JP6793045B2 - Holding member for supporting core for tires - Google Patents

Description

The present invention is a rubber retainer disposed between the outer peripheral surface of the rim into which the pneumatic tire is fitted and the annular core that supports the pneumatic tire from the inside when the internal pressure of the pneumatic tire drops. More specifically, the present invention relates to a holding member for a support core for a tire, which makes it unnecessary to process a vent hole for the core and increases the degree of freedom in the position of a valve arranged on the rim.

Pneumatic tires are mounted on the wheels of vehicles with new transportation systems such as AGT (Automated Guideway Transit) and monorail. In such a new transportation system, if the pneumatic tire punctures and the vehicle cannot run, other vehicles cannot run on the track, and the timetable is significantly disturbed. In order to avoid such inconvenience, an annular core that supports the pneumatic tire from the inside when the internal pressure of the pneumatic tire decreases is installed on the outer peripheral surface of the rim to which the pneumatic tire is fitted. , Even if the pneumatic tire punctures, it is possible to drive to the relay point at the minimum necessary.

Conventionally, in a wheel provided with a support core for a tire of this type, a holding member for the support core for a tire made of a rubber annular body is arranged between the outer peripheral surface of the rim and the core as a cushioning material. Have been proposed (see, for example, Patent Documents 1 and 2). By inserting such a holding member between the outer peripheral surface of the rim and the core, it is possible to prevent the generation of abnormal noise during normal traveling and reduce the generation of vibration during puncture traveling.

However, since a valve for filling air communicates with the outer peripheral surface of the rim, when a rubber holding member is arranged between the outer peripheral surface of the rim and the core, the holding member blocks the valve. There is a disadvantage that the air cannot be filled. Therefore, it is necessary to provide a ventilation path through the annular body constituting the holding member, and to process a ventilation hole in the metal core. However, it takes time and effort to process the ventilation holes for the metal core, and the strength of the core may decrease. Therefore, it is desired to eliminate the processing of the ventilation hole for the core.

Further, since the valve for filling air is generally arranged at the center of the rim, the ventilation path formed in the annular body is arranged at a position corresponding to the center of the rim, and the ventilation path is located at the end of the valve. It is configured to contain (valve rubber). However, the holding member of the support core for the tire having such a structure is effective when the valve for air filling is arranged at the center portion of the rim, but the position where the valve is off the center portion of the rim. It is difficult to apply when placed in, which is a factor that constrains the position of the valve.

JP-A-54-6205 Jitsukosho No. 64-322

An object of the present invention is to provide a holding member for a support core for a tire, which eliminates the need to process a vent hole for the core and increases the degree of freedom in the position of a valve arranged on the rim. It is in.

The holding member of the support core for a tire of the present invention for solving the above object supports the pneumatic tire from the inside when the inner pressure of the pneumatic tire is lowered and the outer peripheral surface of the rim to which the pneumatic tire is fitted. A rubber holding member disposed between an annular core and an annular body having a recess on the outer peripheral surface for receiving a base end portion of the core, and the recess of the annular body. A ventilation hole penetrating the annular body is formed at a position corresponding to the above, and an inner circumferential groove extending in the circumferential direction of the annular body and communicating with the ventilation hole is formed on the inner peripheral surface of the annular body. An outer circumferential groove extending in the circumferential direction of the annular body and communicating with the ventilation hole and a width direction groove extending in the width direction of the annular body and communicating with the outer circumferential groove are formed on the bottom surface of the annular body. The groove is characterized in that it extends on the side surface of the recess in the thickness direction of the annular body.

In the present invention, in the holding member of the support core for a tire made of an annular body having a recess on the outer peripheral surface for receiving the base end portion of the core, ventilation penetrating the annular body at a position corresponding to the recess of the annular body. A hole is formed, and an inner circumferential groove extending in the circumferential direction of the annular body and communicating with the ventilation hole is formed on the inner peripheral surface of the annular body, and extending in the circumferential direction of the annular body on the bottom surface of the recess to communicate with the ventilation hole. A structure is formed in which a lateral groove extending in the width direction of the annular body and a width direction groove extending in the width direction of the annular body and communicating with the outer circumferential groove are formed, and the width direction groove extends in the thickness direction of the annular body on the side surface of the recess. By adopting it, a series of ventilation paths including the above-mentioned inner circumferential groove, ventilation hole, outer circumferential groove and width direction groove can be created between the valve communicating with the outer peripheral surface of the rim and the internal space of the pneumatic tire. Since it is formed, it is possible to eliminate the need for processing of ventilation holes for the core. Further, since the structure is a combination of the inner circumferential groove, the ventilation hole, the outer circumferential groove, and the width direction groove, the position of the inner circumferential groove can be changed according to the position of the valve. Therefore, the degree of freedom in the position of the valve arranged on the rim can be increased.

