JPS58152610A - Tire serving concurrently as soft ground running use - Google Patents

Abstract

PURPOSE:To make the titled tire into a low noise, low oscillation and high speed stabilized running one, by a method wherein tread grooves are provided on both sides of a tread at a predetermined tilting angle, lug parts are formed at a predetermined area ratio with the tread groove and an annular groove in a circumferential direction is formed on a lug part of a center line part. CONSTITUTION:A lug part 20 is marked on a tread part 2 by forming a tread grooves 19 on both sides of a center line 7 of a tread so that the grooves are met at angles of 0-10 deg. with an imaginary line meeting at right angles with the center line 7 of the tread, which are about linear in a longitudinal direction at a tread end 4 and are in parallel with each other. An area of the lug part 20 is set up at 1.2 0.3 times of that of the tread groove. A zigzag annular groove 26 is formed so that each of groove ends 23 is arranged at a far and a near positions against the center line 7 of the tread, which is connected with the lug part 20 between right and left tread grooves 19 in a circumferential direction and makes a detour around the groove ends. With this constitution, the titled tire is made into a low noise and low oscillation one and high speed stabilized running can be obtained.

Description

[Detailed description of the invention] The present invention relates to a tire for running on soft ground such as fields.

To provide a vehicle aimed at running a vehicle smoothly and at high speed with low noise and low vibration, both on general roads and in fields such as wet fields.

Conventionally, tires for general roads have been formed with a tread pattern to prevent noise and vibration from occurring when the vehicle is running, but when the vehicle is driven into agricultural fields such as wet fields, the tires are In the end, mud and dirt got stuck in the tread grooves, making it impossible for the tires to maintain traction on the wet field surface.

The tires would slip, making it impossible to drive in the wet fields.

On the other hand, tires for use on soft terrain have a tread pattern with large undulations in order to maintain the rolling resistance of the tire in the field when the vehicle is running on the RA field.

Therefore, when this vehicle is driven on general roads, the tread pattern is as shown above.

The noise and vibration of the vehicle were extremely high, and it was impossible to drive on general roads with these tires, especially at high speeds.

However, it has been impossible to use tires with conventional tread patterns to drive on both general roads and soft ground such as farm fields. When traveling to other areas, people often drive on general roads, and recently there has been a desire to provide tires that can be used for both general roads and soft ground such as fields.

The present invention was created in response to such conventional demands, and therefore allows the vehicle to operate smoothly with low noise and low vibration on general roads, in fields, on soft ground such as sandy soil, and on soft ground such as 11F.

The purpose of this product is to provide a tire that can be used for running on soft terrain at high speeds, and therefore its characteristics are on both halves of the tread relative to the tread centerline.

A plurality of tread grooves are formed along the circumferential direction of the tread, and the space between these tread grooves is a puffer portion, and the lug portion and
The area ratio with the tread groove is (1,2±0.3):1, and the tread groove portion in the tread end region is approximately linear in the longitudinal force direction, and the above portion of all the tread grooves is in the tread. Intersection angle of 0 to 1σ with respect to the virtual line perpendicular to the center line (
The annular grooves are formed substantially parallel to each other at angles θ, ) and continuous along the tread circumferential direction at the lug portions between opposing tread grooves with respect to the tread center line.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a meridional cross-sectional shape of a tire (1) for running on soft terrain. From the outer surface (3) end to the tread end (4) t
The outer surface (6) of the tread end extends from substantially tangentially to the end of the outer surface (3) of the central portion to form a crown with a short radius (R,).

The tread width (Wl) of the above tread (2) is the tire width (
Approximately 0.9 times W-, the center outer surface (W,) is (0.5±0.2) times the tread width (Wl), and the semi-major axis (
R1) is (1,5±0.5) times the width of the tire (W-).
Bi radius (horse) is (0.7±0.2 of the same tire width (-)
) times, the major axis (to) is always the longer dimension than the minor axis (R@). The center point (6) of the semi-major axis (to) indicates a part of the tread center line (1), and the tread center line (11)
9), that is, a plurality of imaginary lines perpendicular to the tread center line 17) at intervals are set at the front side from the second FjP: the indicated tread center line 17). The virtual lines 11 adjacent to each other in the tread circumferential direction
The tread center line 17) decreases stepwise from the maximum pitch (in) to the minimum pitch (1,)K.
The concave portion υ group formed by the adjacent virtual lines (■) is considered to be a positive half mode (toward).The relationship between the adjacent pitches is as follows: n=2−=H(n is a positive integer).

