JP7116659B2 - tire - Google Patents

Description

An embodiment of the present invention relates to a tire having studs attached to the tread portion.

Studded tires (also referred to as spiked tires) are known as tires that improve running performance on icy and snowy roads.

The studs are mounted in mounting holes provided in the tread portion. The mounting holes are formed by mounting hole forming projections provided on a vulcanization mold during vulcanization molding of the tire. Conventionally, in order to prevent the stud from slipping out of the mounting hole when the tire is running, a bulging portion is provided at the bottom of the mounting hole, and a flange portion that fits into the bulging portion is provided at the lower end of the stud (see Patent Document 1). . However, in order to provide a bulging portion at the bottom of the mounting hole, it is necessary to provide a corresponding bulging shape on the projection for molding the mounting hole. The pot removal resistance) becomes large, and the demoldability is impaired. Thus, it is difficult to achieve both the prevention of the stud from falling off and the releasability of the mold.

In addition, in Patent Documents 2 and 3, a retracting mechanism is embedded in the tread portion in order to allow the stud to retract from the tread surface. It is described that the stud is axially movable by means of a threaded engagement. However, in the techniques described in these documents, a cavity exists below the stud when the stud protrudes from the tread surface. Due to this cavity, the stud becomes unstable when the tire is running, and the stud is buried inside the tread surface due to the ground pressure, which may impair the original performance of the stud.

JP 2017-074924 A JP-A-03-007607 JP-A-11-198613

An object of an embodiment of the present invention is to provide a tire that achieves both good releasability during tire vulcanization molding and good stud drop-off prevention.

A tire according to an embodiment of the present invention includes a stud having a columnar body, a stud provided at the upper end of the body and contacting a road surface, and a tread portion having a columnar inner peripheral surface to which the stud is attached. and a fixing member for fixing the stud to the mounting hole, the fixing member having a tubular shape to be fitted into the mounting hole, and having an internal thread portion on the inner peripheral surface thereof, which is fixed to the mounting hole by an adhesive. and a fixed fixing member. The stud has a male threaded portion on the outer peripheral surface of the body, and when the male threaded portion is screwed into the female threaded portion, the stud protrudes from the tread surface and the stud is formed in a state where there is no cavity below the body. Fixed.

According to this embodiment, since the tread portion is provided with the mounting hole having the cylindrical inner peripheral surface and the fixing member is fixed to the mounting hole with an adhesive, there is no need to provide the bulging portion at the bottom of the mounting hole. Therefore, it is possible to reduce the resistance to coming out of the cauldron at the time of vulcanization molding of the tire, and to improve the releasability. In addition, the stud is fastened and fixed to the mounting hole through the fixing member by screwing the female thread provided on the inner peripheral surface of the fixing member and the male thread provided on the outer peripheral surface of the body of the stud. It can be made difficult to fall off. In addition, when the stud is fixed in the mounting hole, the convex portion of the stud protrudes from the tread surface and there is no cavity below the stud, so the stud is stabilized while the tire is running, and its function can be exhibited. .

Half sectional view of a tire according to one embodiment A diagram showing a tread pattern of a tire according to one embodiment. (A) Sectional view of fixing member according to one embodiment, (B) Sectional view of mounting hole Side view of mounting hole molding projection according to one embodiment (A) Side view of stud according to one embodiment, (B) Cross-sectional view of mounting hole with fixing member A cross-sectional view of a mounting hole fitted with a stud according to one embodiment. Cross-sectional view of a fixing member according to another embodiment Cross-sectional view of mounting holes fitted with studs according to another embodiment

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings.

As shown in FIG. 1 , the tire 10 according to one embodiment is a pneumatic tire, and is a studded tire in which a stud 40 is attached to the tread portion 12 . The tire 10 includes a tread portion 12 , a pair of left and right bead portions 14 , and a pair of left and right sidewall portions 16 interposed between the tread portion 12 and the bead portions 14 . In the figure, the symbol CL indicates the tire equatorial plane corresponding to the axial center of the tire.

The tire 10 includes a carcass layer 18 that straddles the pair of bead portions 14 and extends in a toroidal shape. In the tread portion 12 , a belt layer 20 is provided radially outward of the carcass layer 18 , and a tread rubber 22 is laminated radially outward of the belt layer 20 . The tread rubber 22 has a two-layer structure consisting of a cap rubber layer 26 having a tread surface 24 that contacts the road surface, and a base rubber layer 28 arranged radially inside the cap rubber layer 26 . The tread surface 24 is an outer peripheral surface of the tread portion 12 that forms a contact surface. A general tire structure can be adopted for parts other than the tread portion 12 .