In the present invention, the groove width W1 of the inner circumferential groove is preferably 3 mm or more and 40 mm or less. As a result, the ventilation path can be secured without impairing the holding ability of the core by the holding member and the durability of the holding member.

The groove depth G1 of the inner circumferential groove is preferably 2 mm or more and 15 mm or less. As a result, the ventilation path can be secured without impairing the holding ability of the core by the holding member and the durability of the holding member.

It is preferable that the groove width W2 of the outer circumferential groove satisfies the relationship of 0.80 ≦ W2 / W1 ≦ 1.20 with respect to the groove width W1 of the inner peripheral groove. As a result, the ventilation path can be secured without impairing the holding ability of the core by the holding member and the durability of the holding member.

It is preferable that the groove width W3 of the width direction groove satisfies the relationship of 0.80 ≦ W3 / W1 ≦ 1.20 with respect to the groove width W1 of the inner circumferential groove. As a result, the ventilation path can be secured without impairing the holding ability of the core by the holding member and the durability of the holding member.

It is preferable that the groove depth G2 of the outer circumferential groove satisfies the relationship of 0.40 ≦ G2 / G1 ≦ 1.20 with respect to the groove depth G1 of the inner peripheral groove. As a result, the ventilation path can be secured without impairing the holding ability of the core by the holding member and the durability of the holding member.

It is preferable that the diameter D of the ventilation hole satisfies the relationship of 0.20 ≦ D / W1 ≦ 1.00 with respect to the groove width W1 of the inner circumferential groove. As a result, the ventilation path can be secured without impairing the holding ability of the core by the holding member and the durability of the holding member.

The holding member for the support core for a tire of the present invention is preferably applied to, but is not limited to, a wheel mounted on a vehicle of a new transportation system represented by an AGT or a monorail. It is applicable to various wheels equipped with a support core.

It is a meridian cross-sectional view which shows the wheel provided with the holding member of the support core for a tire which concerns on embodiment of this invention. It is a top view which shows the state which the holding member of the support core for a tire which concerns on embodiment of this invention is developed. It is a bottom view which shows the state which the holding member of the support core for a tire which concerns on embodiment of this invention is developed. It is sectional drawing which shows the holding member of the support core for a tire which comprises embodiment of this invention. It is a top view which shows the developed state of the holding member of the support core for a tire which consists of another embodiment of this invention. It is a bottom view which shows the state in which the holding member of the support core for a tire which comprises the other embodiment of this invention is developed. It is sectional drawing which shows the holding member of the support core for a tire which comprises another embodiment of this invention. It is a meridian cross-sectional view which shows the wheel provided with the holding member of the support core for a conventional tire.

Hereinafter, the configuration of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 shows a wheel provided with a holding member for a tire supporting core according to an embodiment of the present invention, and FIGS. 2 to 4 show a holding member for the tire supporting core.

As shown in FIG. 1, this wheel has an annular rim 1, a valve 2 attached to the rim 1, a pneumatic tire 3 fitted to the rim 1, and when the internal pressure of the pneumatic tire 3 drops. An annular core 4 that supports the pneumatic tire 3 from the inside, and a rubber holding member 5 arranged between the outer peripheral surface of the rim 1 and the core 4 are provided. The valve 2 is arranged at a position deviated from the center portion of the rim 1, and the end portion (valve rubber) of the valve 2 slightly protrudes from the outer peripheral surface of the rim 1. The core 4 is connected to the web 41 extending in the circumferential direction of the core 4 at the center of the rim 1, the inner flange 42 connected to the inner peripheral side of the web 41, and the outer flange side of the web 41. It is composed of an outer flange 43, and a plurality of reinforcing plates 44 extending in the width direction of the core 4 in a region surrounded by the web 41, the inner flange 42, and the outer flange 43. These reinforcing plates 44 are intermittently arranged along the circumferential direction of the core 4.

