JP2013086744A - Vehicle tire and buffing method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle tire and a buffing method of the same, configured to efficiently remove tread without requiring an operator to measure a depth from a tread surface to the outermost belt surface or damaging the outermost belt, in a buffing process for removing the tread of a used tire.SOLUTION: The vehicle tire includes: a groove part formed in a tread part and extended in a tire width direction; a belt disposed on the radially inside of the tread part; and a plurality of recesses formed in a tire radial direction from the groove bottom surface of the groove part. The plurality of recesses include: first recesses provided symmetrically with respect to the tire width-direction center on the thinnest points where the thickness from the belt surface to the groove bottom surface is the minimum; and second recesses separated toward the lateral inside or outside of the first recesses and provided symmetrically with respect to the tire width-direction center.

Description

  The present invention relates to a vehicle tire, and relates to a vehicle tire that can be used again as a tire by removing the tread after use of the tire and arranging a new tread, and a method for buffing the tire.

In recent years, tires for trucks and buses and used vehicle tires used for other construction are removed again by a tire rehabilitation method called a retread in which a new tread is disposed after removing the tread ( It can be used as a retread tire). The retread has a buffing step of removing a tread by buffing a used tire and forming a sticking surface on which a new tread can be disposed.
In the buffing process, first, an operator creates a hole by manually digging from the tread surface of the used tire to the outermost belt surface located in the outermost radial direction of the tire, and this hole is used to create a hole from the tread surface. By measuring the rubber thickness up to the outermost belt surface, setting the buffing amount of the tread to be buffed, and omitting the work of setting the buffing amount, it becomes a guideline for cutting in the buffing process An indicator is pre-molded on the side of the tire, and when the tire reaches the use limit, it is buffed using the set buffing amount and indicator as a guideline, so that the cross-sectional shape of the sticking surface after buffing is a predetermined A method of shaping is disclosed.
However, in vehicle tires represented by construction vehicle tires, the thickness from the outermost belt to the groove bottom of the tread tends to increase, so the operator manually works from the tread surface to the outermost belt. Therefore, the work of digging and providing a hole is very laborious and hinders the improvement of productivity of the retread tire. Also, not only construction vehicle tires, but the belt structure located at the bottom of the tread differs depending on the type of tire, so when buffing using only the indicator provided on the side of the tire as a guide, the outermost belt is exposed by buffing There is a risk of causing damage.

Japanese Utility Model Publication No. 59-19403

  In order to solve the above-mentioned problems, the present invention eliminates the need for the operator to measure the depth from the tread surface to the outermost belt surface in the buffing process for removing the tread of the used tire, An object of the present invention is to provide a vehicle tire and a buffing method for the tire that can efficiently remove a tread without being damaged.