As shown in FIG. 2, the tread portion 12 is provided with main grooves 30 extending in the tire circumferential direction and lateral grooves 32 extending in a direction intersecting the main grooves 30, and a plurality of land portions 34 such as blocks and ribs are defined. formed. A plurality of sipes 36 are provided in the land portion 34 .

As shown in FIGS. 1 and 2, the land portion 34 of the tread portion 12 is provided with a plurality of mounting holes 38, each mounting hole 38 having a stud 40 mounted thereon.

As shown in FIG. 5A, the stud 40 includes a columnar body 42 and a projection 44 provided at the upper end, which is one end in the axial direction, of the body 42 and coming into contact with the road surface. The stud 40 is made of metal, for example. Here, the upper end of the body 42 is the end located on the tread surface 24 side when attached to the tire (that is, the end on the outer side in the tire radial direction). Unless otherwise specified, terms such as upper, upper, upper, lower end, lower, lower, and lower also mean the upper and lower relationships in the tire, and the outer side in the tire radial direction is the upper side. Radially inward is expressed as downward.

The body 42 is a portion that is fitted into the mounting hole 38, and is mounted in the mounting hole 38 from the other end side in the axial direction, that is, from the lower end side. Although the body 42 has a columnar shape in this example, it may have a prismatic shape such as a quadrangular prism shape or a hexagonal prism shape. The size of the body 42 is not particularly limited, and may have a diameter of 5.0 to 7.0 mm, for example.

An outer peripheral surface of the body 42 is provided with a male threaded portion 46 having a spiral groove. The male threaded portion 46 is provided in the lower portion of the body 42 in this example. It is formed in a columnar portion (in this example, a columnar portion) 47 with a constant cross section. The lower end of the stud 40 is not provided with a bulging portion such as a flange extending in the direction perpendicular to the axis to prevent it from coming off.

The convex portion 44 protrudes in the axial direction from the upper end surface, which is one axial end surface of the body 42, and as shown in FIG. and is also called a stud core. The convex portion 44 is formed to have a smaller outer shape than the body 42 in this example. The shape of the convex portion 44 is not particularly limited, and may be, for example, a columnar shape or a prismatic shape.

The mounting hole 38 has a cylindrical inner peripheral surface 48 to which the stud 40 is mounted, as shown in FIGS. The inner peripheral surface 48 of the mounting hole 38 has a cylindrical surface shape in this example, but may have a prismatic surface shape such as a quadrangular prismatic surface shape or a hexagonal prismatic surface shape. The mounting hole 38 is a hole with a bottom having a constant cross section in the axial direction, and does not have a bulge (a bulge extending in the direction perpendicular to the axis) for retaining at the bottom.

FIG. 4 shows a mounting hole forming projection 50 for molding the mounting hole 38. As shown in FIG. The mounting hole forming projection 50 is provided on a mold portion 51 for molding the tread portion 12 in a tire vulcanization mold. The mounting hole forming projection 50 has a columnar shape (in this example, a columnar shape), has a constant cross section in the axial direction, and has no bulging portion extending in the direction perpendicular to the axis at the tip (lower end) 50A. .

As shown in FIG. 6, the stud 40 is fixed in the mounting hole 38 via the fixing member 52. As shown in FIG. That is, the fixing member 52 is a member for fixing the stud 40 to the mounting hole 38 and has a tubular shape to be fitted into the mounting hole 38 . The fixing member 52 is made of, for example, metal, preferably corrosion-resistant metal such as aluminum (including aluminum alloy) or stainless steel, and more preferably lightweight aluminum.

As shown in FIG. 3, the fixing member 52 has a female screw portion 54 formed of a spiral groove on its inner peripheral surface. The female threaded portion 54 is formed to be screwable with the male threaded portion 46 of the stud 40 . In this example, the female threaded portion 54 is provided along the entire axial direction on the inner peripheral surface of the fixing member 52 . Here, the pitch of the threads and the height of the threads of the male threaded portion 46 and the female threaded portion 54 are not particularly limited, and may be set to general dimensions according to the diameters of the male threaded portion 46 and the female threaded portion 54. can be done. Moreover, the shape of the teeth of the screw is not particularly limited, and examples thereof include a triangular screw, a square screw, a trapezoidal screw, a buttress screw, and a round screw.