As shown in FIGS. 2 to 4, the holding member 5 is composed of an annular body 50 having an inner peripheral surface 50A and an outer peripheral surface 50B. The annular body 50 abuts on the bead portions on both sides of the pneumatic tire 3 in a state of being arranged on the outer peripheral surface of the rim 1, and the positions of these bead portions are fixed to the rim 1. On the outer peripheral surface 50B of the annular body 50, a recess 51 for receiving the base end portion (inner flange 42) of the core 4 is formed along the circumferential direction of the annular body 50. A ventilation hole 52 that penetrates the annular body 50 in the thickness direction is formed at a position corresponding to the recess 51 of the annular body 50. On the other hand, the inner peripheral surface 50A of the annular body 50 is formed with an inner circumferential groove 53 extending in the circumferential direction of the annular body 50 and communicating with the ventilation hole 52. The inner circumferential groove 53 is configured to include the end portion of the valve 2 arranged at a position deviated from the center portion of the rim 1. Further, on the bottom surface 51B of the recess 51, a plurality of outer circumferential grooves 55 extending in the circumferential direction of the annular body 50 and communicating with the ventilation hole 52, and a plurality of outer circumferential grooves 55 extending in the width direction of the annular body 50 and communicating with the outer circumferential groove 55. The widthwise groove 56 of the book is formed. Then, at least one widthwise groove 56 reaches the side surface 51C of the recess 51, and extends along the side surface 51C in the thickness direction of the annular body 50. In particular, it is desirable that the groove 56 in the width direction reaches the outer peripheral surface 50B of the annular body 50.

In the wheel provided with the holding member 5 for the support core for a tire described above, in the holding member 5 made of an annular body 50 having a recess 51 for receiving the base end portion of the core 4 on the outer peripheral surface 50B, the annular body 50 A ventilation hole 52 penetrating the annular body 50 is formed at a position corresponding to the recess 51, and an inner circumferential groove extending in the circumferential direction of the annular body 50 and communicating with the ventilation hole 52 on the inner peripheral surface 50A of the annular body 50. 53 is formed, and the width extending in the circumferential direction of the annular body 50 and communicating with the ventilation hole 52 and the width extending in the width direction of the annular body 50 and communicating with the outer peripheral groove 55 on the bottom surface 51B of the recess 51. A directional groove 56 is formed, and by adopting a structure in which the width directional groove 56 extends in the thickness direction of the annular body 50 on the side surface 51C of the recess 51, the valve 2 communicating with the outer peripheral surface of the rim 1 and air are adopted. A series of ventilation paths including an inner circumferential groove 53, a ventilation hole 52, an outer circumferential groove 55, and a width direction groove 56 are formed between the inner space of the tire 3. Therefore, it is possible to eliminate the need to process the ventilation hole for the core 4. Further, since the structure is a combination of the inner circumferential groove 53, the ventilation hole 52, the outer circumferential groove 55, and the width direction groove 56, the position of the inner circumferential groove 53 can be changed according to the position of the valve 2. It will be possible. Therefore, the degree of freedom in the position of the valve 2 arranged on the rim 1 can be increased.

5 and 7 show a holding member for a tire support core according to another embodiment of the present invention. In FIGS. 5 to 7, the same objects as those in FIGS. 1 to 4 are designated by the same reference numerals, and detailed description of the parts thereof will be omitted.

In FIGS. 5 to 7, a recess 51 for receiving the base end portion of the core 4 is formed on the outer peripheral surface 50B of the annular body 50 constituting the holding member 5. A ventilation hole 52 penetrating the annular body 50 is formed at a position corresponding to the recess 51 of the annular body 50. On the other hand, the inner peripheral surface 50A of the annular body 50 is formed with an inner circumferential groove 53 extending in the circumferential direction of the annular body 50 and communicating with the ventilation hole 52. Further, on the bottom surface 51B of the recess 51, a plurality of outer circumferential grooves 55 extending in the circumferential direction of the annular body 50 and communicating with the ventilation hole 52, and a plurality of outer circumferential grooves 55 extending in the width direction of the annular body 50 and communicating with the outer circumferential groove 55. A widthwise groove 56 of the book is formed, and the widthwise groove 56 extends in the thickness direction of the annular body 50 on the side surface 51C of the recess 51. The ventilation hole 52, the inner circumferential groove 53, and the outer circumferential groove 55 are arranged at the center of the annular body 50. Therefore, when the valve 2 is arranged at the center portion of the rim 1, the inner peripheral groove 53 includes the end portion of the valve 2.

