JP2016030449A - Stud pin for pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the drawing resistance of a stud pin without damaging the assembling workability of the stud pin.SOLUTION: A stud pin 10 to be embedded in the stud pin hole 20 formed on the tread part 2 of a pneumatic tire 1 comprises: a pin body 11 embedded in the stud pin hole 20 so that the axial line of the stud pin extends to the direction in which a tread of the tread part 2 faces the hole bottom of the stud pin hole 20; a protrusion 14 which protrudes from the peripheral part of the pin body 11 outside a radial direction and extends spirally while spacing the axial direction S of the pin body 11; and at least one protrusion 15 protruding outside the radial direction from the top of the protrusion 14.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a stud pin embedded in a stud pin hole formed in a tread portion of a pneumatic tire.

  2. Description of the Related Art Conventionally, a studded tire in which stud pins are embedded in a tread portion is known as a tire that has improved running performance on icy and snowy road surfaces. The stud pin is driven into a stud pin hole formed in the tread portion, and the periphery is held by the tread portion by being tightened by the elastic force of the tread portion.

  In such a studded tire, the stud pin receives a road surface input during traveling and rotates in the stud pin hole or is displaced to deform the inside of the stud pin hole. Rubber is easy to wear out. As the wear of the tread rubber progresses, there is a problem that the elastic force of the tread rubber tightening around the stud pin is weakened and the stud pin falls out of the stud pin hole.

  In Patent Document 1, a stud pin is composed of a case, a pin main body, and a plurality of movable claws, and when the pin main body is inserted into the case, the pin main body is engaged with the movable claw, and the movable claw is attached to the case. It is disclosed that the case and the pin main body are fixed to the tread portion by a reaction force from the tread portion via the movable claw while projecting to the tread portion side through the through hole. Patent Document 2 discloses a stud pin in which a thread portion is formed on a peripheral portion.

JP 2013-82309 A Japanese Utility Model Publication No. 49-84801

  According to the stud pin of Patent Document 1, the stud pin is composed of a plurality of components, and the work of assembling the stud pins becomes complicated due to an increase in the number of components. According to the stud pin of Patent Document 2, as shown in FIG. 10, the thread portion of the peripheral portion of the stud pin is made of a tread rubber having a predetermined rubber hardness because the change in the radial direction is severe at a narrow pitch. It is difficult to make the hole wall surface of the stud pin hole follow the screw portion. For this reason, according to the stud pin of patent document 2, engagement with the hole wall surface of a thread part becomes inadequate.

  The present invention has been made in view of the above problems, and an object of the present invention is to improve the resistance to pulling out of the stud pin without impairing the workability of assembling the stud pin.

  The present invention is a stud pin embedded in a stud pin hole formed in a tread portion of a pneumatic tire, wherein an axis extends in a direction in which a tread surface of the tread portion and a hole bottom of the stud pin hole face each other. A pin body embedded in the stud pin hole, and a protrusion that protrudes radially outward from a peripheral portion of the pin body and extends in a spiral manner with an interval in the axial direction of the pin body And at least one protrusion protruding outward in the radial direction from the top of the protrusion.

  According to this configuration, since the spiral protrusions extend while being spaced apart in the axial direction of the pin body, the change in the axial direction of the radial protrusion of the peripheral portion of the pin body becomes gentle. . As a result, the hole wall surface of the stud pin hole can be easily along the peripheral portion of the pin body and the protrusion, and the protrusion can be firmly engaged with the hole wall surface of the stud pin hole.

  Moreover, the stud pin can be easily guided to be embedded in the stud pin hole by rotating the stud pin along the extending direction of the protrusion toward the hole bottom side end. Therefore, it is possible to improve the resistance to pulling out the stud pin without impairing the workability of assembling the stud pin into the stud pin hole.

  In addition to the engagement between the hole wall surface of the stud pin hole and the protrusion, the engagement can be configured between the protrusion and the hole wall surface. In addition, since the protrusion further protrudes radially outward from the protrusion, the protrusion is more securely engaged with the hole wall surface. Accordingly, it is possible to further improve the resistance to pulling out of the stud pin.

