KR100534667B1 - Small-sized aircraft tire with reduced depth of shoulder groove - Google Patents

Abstract

According to the present invention, a tread reinforcement cord layer is formed between the carcass cord layer and the tread rubber layer; A tread block pattern comprising a center groove formed at the center portion of the tread, a shoulder groove formed at the shoulder portion of the tread, a center block partitioned by the groove and formed at the center portion of the tread and a shoulder block formed at the shoulder portion; In a small aircraft tire, the depth of the shoulder groove is characterized in that 5.7 ~ 6.5mm.

In addition, the present invention is characterized in that the inclination angle of the shoulder groove in contact with the center block is 14 to 16 °, the inclination angle of the shoulder groove in contact with the shoulder block is 9 to 11 °.

In addition, the present invention is characterized in that the width of the shoulder groove is 7.8 ~ 8.2mm.

As described above, the present invention effectively suppresses the unbalanced wear of the center and the shoulder portion by changing the depth of the shoulder groove, the width of the shoulder groove, and the angle of inclination of the shoulder groove, and improves overall performance and durability, and also as a crack of the shoulder groove. Early accidents can be prevented.

Description

Small-sized Aircraft Tire With Reduced Depth of Shoulder Groove}

The present invention relates to a small aircraft tire, and more particularly, to reduce the depth of the shoulder groove located in the shoulder portion of the tread to reduce the flow of the tread block due to the stress concentrated in the corner portion connecting the center block and the shoulder groove The present invention relates to a small aircraft tire that reduces cracking at the shoulder groove corner and breaks the tread reinforcement cord and improves tire durability and wear resistance.

In general, tires can be classified as aircraft tires, automobile tires, and tires for other purposes.

The aircraft tires are operated at a high pressure of about 310 psi, a high load of about 16,200 lbs, and a high speed of about 250 mph, so that the use conditions are much harsher than those for automobile tires.

The tire for an aircraft as described above will be described in more detail with reference to FIG. 1.

As shown in FIG. 1, the tire for an aircraft includes an inner liner rubber layer (I) for protecting a cord and preventing water absorption with a rubber layer attached to the inside of the tire; Carcass cord layer (L) to support the load with the cord layer inside the tire, to withstand impact and strong fatigue resistance to the flexing movement during driving; A tread rubber layer that is a portion in direct contact with the road surface; A belt cord layer formed between the tread rubber layer and the carcass cord layer (L) to strengthen the tread and minimize the increase in flexion, and a reinforcement formed at the bottom of the tread rubber layer to protect the carcass from the external impact or foreign matter penetration of the tire. It includes a code layer.

In the present specification, the belt cord layer is referred to as a first belt cord layer B1 and a second belt cord layer B2 in the order from the bottom upward.

In the present specification, the reinforcement cord layer is referred to as a first reinforcement cord layer C1, a second reinforcement cord layer C2, and a third reinforcement cord layer C3 in the order from the bottom upward.

The tread portion includes a center groove G1 formed on a center portion of the tread, that is, on a tire center line C / L; A shoulder groove G2 formed at the shoulder portion of the tread; A center block (rib) (R1) defined by the groove and formed at the center of the tread; And a shoulder block R2 at the shoulder portion of the tread.

Reference numerals V1 and V2 are bead portions.

Conventional aircraft tires, particularly small aircraft tires, which are constituted as described above, are concentrated in the vicinity of edges T1, T2, and T3 where blocks (ribs) and grooves contact when a high load acts on the tread portion.

That is, compressive stress is applied to the corner portion T1 located between the center block (rib) and the center groove when pneumatic expansion of the tire, and sheared downward to the corner portion (T2) located between the center block and the shoulder groove. The stress is applied, the compressive stress is applied to the edge portion (T3) located between the shoulder groove and the shoulder block.

When the above-mentioned phenomenon occurs repeatedly in the tread section, the properties of the rubber constituting the tire are weak at the point T2 at which the shear stress acts rather than the points T1 and T3 at which the compressive stress acts. Rubber block is maximized.