As a first aspect of the present invention, a groove portion formed in the tread portion and extending in the tire width direction, a belt disposed radially inward from the tread portion, and a plurality of recesses in the tire radial direction from the groove bottom surface of the groove portion A plurality of recesses, the first recess provided symmetrically with respect to the center in the tire width direction on the thinnest point where the thickness from the belt surface to the groove bottom surface is the thinnest, and the first recess Rather than the second concave portion spaced inward or outward in the tire width direction.
According to this aspect, a groove portion formed in the tread portion of the tire and extending in the tire width direction, a belt disposed radially inward from the tread portion, and a plurality of recesses recessed in the tire radial direction from the groove bottom surface of the groove portion. A first recess provided symmetrically with respect to the center in the tire width direction on the thinnest point where the thickness from the belt surface to the groove bottom surface is the thinnest, and the plurality of recesses from the first recess In addition, by having a second concave portion spaced inward or outward in the tire width direction, it is possible to buff the tread portion with the concave portion as a guide, and from the bottom of the tire groove before buffing to the outermost side in the tire radial direction. The operation of measuring the rubber thickness of the tread portion up to the belt positioned and setting the buffing amount (cutting depth) of the tread portion can be eliminated. And a tread part can be shape | molded in a desired shape by buffing a tread part until the some recessed part provided in the groove bottom face cannot be visually recognized. In addition, since the first recess is provided at a position where the thickness from the outermost belt to the bottom surface of the tire groove is the thinnest, the outermost belt is not damaged in the buffing process.
As another aspect of the present invention, the first recess is located on the inner side in the width direction from the reference point obtained by multiplying the tire width dimension by a quarter from the center in the tire width direction, and the second recess is A distance obtained by multiplying the tire width dimension by one-eighth from the one concave portion is set to be separated to the outer side in the tire width direction.
According to this aspect, in addition to the above-described effects, the first recess and the second recess are arranged in the tread portion in an equally divided region, and the distance from each other is 1/8 of the tire width dimension. When the tread portion is buffed, the first concave portion and the second concave portion can be arranged substantially evenly on the tread portion when buffing the tread portion, so that the entire tread portion can be uniformly buffed when buffing the tread portion. Can be hung. That is, by buffing the first concave portion and the second concave portion so as to connect the first concave portion and the second concave portion, the thickness from the outermost belt to the attaching surface on which a new tread is attached is set to an optimum value, and the tread portion is formed in a desired shape. Therefore, the tread surface of a tire to which a new tread is stuck after buffing becomes a tire having a crown shape with an optimal curvature in terms of tire performance.
As another aspect of the present invention, the first recess is located on the outer side in the width direction from the reference point obtained by multiplying the tire width dimension by a quarter from the center in the tire width direction, and the second recess is It was set as the aspect spaced apart in the tire width direction inner distance which multiplied 1/8 to the tire width dimension rather than one recessed part.
According to this aspect, in addition to the above-described effects, the first recess and the second recess are arranged in the tread portion in an equally divided region, and the distance from each other is 1/8 of the tire width dimension. When the tread portion is buffed, the first concave portion and the second concave portion can be arranged substantially evenly on the tread portion when buffing the tread portion, so that the entire tread portion can be uniformly buffed when buffing the tread portion. Can be hung. That is, by buffing the first concave portion and the second concave portion so as to connect the first concave portion and the second concave portion, the thickness from the outermost belt to the attaching surface on which a new tread is attached is set to an optimum value, and the tread portion is formed in a desired shape. Therefore, the tread surface of a tire to which a new tread is stuck after buffing becomes a tire having a crown shape with an optimal curvature in terms of tire performance.
As another embodiment of the present invention, the plurality of recesses further include a third recess provided at the center in the tire width direction.
According to this aspect, in addition to the above effects, the tread portion can be buffed more accurately by further including the third recess provided in the center in the tire width direction.
Further, as a tire buffing method according to the present invention, based on the tire design drawing, the thickness of the belt disposed radially inward from the tread portion and the groove bottom surface of the groove portion extending in the tire width direction formed in the tread portion. Identifying the thinnest point with the thinnest thickness, forming a recess recessed in the tire radial direction from the groove bottom surface on the thinnest point, and symmetrically with respect to the center in the tire width direction, and the recess visually recognizing the tread portion And a step of removing until it becomes impossible.
According to this aspect, on the basis of the tire design drawing, the belt between the belt disposed radially inward from the tread portion and the groove bottom surface of the groove portion formed in the tread portion extending in the tire width direction has the smallest thickness. By identifying the thin point, forming a recess recessed in the tire radial direction from the groove bottom surface on the thinnest point with respect to the center in the tire width direction, and removing the tread until the recess becomes invisible, Measure the rubber thickness of the tread from the bottom of the tire groove to the belt located in the outermost radial direction of the tire before tying, eliminating the need to set the buffing amount (cutting depth) of the tread. By buffing until the concave portion can no longer be seen, the tread portion can be formed into a desired shape. Further, since the recess is provided at a position where the thickness from the outermost belt to the bottom surface of the tire groove is the thinnest, the outermost belt is not damaged in the buffing process.
As another aspect of the tire buffing method of the present invention, after forming a recess on the thinnest point, the recess is separated from the recess inward or outward in the tire width direction and provided symmetrically with respect to the center in the tire width direction. A step of forming the second recess is provided.
According to this aspect, in addition to the above-described effects, it is possible to perform buffing with higher accuracy by further providing a concave portion that serves as a guide for buffing and buffing.