  The protrusion includes a first portion that gradually protrudes from a protrusion start position on the top of the protrusion in a direction in which the protrusion extends toward the end on the tread surface side of the pin body; and It is preferable to include a second portion that extends from one portion along the radial direction of the pin body and returns to the protruding end position on the top of the ridge.

  According to this configuration, when the stud pin is embedded in the stud pin hole while rotating the protrusion along the extending direction (referred to as the embedded rotation direction) of the protrusion toward the hole bottom end of the pin main body, Is embedded in the hole wall surface of the stud pin hole from the first portion of the protrusion. Since the 1st part of protrusion protrudes gradually from the top part of a protrusion, embedding to the stud pin hole of a stud pin is not prevented.

  On the other hand, when an external force on the tread surface side acts on the stud pin, the stud extends along the extending direction (referred to as the loose rotation direction) toward the end portion on the tread surface side by the spirally extending ridge. A force to rotate the pin is generated. However, the force that loosens and rotates the stud pin in the rotational direction is hindered by the second portion of the protrusion, and rotation of the stud pin in the loose rotational direction is prevented. That is, since the second portion of the protrusion extends from the first portion along the radial direction of the pin body, it acts as a return portion that resists rotation of the stud pin in the loose rotation direction, and thereby the stud The pin can be prevented from rotating in the loose rotation direction.

  Therefore, it is possible to improve the resistance to pulling out the stud pin without impairing the workability of assembling the stud pin into the stud pin hole while providing the protrusion.

  It is preferable that a plurality of the protrusions are provided.

  According to this configuration, the plurality of return portions are formed between the plurality of protrusions and the hole wall surface of the stud pin hole, so that the stud pin can be further prevented from rotating in the loose rotation direction.

  The plurality of protrusions are preferably provided at equiangular intervals around the axis of the pin body.

  According to this configuration, since the protrusions can be arranged with good balance in the circumferential direction of the pin body, the stud pin can be stably embedded in the stud pin hole.

  According to the stud pin according to the present invention, it is possible to improve the resistance to pulling out of the stud pin without impairing the assembling workability of the stud pin.

The top view which expands and shows the tread pattern formed in the tread part of the pneumatic tire concerning one embodiment of the present invention. Sectional drawing of the stud pin hole formed in the tread part. The perspective view of a stud pin. The side view of a stud pin. Sectional drawing along the VV line | wire of FIG. Sectional drawing which shows the state which embed | buried the stud pin in the stud pin hole. Sectional drawing which shows the state in which the external force toward the tread surface acted on the stud pin. Sectional drawing along the AA line of FIG. 7A. Sectional drawing which shows the state in which the external force toward the hole bottom side acted on the stud pin. Sectional drawing along the BB line of FIG. 8A. Sectional drawing along the IX-IX line of FIG. 5 which expands and shows the principal part of the stud pin which concerns on other embodiment. Sectional drawing which shows the state which embed | buried the stud pin which concerns on a prior art example in the stud pin hole.

  Embodiments according to the present invention will be described below with reference to the accompanying drawings. In addition, the following description is only illustrations essentially and does not intend restrict | limiting this invention, its application thing, or its use.

  FIG. 1 is a plan view showing a developed tread portion 2 of a pneumatic tire 1 according to an embodiment of the present invention. As shown in FIG. 1, the tread portion 2 is formed with a plurality of main grooves 3 extending zigzag in the tire circumferential direction and a plurality of lateral grooves 4 extending in the tire width direction. A plurality of blocks 5 are defined by the main grooves 3 and the lateral grooves 4. The stud pin 10 is embedded in a stud pin hole 20 formed in a part of the block 5.

  FIG. 2 is a cross-sectional view along the axial direction of the stud pin hole 20 and shows a state where the stud pin 10 is not embedded. As shown in FIG. 2, the stud pin hole 20 is provided adjacent to the tread-side cylindrical portion 21 that opens to the tread surface of the tread portion 2 and the bottom portion of the tread-side cylindrical portion 21. It has the enlarged diameter part 22 expanded more than the diameter.

