JP4521265B2 - Pneumatic tire and tire / rim assembly - Google Patents

Description

  The present invention relates to a pneumatic tire and a tire / rim assembly, and in particular, a pneumatic tire in which a tire air chamber is divided into a plurality of portions in a tire width direction by a partition wall formed inside the tire, and a tire / rim. It relates to an assembly.

  BACKGROUND ART Conventionally, a pneumatic tire is known in which a tire air chamber is divided into a plurality of tire width directions by a partition wall formed inside the tire (see, for example, Patent Document 1).

  For example, in the pneumatic tire described in Patent Literature 1, when the pneumatic tire is mounted on the rim, a pair of partition walls that divide the tire chamber formed between the pneumatic tire and the rim into three in the tire width direction. Is provided.

According to the pneumatic tire described in Patent Document 1, the tire air chamber can be divided into three independent tire air chambers in the tire width direction by the partition wall portion. It is possible to set all the air pressures at different pressures.
Japanese Patent Laid-Open No. 2003-39914 (FIG. 3)

  However, the pneumatic tire described in Patent Document 1 has the following problems because the inner diameter of the outer bead portion and the inner diameter of the inner bead portion are set to be the same. That is, in the rim described in Patent Document 1, since the bead sheet has a constant diameter in the width direction, the partition wall portion may move and cause air leakage, such as when the internal pressures of adjacent air chambers are different.

  Therefore, in fact, in order to fix the inner bead portion formed in the partition wall portion, it is necessary to fix the rim having a constant diameter with an adhesive, and when the adhesive is not used, the inner bead is fixed. A specially shaped rim with a tall hump to prevent movement of the part is located beside the inner bead, and the inner bead of the partition wall is caught by the hump when assembling the rim. Also, since the inside of the tire is not visible, it is difficult to arrange the inner bead portion of the partition wall at a predetermined position, and the rim assembling work is very difficult.

  Further, in a pneumatic tire including a partition portion inside the tire as described in Patent Document 1, when the tire side portion and the connecting portion between the tread portion and the partition portion are located in the ground tread surface of the tread portion, the partition wall Since the force applied to the partition wall from the road surface increases as the formation direction of the portion and the normal line of the tread portion approach each other, the partition wall may be damaged.

  The present invention has been made in view of the above circumstances, and in a pneumatic tire and a tire / rim assembly in which a tire air chamber is divided into a plurality of tire width directions by a partition wall portion formed inside the tire, An object of the present invention is to improve the work of assembling the pneumatic tire to the rim, prevent damage to the partition wall, and improve the durability of the pneumatic tire.

  The pneumatic tire according to claim 1 is a pair of left and right tire side portions formed on both sides in the tire width direction, and a tire radial outer end of one tire side portion and the other of the pair of left and right tire side portions. The outer bead portion is provided spaced apart in the tire width direction between the tread portion that connects the tire radial outer end of the tire side portion and the outer bead portion formed on each of the pair of left and right tire side portions. The tire side portion and the tread portion extend from the inner surface of the tire in the tire radial direction and have an inner bead portion in contact with the rim at the inner radial end of the tire, and the tire A pneumatic tire comprising a pair of left and right partition walls that divide a tire air chamber formed by a side portion, the tread portion, and the rim into three in the tire width direction. The inner diameter of the outer bead portion is RO and the inner diameter of the inner bead portion is RI. The ground contact width of the tread portion on a flat surface in a state where a specified internal pressure is filled and a specified load is applied is TW. A first virtual reference line that extends along the tire side part and the tread part and passes through a middle point in the thickness direction of the tire side part and the tread part, and extends along the partition part and has a thickness of the partition part. The intersection with the second virtual reference line passing through the intermediate point in the thickness direction is a connecting portion between the tire side portion, the tread portion, and the partition portion, and the tire width direction between one and the other of the connecting portions. RO> RI, TW ≦ K, where KW is KW, tire height is TH, and KD is 1/2 of the dimension obtained by subtracting the inner diameter of the outer bead from the inner diameter of the connecting portion. Satisfy the KD ≧ 1 / 2TH, it is characterized by.

  Note that the contact width of the tread portion is measured with the following specified load and specified internal pressure.

  The specified load is the maximum load (maximum load capacity) of a single wheel at the applicable size (ply rating) described in the following standard. The specified internal pressure is the single wheel at the applicable size described in the following standard. The air pressure corresponding to the maximum load (maximum load capacity).

  The standard is determined by an industrial standard effective in the region where the tire is produced or used. For example, in the United States it is “The Tire and Rim Association Inc. Year Book”, in Europe it is “The European Tire and Rim Technical Organization Standards Manual”, and in Japan it is the Japan Automobile Tire Association “JATMA Year Book”. It is prescribed.

  Next, the operation of the pneumatic tire according to claim 1 will be described.

  2. The pneumatic tire according to claim 1, wherein an inner diameter RO of the outer bead portion is formed larger than an inner diameter RI of the inner bead portion, and the outer bead seat set to the same diameter as the inner diameter of the outer bead portion. The three tire air chambers are assembled to a rim provided with an inner bead seat that is provided on the inner side in the tire axial direction via a step portion and set to the same inner diameter as the inner bead portion. A tire / rim assembly provided with

  This tire / rim assembly supports the load in other punctured tire chambers, such as punctures on the ground contact surface due to nails, etc., and side punctures due to curb rubbing, etc. However, it is possible to continue driving safely without any problems.