  The above summary of the invention does not enumerate all the necessary features of the present invention, and sub-combinations of these feature groups can also be the invention.

The external appearance perspective view and top view of the tire for construction vehicles. The tire sectional view in the AA arrow of Drawing 1 (a). The elements on larger scale of the tread part in a tire sectional view. The partial enlarged view of the tread part which shows a recessed part. The schematic block diagram of a buffing device. The figure which shows the different form of the tire which has a recessed part.

  FIG. 1A is an external perspective view of a tire T for a construction vehicle as an example, and FIG. 1B is a plan view of the tire T. FIG. 2 is a cross-sectional view taken along the line AA in FIG. The tire T is a tire used for a vehicle such as a dump truck, a motor grader wheel loader, an excavator loader, or a crane used in a construction site or a mine. Hereinafter, the tire T according to the present invention will be described.

  As shown in FIG. 2, the tire T is roughly composed of a carcass 11 that forms a skeleton of a radial tire, a pair of left and right bead cores 12 for fixing the tire T to a rim of the wheel, and the rigidity of the tire by tightening the carcass 11. Belt layer 13 for improving The carcass 11 is formed in a toroidal shape so as to straddle the left and right bead cores 12, and is configured by laminating a plurality of members called plies. The ply is a band formed by arranging cords such as rubber-coated fiber cords and steel cords in a hook shape, and is laminated so that the extending direction of the cords is the radial direction of the tire T. The bead core 12 is formed by winding a steel cord in an annular shape, for example, in an annular shape having a hexagonal cross section, and is provided apart from each other in the width direction of the tire T. A bead filler 14 having a substantially triangular cross section is disposed on the outer periphery of the bead core 12. The bead filler 14 is a member made of hard or soft rubber, and is surrounded by the end portion of the carcass 11 together with the bead core 12 to constitute a bead portion in the tire T.

The belt layer 13 is formed by laminating a plurality of belts having different widths at the upper center of the carcass 11. Each belt is a member in which steel cords are arranged in a bowl shape, covered with a belt rubber, and formed into a belt shape having a predetermined width. The steel cord constituting the belt is disposed to be inclined at a predetermined angle with respect to the belt extending direction. The belt layer 13 in this example has a five-layer structure in which five belts are stacked.
From the belt closest to the carcass 11 to the outermost belt, the first belt 13A, the second belt 13B, the third belt 13C, the fourth belt 13D, and the fifth belt 13E Each belt width has a relationship of 4th belt 13D <5th belt 13E <3rd belt 13C <1st belt 13A <2nd belt 13B. In the following description, the fifth belt 13E is a belt positioned radially outermost in the belt layer 13 constituting the tire T, and therefore will be described as the outermost belt 13E.
The belt layer 13 is not limited to the above five-layer structure, and can be increased or decreased, and the belt width and the belt stacking order can be appropriately changed.

  An inner liner rubber 15 that covers the entire inner peripheral surface of the tire T is disposed on the inner peripheral surface of the carcass 11. The inner liner rubber 15 is made of a rubber member having low air permeability, and holds the internal pressure of the tire T so that air filled in the tire T does not leak. Further, a sidewall rubber 16 that protects the carcass 11 and ensures cushioning properties of the tire T is disposed on the tire side surface of the outer peripheral surface of the carcass 11, and a side portion of the tire T is formed. Further, a tread rubber 17 that protects the belt layer 13 and is in direct contact with the road surface is disposed outside the outermost belt 13E in the radial direction, and a tread portion of the tire T is formed.