  The enlarged diameter portion 22 of the stud pin hole 20 is divided into an enlarged diameter portion lower portion 22b located on the lower side and an enlarged diameter portion upper portion 22c located on the upper side with the outermost diameter portion 22a interposed therebetween. The enlarged diameter portion lower portion 22 b forms the bottom portion of the stud pin hole 20. The enlarged diameter portion upper portion 22c is formed to be tapered toward the tread surface side so as to reach the lower end portion of the tread surface side cylindrical portion 21 from the outermost diameter portion 22a.

  FIG. 3 is a perspective view of the stud pin 10 as viewed from the top side. As shown in FIG. 3, the stud pin 10 includes a pin main body 11, a tip 12 provided on the top side of the pin main body 11 (upper end side in FIG. 3), and a base end side of the pin main body 11 (FIG. 3). And a flange 13 having an outer diameter larger than the outer diameter of the pin main body 11 on the middle and lower end side). In addition, the stud pin 10 includes a protrusion 14 that spirally extends around the periphery of the pin body 11 and a plurality of protrusions 15 that further protrude radially outward from the top of the protrusion 14 in the radial direction. And are provided.

  In the state where the stud pin 10 is embedded in the stud pin hole 20, the pin body 11, the protrusion 14, and the protrusion 15 are formed on the tread side cylindrical portion 21 of the stud pin hole 20 while exposing the tip 12 from the tread side. The flange 13 is formed so as to be positioned corresponding to the enlarged diameter portion 22 of the stud pin hole 20.

  The pin body 11 is made of a light metal material (for example, aluminum alloy), and a flange 13 is integrally formed at the bottom. The tip 12 is made of a hard metal material (for example, tungsten or cemented carbide) so as to abut on the road surface and pulverize ice and snow, and is joined to the top of the pin body 11 by, for example, brazing. The protrusions 14 and the protrusions 15 may be integrally formed with the pin body 11 by rolling or casting, for example, or the protrusions 14 and protrusions 15 formed separately are joined to the pin body 11 by brazing, for example. May be.

  FIG. 4 is a side view of the stud pin 10. As shown in FIG. 4, when the pin main body 11 is embedded in the stud pin hole 20, the pin main body 11 is located on the tread portion side end portion 11 a located on the tread portion 2 side and the stud pin hole 20 on the bottom side. And a hole bottom side end portion 11b. The pin main body 11 has a substantially rod-like form, and connects the cylindrical portion 11c located on the tread surface side end portion 11a side, the cylindrical portion 11c, and the flange 13, and has a reduced diameter portion that is reduced in diameter than the cylindrical portion 11c. 11d.

  The outer diameter D1 of the pin main body 11 is formed larger than the hole diameter D2 (see FIG. 2) in the tread surface side cylindrical portion 21 of the stud pin hole 20, and is preferably set in a range of 6 mm to 8.5 mm. Yes. Similarly, the outer diameter D3 of the flange 13 is formed larger than the hole diameter D4 (see FIG. 2) in the outermost diameter portion of the enlarged diameter portion 22 of the stud pin hole 20. In this way, the outer diameter of each part of the stud pin 10 is formed to be larger than the hole diameters in the tread surface side cylindrical part 21 and the enlarged diameter part 22 of the corresponding stud pin hole 20, respectively. The stud pin 10 is elastically held in the stud pin hole 20.

  The protrusion 14 protrudes radially outward from the peripheral portion of the pin main body 11, and extends in a spiral shape with an interval along the axial direction S of the pin main body 11. The formation pitch P of the ridges 14 is set so that the ridges 14 are formed at intervals in the axial direction S, and preferably with respect to the length L of the cylindrical portion 11 c of the pin body 11. The range is set to 1/5 to 1/3.