Jog ”log(n-1)lon-1)l
o ″ log (n −2) = constant force 1 preferably, t. The maximum pitch (in) is the minimum pitch (16
) is preferably (1.4 to 2.0) times. In the above case, the maximum pitch (lt) is 1 of the minimum pitch (1,)
．． When it is 4 times or less, the noise of the tire (1) during running becomes large.
dB > mutual difference is large), which is undesirable, and if the above value is more than double, the difference between the maximum pitch (Jn) and the minimum pitch (1,)K of the component parts will become too large, resulting in uneven wear. This is undesirable because it causes

Also, from the positive half mode (to) end, the same arrow a11 as above
An imaginary line adjacent to the direction (lα is the same pitch (1
,,1,...ln+,,1n)K is arranged and set to the reverse beef cattle mode side, and the above forward/reverse beef cattle mode (to)
The α aneurysm is considered to be the first mode (to) as a whole, and in the example in Figure 1,
A half-seventh chord consists of three pitches, that is, a one-t- chord consists of six pitches.

On the other hand, the other half of the tread (
In the circumferential direction of the same arrow an, the forward half mode α field and the positive half mode (to) are successively adjacent to each other in the circumferential direction of the same arrow an. Then, the above 1st and 24th needs (to) G with the same number of husband rights.
is seen as a single mode with a positive integer number of pitches, preferably 1-7, over the entire circumference of the tread.

Each of the above components υ has an opening in the tread side wall (end).

A tread groove (2) is formed extending from the opening toward the tread center line 1, and these tread grooves (2)
) is like a lug part, and the lug ac in each component part 02
The area ratio of lB and the tread groove (to) is approximately the same for each component (2), that is, the area ratio of the puffer part ω to the tread groove (2) in the unit area of the tread is approximately equal to that of the tread (1).
) Preferably, the area ratio of the puffer portion ω and the tread groove (to) is (1,2±0.5), which is approximately the same in each part.
:1.

The tread end groove in the tread end (4) region is approximately linear in the longitudinal direction, and this single core is the center of the tread! 1171 K substantially orthogonal space (formed,
From the tread center line) side edge of this tread end groove @,
On one half of the tread (9), a bending groove that curves in a convex shape in plan view extends in the direction opposite to the circumferential direction of arrow 00, and on the other half of the tread, a bending groove is bent in the circumferential direction of arrow α in the same manner as above. 4o is extended, and the tread center line 171 side of each bending groove UIJ -
has a triangular head shape in which the groove width gradually decreases substantially linearly toward the tread centerline 171K.

The tread center line side groove end (C), which is the groove apex of the tread groove (2), is located on the center line @ between the two imaginary lines (the center line between the imaginary lines at the center of the seagull) between the constituent parts of the tread groove (2), and , located in front of the tread center line 17). In addition, selection is made from the positive direction groove width (W,) from the tread half surface (91, the center line between the imaginary lines) to the edge of the tread end groove e211 at the circumferential position of the arrow αD, and the center line between the imaginary lines @. The dimension ratio with the opposite direction groove width (W, ) is approximately 1: (1°1
5 to 1.35), and these forward and reverse groove widths (w, f
fa), that is, the groove width of the tread end groove Q11 is set to be MrO16 times the both virtual line pitches □□□ in the component Q3 of the tread groove (to). On the other hand, on the other half of the tread, tread grooves (6) are formed in the opposite direction from the imaginary line center line @ to the horse direction of the arrow αυ in the same manner as described above.