  The rim prevents the inner bead portion from moving outward in the tire width direction due to the difference in diameter between the outer bead seat to which the outer bead portion is attached and the inner bead seat to which the inner bead portion is attached. Since the step is formed, it is not necessary to form a tall hump part on the outer side in the tire width direction of the inner bead part which causes the inner bead part to be pulled and deteriorates workability when assembling the rim. Become.

  In addition, the hump part inside a tire width direction of an inner bead part is not essential.

  In the pneumatic tire according to claim 1, the contact width of the tread portion on the flat surface in a state where the specified internal pressure is filled and the specified load is applied is TW, and extends along the tire side portion and the tread portion. The intersection of the first virtual reference line passing through the thickness direction intermediate point of the tire side part and the tread part and the second virtual reference line extending along the partition wall part and passing through the thickness direction intermediate point of the partition wall part Is a connecting part between the tire side part and the tread part and the partition part, and when the dimension in the tire width direction between one and the other of the connecting parts is KW, TW ≦ KW is satisfied. Yes.

  That is, the tire side part and the connecting part between the tread part and the partition part are located on the normal line passing through the grounding end of the tread part or on the outer side in the tire width direction.

  Compared to the configuration in which the tire side portion and the connecting portion between the tread portion and the partition wall portion are located on the inner side in the tire radial direction of the normal line passing through the ground contact end of the tread portion, as in the conventional case, the tire Since the connecting portion between the side portion and the tread portion and the partition portion is separated from the tread portion, this makes it difficult for force from the road surface to be transmitted to the partition portion, so that the force applied from the road surface to the partition portion can be reduced. Accordingly, the partition wall can be prevented from being damaged, and the durability of the tire can be improved as compared with the conventional case.

  In the pneumatic tire according to claim 1, KD ≧ 1 / 2TH, where TY is a tire height TH, and KD is ½ of a dimension obtained by subtracting the inner diameter of the outer bead portion from the inner diameter of the connecting portion. It is configured to satisfy.

  That is, the connecting portion is configured to be located on the outer side in the tire radial direction with respect to 1/2 of the tire height TH.

  At this time, if KD <1 / 2TH, the tire air chamber formed by the tire side portion and the partition wall portion becomes extremely small, so that the effect of dividing the tire air chamber into three parts can be exhibited. However, if the tire is set to satisfy KD ≧ 1 / 2TH as in the pneumatic tire according to claim 1, a tire air chamber formed by the tire side portion and the partition wall portion can be sufficiently secured. This is preferable because it is possible.

  The invention according to claim 2 is the pneumatic tire according to claim 1, wherein the inner diameter RO of the outer bead portion and the inner diameter RI of the inner bead portion satisfy 0 <RO-RI <50 mm. It is characterized by.

  Next, the operation of the pneumatic tire according to claim 2 will be described.

  When the relationship between the inner diameter RO of the outer bead part and the inner diameter RI of the inner bead part is RO = RI, the inner bead part formed in the partition wall part is taller to prevent movement outward in the tire axial direction. A rim provided with a hump portion must be used, and the assembling work must be very difficult. Further, when RO-RI ≧ 50 mm, it is difficult and unrealistic to manufacture a tire using the current tire manufacturing method.

  Furthermore, if the relationship between the inner diameter RO of the outer bead portion and the inner diameter RI of the inner bead portion is RO-RI ≧ 50 mm, the inner diameter of the inner bead portion becomes too small with respect to the inner diameter of the outer bead portion. As a result, the diameter of the brake that can be mounted on the inner side of the rim is reduced. This is not preferable because there is a possibility that the vehicle motion performance is deteriorated.

  Therefore, it is preferable to satisfy 0 <RO-RI <50 mm because it is possible to prevent inconvenience as described above.

  The invention according to claim 3 is the pneumatic tire according to claim 1 or 2, wherein the pair of left and right outer bead portions are provided with outer bead cores extending along the tire circumferential direction, respectively. The pair of left and right inner bead portions are respectively provided with inner bead cores that are disposed on the inner side in the tire width direction of the outer bead core and extend along the tire circumferential direction, and the other from the one tire side portion to the other through the tread portion. In a region extending to the tire side portion, a first carcass ply configured to straddle between the pair of outer bead cores in a toroidal manner and having both ends in the tire width direction locked to the pair of outer bead cores, respectively. In the region from one partition wall to the other partition wall through the tread portion, the first carcass plastic is provided. A second carcass ply is provided that is disposed inside the tire and configured to straddle a toroidal shape between the pair of inner bead cores and has both ends in the tire width direction locked to each of the pair of inner bead cores, One end side in the tire width direction of the second carcass ply is wound around one of the pair of left and right inner bead cores from the outer side to the inner side of the tire, and the other end side in the tire width direction of the second carcass ply is The other of the pair of inner bead cores is wound up from the tire outer side toward the inner side.

  Next, the operation of the pneumatic tire according to claim 3 will be described.