Accordingly, the conventional small aircraft tires exhibit interfacial separation due to shear fatigue stress at the rubber interface of the reinforcement cord, and finally the rubber splits at the bottom of the shoulder groove G2.

In addition, the tread reinforcement cord subjected to repetitive shear stress and centrifugal force at high speed through the tread is degraded due to high temperature, the cord breakage according to this causes a problem that the tread is peeled off.

In use, the bias aircraft tires also wear out relatively quickly in the center portion compared to the shoulder portion.

In addition, in the related art, in order to prevent cracking of the groove bottom 7 of the tread part 1 described above, the specification of the groove may be changed from FIG. 2A to FIG. 2B.

That is, the width of the groove was enlarged from A 'to A, and the corner radius of the groove bottom was enlarged from R' to R.

As mentioned above, although the groove width (A '-> A) and the corner radius (R'-> R) of the bottom are enlarged to increase the heat dissipation effect, it is intended to improve durability, but the aircraft tire operated at high speed and high load Due to the characteristics, tread block flow due to high heat, repeated bending, stress concentration, and centrifugal force is generated.

By repeating the flow of the tread block as described above, the groove corner part 6 is cracked and connected to an accident in which the tread part is separated, and the tread part center part and the tread part center part are in use due to the bias tire characteristic that the shoulder part center center part is quickly worn out. Unbalanced wear of the shoulder groove occurred.

The present invention has been made to solve the above problems, the object is to reduce the depth of the shoulder groove located in the shoulder portion of the tread tread block due to the stress concentrated in the corner portion of the center block and the shoulder groove is connected The present invention provides a small aircraft tire that can prevent cracking or breakage of the tread reinforcement cord at the shoulder groove corner portion and improve tire durability and wear resistance.

The present invention for achieving the above object, a tread reinforcement cord layer is formed between the carcass cord layer and the tread rubber layer;

A tread block pattern comprising a center groove formed at the center portion of the tread, a shoulder groove formed at the shoulder portion of the tread, a center block partitioned by the groove and formed at the center portion of the tread and a shoulder block formed at the shoulder portion; In a small aircraft tire, the depth of the shoulder groove is characterized in that 5.7 ~ 6.5mm.

If the depth of the shoulder groove is less than 5.7 mm, the performance of the drainage performance and the heat dissipation performance due to the increase of the shoulder gauge (G / A) is reduced, and the tire life is shortened in use, and the depth of the shoulder groove is 6.5 mm. If it is exceeded, it is not preferable because cracks are generated at the corner of the shoulder groove due to increased tread block flow at the center block and the shoulder block edge adjacent to the shoulder groove.

In addition, the present invention is characterized in that the inclination angle of the shoulder groove in contact with the center block is 14 to 16 °, the inclination angle of the shoulder groove in contact with the shoulder block is 9 to 11 °.

If the angle of inclination of the shoulder groove in contact with the center block is less than 14 °, a problem occurs that the shear stress between the center block part cord and the rubber adjacent to the shoulder groove is actuated, and the angle of inclination of the shoulder groove in contact with the center block exceeds 16 °. Relative stress is concentrated at the edges of the shoulder block relative to the center block adjacent to the shoulder groove, thereby causing a problem in that the uneven ground pressure is distributed.

If the angle of inclination of the shoulder groove in contact with the shoulder block is less than 9 °, cracks are generated at the corner of the groove due to stress concentration acting on the edge of the shoulder block part at the corner of the shoulder block adjacent to the shoulder groove, and the shoulder is in contact with the shoulder block. When the inclination angle of the groove exceeds 11 °, it is not preferable because a problem arises in that a non-uniform ground pressure is distributed due to the concentration of relative stress at the edge of the center block relative to the shoulder block adjacent to the shoulder groove.

In addition, the present invention is characterized in that the width of the shoulder groove is 7.8 ~ 8.2mm.