In the tire supporting core holding member 5 described above, the inner circumferential groove 53, the ventilation hole 52, and the outer circumferential groove 55 are between the valve 2 communicating with the outer peripheral surface of the rim 1 and the internal space of the pneumatic tire 3. A series of ventilation paths including the width direction groove 56 and the width direction groove 56 are formed. Therefore, as in the above-described embodiment, it is possible to eliminate the need to process the ventilation hole for the core 4. Further, the position of the inner circumferential groove 53 can be appropriately changed according to the position of the valve 2.

In the holding member 5 of the support core for a tire, the groove width W1 of the inner circumferential groove 53 is preferably 3 mm or more and 40 mm or less, more preferably 15 mm or more and 30 mm or less. As a result, the ventilation path can be secured without impairing the holding ability of the core 4 by the holding member 5 and the durability of the holding member 5. If the groove width W1 of the inner circumferential groove 53 is too small, it becomes difficult to secure a ventilation path, and conversely, if it is too large, the holding capacity of the core 4 and the durability of the holding member 5 deteriorate. The groove width W1 of the inner circumferential groove 53 needs to be larger than the diameter of the valve rubber.

In the holding member 5 of the support core for a tire, the groove depth G1 of the inner circumferential groove 53 is preferably 2 mm or more and 15 mm or less, more preferably 4 mm or more and 10 mm or less. As a result, the ventilation path can be secured without impairing the holding ability of the core 4 by the holding member 5 and the durability of the holding member 5. If the groove depth G1 of the inner circumferential groove 53 is too small, it becomes difficult to secure a ventilation path, and conversely, if it is too large, the holding capacity of the core 4 and the durability of the holding member 5 deteriorate. The groove depth G1 of the inner circumferential groove 53 needs to be larger than the height of the valve rubber.

In the tire support core holding member 5, the groove width W2 of the outer circumferential groove 55 satisfies the relationship of 0.80 ≦ W2 / W1 ≦ 1.20 with respect to the groove width W1 of the inner peripheral groove 53. good. As a result, the ventilation path can be secured without impairing the holding ability of the core 4 by the holding member 5 and the durability of the holding member 5. If the groove width W2 of the outer circumferential groove 55 is too small, it becomes difficult to secure a ventilation path, and conversely, if it is too large, the amount of deformation of the holding member 5 becomes large, so that the holding capacity of the core 4 and the durability of the holding member 5 become large. The sex is reduced.

In the holding member 5 of the support core for a tire, the groove width W3 of the width direction groove 56 may satisfy the relationship of 0.80 ≦ W3 / W1 ≦ 1.20 with respect to the groove width W1 of the inner circumferential groove 53. .. As a result, the ventilation path can be secured without impairing the holding ability of the core 4 by the holding member 5 and the durability of the holding member 5. If the groove width W3 of the groove 56 in the width direction is too small, it becomes difficult to secure a ventilation path, and conversely, if it is too large, the amount of deformation of the holding member 5 becomes large, so that the holding capacity of the core 4 and the durability of the holding member 5 become large. Decreases.

In the tire support core holding member 5, the groove depth G2 of the outer circumferential groove 55 has a relationship of 0.80 ≦ G2 / G1 ≦ 1.20 with respect to the groove depth G1 of the inner peripheral groove 53. More preferably, the relationship of 0.90 ≦ G2 / G1 ≦ 1.10 is satisfied. Further, the groove depth G2 of the outer circumferential groove 55 is preferably 2 mm or more and 15 mm or less, more preferably 4 mm or more and 10 mm or less. As a result, the ventilation path can be secured without impairing the holding ability of the core 4 by the holding member 5 and the durability of the holding member 5. If the groove depth G2 of the outer circumferential groove 55 is too small, it becomes difficult to secure a ventilation path, and conversely, if it is too large, the amount of deformation of the holding member 5 increases, so that the holding capacity of the core 4 and the holding member 5 Durability is reduced.