  The first carcass ply reinforces the tire side part (bead part, sidewall part, tire shoulder part) and tread part, and the second carcass ply reinforces the partition part and tread part. The central tire chamber mainly shares the tension of the belt provided on the first carcass ply, so the internal pressure here is set lower than the tire chambers on both sides. A ground contact area can be ensured and, for example, the grip force can be improved.

  On the other hand, the tire chambers on both sides mainly share the ply tension of the tire side portion, so by setting the internal pressure here higher than the central tire chamber, the tire lateral rigidity can be increased, for example, The steering stability can be improved.

  By the way, when using a pneumatic tire in which the widthwise end of the second carcass ply is wound up from the inner side of the tire to the inner side of the inner bead core, the inner pressure of the tire chambers on both sides is temporarily set to the central tire chamber. By contrast, if the pressure is set high, the partition wall is pressed toward the center of the tire due to the pressure difference. A force is applied to rotate the rubber in the direction of arrow A in FIG.

  Therefore, when the internal pressure of the tire chambers on both sides is relatively higher than the internal pressure of the central tire chamber, and the differential pressure between the central tire chamber and the tire chambers on both sides becomes large (for example, a difference of 50 kPa or more). Pressure), and the partition wall may come off a predetermined position of the rim.

  On the other hand, as in the invention according to claim 3, one end side in the tire width direction of the second carcass ply is wound up from one side of the pair of left and right inner bead cores from the tire outer side to the inner side, and the tire width of the second carcass ply When the other end in the direction is wound around the other of the pair of left and right inner bead cores from the outside of the tire to the inside, the inner pressure of the air chambers on both sides is below the bead core and bead core due to the cord tension applied to the second carcass ply in the partition wall. A force is applied to rotate the rubber in the direction of arrow B in FIG.

  Therefore, if the internal pressure of the tire chambers on both sides is relatively higher than the internal pressure of the central tire chamber and the differential pressure between the central tire chamber and the tire chambers on both sides is large, As a result, even if the internal pressure of the central tire chamber becomes zero, the partition wall portion does not deviate from the predetermined position of the rim, and the internal pressures of the tire chambers on both sides in the tire axial direction can be maintained.

  A tire / rim assembly according to a fourth aspect includes the pneumatic tire according to any one of the first to third aspects, and a rim on which the pneumatic tire is mounted. A pair of left and right outer bead seats that are in contact with the inner peripheral surfaces of the pair of left and right outer bead portions; A pair of left and right inner bead sheets that are set to have a smaller diameter and come into contact with the inner peripheral surfaces of the pair of left and right inner bead parts, and are provided between one and the other of the pair of left and right inner bead sheets, And a drop having a smaller diameter than the bead sheet.

  Next, the operation of the tire / rim assembly of claim 4 will be described.

  By mounting the pneumatic tire according to any one of claims 1 to 3 on a rim, the inner peripheral surface of the bead portion contacts the side bead sheet, and the inner peripheral surface of the partition wall portion is the inner bead sheet. Thus, a tire / rim assembly having three tire air chambers independent in the tire axial direction can be obtained.

  For this reason, in any of the punctures on the contact surface due to nailing, etc., and the side punctures due to curb rubbing, etc., the other non-punctured tire chambers support the load, so there is some steering stability and Although the vibration ride quality deteriorates, the vehicle can continue to travel safely without problems.

  Also, the rim does not have a hump part that deteriorates workability by hooking the partition wall when assembling the rim as in the prior art, and the bead part and the partition wall can be dropped into the drop when assembling the rim. A pneumatic tire can be easily assembled.

  According to a fifth aspect of the present invention, in the tire / rim assembly according to the seventh aspect, the internal pressure of the tire chamber formed on both sides in the tire axial direction of the tire chamber is formed in the center in the tire axial direction. It is characterized by being set higher than the internal pressure of the tire chamber.

  Next, the operation of the pneumatic tire according to claim 5 will be described.

  For example, each tire chamber is set to a standard air pressure, then the air in the tire chamber in the center in the tire axial direction is evacuated, and the internal pressure in the tire chamber on both sides in the tire axial direction is set to be higher than the internal pressure in the tire chamber in the center in the tire axial direction. When the setting is relatively high, the rigidity in the longitudinal direction of the tire is lowered and the contact area is increased, so that it is possible to improve the vibration riding comfort when traveling on rough roads and the grip performance when traveling on icy and snowy roads.

  Also, if the tire pressure chambers on both sides in the tire axial direction are filled with air to increase the internal pressure, it is possible to increase the lateral rigidity and longitudinal rigidity of the tire. Steering stability can be improved while improving grip when traveling on the road.

  As described above, according to the pneumatic tire of the present invention, the tire side portion and the connecting portion of the tread portion and the partition wall portion are on the normal line passing through the grounding end of the tread portion or on the outer side in the tire width direction than that. Compared to the configuration in which the connecting portion between the tire side portion and the tread portion and the partition wall portion is located on the inner side in the tire radial direction of the normal passing through the grounding end of the tread portion as in the prior art. Thus, since the force from the road surface is not easily transmitted to the partition wall, the force applied to the partition wall from the road surface can be reduced. As a result, damage to the partition wall can be prevented, so that the durability of the tire can be improved as compared with the conventional case.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. It should be noted that members, arrangements, and the like described below do not limit the present invention, and it goes without saying that various modifications can be made in accordance with the spirit of the present invention.