If the width of the shoulder groove is less than 7.8 mm, the stress of the center block and the shoulder block adjacent to the shoulder groove causes stress concentration between the rubber and the cord at the corner of the shoulder groove, and the physical property decreases due to the increase in the deformation energy. In this case, when the width of the shoulder groove exceeds 8.2 mm, the ground pressure is increased by reducing the ground area of the tread block with respect to the load, and thus, the tread block deformation flow is increased and the heat dissipation performance is deteriorated.

Hereinafter, the tread block pattern of the small aircraft tire according to the present invention will be described with reference to FIGS. 3A and 3B.

Figure 3a is an enlarged cross-sectional view of a portion of a small aircraft tire according to the prior art, Figure 3b is an enlarged cross-sectional view of a portion of a small aircraft tire according to an embodiment of the present invention.

3A and 3B, a tread portion of a small aircraft tire includes a plurality of grooves and a plurality of blocks partitioned by the grooves.

The groove includes a center groove G1 formed in the tire running direction, located on the center line of the tire, and a shoulder groove G2 located on the shoulder portion of the tread.

The block includes a center block R1 located between the center portion of the tread, that is, the center groove G1 and the shoulder groove G2, and a shoulder block R2 positioned at the shoulder portion of the tread.

Conventionally, the depth (ASDS ') of the shoulder groove was 7.5 mm, but in the present invention, the depth (ASDS) of the shoulder groove is changed to 5.7 to 6.5 mm.

If the depth of the shoulder groove (ASDS) is less than 5.7mm, the performance of the drainage performance and the heat dissipation performance due to the increase in the shoulder portion gauge (G / A) is reduced and the tire life is shortened in use, the depth of the shoulder groove If (ASDS) exceeds 6.5 mm, it is not preferable because cracks are generated at the corners of the shoulder grooves due to the increased tread block flow at the edges of the center block R1 and the shoulder block R2 adjacent to the shoulder grooves G2.

As described above, by changing the depth of the shoulder groove from 7.5 mm (ASDS ') to 5.7 to 6.5 mm (ASDS), the wear rate of the center part and the shoulder part during operation is similar to the wear resistance, and the rubber block can be improved. It is possible to prevent corner break at the bottom of the groove due to flow and breakage due to shear stress or interference of the reinforcing cord.

In the present invention, it is preferable that the inclination angles (P) (Q) on both sides of the shoulder groove are different from each other.

That is, the inclination angle P 'of the shoulder groove in contact with the center block according to the related art is 10 °, but the inclination angle P of the shoulder groove in contact with the center block according to the present invention is preferably 14 to 16 °. .

Here, the "inclined angle" refers to the groove angle with respect to the groove depth direction (vertical direction).

In this invention, it is more preferable that the inclination-angle P of the shoulder groove which contact | connects the said center block is 15 degrees.

Accordingly, the edge portion of the shoulder groove in contact with the center block is inclined more slowly than the prior art.

That is, the radius of the corner portion of the shoulder groove in contact with the center block is larger in the present invention (F) than in the conventional (F ').

In addition, the inclination angle Q 'of the shoulder groove in contact with the shoulder block according to the related art is 15 °, but the inclination angle Q of the shoulder groove in contact with the shoulder block according to the present invention is preferably 9 to 11 °. .

In the present invention, it is more preferable that the inclination angle Q of the shoulder groove in contact with the shoulder block is 10 °.

Accordingly, the edge portion of the shoulder groove in contact with the shoulder block is inclined more sharply in the present invention than in the prior art.

That is, the radius of the edge portion of the shoulder groove in contact with the shoulder block is smaller in the present invention (H) than in the conventional (H ').

If the inclination angle P of the shoulder groove in contact with the center block is less than 14 °, a problem occurs that the shear stress between the center block portion cord and the rubber adjacent to the shoulder groove is applied, and the inclination angle of the shoulder groove in contact with the center block. If it exceeds 16 °, it is not preferable because a problem arises in that a non-uniform ground pressure is distributed due to concentration of relative stress at the edge of the shoulder block relative to the center block adjacent to the shoulder groove.