  As shown in FIGS. 1 (a) and 1 (b), the tread portion 5 includes a tread pattern in which water is removed from the wet road surface and a driving force and a braking force are applied. The tread pattern of this example is a so-called block pattern. The tread portions 5 are provided at equal intervals in the circumferential direction of the tire T, and the circumferential direction of the tire T so as to connect the widthwise grooves 21 extending along the width direction of the tire T and the adjacent widthwise grooves 21. A plurality of tread blocks 20 having circumferential grooves 22 extending in the direction and defined by the width grooves 21 and the circumferential grooves 22 are formed.

The width direction groove | channel 21 is provided with several recessed part 23; 24; 25 spaced apart in the tire width direction mutually. Specifically, the width direction groove 21 includes a central recess 23 that is recessed in the tire center O direction at the center C in the width direction of the tire T, and recesses 24 and 24 that are provided symmetrically in the tire width direction around the center C in the width direction. Similarly, it is provided symmetrically in the tire width direction with the center C in the width direction as a center, and has a recess 25; 25 located outside the recess 24; 24 in the tire width direction. In other words, the width direction groove 21 includes a total of five concave portions 23, 24; 24, 25; 25 along the extending direction.
In addition, in this specification, the width direction outer side is the direction of both side portions when the width direction center C is used as a reference, but the concave portions 24; 25 provided on one side with respect to the width direction center C as a reference. It is also possible to grasp the direction in which the concave portion 24; 25 provided on the other side is located as the outer side or the inner side in the width direction. Moreover, the recessed part 24; 24 should just be symmetrical in the width direction centering on the center C of the width direction, and may be displaced in the circumferential direction. Moreover, the recessed part 25; 25 should just be symmetrical in the width direction centering on the center C of the width direction, and may be displaced in the circumferential direction.

3 is a partially enlarged view of the tread portion 5 in the tire cross-sectional view, and FIG. 4 is a partially enlarged view showing the concave portions 23; 24; Hereinafter, the plurality of concave portions 23; 24; 25 will be described with reference to FIGS.
As shown in FIGS. 3 and 4, the central recess 23 has, for example, a cylindrical shape with a diameter d1 and a depth L1. The axis of the central recess 23 having a cylindrical shape is located at the center C in the width direction of the tire T and coincides with the normal N of the tire T. That is, the center C in the width direction of the tire T coincides with the axis. Moreover, the diameter d1 of the center recessed part 23 is set from 2 mm to 10 mm, for example so that it may become a diameter shorter than the groove width MW of the width direction groove | channel 21, and the depth L1 is set to 4 mm-10 mm, for example. (See FIG. 1 (b)).

The recesses 24 and 25 located on the outer side in the width direction with respect to the central recess 23 have the same cylindrical shape as the center recess 23. The recess 24 has a diameter d2 and a depth L2, and the recess 25 has a diameter d3 and a depth L3.
The positional relationship between the concave portions 24; 25 is the distance from the thinnest point P where the thickness from the groove bottom surface 21a of the width direction groove 21 to the surface of the outermost belt 13E is the thinnest, and the center C in the width direction on the groove bottom surface 21a. Is defined by the relationship with the reference point Q.

More specifically, first, at least one of the recesses 24; 25 is formed so as to be located on the thinnest point P (in the illustrated example, the recess 24). Specifically, the axial center of the concave portion 24 having a cylindrical shape is formed so as to pass through the thinnest point P, and functions as a guide indicating the thinnest point P in the subsequent buffing step.
The other concave portion 25 is arranged on the outer side in the width direction or the inner side in the width direction than the thinnest point P due to the relationship between the thinnest point P and the reference point Q. Here, the reference point Q is a virtual point that is a predetermined distance away from the center C in the width direction, and in this example, a distance obtained by multiplying the tire width dimension W by a quarter from the center C in the width direction, tire It is set at a position spaced outward in the width direction.
And the position of the recessed part 25 is determined by whether the thinnest point P exists in the width direction inner side with respect to the reference point Q set as mentioned above, or exists in the width direction outer side. Specifically, when the thinnest point P exists in the width direction inner side than the reference point Q as shown in the drawing, the position of the recess 25 is set to the outer side in the width direction than one of the recesses 24. When the thin point P exists on the outer side in the width direction than the reference point Q, the position of the recess 25 is set on the inner side in the width direction with respect to the one recess 24.