[First embodiment]
First, a tire / rim assembly according to a first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a cross-sectional view showing a configuration of a tire / rim assembly in which a pneumatic tire (size: 225 / 55R17) is mounted on a rim, showing a first embodiment of the present invention.

(Composition of pneumatic tire)
The pneumatic tire 10 of the present embodiment is suitably used as a tire for a passenger car, and includes an outer bead core 18, an inner bead core 31, a first carcass ply 32, a second carcass ply 37, A tread rubber layer 23, a side rubber layer 19, a partition rubber layer 27, a belt 36, and inner liners 35 and 39 are provided as main components.

  The outer bead core 18 is configured to extend along the tire circumferential direction, and the inner bead core 31 is disposed on the inner side in the tire width direction of the outer bead core 18 and is configured to extend along the tire circumferential direction.

  The first carcass ply 32 is configured to straddle a toroidal shape between the pair of outer bead cores 18. Both ends of the first carcass ply 32 in the tire width direction are locked to the pair of outer bead cores 18 so as to be wound up from the tire inner side toward the outer side.

  The second carcass ply 37 is disposed inside the tire of the first carcass ply 32 and is configured to straddle between the pair of inner bead cores 31 in a toroidal shape. Both ends of the second carcass ply 37 in the tire width direction are locked to the pair of inner bead cores 31 so as to be wound up from the tire inner side toward the outer side.

  The first carcass ply 32 and the second carcass ply are constituted by a rubber coating of a plurality of organic fiber cords arranged in parallel to each other such as a radially arranged polyester cord and nylon cord.

  The first carcass ply 32 reinforces the outer bead portion 16, the tire side portion 20, and the tread portion 22 described later, and the second carcass ply 37 reinforces the partition wall portion 24 and the tread portion 22 described later. is doing.

  The tread rubber layer 23 is provided on the outer side in the tire radial direction of the first carcass ply 32, and in this example, the tread portion 22 is formed on the tire 10 by the tread layer 23. Further, a belt 36 is disposed on the tread portion 22 of the pneumatic tire 10 of the present example at a position on the outer side in the tire radial direction of the first carcass ply 32. The belt 36 is composed of, for example, two or more steel cord crossing layers.

  The side rubber layer 19 is provided on the outer side in the tire axial direction of the first carcass ply 32, and in this example, the tire side portion 20 is configured on the tire 10 by the side rubber layer 19. The tire side portion 20 includes regions of a tire shoulder portion 21, a sidewall portion 15, and an outer bead portion 16.

  The outer bead portion 16 of this example is formed so as to come into contact with the outer bead seat 46 of the rim 12, and the outer bead portion 16 includes a winding portion 32 </ b> A and a main body portion 32 </ b> B of the first carcass ply 32. In the middle, an outer bead filler 34 extending from the outer bead core 18 to the outer side in the tire radial direction is embedded.

  The partition rubber layer 27 is configured to extend inward in the tire radial direction along the tire outer side of the second carcass ply 37 from the tire inner side of the tire shoulder portion 21, and the inner end of the partition rubber layer 27 in the tire radial direction is The inner rim 12 is formed so as to contact the inner bead sheet 48 of the rim 12.

  In this example, the partition rubber layer 27 is formed along the second carcass ply 37 in this way, so that the tire air chamber formed by the tire side portion 20, the tread portion 22, and the rim 12 is changed to the tire width. A pair of left and right partition walls 24 divided into three in the direction is configured.

  That is, in this example, the main air chamber 26 is formed between the partition wall portion 24 and the partition wall portion 24, and the first auxiliary air chamber 28 is formed between the tire side portion 20 on the arrow L direction side and the partition wall portion 24. The second auxiliary air chamber 30 is formed between the tire side portion 20 and the partition wall portion 24 on the arrow R direction side.

  As described above, since the inner end in the tire radial direction of the inner bead portion 25 is in close contact with the rim 12, the main air chamber 26, the first sub air chamber 28, and the second sub air chamber 30 are independent of each other. Yes. An inner liner 35 is provided on the inner side surface of the auxiliary air chamber 26, and an inner liner 39 is provided on the inner side surfaces of the first auxiliary air chambers 28 and 30.

  Here, in the pneumatic tire of this example, the ground contact width of the tread portion 22 on the flat surface in a state where the specified internal pressure is filled and the specified load is applied is TW, and extends along the tire side portion 20 and the tread portion 22. The first virtual reference line L1 passing through the thickness direction intermediate point P1 of the tire side portion 20 and the tread portion 22 and the first virtual reference line L1 extending along the partition wall portion 24 and passing through the thickness direction intermediate point P2 of the partition wall portion 24. The intersection with the second virtual reference line L2 is the connecting portion 29 of the tire side portion 20 and the tread portion 22 and the partition wall portion 24, and the dimension in the tire width direction between one and the other of the connecting portions 29 is KW. Sometimes, TW ≦ KW is satisfied.

  In other words, the tire side portion 20 and the connecting portion 29 between the tread portion 22 and the partition wall portion 24 are located on the normal line 22a passing through the ground contact end of the tread portion 22 or on the outer side in the tire width direction.