In the tire support core holding member 5, the groove depth G3 of the width direction groove 56 has a relationship of 0.80 ≦ G3 / G1 ≦ 1.20 with respect to the groove depth G1 of the inner circumferential groove 53. It is preferable that the relationship of 0.90 ≦ G3 / G1 ≦ 1.10 is satisfied. Further, the groove depth G3 of the width direction groove 56 is preferably 2 mm or more and 15 mm or less, more preferably 4 mm or more and 10 mm or less. As a result, the ventilation path can be secured without impairing the holding ability of the core 4 by the holding member 5 and the durability of the holding member 5. If the groove depth G3 of the width direction groove 56 is too small, it becomes difficult to secure a ventilation path, and conversely, if it is too large, the amount of deformation of the holding member 5 becomes large, so that the holding capacity of the core 4 and the durability of the holding member 5 become large. The sex is reduced.

In the tire support core holding member 5, the diameter D of the ventilation hole 52 has a relationship of 0.20 ≦ D / W1 ≦ 1.00 with respect to the groove width W1 of the inner circumferential groove 53, more preferably 0. It is preferable that the relationship of 50 ≦ D / W1 ≦ 1.00 is satisfied. Further, the diameter D of the ventilation hole 52 is preferably 3 mm or more and 15 mm or less. As a result, the ventilation path can be secured without impairing the holding ability of the core 4 by the holding member 5 and the durability of the holding member 5. If the diameter D of the ventilation hole 52 is too small, it becomes difficult to secure the ventilation path, and conversely, if it is too large, the amount of deformation of the holding member 5 increases, so that the holding capacity of the core 4 and the durability of the holding member 5 decrease. To do.

Hereinafter, for comparison with the present invention, a wheel provided with a holding member for a conventional support core for a tire will be described. FIG. 8 shows a wheel provided with a conventional tire support core holding member. As shown in FIG. 8, in the conventional wheel, the valve 2 is arranged at the center portion of the rim 1. On the other hand, in the center portion of the annular body 50 constituting the holding member 5, a ventilation path 52X penetrating the annular body 50 is formed along the circumferential direction of the annular body 50. Further, a ventilation hole 45 is formed in the vicinity of the web 41 of the core 4.

As described above, in the conventional wheel, the ventilation path 52X is formed in the center portion of the annular body 50 constituting the holding member 5 in order to correspond to the valve 2 arranged in the center portion of the rim 1, while the core 4 is formed. However, although the ventilation hole 45 is formed by drilling or the like, the work of processing the ventilation hole 45 for the metal core 4 is troublesome and may cause a decrease in the strength of the core 4. is there. Further, in the structure in which the ventilation path 52X is formed in the center portion of the annular body 50, the position of the valve 2 is limited to the center portion of the rim 1. On the other hand, in the present invention, it is possible to eliminate the above-mentioned inconvenience.

An annular rim, a valve attached to the rim, a pneumatic tire fitted to the rim (tire size: 315 / 70R20), and the pneumatic tire being supported from the inside when the internal pressure of the pneumatic tire drops. Conventional Examples and Examples in which the configurations of the core and the holding member are different in the wheel provided with the annular core and the rubber holding member arranged between the outer peripheral surface of the rim and the core. 1 to 13 wheels were manufactured.

In the conventional example, a valve is arranged at the center of the rim, a recess for receiving the base end of the core is formed on the outer peripheral surface of the annular body constituting the holding member, and the annular body is placed at the center of the annular body. A ventilation path was formed along the circumferential direction of the annular body, while a ventilation hole was formed near the web of the core. The groove width of the ventilation path was 45 mm, and the groove depth was 20 mm.

In Examples 1 to 13, the valve is arranged at a position deviated from the center portion of the rim, and a recess for receiving the base end portion of the core is formed on the outer peripheral surface of the annular body constituting the holding member to form the annular body. A ventilation hole is formed at a position corresponding to the recess, an inner circumferential groove communicating with the ventilation hole is formed on the inner peripheral surface of the annular body, and an outer circumferential groove communicating with the ventilation hole and the outer circumferential groove are formed on the bottom surface of the recess. A widthwise groove communicating with the groove was formed, and the widthwise groove was extended on the side surface of the recess in the thickness direction of the annular body. Groove width W1 of inner circumferential groove, groove depth G1 of inner circumferential groove, ratio W2 / W1 of groove width W2 of outer circumferential groove to groove width W1 of inner circumferential groove, groove width W1 of inner circumferential groove Ratio W3 / W1 of the groove width W3 of the width direction groove with respect to the ratio W3 / W1 of the groove width W3 of the width direction The ratio D / W1 of the diameter D of the above was set as shown in Tables 1 and 2. On the other hand, no ventilation holes were formed in the core.