If the inclination angle Q of the shoulder groove in contact with the shoulder block is less than 9 °, cracks are generated at the corner of the groove due to stress concentration acting on the edge of the shoulder block part at the corner of the shoulder block adjacent to the shoulder groove. When the angle of inclination (Q) of the shoulder groove in contact with the shoulder groove exceeds 11 °, it is not preferable because a problem arises in that the uneven ground pressure is distributed due to the concentration of relative stress at the edge of the center block relative to the shoulder block adjacent to the shoulder groove.

As described above, the present invention by changing the inclination angle of the shoulder groove in contact with the center block from 10 ° to 14 to 16 °, and changing the inclination angle of the shoulder groove in contact with the shoulder block from 15 ° to 9 to 11 ° center block and shoulder It is possible to prevent cracking and cord breakage at the base of the groove by preventing stress concentration occurring in the block to form a uniform distribution of earth pressure and reducing shear stress and tread block flow between the groove corner cord and rubber.

In addition, the width (U ') of the shoulder groove was conventionally 9mm, the present invention is characterized in that the width (U) of the shoulder groove is 7.8 ~ 8.2mm.

If the width (U) of the shoulder groove is less than 7.8 mm, the stress of the center block and the shoulder block adjacent to the shoulder groove causes stress concentration between the rubber and the cord at the corner of the shoulder groove, and the property of the deformation energy increases. If the width (U) of the shoulder groove exceeds 8.2 mm, the ground pressure is increased due to the decrease of the ground area of the tread block against the load, and thus the tread block deformation flow is increased and the heat dissipation performance is deteriorated. do.

As described above, by changing the width of the shoulder groove from 9 mm to 7.8 to 8.2 mm, the tread block flow at the edges of the shoulder rib and the center rib can be reduced.

As described above, in addition to changing the specification of the shoulder groove, the reinforcing cord (C1, C2, C3) located in the lower portion of the shoulder groove is preferably formed more gently than the prior art.

Unmarked ASDC is the depth of the center groove.

As described above, the present invention effectively suppresses the unbalanced wear of the center and the shoulder portion by changing the depth of the shoulder groove, the width of the shoulder groove, and the angle of inclination of the shoulder groove, and improves overall performance and durability, and also as a crack of the shoulder groove. Early accidents can be prevented.

1 is a cross-sectional view of a small aircraft tire according to the prior art.

2a and 2b is a view showing the tread portion of a small aircraft tire according to the prior art.

Figure 3a is an enlarged cross-sectional view of a portion of a small aircraft tire according to the prior art.

3B is an enlarged cross-sectional view of a portion of a tire for a small aircraft according to an embodiment of the present invention.

※ Explanation of symbols about main part of drawing ※

R1: center block (rib) R2: shoulder block (rib)

G1: center groove G2: shoulder groove

ASDS, ASDS ': Depth of shoulder groove U, U': Width of shoulder groove

F, F ': Radius of the edge of the shoulder groove in contact with the center block

H, H ': Radius of the edge of the shoulder groove in contact with the shoulder block

P, P ': inclination angle of the shoulder groove in contact with the center block

Q, Q ': Angle of inclination of the shoulder groove in contact with the shoulder block

D, D ': radius of shoulder groove

1, 1 ': tread part 2, 2': groove

4, 4 ′: groove inner sidewall 5, 5 ′: groove outer sidewall

6, 6 ': corner 7, 7': bottom

A, A ': Groove width R, R': Radius

Claims (3)

A tread reinforcement cord layer is formed between the carcass cord layer and the tread rubber layer, a center groove formed at the center portion of the tread, a shoulder groove formed at the shoulder portion of the tread, and a center defined by the groove and formed at the center portion of the tread. In a small aircraft tire having a tread block pattern comprising a block and a shoulder block formed at the shoulder portion, wherein the shoulder groove has a depth of 5.7 to 6.5 mm, the inclination angle of the shoulder groove in contact with the center block is 14 to 16 °. , The inclination angle of the shoulder groove in contact with the shoulder block is a small aircraft tire, characterized in that 9 to 11 °. delete delete