  The contact width of the tread portion 22 is measured with the following specified load and specified internal pressure.

  The specified load is the maximum load (maximum load capacity) of a single wheel at the applicable size (ply rating) described in the following standard. The specified internal pressure is the single wheel at the applicable size described in the following standard. The air pressure corresponding to the maximum load (maximum load capacity).

  The standard is determined by an industrial standard effective in the region where the tire is produced or used. For example, in the United States it is “The Tire and Rim Association Inc. Year Book”, in Europe it is “The European Tire and Rim Technical Organization Standards Manual”, and in Japan it is the Japan Automobile Tire Association “JATMA Year Book”. It is prescribed.

  In the pneumatic tire 10 of this example, the inner portion in the tire radial direction of the partition wall portion 24 is formed as an inner bead portion 25 having an inner bead core 31. An inner bead filler 33 extending from the inner bead core 31 to the outer side in the tire radial direction is embedded in the inner bead portion 25 between the winding portion 37A of the second carcass ply 37 and the main body portion 37B.

  Here, in this example, the inner diameter of the outer bead portion 16 is formed larger than the inner diameter of the inner bead portion 25 (= rim diameter, hereinafter the same). It is preferable to set so that 0 <RO-RI <50 mm is satisfied, where RO is the inner diameter of the outer bead portion 16 and RI is the inner diameter of the inner bead portion 25.

  If RO = RI, it is necessary to use a rim provided with a tall hump part for preventing the partition part 24 from moving outward in the tire axial direction, and the assembling work becomes very difficult. This is because if it is inevitable and RO-RI ≧ 50 mm, it is difficult and unrealistic to manufacture a tire using the current tire manufacturing method.

  Further, when RO-RI ≧ 50 mm, the inner diameter of the inner bead portion 25 becomes too small with respect to the inner diameter of the outer bead portion 16, and the inner diameter of the rim is accordingly reduced. The brake diameter becomes smaller. This is not preferable because there is a possibility that the vehicle motion performance is deteriorated. Therefore, it is necessary to satisfy 0 <RO-RI <50 mm.

  Further, in the pneumatic tire 10 of this example, when the tire height is TH, and KD is 1/2 of the dimension obtained by subtracting the inner diameter of the outer bead portion 16 from the inner diameter RD of the connecting portion 29, KD ≧ 1 / It is set to satisfy 2TH.

  That is, the connecting portion 29 is configured to be positioned on the outer side in the tire radial direction with respect to 1/2 of the tire height TH.

  At this time, if KD <1 / 2TH, the first auxiliary air chamber 28 and the second auxiliary air chamber 30 formed by the tire side portion 20 and the partition wall portion 24 become extremely small. Although the effect of dividing into three parts cannot be exhibited, the first sub-form formed by the tire side portion 20 and the partition wall portion 24 is set so as to satisfy KD ≧ 1 / 2TH as in this example. Since the air chamber 28 and the second auxiliary air chamber 30 can be sufficiently secured, it is preferable.

(Rim structure)
The rim 12 includes a pair of outer bead seats 46 on which the outer bead portion 16 is disposed, and an inner bead seat 48 that is disposed on the inner side in the tire axial direction of the outer bead seat 46.

  The outer bead sheet 46 is formed according to the inner diameter of the outer bead portion 16, and the inner bead sheet 48 is formed according to the inner diameter of the inner bead portion 25. In this example, as described above, the inner diameter of the outer bead portion is larger than the inner diameter of the inner bead portion. Accordingly, the outer bead sheet 46 is set to have a smaller diameter than the outer bead sheet 46. Yes.

  A flange 50 that serves to prevent the outer bead portion 16 from being pushed outward in the tire width direction is formed on the outer side in the axial direction of the outer bead sheet 46, and between the inner bead sheet 48 and the outer bead sheet 46. Is formed with a step portion 52 that serves to prevent the inner bead portion 25 from being pushed outward in the tire width direction.

  Further, a drop portion (well) 54 in which the diameter of the groove bottom is smaller than that of the inner bead sheet 48 is provided in the center of the rim 12 in the axial direction.

  The rim 12 has a first air valve 40 for filling the first auxiliary air chamber 28 with gas, a second air valve 41 for filling the second auxiliary air chamber 30 with gas, and the main air chamber 26. A third air valve 42 for filling the gas is provided.

(Function)
First, in the rim 12 of the present embodiment, the inner diameter RO of the outer bead portion 16 is set larger than the inner diameter RI of the inner bead portion 25, and the drop 54 is provided in the middle portion. At the time of mounting, the outer bead portion 16 and the inner bead portion 25 can be dropped into the drop 54, and the assembly work of the pneumatic tire 10 to the rim 12 is facilitated in the same manner as the assembly of a conventional general pneumatic tire. .

  Further, the tire width of the inner bead portion 25 is determined by the difference in diameter between the outer bead seat 46 to which the outer bead portion 16 is attached and the inner bead seat 48 to which the inner bead portion 25 is attached. Since the stepped portion 52 that prevents movement outward in the direction is formed, a tall hump portion that causes the inner bead portion 25 to be pulled and deteriorates workability when assembling the rim is formed on the outer side in the tire width direction of the inner bead portion 25. There is no need to form the rim, and rim assembly is facilitated.