As shown in FIG. 3 , the fixing member 52 is inserted into the mounting hole 38 of the tire 10 after being vulcanized and fixed using an adhesive 56 . That is, as shown in FIG. 5A, the outer peripheral surface 58 of the fixing member 52 and the inner peripheral surface 48 of the mounting hole 38 are adhesively fixed via an adhesive 56 . The adhesive 56 is not particularly limited, and if the fixing member 52 is made of metal, an adhesive capable of bonding metal and rubber, for example, a chloroprene rubber adhesive, a modified silicone adhesive, or a special adhesive containing a silyl group. Examples include polymer-based adhesives.

The thickness of the fixing member 52 (thickness of the peripheral wall) is not particularly limited because it can be appropriately set depending on the material and the like, and can be formed thin as long as the material is hard.

As shown in FIG. 3, the size (diameter) of the fixing member 52 may be substantially the same as the size (diameter) of the mounting hole 38, and the fixing member 52 may be fitted into the mounting hole 38 as it is. Alternatively, the size (diameter) of the fixing member 52 may be formed larger than the size (diameter) of the mounting hole 38, and the fixing member 52 may be fitted so as to expand the mounting hole 38. .

In this example, the fixing member 52 is located inside the mounting hole 38 and spaced apart from the tread surface 24 as shown in FIG. 5(B). Specifically, the fixing member 52 is formed so that its axial dimension is smaller than the depth of the mounting hole 38 and is attached to the bottom of the mounting hole 38 . Therefore, the upper end 52A of the fixing member 52 (that is, the end on the tread surface 24 side) is located below the tread surface 24 at a predetermined distance (that is, inside in the tire radial direction). Although the distance between the upper end 52A of the fixing member 52 and the tread surface 24 is not particularly limited, it is preferably about 30 to 70% of the depth of the mounting hole 38.

The stud 40 is attached and fixed by screwing the fixing member 52 into the fixing hole 38, as shown in FIGS. That is, the stud 40 is inserted into the mounting hole 38 from the side of the male threaded portion 46 at the lower end thereof, and while the male threaded portion 46 is screwed into the female threaded portion 54 of the fixing member 52, the body 42 of the stud 40 is pushed into the bottom of the mounting hole 38 (that is, , lower end) 39 and fix it. As a result, the entire body 42 of the stud 40 is inserted into the mounting hole 38 , and the projection 44 at the upper end protrudes from the tread surface 24 . At this time, there is no cavity below the body 42 (that is, inside in the tire radial direction), and the lower end of the stud 40 (that is, the lower surface of the body 42) is the bottom 39 of the mounting hole 38, more specifically, the bottom surface. It is in a state of being supported by the supporting surface as the supporting surface.

According to the above-described embodiment, the tread portion 12 is provided with the mounting hole 38 having the cylindrical inner peripheral surface 48, and the fixing member 52 is fixed to the mounting hole 38 with the adhesive 56. As shown in FIG. It is not necessary to provide a bulging portion at the bottom of the mounting hole 38, as in the case of the above. Therefore, as shown in FIG. 4, the mounting hole forming projection 50 can be formed into a columnar shape having a constant cross section without a bulging portion at the tip, and the mounting hole forming projection 50 can be removed from the tread portion 12 after the tire is vulcanized and molded. It can be easily pulled out, and the hook pull-out resistance can be reduced. Therefore, demoldability during tire vulcanization molding is improved.

In addition, the stud 40 can be fastened and fixed to the mounting hole 38 via the fixing member 52 by screwing the female threaded portion 54 of the fixing member 52 and the male threaded portion 46 of the stud 40, so that the retaining member can be prevented from coming off like the conventional one. It is possible to make the stud 40 less likely to fall out of the mounting hole 38 even though there is no bulging portion for mounting.

Further, when the stud 40 is fixed with the protrusion 44 protruding from the tread surface 24, since there is no cavity below the stud 40, the stud 40 is supported by the bottom 39 of the mounting hole 38 when the tire 10 touches the ground. can be stabilized and perform its function.