  In other words, the formation pitch P is set so that the hole wall surface of the stud pin hole 20 easily follows the periphery of the pin body 11 and the protrusion 14 in a state where the stud pin 10 is embedded in the stud pin hole 20. Yes. In other words, the formation pitch P is set so that the protrusions 14 do not gather densely along the axial direction S or do not adjoin each other.

  When the stud pin 10 is rotated along the extending direction of the protrusion 14 toward the tread side end portion 11a, the stud pin 10 is guided by the spiral protrusion 14 and moved to the tread portion 2 side of the tread portion 2. Become. Conversely, when the stud pin 10 is rotated along the extending direction of the protrusion 14 toward the hole bottom side end portion 11 b, the stud pin 10 moves to the hole bottom side of the tread portion 2. Here, the rotation direction when the ridge 14 is rotated in the extending direction toward the tread-side end portion 11a is referred to as a loose rotation direction R, and the ridge 14 is rotated in the extending direction toward the hole bottom-side end portion 11b. The rotational direction at that time will be referred to as an embedded rotational direction F and will be described below.

  FIG. 5 is a cross-sectional view taken along the line VV in FIG. 4 and shows a cross section perpendicular to the axial direction S in the cylindrical portion 11 c of the stud pin 10. As shown in FIG. 5, the peripheral portion of the pin body 11 of the ridge 14 so that the outer diameter D5 at the top position of the ridge 14 is 1.15 to 1.2 times the outer diameter D1 of the pin body 11. Projection height H2 is set.

  The protrusions 15 are provided on each circumference at four locations around the pin body 11 at equal angular intervals per circumference. Each protrusion 15 is loosened along the extending direction of the protrusion 14 from the protrusion start position 14a on the radially outer top of the protrusion 14, and gradually protrudes in the rotational direction R. The second portion 15 b extends from the first portion 15 a along the radial direction of the pin body 11 and returns to the protruding end position 14 b on the top of the protrusion 14. In other words, the step portion 16 is formed between the first portion 15 a and the second portion 15 b of the protrusion 15.

  Preferably, the circumferential length W of the protrusion 15 is set in a range of 1/6 to 1/3 of the outer diameter D1 of the pin body 11. When the circumferential length W of the protrusion 15 is smaller than 1/6 of the outer diameter D1 of the pin body 11, the engagement of the protrusion 15 with the hole wall surface becomes weak, and 1 / of the outer diameter D1 of the pin body 11 is reduced. When it is larger than 3, the workability of assembling the stud pin 10 into the stud pin hole 20 is deteriorated.

  The maximum protrusion height H1 of the protrusion 15 from the peripheral portion of the pin body 11 is formed to be approximately twice the protrusion height H2 of the protrusion 14 from the peripheral portion of the pin body 11.

  The second portion 15b is formed to have an acute angle with respect to the top of the protrusion 14, and preferably, an angle between the normal line N1 in the peripheral portion of the pin body 11 and the second portion 15b. α is set in the range of 3 to 7 degrees. According to the 2nd part 15b formed in this way, the return part which resists rotation to the loose rotation direction R of the stud pin 10 can be comprised. Moreover, by forming the second portion 15b at an acute angle with respect to the top of the protrusion 14, the second portion 15b is more firmly engaged with the hole wall surface of the stud pin hole 20, It is easy to resist the rotation of the stud pin 10 in the loose rotation direction R.

  FIG. 6 is a cross-sectional view showing a state where the stud pin 10 is embedded in the stud pin hole 20. Since the protrusions 14 are provided on the periphery of the pin body 11 of the stud pin 10 so as to extend in a spiral manner with a space in the axial direction S, the periphery of the pin body 11 of the stud pin 10 and the protrusion 14 are provided. And the hole wall surface of the stud pin hole 20 follows the protrusion 15.

  Next, the effect | action by the stud pin 10 comprised in this way is demonstrated with reference to FIG. 7, FIG.