Tread center line (7) of each of the above tread end grooves (sha) @
The ends are located at approximately the same position in the tread width direction, and approximately 0.36 of the tread width (WI) from the tread center line ()).
It is formed at the double position, and the bending apex of the bending groove is
They are formed at substantially the same position in the tread width direction, and the tread center line 111 is also formed at a position approximately 0.27 times the tread width (Wl).

The above tread center line side groove end is the tread center line 111
In contrast, the grooves are formed alternately at far and near positions in the tread circumferential direction, and the ends of each tread centerline side groove at the far position and the ends of each tread centerline side groove at the near position are approximately at the same position in the tread width direction. The tread center line side groove end near the tread center line is (0,04~) of the tread width (Wl) from the tread center line 1
0.16) The tread center line side groove end at the far position where the tread width is (0.12 to 0.25) times the tread width (L) from the tread center 1iIT+.

Tread center line m - [opposing tread structure (to)
An annular groove (to) that is continuous along the circumferential direction of the tread and spaced apart from the tread groove (2) is formed in the puffer part (2) between the two. In the illustrated example, the tread center M of the tread grooves (2) alternately facing the tread center line (71) in the tread circumferential direction is shown.
The annular groove (to) is formed in a zigzag shape so as to bypass the ill groove end, and the runout width (W,) of this zigzag shape is preferably approximately 0.1 times the tread width (W-).
Preferably, the pitches have substantially equal lengths corresponding to the pitches forming the tread pattern. Also, the groove width (W, ) of this annular groove (to) is (0.02 to 0.05) times the tread width (W, ), and the groove depth 'L,) is the width of the tread (2). It is preferable that the height is (0.2 to 0.6) times the height of the tread groove portion at 174 points in the direction.

The annular groove j may have a wavy shape in which alternately inverted circular arc shapes are continuously arranged, or may have a linear shape or a plurality of grooves.

Fig. 2) Fi, the tread groove (to) inclined with respect to the imaginary line IMIIK orthogonal to the tread center line (7)K is shown as a simplified tread pattern, and the tread edge (
4) The tread groove portion of the area is substantially straight in the longitudinal direction, and
The above-mentioned portions of all the tread grooves (6), that is, the tread ends @@, have a predetermined intersection angle (σ,) with respect to the above-mentioned virtual line -.
and are formed approximately parallel to each other. The intersection angle (θl)
is preferably Oo, but may be in the range of 0 to 10°.

FIG. 2(b) is a simplified diagram showing a modified example of the tread groove (to), and shows each half surface n of the tread relative to the tread center line (11).
1 (18), the tread centerline side groove ends of the treads 5 (2) arranged in the tread center direction are formed at the same position in the tread width direction.

11113 (al to (1)) each figure shows the tread groove (
(to)), and each cross section has a configuration in which the groove width gradually increases from the bottom of the tread groove (to) toward the opening, and the tread groove (to) near the outer surface of the lug portion (
2) The wall surface has a groove edge angle (θ-) of 20° to 4°0” with respect to the vertical line (support) of the outer surface of the lug portion, and the bottom surface of the tread groove (to) It is formed by an arc whose tangent is the lower end of the wall surface.In the above case, the groove edge angles (θ1) of both opposing wall surfaces do not need to be the same.

More specifically, the groove edge angle (θ,
) is preferably approximately 25° (Fig. 5(a), Fig. 5(b)
). In addition, at the position of the bending groove, the groove edge angle (θ,) at the suction groove edge when viewed from the imaginary line center line @ is the tread edge (
4) side is preferably approximately 5σ (Fig. 3 (0) left groove edge) and approximately 25° at the tray arc groove edge (Fig. 3 (0) right groove edge, third diagram). In addition, the groove edge angle (θ-) at the tread center filament 1 side end position of the bending groove In the case of a tread groove (to) with an end position, the tread center line (7) of the bent groove @ the groove edge angle at the end position (0 mouth is approximately 30° on the suction groove edge side (the 5(b)), and approximately 25° on the edge side of the 6-arc groove (FIG. 5(1)).