  Further, the recesses 24; 25 formed with the above relationship are spaced apart from each other in the width direction by a distance obtained by multiplying the tire width dimension W by 1/8 on the groove bottom surface 21a. Moreover, the axial centers of the recesses 24; 25 are formed so as to coincide with the normal line N of the cross-sectional shape in the width direction of the groove bottom surface 21a. The diameters of the recesses 24; 25 are set between 2 mm and 10 mm so as to be shorter than the groove width MW of the width direction groove 21. Moreover, the depth of the center recessed part 23 is set to 4 mm-10 mm, for example. The diameters d1; d2; d3 of the central recess 23 and the pair of recesses 24; 25 need not be the same, but in the present embodiment, the depths L1; L2; L3 are set to be the same. Further, the central recess 23 and the recesses 24; 25 are formed uniformly in the width direction of the tread portion 5.

  A group of recesses composed of the central recess 23 and the plurality of recesses 24; 25 is molded together with a tread pattern by a vulcanization molding process when manufacturing the tire T as a product. In detail, by the protrusion protruding from the molding surface of the molding die for forming the tread pattern and protruding from the surface of the protrusion for forming the width direction groove, further into a cylindrical shape having a diameter of 2 mm to 10 mm and a length of 4 mm to 10 mm. Molded and formed. Moreover, you may form with tools, such as an end mill and a drill blade, with respect to the vulcanized tire.

FIG. 5 is a schematic view of a buffing device 50 used in the buffing process.
As shown in FIG. 5, the buffing device 50 generally includes a drum 51 for fixing the tire T to be buffed, a grinder 52 for buffing the tread portion 5 of the tire T fixed to the drum 51, and a buffing device. And a control device 100 for controlling buffing by 50. The drum 51 is fixed to one end of a rotating shaft 53 that extends substantially horizontally. The rotating shaft 53 is connected to the motor via a transmission mechanism (not shown) and rotates by the rotation of the motor. The motor is connected to the control device 100, and rotates and stops based on a signal output from the control device 100. The drum 51 is a substantially cylindrical cylindrical body, and an internal pressure is applied to the tire T fixed to the drum 51 and an expansion / contraction mechanism that fixes the tire T by moving a plurality of drum segments 51 a constituting the outer peripheral surface in the radial direction. And an internal pressure applying means for applying.

The expansion / contraction mechanism is connected to the control device 100, and moves the drum segment 51a in the radial direction based on a signal output from the control device 100, thereby enabling the tire T to be attached and detached. The internal pressure applying means incorporates an electric valve for supplying preset air pressure, and is connected to a pipe extending from an air supply means 54 such as a compressor provided in the factory.
Therefore, in the tire T to be buffed, the bead portion and the outer peripheral surface of the drum 51 are brought into close contact with each other by expanding the diameter of the drum 51, and the air supplied from the air supply unit 54 passes through the tire T through the internal pressure application unit. By being supplied inside, the tire T is fixed to the drum 51 in a state where an internal pressure is applied. Then, by rotating the rotating shaft 53, it is possible to rotate the tire T in a state where the internal pressure is applied.

  The grinder 52 is accommodated in a housing 59 opened on one side, and is disposed at a position facing the outer peripheral surface of the tire T fixed to the drum 51. A housing 59 including the grinder 52 is installed on the moving table 55. The moving table 55 is mounted on the first table 56 extending in parallel along the radial direction of the tire T fixed to the drum 51, and extends in parallel along the width direction of the tire T. And a third table 58 that is placed on the second table 57 and rotates within the horizontal plane of the second table 57. The second table 57 is movable on the first table 56 in the extending direction and the width direction of the first table 56. A housing 59 having a grinder 52 is installed on the third table 58. Accordingly, the grinder 52 can move in the proximity direction and the width direction of the tire T, and the rotation axis of the grinder 52 is inclined with respect to the rotation axis 53 of the drum 51 in a horizontal plane including the contact position between the tire T and the grinder 52. It is possible to make it. That is, the moving table 55 can freely move the grinder 52 with respect to the outer peripheral surface of the tire T.