With respect to the wheels of the above-mentioned conventional examples and Examples 1 to 13, the necessity of the core drilling process and the degree of freedom of the valve position were determined, and the air permeability and the core retention were evaluated by the following evaluation methods. The results are also shown in Tables 1 and 2.

Breathability:
Air was filled through the valve of the rim from the state of 0 kPa until it reached 900 kPa, and the time required for the filling was measured. The evaluation result is shown by an index of 100 in the conventional example using the reciprocal of the measured value. The larger the index value, the better the air permeability.

Core retention:
After mounting the above wheels on an indoor drum tester and running for 60 minutes under the condition of a load of 4000 kgf and a speed of 15 km / h with the valve open, the amount of crushing of the holding member in the thickness direction was measured, and the maximum value thereof was measured. Asked. The evaluation result is shown by an index of 100 in the conventional example using the reciprocal of the measured value. The larger the exponential value, the better the core retention.

As shown in Tables 1 and 2, in the wheels provided with the holding members for the support cores for tires of Examples 1 to 13, it is not necessary to process the ventilation holes for the cores, and the degree of freedom in valve position is high. There is an advantage. Moreover, in the wheels provided with the holding members for the support cores for tires of Examples 1 to 13, it was possible to sufficiently secure the ventilation path without substantially impairing the holding ability of the cores by the holding members.

1 Rim 2 Valve 3 Pneumatic tire 4 Core 5 Retaining member 50 Ring body 50A Inner peripheral surface 50B Outer peripheral surface 51 Recessed 51B Bottom surface 51C Side surface 52 Vent hole 53 Inner circumferential groove 55 Outer circumferential groove 56 Width groove

Claims (7)

A rubber holding member arranged between the outer peripheral surface of the rim into which the pneumatic tire is fitted and the annular core that supports the pneumatic tire from the inside when the internal pressure of the pneumatic tire decreases. The outer peripheral surface of the annular body is provided with a recess for receiving the base end portion of the core, and a ventilation hole penetrating the annular body is formed at a position corresponding to the recess of the annular body. An inner circumferential groove extending in the circumferential direction of the annular body and communicating with the ventilation hole is formed on the inner peripheral surface of the concave portion, and an outer peripheral circumference extending in the circumferential direction of the annular body and communicating with the ventilation hole on the bottom surface of the recess. A width direction groove extending in the width direction of the annular body and the directional groove and communicating with the outer circumferential groove is formed, and the width direction groove extends in the thickness direction of the annular body on the side surface of the recess. A characteristic holding member for a support core for a tire. The holding member for a tire supporting core according to claim 1, wherein the groove width W1 of the inner circumferential groove is 3 mm or more and 40 mm or less. The holding member for a tire support core according to claim 1 or 2, wherein the groove depth G1 of the inner circumferential groove is 2 mm or more and 15 mm or less. Any of claims 1 to 3, wherein the groove width W2 of the outer circumferential groove satisfies the relationship of 0.80 ≦ W2 / W1 ≦ 1.20 with respect to the groove width W1 of the inner peripheral groove. Holding member for supporting core for tires described in Crab. Any of claims 1 to 4, wherein the groove width W3 of the width direction groove satisfies the relationship of 0.80 ≦ W3 / W1 ≦ 1.20 with respect to the groove width W1 of the inner peripheral direction groove. The holding member for the support core for a tire described in 1. Claims 1 to 5 are characterized in that the groove depth G2 of the outer circumferential groove satisfies the relationship of 0.80 ≦ G2 / G1 ≦ 1.20 with respect to the groove depth G1 of the inner peripheral groove. The holding member for the support core for a tire according to any one of. The invention according to any one of claims 1 to 6, wherein the diameter D of the ventilation hole satisfies the relationship of 0.20 ≦ D / W1 ≦ 1.00 with respect to the groove width W1 of the inner circumferential groove. Holding member for supporting cores for tires.

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