  As shown by white arrows in FIG. 7A, when an external force X toward the tread surface is applied to the stud pin 10 embedded in the stud pin hole 20, a plurality of protrusions 14 and a plurality of protrusions 14 formed on the peripheral portion of the stud pin 10 The protrusion 15 prevents the stud pin 10 from moving to the tread surface side. The external force X toward the tread side is directed by the spirally formed ridge 14 in the extending direction toward the tread side, that is, the stud pin 10 is loosened and rotated in the rotation direction R. It is converted into the rotational force XR to be made.

  At this time, in FIG. 7B showing a cross section taken along the line AA of FIG. 7A, the rotational force XR in the loose rotation direction R is caused by the engagement between the second portion 15b of the protrusion 15 and the hole wall surface of the stud pin hole 20. This prevents the stud pin 10 from rotating in the loose rotation direction R. Since the second portion 15b of the protrusion 15 is formed at an acute angle with respect to the top of the protrusion 14, the second portion 15b and the hole wall surface of the stud pin hole 20 are more securely fixed. An engaging portion is configured. As a result, the stud pin 10 is more difficult to rotate in the loose rotation direction R.

  On the other hand, when an external force Y toward the bottom of the hole is applied to the stud pin 10 embedded in the stud pin hole 20, as shown by the white arrow in FIG. In the extending direction, it is directed by the spirally formed protrusion 14, that is, converted into a rotational force YF that rotates the stud pin 10 in the embedded rotation direction F.

  At this time, in FIG. 8B showing a cross section taken along line BB in FIG. 8A, the stud pin 10 is pressed against the bottom side of the stud pin hole 20 by the rotational force YF in the embedded rotation direction F. Since the protrusion 15 is formed with a first portion 15a that gradually protrudes from the top of the ridge 14 in the burying rotation direction F, the first portion 15a guides the rotation of the stud pin 10 in the burying direction. It is like that.

  According to the stud pin 10 described above, the following effects can be exhibited.

(1) Since the spiral protrusion 14 extends in the axial direction S of the pin main body 11 with a gap, the change in the radial protrusion of the peripheral portion of the pin main body 11 in the axial direction S is gentle. Become. As a result, the hole wall surface of the stud pin hole 20 can easily follow the peripheral portion of the pin main body 11 and the protrusion 14, and the protrusion 14 can be firmly engaged with the hole wall surface of the stud pin hole 20.

  Moreover, the stud pin 10 can be easily guided to be embedded in the stud pin hole 20 by rotating the stud 14 along the extending direction of the protrusion 14 toward the hole bottom end portion 11b. Accordingly, it is possible to improve the resistance to pulling out of the stud pin 10 without impairing the workability of assembling the stud pin 10 into the stud pin hole 20.

(2) In addition to the engagement between the hole wall surface of the stud pin hole 20 and the protrusion 14, the engagement can be configured between the protrusion 15 and the hole wall surface. Moreover, since the protrusion 15 protrudes further outward in the radial direction than the protrusion 14, the protrusion 15 is more firmly engaged with the hole wall surface. Accordingly, it is possible to further improve the resistance to pulling out of the stud pin 10.

(3) When the stud pin 10 is rotated along the embedding rotation direction F and embedded in the stud pin hole 20, the protrusion 15 is embedded in the hole wall surface of the stud pin hole 20 from the first portion 15a. Become. That is, since the first portion 15a of the protrusion 15 protrudes gradually from the protrusion start position 14a on the top of the protrusion 14, the embedding of the stud pin 10 in the stud pin hole 20 is not hindered.

  On the other hand, when an external force on the tread surface side acts on the stud pin 10, a force for rotating the stud pin 10 in the loose rotation direction R is generated by the spirally extending protrusion 14. However, the force that loosens and rotates the stud pin 10 in the rotation direction R is hindered by the second portion 15b of the protrusion 15, and the rotation of the stud pin 10 in the loose rotation direction R is prevented.