Also, the fixing member 52 is fixed to the bottom side of the mounting hole 38 and is positioned away from the tread surface 24 . Therefore, when the depth of the mounting hole 38 becomes shallow due to wear of the tread surface 24, the life of the tire 10 can be extended by replacing the stud 40 with one having a lower height. The height of the fixing member 52 may be the same as the depth of the mounting hole 38 so that the fixing member 52 and the stud 40 are screwed together over the entire depth of the mounting hole 38 .

If the stud 40 falls out of the mounting hole 38 together with the fixing member 52, it can be replaced with a new stud 40 by attaching a new fixing member 52 to the mounting hole 38 with an adhesive 56. Continuous use is possible.

The studs 40 do not have to use the same shape of the protrusions 44 for all the mounting holes 38 provided in the tire 10, and the studs have the shape of the protrusions 44 according to the purpose depending on the position of the tread surface 24. 40 can be attached.

In addition, the tire 10 may be sold with the stud 40 attached, but may be sold as a set with the stud 40 without the stud 40 attached, making it easy for the user to attach and detach the stud 40. is.

Moreover, the studs 40 do not need to be mounted in all the mounting holes 38 provided in the tire 10, and the number of studs 40 to be mounted can be set according to the regulations (regulations on the number of studs) of each country. For example, the number of mounting holes 38 provided in the tire 10 may be set to the maximum number of regulations of multiple countries (for example, the whole world), and a predetermined number of studs 40 may be mounted according to the regulations of the country in which the tire 10 is distributed. .

FIG. 7 shows a modification of the fixing member 52. As shown in FIG. In the modified example, the fixing member 52 is not simply tubular, but has a bottomed tubular shape, and has a shape in which one end of the tubular portion having the female screw portion 54 is closed by the bottom wall 60 .

When the fixing member 52 has the bottom wall 60 in this way, the fixing member 52 has adhesive 56 not only on its outer peripheral surface 58 but also between the bottom wall 60 and the bottom 39 of the mounting hole 38, as shown in FIG. can be fixed by Therefore, the fixing member 52 is less likely to come off.

Further, when the stud 40 is fixed to the mounting hole 38, as shown in FIG. 8, the lower end of the stud 40 (ie, the lower surface of the body 42) is supported by the bottom wall 60 of the fixing member 52 as a supporting surface. state. That is, when the male threaded portion 46 of the stud 40 is screwed into the female threaded portion 54 of the fixing member 52 and the stud 40 is fixed in the mounting hole 38 , the body 42 is in a state where the convex portion 44 of the stud 40 protrudes from the tread surface 24 . There is no void below the . Therefore, the stud 40 is supported and stabilized by the bottom wall 60 while the tire 10 is running, and can exhibit its function.

In the embodiment shown in FIGS. 7 and 8, other configurations and effects are the same as those of the embodiment shown in FIGS. 1 to 6, and description thereof is omitted.

Tires according to the present embodiment include tires for various vehicles, such as tires for passenger cars, tires for heavy loads such as trucks, buses, and light trucks (for example, SUVs and pickup trucks).

Although several embodiments have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and modifications can be made without departing from the scope of the invention. These embodiments and their modifications are included in the scope and spirit of the invention, as well as the scope of the invention described in the claims and equivalents thereof.

DESCRIPTION OF SYMBOLS 10... Tread part, 24... Tread surface, 38... Mounting hole, 40... Stud, 42... Body, 44... Convex part, 46... Male screw part, 52... Fixing member, 54... Female screw part, 56... Adhesive

Claims (2)

a stud comprising a columnar body and a protrusion provided at the upper end of the body and in contact with the road surface;
A mounting hole provided in the tread portion and having a cylindrical inner peripheral surface to which the stud is mounted;
a fixing member for fixing the stud to the mounting hole, the fixing member having a tubular shape to be fitted into the mounting hole, having a female thread portion on an inner peripheral surface thereof, and fixed to the mounting hole by an adhesive; , and
The mounting hole is a bottomed hole having a constant cross section in the axial direction,
The stud has a male threaded portion on the outer peripheral surface of the body, and when the male threaded portion is screwed into the female threaded portion, the stud protrudes from the tread surface and the stud is formed in a state where there is no cavity below the body. fixed,
A tire characterized by: 2. The tire of claim 1, wherein the fixing member is spaced from the tread surface inside the mounting hole.

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