  The control device 100 is a so-called computer, and includes a CPU as a calculation unit, a ROM and a RAM as storage units, and an input / output interface as a communication unit, and constitutes a storage unit 101 and a control unit 102. The control device 100 is connected to a touch panel type input display means 103 via an input / output interface. The storage unit 101 stores a buff shape corresponding to each tire product number of the tire T to be buffed and an appropriate internal pressure value for each tire product number. The buff shape is a cross-sectional shape in which the shape of the tire tread is substantially the same as that of the product tire when a new tread is integrated with the pasted surface after cutting. The control unit 102 has an expansion signal for expanding the drum 51 by the expansion / contraction mechanism, an internal pressure application signal for supplying air to the tire T by the air supply means 54, and a tire rotation signal for rotating the drum 51 by an unillustrated motor. Is output. Further, the control unit 102 reads the buff shape corresponding to the tire product number input from the input display unit 103 from the storage unit 101, and sends a movement signal to the movement table 55 so that the grinder 52 moves along the locus corresponding to the buff shape. Output. Further, the control unit 102 outputs a rotation signal for rotating the grinder 52 to a drive mechanism (not shown) of the buff device 50.

Hereinafter, a method for buffing the tire T by using the buffing device 50 having the above-described configuration to form the sticking surface will be described.
First, an operator places the tire T to be buffed on the drum 51. Next, the operator inputs the tire product number and tire size of the tire T arranged on the drum 51 from the input display means 103. The control unit 102 of the control device 100 reads the buff shape corresponding to the tire product number and tire size input from the storage unit 101 and the internal pressure value to be applied, the diameter expansion signal corresponding to the input tire size, and the tire An internal pressure application signal having an internal pressure value corresponding to the product number is output. The expansion / contraction mechanism expands the diameter of the drum 51 based on the diameter expansion signal to fix the tire T, and based on the internal pressure application signal, the tire T so that the air supplied from the air supply means 54 has a predetermined internal pressure value. Supply in.
Next, the control device 100 outputs a movement signal to the moving table 55 having the grinder 52 and moves the moving table 55 so that the outer peripheral surface of the tire T and the outer peripheral surface of the grinder 52 are opposed to each other. The tread portion 5 of the tire T is brought into contact. At this time, for example, the center in the width direction of the grinder 52 and the center C in the width direction of the tire T are in contact with each other, and the rotating shaft of the grinder 52 and the rotating shaft 53 of the tire T are arranged in parallel.

Next, the operator controls the buffing start signal for starting buffing by operating the input display means 103 after visually confirming the positions of the recesses 23; 24; 25 in the tire T fixed to the drum 51. Output to the device 100. When the buffing start signal is input, the control device 100 outputs the buffing signal to the grinder 52 and the moving table 55 so as to obtain a buff shape corresponding to the tire product number. When the buffing signal is input, the grinder 52 starts rotating, and the moving table 55 moves the grinder 52 close to the tread portion 5 so as to abut on the tread portion 5 from the outer side in the tire radial direction. The grinder 52 is moved in the tire width direction and the tire radial direction with respect to the tread portion 5 of the tire T so that the outer peripheral surface of the tire T has a buff shape having a predetermined curvature.
And the tread part 5 of the tire T is gradually cut by the movement table 55 moving to the tire T side. When the tread block of the tread portion 5 is removed by buffing, the groove bottom surface 21a is eventually exposed, and the concave portions 23; 24; 25 are visually observed in a linear shape on the tire surface of the rotating tire T by the afterimage effect.
When the recesses 23; 24; 25 cannot be visually recognized during the rotation of the tire T, the rotation of the tire T may be temporarily stopped to check the depth to be buffed of the recesses 23; 24; 25. An operator confirms the recessed part 23; 24; 25 which can be visually recognized on the rotating tire surface, and continues buffing until the recessed part 23; 24; 25 becomes invisible. When the operator can no longer visually recognize the recesses 23; 24; 25, the input display means 103 is operated to output a buffing stop signal to the control device 100 and stop the buffing. A sticking surface on which a tread is disposed is formed on the tire surface.