FIG. 3(j) is a cross section in the longitudinal direction of the tread 5I (end), and the cross section has an upper lobe-shaped groove;
The wall surface of the tread groove (6) near the outer surface of the lug portion ω is substantially perpendicular to the outer surface of the puffer portion ω.

In the above case, the bottom surface of the tread groove (6) may be a concave arc surface with tangents to both opposing wall surfaces. In addition, the cross section of the same as above is triangular in shape.

In Fig. 1, the tread center line side groove end in the longitudinal cross section of each tread groove (■) is located in front of the tread center line (7), and the tread center line (11) of the tread groove (2) is located in front of the tread center line (7).
The 1JE plane is formed into a concave arc surface with a first radius (bird). The first radius (approximately) has a diameter of (65 ± 15), and the concave arc surface passes through or near the end of the side groove of the center binding of the trade, and the tire radial direction line 1 $) The center of the first radius (R,) is determined so as to be substantially tangent to the arc of the second radius (R4) having its center above. The center of the above @2 radius (8) is determined as follows. i.e. J18I)
870 value in 4202 (This value indicates the K11l value in the tire when the tire is installed on a rim that accounts for 70% of the tire in the meridian section.)
Approximately Q, Ki in the direction perpendicular to the tire radial direction line l at 1 times the dimension
The second radius (R
,) C) A circular arc is drawn, and the dimension of the radius (R,) is (0,7 to 1.0) times that of the upper Ia870 cage.
-The tread end (4) side of the center ill bottom surface ■ is as follows:
The second half is formed by an arc (goods) due to i(R,),
The bottom surface (to) of the intermediate portion extends as a convex arc surface from the end of the bottom surface on the center side, and the bottom surface (to) on the tread edge side extends from the bottom surface (to) of the intermediate portion as a second concave arc surface. , the tread end lIl bottom surface (to) opens to the tread end (4) and the tread side wall (to).

The bottom surface (to) of the tread end side is formed by the third radius (R-), and the center (to) of the -1ui*s radius (R,) is:
It is located approximately on a line (to) that passes through the tread center line 17) and intersects perpendicularly with the tire radial direction line 18), and its dimensions are equal to the second radius (
(07 to 1.0) times (07 to 1.0), and the tread edge <
The boundary between the m* plane (to) and the tread side wall (to) is (0,2 to 0) of the tire cross-sectional height
．． 35) Located at a distance of twice the dimension.

The bottom surface (to) of the intermediate portion is formed by a fourth radius (R,)K, and both ends of the bottom surface (to) the intermediate portion are circular arcs by the second radius (be), that is, the ends located on the bottom surface on the center side, The dimension of the arc by the fifth radius (in), that is, the dimension of the radius (R,) of the second radius (bird), which is in contact with the bottom surface of the ) will be doubled.

In Figures 1 and 4, the carcass (to) of the tire (11) and the code of the breaker (9) tV (9)
has the following structure.

That is, first, the material of the tread rubber has a hardness (71B-
) is 60°-65°, dynamic viscoelastic properties are 2σC, 11
If ffl has a loss tangent (tan J) of 0.15 or more, a dynamic modulus of elasticity (to) of °201- or more, and a relatively large hysteresis loss, the carcass (to) code angle A/(
θ, ), that is, the angle of the cord of the carcass (to) with respect to the virtual line (to) K perpendicular to the tread center line 571 is 47°.
to less than 52°.

@2, the material of the tread rubber has a hardness of 55 to 60, and a dynamic viscoelastic property of 2σG and 110H1! The loss tangent (ta
nJ) 0.15 or less, dynamic elastic modulus (1)' 15r+z
- or less and when the hysteresis loss is relatively small, the cord angle (#,) of the carcass is set from 52 or more to 57°.

Fifth, if the second tread rubber material has a breaker surface added to the carcass (to), the carcass (to)
The code angle (θ, ) of the breaker (b) is from 47 to less than 52°.