  Furthermore, in the tire / rim assembly 14 of the present embodiment, the first auxiliary air chamber 28, the main air chamber 26, and the second auxiliary air that are partitioned by the partition wall 24 between the pneumatic tire 10 and the rim 12. Since the chamber 30 is formed in the tire width direction, any other puncture is caused in the puncture on the ground contact surface due to the tread of the tread portion 22 or the puncture of the tire tire side portion 20 due to curb rubbing or the like. Since the two air chambers that do not support the load, a slight decrease in tire height, a slight deterioration in steering stability and vibration ride comfort are accompanied, but the vehicle can continue to travel safely without problems.

  Here, the internal pressure of the first sub air chamber 28, the internal pressure of the second sub air chamber 30, and the internal pressure of the main air chamber 26 may be the same or different from each other. The internal pressure of the first auxiliary air chamber 28, the internal pressure of the second auxiliary air chamber 30, and the internal pressure of the main air chamber 26 can all be set to arbitrary different pressures.

  For example, if the internal pressure of the first sub air chamber 28, the internal pressure of the second sub air chamber 30, and the internal pressure of the main air chamber 26 are the same, the same characteristics as those of a conventional pneumatic tire can be obtained.

  Further, from the state in which the internal pressures of the three air chambers are set to be the same as described above, the air in the main air chamber 26 is extracted, and the main air is higher than the internal pressure in the first sub air chamber 28 and the internal pressure in the second sub air chamber 30. When the internal pressure of the chamber 26 is decreased, the rigidity in the tire longitudinal direction is reduced and the ground contact area is increased, so that it is possible to improve the vibration riding comfort when traveling on rough roads and the grip performance when traveling on icy and snowy roads.

  Furthermore, when the first auxiliary air chamber 28 and the second auxiliary air chamber 30 are filled with air to increase the internal pressure, it becomes possible to increase the lateral rigidity and the longitudinal rigidity of the tire. Steering stability can be improved while improving the ride comfort and gripping performance on icy and snowy roads.

  Further, in the pneumatic tire 10 of this example, as described above, the ground contact width of the tread portion 22 on the flat surface in a state where the specified internal pressure is filled and the specified load is applied is TW, and the tire side portion 20 and the tread portion are A first virtual reference line L1 extending along the thickness direction intermediate point P1 of the tire side portion 20 and the tread portion 22 and extending along the partition wall portion 24 and extending along the partition wall portion 24. The intersection with the second virtual reference line L2 passing through P2 is a connecting portion 29 of the tire side portion 20 and the tread portion 22 and the partition wall portion 24, and in the tire width direction between one and the other of the connecting portions 29. When the dimension is set to KW, TW ≦ KW is satisfied.

  In other words, the tire side portion 20 and the connecting portion 29 between the tread portion 22 and the partition wall portion 24 are located on the normal line 22a passing through the ground contact end of the tread portion 22 or on the outer side in the tire width direction.

  With this configuration, the tire side portion 20 and the connecting portion 29 of the tread portion 22 and the partition wall portion 24 are located on the inner side in the tire radial direction of the normal line 22a passing through the ground contact end of the tread portion 22 as in the conventional case. In comparison with the tire side portion 20 and the connecting portion 29 between the tread portion 22 and the partition wall portion 24, the force from the road surface is less likely to be transmitted to the partition wall portion 24. The force applied to 24 can be reduced. Therefore, the partition wall 24 can be prevented from being damaged, and the durability of the tire can be improved as compared with the conventional case.

  In this example, when the tire height is TH, and KD is 1/2 of the dimension obtained by subtracting the inner diameter RO of the outer bead portion 16 from the inner diameter RD of the connecting portion 29, KD ≧ 1 / 2TH is satisfied. Thus, the first auxiliary air chamber 28 and the second auxiliary air chamber 30 formed by the tire side portion 20 and the partition wall portion 24 can be sufficiently secured.

[Second Embodiment]
Next, a tire / rim assembly according to a second embodiment of the present invention will be described with reference to FIG. FIG. 3 is a cross-sectional view showing a configuration of a tire / rim assembly in which a pneumatic tire (size: 225 / 55R17) is mounted on a rim, showing a second embodiment of the present invention. In addition, the same code | symbol is attached | subjected to the same structure as 1st embodiment, and the description is abbreviate | omitted.

  As shown in FIG. 2, in the present embodiment, both ends of the second carcass ply 37 in the tire width direction are locked to the pair of inner bead cores 31 so as to be wound up from the tire outer side toward the inner side. Yes. Other configurations are the same as those in the first embodiment.

  Thus, when the tire width direction both ends of the second carcass ply are wound up from the tire outer side to the inner side with respect to the inner bead core 31, the internal pressure of the first auxiliary air chamber 28 and the second auxiliary air chamber 30 is increased. 2 is applied to the second carcass ply 37 in the partition wall 24 adjacent to each other, and a force is applied to the inner bead core 31 and the rubber under the inner bead core 31 to rotate in the direction of arrow B in FIG.