  That is, since the second portion 15b of the projection 15 extends from the first portion 15a along the radial direction of the pin body 11, it acts as a return portion that resists rotation of the stud pin in the loose rotation direction, Thereby, the rotation to the loose rotation direction R of the stud pin 10 can be prevented. In other words, a locking portion that resists rotation in the loose rotation direction R of the stud pin 10 can be configured between the second portion 15 b of the protrusion 15 and the hole wall surface of the stud pin hole 20.

  Therefore, while providing the protrusions 15, it is possible to improve the resistance to pulling out the stud pins 10 without impairing the workability of assembling the stud pins 10 into the stud pin holes 20.

(4) The stud pins 10 can be stably embedded in the stud pin holes 20 by arranging the plurality of protrusions 15 in the circumferential direction of the pin main body 11 at equal angular intervals in a balanced manner.

  Instead of the protrusion 15 described in the above embodiment, a protrusion 150 inclined toward the tread surface side may be provided. That is, in FIG. 9 which shows sectional drawing along the IX-IX line of FIG. 5, the protrusion 150 is provided so that it may incline toward the tread side from the top part of the protrusion 14. Preferably, the angle β between the protrusion 150 and the normal line N2 at the top of the protrusion 14 is set to about 30 degrees. Thereby, the movement to the tread surface side of the stud pin 10 can further be suppressed.

  Further, the protrusion 14 and the protrusion 15 may be provided not only on the peripheral portion of the cylindrical portion 11 c of the pin body 11 but also on the peripheral portion of the reduced diameter portion 11 d and / or on the peripheral portion of the flange 13. .

  The present invention is not limited to the illustrated embodiments, and it goes without saying that various improvements and design variations are possible without departing from the spirit of the present invention.

  Next, the verification test was implemented about the effect of the stud pin demonstrated above. A studded tire (Example 1) in which the stud pin of the present invention configured as shown in Table 1 was embedded in the tread portion and a studded tire (Comparative Example 1) in which a comparative stud pin was embedded in the tread portion were produced. .

  The stud pin of the present invention is the stud pin 10 described in the above embodiment. That is, the stud pin 10 includes a spiral protrusion 14 on the periphery of the pin body 11 and a plurality of protrusions 15 on the top of the protrusion 14. ing. The comparison stud pin is not provided with the protrusion 14 or the protrusion 15.

  Each studded tire was mounted on the rim for evaluation, and after traveling 150 km by slalom running on a dry road at an air pressure of 210 kPa, the presence or absence of the stud pin was confirmed, and the results shown in Table 1 were obtained. .

  As shown in Table 1, the stud pin tire according to Comparative Example 1 has the stud pin falling off, but the stud pin tire according to Example 1 does not have the stud pin falling off.

DESCRIPTION OF SYMBOLS 1 Pneumatic tire 2 Tread part 3 Main groove 4 Lateral groove 5 Block 10 Stud pin 11 Pin main body 11a Tread surface side end part 11b Hole bottom side end part 12 Tip 13 Flange 14 Projection 15 Projection 20 Stud pin hole 21 Tread surface side cylindrical part 22 Expanded part R Loose rotation direction F Embedded rotation direction

Claims (4)

A stud pin embedded in a stud pin hole formed in a tread portion of a pneumatic tire,
A pin body embedded in the stud pin hole such that an axis extends in a direction in which the tread surface of the tread portion and the hole bottom of the stud pin hole face each other;
A protrusion that protrudes radially outward from the peripheral portion of the pin body, and extends in a spiral manner with a gap in the axial direction of the pin body;
A stud pin comprising: at least one protrusion that protrudes radially outward from the top of the protrusion. The protrusion is
A first portion that gradually protrudes from a protruding start position on the top of the ridge as the ridge advances in an extending direction toward the tread surface side end of the pin body;
The stud pin according to claim 1, further comprising: a second portion extending from the first portion along a radial direction of the pin body and returning to a protruding end position on the top portion of the ridge.   The stud pin according to claim 1, wherein a plurality of the protrusions are provided.   The stud pin according to claim 3, wherein the plurality of protrusions are provided at equiangular intervals around an axis of the pin body.

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