In the above case, the carcass (to) and breaker (9) are made of 840 denier two-stranded nylon cord, 1260 denier two-stranded nylon cord, or polyester cord; (
9) is 1 or 2 bly, and the adjacent ply has a code angle lL/(θ
,) are sequentially stacked.

Therefore, under each of the above conditions, the level of noise is small within the range of the code angle color), and the level of noise is large outside the code angle range.

Next, experimental results using tires configured as described above will be shown.

<For tires with tire size 5.00-10> Number of modes: 5 Number of 17th pitches: 6 Minor radius: 80m Major radius: 150m Tire internal pressure: 1.8Q/Cj Grape weight: 26011 Under the above conditions When I drove on a general road at 80km/b and listened to the sound inside the car, the noise level was 75 (dB).
Compared to the noise level determined by snow tires at the same speed, this noise level was slightly lower than that of snow tires and did not pose any problem to the running of the vehicle. However, the noise level (dB) for each frequency (1-1,) of the above-mentioned noise has a large difference in snow tires, but the tire according to the present invention has a relatively small difference. With the tire according to the invention, a reduction in noise was achieved in terms of perceived noise level.

In addition, in a running experiment at Nabara, when both the front and middle layer hardness (read value) were 25Lb8, the tire according to the present invention was able to run and start, which was not possible with sand, snow tires, and general ribbed tires.

In addition, in running tests on grass and sand, there was no improvement in running compared to snow tires, snow tires, and regular ribbed tires.

According to the present invention, since the area ratio between the lug member and the tread #lau+ is set appropriately, and the tread groove (2) is set at a predetermined crossing angle (θ-), the puffer part - is covered. This is beneficial because it allows for effective embedding in the running surface and allows for single-track running on sandy ground.

In addition, especially by providing the ring #1-, especially on the general road IN! One run? ``When the road surface is flying at time T, the water between the puffer part ω and the road surface is smoothly drained into the annular groove (to).
Therefore, braking performance is good and useful.

However, in view of the overall configuration of the present invention, the tire (1) according to the present invention is advantageous because it can be run on general roads and on soft ground such as four fields with low noise and low vibration.

[Brief explanation of the drawing]

(a) Simplified diagram showing a modification of U) Red, Fig. 2 (b)
is a partial cross-sectional view corresponding to the cross-sectional view, No. 31jA(j) is a cross-sectional view showing a modification of the tread groove, and FIG. 44 is a clear view showing the cord angle of the carcass and the breaker. (1)...tire, (2)...tread, (ri...
・Tread center outer surface, (4)...Tread edge, (5
)...Tread edge outer surface, 11)...Tread center line, (@1...Tread - half surface, ()...Virtual line, (
2)...Construction part, (to)...Square beef cow mode, or...
・Reverse half-seventh degree, (to) ・1s1 mode, (2
)...Other half of the tread, υ...wi2 mode, (To)...Tread wall, (To)...Tread groove, -...
... Lug part, Qt... Tread end groove, J... Tread center line side groove end, ■... Annular groove, Young... Wall surface, ■...
・・Tread center line side bottom surface, (to) ・・Middle part bottom surface,
(To)...Tread end side bottom surface, (R,)...Major axis, (B,)...Short radius, (W□)...Tread width,
(W,)...Tyre width, (W,)...Tread center outer surface, (Ll)...1 mode length in direction.

Claims (1)

[Claims] 1. Both tread halves 18 relative to the tread center line 111
1-, the tread groove (to) along the circumferential direction of the tread
A plurality of tread grooves are formed, and the lug portion is located between these tread grooves.
and the area ratio between the puffer member and the tread groove (to) is (1,2±0.3):1, and
The tread groove (end) portion of the tread end (4) region is approximately linear in the longitudinal direction, and the above portion of all the tread grooves (2) is 0 to 0 with respect to the imaginary line - perpendicular to the tread center line (7) K.
are formed substantially parallel to each other at an intersection angle (θ1) of 10°,
A tire for running on soft terrain, characterized in that an annular groove (to) continuous along the tread circumferential direction is formed in a puffer portion ω between opposing tread grooves (to) with respect to a tread centerline (7).