  Therefore, when the internal pressure of the main air chamber 26 is relatively higher than the internal pressure of the first sub air chamber 28 and the internal pressure of the second sub air chamber 30, or the internal pressure of the main air chamber 26 becomes zero due to puncture or the like. Even in this case, the partition wall portion 24 does not deviate from the predetermined position of the rim 12 and can maintain the internal pressure of the first sub air chamber 28 and the internal pressure of the second sub air chamber 30. Other operations and effects are the same as those in the first embodiment.

(Test example)
In order to confirm the effect of the present invention, one type of tire / rim assembly 414 of the conventional example (see FIG. 5) and one type of tire / rim assembly 214, 314 according to the comparative example (see FIGS. 3 and 4). ) And four types (see FIGS. 1 and 2) of tire / rim assemblies 14 and 114 of the examples to which the present invention was applied were prepared, and a high-speed durability test was conducted.

  The conventional tire / rim assembly 414 shown in FIG. 5 is obtained by removing the partition wall portion 24 and the second carcass ply 37 from the tire / rim assembly 14, 114 of this example. Has the same configuration as the tire / rim assemblies 14 and 114 of this example.

  A tire / rim assembly 214 according to Comparative Example 1 shown in FIG. 3 has a partition wall 24 as in the present example. However, in the tire / rim assembly 214 according to Comparative Example, the tire height TH is And the relationship with the dimension KD is such that KD <1 / 2TH.

  That is, in the tire / rim assembly 214 according to Comparative Example 1, the connecting portion 29 is configured to be located on the inner side in the tire radial direction with respect to 1/2 of the tire height TH, and the tire height TH and the dimension KD are configured. Is outside the numerical range of the present invention.

  Also, the tire / rim assembly 314 according to Comparative Example 2 shown in FIG. 4 has the partition wall portion 24 as in the present example, but the tire / rim assembly 314 according to the comparative example is filled with the specified internal pressure. In addition, the relationship between the ground contact width TW of the tread portion 22 on a flat surface in a state where a specified load is applied and the dimension KW in the tire width direction between one and the other of the connecting portions 29 is TW> KW. It is configured.

  That is, in the tire / rim assembly 314 according to the comparative example 2, the tire side portion 20 and the connecting portion 29 of the tread portion 22 and the partition wall portion 24 are located in the ground tread surface of the tread portion 22, and the ground contact width TW and The relationship with the dimension KW is outside the numerical range of the present invention.

  Vertical rigidity and lateral rigidity are measured by applying a load of 570 kg to each tire. For the vertical stiffness index, the reciprocal of each measured value is expressed as 100 in the prior art. That is, the larger the index, the lower the vertical rigidity and the better the tire.

  In addition, for the lateral stiffness index, each measured value is represented as 100. That is, the larger the index, the greater the lateral rigidity and the better the tire.

  The high-speed durability test is performed based on the high-speed performance test B of JIS standard, and the high-speed durability index represents the failure speed of the conventional tire / rim assembly as 100. In other words, the larger the index, the higher the failure limit speed, and the better the durability at high speeds. The test tires are for passenger cars, and all have a size of 225 / 55R17. Table 1 shows the results of the high-speed durability test.

比較例１のタイヤ・リム組立体２１４では、ＫＤ＜１／２ＴＨとなるように構成されており、タイヤ高さＴＨと寸法ＫＤとの関係が本発明の数値範囲外となっている。これにより、表１に示すように、比較例１のタイヤ・リム組立体２１４は、上下剛性で優れるものの第一副気室２８及び第二副気室３０の体積を確保できないために横剛性が従来よりも劣り、高速耐久性が従来例のタイヤ・リム組立体４１４と同等に留まる結果となった。

The tire / rim assembly 214 of Comparative Example 1 is configured to satisfy KD <1 / 2TH, and the relationship between the tire height TH and the dimension KD is outside the numerical range of the present invention. As a result, as shown in Table 1, the tire / rim assembly 214 of Comparative Example 1 is superior in vertical rigidity, but cannot secure the volume of the first auxiliary air chamber 28 and the second auxiliary air chamber 30, so that the lateral rigidity is low. The result was inferior to that of the prior art, and the high-speed durability remained equivalent to that of the conventional tire / rim assembly 414.

  In the tire / rim assembly 314 of Comparative Example 2, the tire side portion 20 and the connecting portion 29 of the tread portion 22 and the partition wall portion 24 are located in the grounding tread surface of the tread portion 22, and the grounding width TW and the dimension KW are This relationship is outside the numerical range of the present invention. As a result, since the force from the road surface is easily transmitted to the partition wall portion 24, as shown in Table 1, the tire / rim assembly 314 of Comparative Example 2 is superior in lateral rigidity but inferior to that in the conventional case in terms of vertical rigidity. As a result, the high-speed durability was inferior to that of the conventional tire / rim assembly 414.

  On the other hand, in the tire / rim assemblies 14 and 114 of the embodiment, the tire side portion 20 and the connecting portion 29 of the tread portion 22 and the partition wall portion 24 are located on the outer side in the tire width direction of the ground tread surface of the tread portion 22. Since the force from the road surface is not easily transmitted to the partition wall 24, the force applied to the partition wall 24 from the road surface can be reduced. For this reason, as shown in Table 1, the tire / rim assemblies 14 and 114 of the examples all have the result that the high-speed durability of the tire is superior to that of the conventional tire / rim assembly 414.