  As described above, according to the tire T according to the present invention, by providing the tread groove bottom surface 21a with the plurality of recesses 23; 24; 25, the remaining from the tread surface to the outermost belt 13E surface in the buffing process. It is not necessary to measure the thickness, and the worn tread can be easily removed by buffing with the recesses 23; 24; 25 as a guide. Further, since the position where the recess 24 is formed is the thinnest position P where the thickness from the groove bottom surface 21a to the surface of the outermost belt 13E is the thinnest, when buffing is performed until the recess 24 cannot be visually recognized. It is possible to reliably prevent the outermost belt 13E from being damaged. Furthermore, by providing the position of the recessed portion 25 at a predetermined distance apart on the width direction center C side or the width direction outer side depending on the position of the recessed portion 24, it is possible to reliably prevent the belts other than the outermost belt 13E from being damaged during buffing. . Further, by buffing the central concave portion 23 and the concave portion 24; 25 at the center C in the width direction until the central concave portion 23 and the concave portions 24; 25 at the central portion C in the width direction become invisible, accuracy in the tire cross-sectional shape is obtained. Since it can be buffed well, the tread surface of the tire to which a new tread is attached after buffing becomes a tire having a crown shape with an optimal curvature in terms of the performance of the tire. It is more excellent in rolling resistance and has improved fuel efficiency and uneven wear performance.

  The tire T with the sticking surface formed by buffing becomes a so-called stand tire, and an adhesive layer for sticking the tread to the sticking surface is formed. The adhesive layer is formed by winding unvulcanized sheet-like rubber or belt-like rubber around the sticking surface or spraying liquid rubber on the sticking surface. A vulcanized belt-like or annular tread is disposed on the adhesive layer. The tire T on which the tread is disposed is covered with a envelope body called an envelope and is put into a vulcanization facility called a vulcanization can. In the vulcanizing can, the newly disposed tread is fixed to the sticking surface by vulcanizing the adhesive layer. When vulcanization by the vulcanizing can is completed, the tire T and the tread are firmly fixed by the vulcanized adhesive layer, and a retread tire as a product is obtained. In addition, the tire buffed with the recesses 23; 24; 25 according to the present invention as a guide and the sticking surface is formed is a so-called cold manufacturing method in which the vulcanized belt-like or annular tread is disposed. The present invention is not limited to the rehabilitation method described above, and can also be applied to a case where a tire is rehabilitated by a hot manufacturing method in which an unvulcanized tread is disposed on a sticking surface and a tread pattern is formed by a mold.

  In order to verify the effect of the present invention, a tire T having recesses 23; 24; 25 is prepared, a tire T having recesses 23; 24; 25, and a tire not having recesses 23; 24; 25. As a result of investigating the time required for tire regeneration, it was possible to reduce the time by 30%.

FIG. 6 shows a different form of tire T with recesses 23; 24;
In the above embodiment, each of the width direction grooves 21 is provided with the recesses 23; 24; 25. However, the width direction grooves 21 may be formed only in one width direction groove 21. Moreover, as shown in FIG. 6, you may make it form one recessed part 23; 24; 25 one for every width direction groove | channel 21 adjacent to the circumferential direction. In the above embodiment, the tire T is described as having the recesses 23; 24; 25 in advance. However, when the tire T does not include the recesses 23; 24; 25, the recesses 23; 24; 25 may be formed on the groove bottom surface 21a. Specifically, if the thinnest point P is specified based on the design drawing of the tire T to be buffed, and the recess 24 is formed on the thinnest point P, the recess 24 is used as a guide for buffing. Is possible. Moreover, what is necessary is just to make it have the same relationship as the above-mentioned embodiment, when forming the recessed part 25. FIG. Thus, by forming the recesses 23; 24; 25 in the tire T that does not include the recesses 23; 24; 25, there is a risk of damaging the outermost belt 13E when the cutting depth is measured manually. Sex can be avoided. Further, since the recesses 23; 24; 25 may be mechanically formed at the above positions based on the drawings, the skill level of the operator is not required, so that the work time in the buffing process can be shortened. .

