating sinusoidal element in the direction of the tangent plane, the form of a periodically repeating sinusoidal element in the direction of the tangent plane, and in the direction of the radial plane has the form of a periodically repeating sinusoidal element 6 introduced in the direction of the radial plane , is interrupted in the radial direction at a certain interval and is replaced by a sinusoidal surface formed from the same periodically repeating element 7, displaced by 1/2 period, forming 3D slit-like slots, the angles of which with p the adial plane a is 55 ± 10 °, and the sinusoids have the same wavelength b, in particular from 4 mm to 8 mm, depending on the configuration of the lamella of a complex shape, and the number of alternating protrusions and depressions that form block sequences depends on the longitudinal length three-dimensional slits. In a particular case, at least one lamella element can have a flat lateral plane.

List of drawings explaining the concept of the created inventions:

FIG. 1. 3D slot in the tire tread block (layered disclosure). General form.

FIG. 2. A plate for fixing a complex three-dimensional shape in a vulcanization mold. General form.

FIG. 3. Simple sipe in the tire tread block. General form.

FIG. 4. Plate for fixing in a vulcanizing mold of simple shape. General form.

FIG. 5. A plate forming a three-dimensional slit in the tire tread block, according to the patent RU 2 388 619 C1 (the closest analogue).

The possibility of achieving a technical result by each invention during its implementation is shown by the following examples of implementation.

Were made and conducted comparative tests of prototype tires 255 / 55R20, using 3D sipes of the above-described complex shape according to the present invention (Fig. 1), formed using the second invention of a plate for fixing in a vulcanization mold for their formation in the tire tread block (Fig. 2 ) and testing of 255 / 55R20 tires, using serial designs of sipes of a simple configuration, the shape of sipes in the tread blocks, namely the same shape in the direction of the tangent plane and a flat, without protrusions, surface in the direction of the radial plane (Fig. 3, 4) ... Traction tests were carried out, in particular braking tests and driving behavior tests on various road surfaces (snowy, wet and dry), prototype and test tires. Experimental tires were manufactured with a design completely similar in terms of dimensions, polymer composition and tread pattern in comparison with prototype tires, but differed in the shape of the sipes, using known technologies for molding and vulcanizing tires with the same parameters in the vulcanization forms of known former cure-vulcanizers. The plate for curing in a mold to form a sipe in the tread block of the tire was made using 3D printing technology.

Compared tires were manufactured in 2 versions: with the length of the sinusoidal elements in the direction of the radial plane, they have the same wavelength of 4 and 8 mm, all other things being equal. For them, similar results were obtained.

The developed solutions can be applied to other standard sizes of tires. For practical reasons, all tire sizes have not been manufactured.

Comparative tests of prototype tires made with a design completely similar in terms of dimensions, polymer composition and tread pattern, using the proposed design of a sipe of complex 3D shape for adhesion to the road, in particular, braking tests and tests for behavior when driving on different road surfaces (snow-covered , wet and dry), in comparison with serial designs of sipes, having a simple form of sipes in the tread blocks, are shown in Table 1.

Thus, the proposed design of the sipes (Fig. 1) and the proposed design of the plate for fixing in a vulcanization mold for their formation in the tire tread block (Fig. 2) improve the performance of tires produced according to the present inventions in comparison with tires having sipes simple shape (Fig. 3) and plate structures for fixing in a vulcanization mold for their formation in the tire tread block (Fig. 4), all other things being equal unchanged parameters of tires and vulcanization molds.

Experimental tires according to the present invention, after vulcanization, were smoothly removed from the molds without deformations and breaks of the sipes in the blocks of the tread bracelet.

The inventions are united by a common creative concept, have an inventive step, are implemented in aggregate and achieve a common result for the created group of inventions: a set of improved technological characteristics of tires when they are removed from molds and performance characteristics of tires in conditions of wet and dry road surfaces, performance characteristics on snow-covered road surfaces, expanding the arsenal of technical means.

Claims (6)

1. A tire tread containing at least one row of blocks located in the circumferential direction of the tire, wherein at least one of the blocks is provided with one or more profiled three-dimensional sipes in the radial direction, and the profiled sipe is delimited by two mutually matching profiled surfaces - the sides of the sipe formed by the plate during vulcanization, characterized in that each side of the three-dimensional sipe has the form of a periodically repeating sinusoidal element in the direction of the tangential plane, and in the direction of the radial plane has the form of a periodically repeating sinusoidal element introduced in the direction of the radial plane, is interrupted in radial direction at a certain interval and is replaced by a sinusoidal surface formed from the same periodically repeating element, displaced by 1/2 period, forming 3D slot-like slots, the corners of which with a radial plane are 55 ± 10 °, and the sinusoids have the same wavelength, depending on the configuration of the lamella of a complex shape, and the number of alternating protrusions and depressions that form block sequences depends on the longitudinal extent of three-dimensional slits. 2. A tire tread according to claim 1, characterized in that the sinusoids in the direction of the radial plane have the same wavelength from 4 to 8 mm. 3. A tire tread according to claim. 1, characterized in that at least one element of the three-dimensional sipe has a flat side plane. 4. Plate for fixing in a vulcanization mold to form a sipe in the tire tread block according to any one of paragraphs. 1-3, characterized in that it has the form of a periodically repeating sinusoidal element in the direction of the tangent plane, and in the direction of the radial plane has the form of a periodically repeating sinusoidal element introduced in the direction of the radial plane, is interrupted in the radial direction at a certain interval and is replaced by a sinusoidal surface, formed from the same periodically repeating element, displaced by 1/2 period, forming 3D slit slots, the angles of which with the radial plane are 55 ± 10 °, and the sinusoids have the same wavelength depending on the configuration of the lamella of complex shape, and the number of alternating protrusions and the depressions that form block sequences depend on the longitudinal extent of the three-dimensional lamellas. 5. The plate according to claim 4, characterized in that the sinusoids in the direction of the radial plane have the same wavelength from 4 to 8 mm. 6. A plate according to claim. 4, characterized in that at least one lamella element has a flat lateral plane.

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