  Further, as shown in Table 1, in the tire / rim assemblies 14 and 114 of the example, the dimension KW in the tire width direction between one and the other of the connecting portions 29 is made larger than the ground contact width TW of the tread portion 22. As a result, it became clear that the high-speed durability of the tire was improved.

  Further, the tire / rim assemblies 14 and 114 of the embodiment are both smaller in vertical rigidity than the tire / rim assembly 414 according to the conventional example, and the tire / rim assembly according to the conventional example in terms of lateral rigidity. It became larger than the solid 414. From this, it became clear that the tire / rim assemblies 14 and 114 of the example are tires having a better rigidity balance than the tire / rim assembly 414 according to the conventional example.

1 is a cross-sectional view of a tire / rim assembly according to a first embodiment of the present invention. It is sectional drawing of the tire and rim assembly which concerns on 2nd embodiment of this invention. 2 is a cross-sectional view of a tire / rim assembly according to Comparative Example 1. FIG. 6 is a cross-sectional view of a tire / rim assembly according to Comparative Example 2. FIG. It is sectional drawing of the tire and rim assembly which concerns on a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Pneumatic tire 12 Rim 14 Tire / rim assembly 16 Outer bead part 17 Tire inner side face 18 Outer bead core 20 Tire side part 22 Tread part 24 Partition part 25 Inner bead part 26 Main air chamber 28 First sub air chamber 30 Second Auxiliary air chamber 31 Inner bead core 32 First carcass ply 37 Second carcass ply 46 Outer bead sheet 48 Inner bead sheet 50 Flange 52 Step part 54 Drop

Claims (5)

A pair of left and right tire side portions formed on both sides in the tire width direction;
A tread portion that connects a tire radial direction outer end of one tire side portion and a tire radial direction outer end of the other tire side portion of the pair of left and right tire side portions;
Between the outer bead portion formed on each of the pair of left and right tire side portions, the outer bead portion is provided to be separated in the tire width direction, and at least one tire inner surface of the tire side portion and the tread portion is provided. The tire air chamber is configured to have an inner bead portion extending inward in the tire radial direction and in contact with the rim at the inner end in the tire radial direction, and formed by the tire side portion, the tread portion, and the rim. In a pneumatic tire provided with a pair of left and right partition walls that divide the tire in the tire width direction,
The inner diameter of the outer bead portion is RO and the inner diameter of the inner bead portion is RI.
The ground contact width of the tread portion on the flat surface in a state where the specified internal pressure is filled and the specified load is applied is TW,
A first virtual reference line that extends along the tire side portion and the tread portion and passes through a midpoint in the thickness direction of the tire side portion and the tread portion, and extends along the partition wall portion and of the partition wall portion. The intersection of the second virtual reference line passing through the intermediate point in the thickness direction is a connecting portion between the tire side portion, the tread portion, and the partition portion, and the tire width between one and the other of the connecting portions. The dimension in the direction is KW,
Let the tire height be TH,
When KD is 1/2 of the dimension obtained by subtracting the inner diameter of the outer bead portion from the inner diameter of the connecting portion,
A pneumatic tire characterized by satisfying RO> RI, TW ≦ KW, and KD ≧ 1 / 2TH.   2. The pneumatic tire according to claim 1, wherein an inner diameter RO of the outer bead portion and an inner diameter RI of the inner bead portion satisfy 0 <RO−RI <50 mm. The pair of left and right outer bead portions are provided with outer bead cores extending along the tire circumferential direction, respectively.
The pair of left and right inner bead portions are each provided with an inner bead core that is disposed on the inner side in the tire width direction of the outer bead core and extends along the tire circumferential direction,
A region extending from the one tire side portion to the other tire side portion via the tread portion is configured to straddle between the pair of outer bead cores in a toroidal shape, and both ends in the tire width direction are the pair of tire side portions. A first carcass ply locked to each of the outer bead cores is provided;
A region extending from one partition wall to the other partition wall via the tread portion is disposed inside the tire of the first carcass ply and is configured to straddle between the pair of inner bead cores in a toroidal shape. And a second carcass ply in which both ends in the tire width direction are locked to each of the pair of inner bead cores,
One end side in the tire width direction of the second carcass ply is wound up from one side of the pair of left and right inner bead cores from the tire outer side to the inner side,
The other end side in the tire width direction of the second carcass ply is wound up around the other of the pair of left and right inner bead cores from the tire outer side toward the inner side. Pneumatic tire. The pneumatic tire according to any one of claims 1 to 3,
A rim for mounting the pneumatic tire,
The rim has a pair of left and right outer bead seats that respectively contact inner peripheral surfaces of the pair of left and right outer bead parts;
Each of the pair of left and right outer bead seats is provided via a step portion on the inner side in the rim axial direction, is set to have a smaller diameter than the outer bead seat, and contacts each inner peripheral surface of the pair of left and right inner bead seats. A pair of left and right inner bead seats;
A tire / rim assembly, comprising: a drop provided between one of the pair of left and right inner bead sheets and the other and having a smaller diameter than the inner bead sheet.   The internal pressure of the tire air chamber formed on both sides in the tire axial direction of the tire air chamber is set higher than the internal pressure of the tire air chamber formed in the center in the tire axial direction. The described tire / rim assembly.

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