  Moreover, although the said recessed part 23; 24; 25 was demonstrated as a cylindrical shape, the shape when it sees from the tire tread surface side may be a pillar and a cone which have polygonal cross-sectional shapes, such as a triangle and a quadrangle | tetragon. . Moreover, you may use combining a cylindrical shape and a polygonal column. In the case of a polygonal column, the size of the cross-sectional shape may be formed so that the diameter of a circumscribed circle that circumscribes the cross-sectional shape or the diameter of the inscribed circle inscribed in the cross-sectional shape is 2 mm to 10 mm.

  In the above embodiment, the vulcanized tread is described as being disposed. However, an unvulcanized tread rubber may be attached. In this case, the retreaded tire is formed with the recesses 23; 24; 25 by integrating the tread by vulcanization molding using a molding die for molding the product tire. During the rehabilitation, the worn tread portion 5 can be easily removed with the recesses 23; 24; 25 as a guide. The tire T has been described as a radial tire, but may be a bias tire.

  In addition, when the width direction groove | channel is divided | segmented into right and left in a tire width direction and there is no width direction groove | channel extended continuously on both tire side surfaces, the center recessed part 23 does not need to be formed.

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. Various modifications or improvements can be added to the above embodiment.

5 treads, 11 carcass, 12 bead cores,
13 belt layer, 13E outermost belt, 14 bead filler,
15 inner liner rubber, 16 sidewall rubber, 17 tread rubber,
20 tread block, 21 width direction groove, 21a groove bottom surface, 22 circumferential groove,
23 central recess, 24; 25 recess, C width center, d1; d2; d3 diameter,
L1; L2; L3 depth, T tire, W tire width dimension.

Claims (6)

A groove formed in the tread portion and extending in the tire width direction;
A belt disposed radially inward from the tread portion;
A plurality of recesses recessed in the tire radial direction from the groove bottom surface of the groove part,
The plurality of recesses, a first recess provided symmetrically with respect to the center in the tire width direction on the thinnest point where the thickness from the belt surface to the groove bottom surface is the thinnest,
The vehicle tire which has a 2nd recessed part spaced apart in the tire width direction inner side or the outer side rather than said 1st recessed part. The first recess is located on the inner side in the width direction from a reference point obtained by multiplying the tire width dimension by a quarter from the center in the tire width direction,
2. The vehicle tire according to claim 1, wherein the second concave portion is spaced outward by a distance in the tire width direction by multiplying the tire width dimension by one-eighth than the first concave portion. The first recess is located on the outer side in the width direction from a reference point obtained by multiplying the tire width dimension by a quarter from the center in the tire width direction,
2. The vehicle tire according to claim 1, wherein the second concave portion is spaced further inward in the tire width direction by a distance obtained by multiplying the tire width dimension by 1/8 than the first concave portion.   The vehicle tire according to any one of claims 1 to 3, wherein the plurality of recesses further includes a third recess provided in the center in the tire width direction. Based on the tire design drawing, a step of identifying the thinnest point with the smallest thickness between the belt disposed radially inward from the tread portion and the groove bottom surface of the groove portion extending in the tire width direction formed in the tread portion. When,
Forming a recess recessed in the tire radial direction from the groove bottom surface on the thinnest point symmetrically with respect to the center in the tire width direction;
Removing the tread portion until the concave portion becomes invisible.   After forming the said recessed part on the thinnest point, it separated from the said recessed part inside the tire width direction or the outer side, and provided with the process of forming the 2nd recessed part provided symmetrically with respect to the tire width direction center. Item 6. A vehicle tire buffing method according to Item 5.

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