JPS63134306A - Pneumatic tire and manufacture thereof - Google Patents

Abstract

PURPOSE:To keep the grounded pressure of a tread part uniform by dividing the tread radius in the region ranging from the center line in the peripheral direction of a tire to the shoulder part into plural parts and specifying the relation between each region and the distance of the tread surface ranging from the center line in the peripheral direction of the tire to the crossing point of each region. CONSTITUTION:The tread radius in the region ranging from the center line (m) in the peripheral direction of a tire to the shoulder part 6 is divided into R1 and R2, and the following relations are satisfied for R1 and R2. In this case, R1=RX(1.5-3.0). R2=RX(0.5X1.0). In the above, R is the tire shape in the case when the tire is charged with a regular internal pressure after vulcanization, i. e., the tread radius of the product shape 4. The distance P of the tread surface ranging from the center line (m) in the peripheral direction of the tire to the crossing point between R1 and R2 shall be satisfy the following relation: P<(w/2)X(3/5). In this case, (w) is the tread development width of the tire in the case when the tire is charged with 5% of the regular internal pressure. Therefore, the grounded pressure distribution at the tread part can be kept uniform independently of the variation of the using condition.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a pneumatic tire for tire rollers used in paving work and a method for manufacturing the same.

[Prior art]

Conventionally, tire-type tire rollers have been mainly used as compaction machines for compacting road surfaces used in paving works. However, in recent years, with changes in pavement construction methods, vibrating rollers and road rollers (iron wheels) have also come to be used together with tire rollers.

In terms of the rolling force characteristics of these rolling machines, when paving a road surface 2 with rollers 1 as shown in Figure 5, vibrating rollers and road rollers are advantageous in order to obtain high density deep underground. , Tire rollers are suitable for obtaining high density in shallow underground areas. As can be seen from Figure 5, in order to obtain 100% density underground, roller 1 must be approximately 5 cm deep if it is a tire roller, approximately 8 cm if roller 1 is a road roller, and approximately 8 cm deep if roller 1 is a vibrating roller. It is about 13cm.

Therefore, as the primary rolling pressure, vibrating rollers and road rollers are used to obtain high density in the deep part, and at the same time
The road surface 2 is finished by building up flatness and obtaining high density in shallow areas using tire rollers in the second rolling pressure. This type of work has become the latest pavement construction method.

Furthermore, in recent pavement construction methods, the load applied to tire rollers has been increasing. In the past, when the primary and secondary spreading pressures were mainly carried out using tire rollers, paving materials were introduced in stages in order to achieve high density in the deep areas, and tire rollers were used each time. In addition, in order to improve the flatness of the road surface, the shape of the pneumatic bias tires used in tire rollers was devised to ensure a uniform distribution of ground pressure on the tire tread.

By the way, as shown in Figure 6, a pneumatic bias tire changes from the shape (mold shape) 3 when it is vulcanized in a mold to the shape (product shape) 4 when it is filled with the normal internal pressure. Causes large dimensional changes. That is, the outer diameter, width, tread radius, etc. change significantly.

Although the cause of this varies depending on the height and width of the mold cavity or the tire structure, it is common that a portion of the crown center protrudes compared to both shoulder portions. Therefore, as shown in FIG. 7, a so-called concape profile in which a concave portion is provided in the crown center portion 5 of the mold shape 3 has been proposed. This is done by forming a recess 5 in the mold shape 3 in advance in consideration of the fact that the crown center part 5 will protrude compared to the shoulder part 6 when the product shape 4 is achieved. By setting a uniform and large tread radius, the ground contact pressure on the tire tread is made uniform.

However, tire roller tires manufactured with a concape profile can fully demonstrate their performance when used under relatively light loads as in the past, but when used under high loads as in recent years. When used, a so-called buckling phenomenon occurs in which the ground contact pressure of the crown center portion 5 is significantly lower than that of the shoulder portion 6, as shown in the ground contact profile diagram 10 of FIG. 8(A). When the buckling phenomenon occurs in this way, on the road surface 2 in contact with the tread surface 12 of the tire 11, a waving phenomenon occurs in which the shoulder portion is depressed more than a part of the crown center, as shown in FIG. 8(B), and the road surface The original function of the tire roller, which is to flatten the surface, will be impaired. In addition, Figure 8 (
Graph B) is a measurement of the ground pressure distribution from the crown center part of the tire tread to the shoulder part.The ground pressure distribution of the tire that is causing the above-mentioned waving phenomenon is uniform from the crown center part to the shoulder part. It turns out that it is not.

Figures 9(A) to (D) show tire roller tires (900-20-1) manufactured by concave profile.
0PR) are shown. Figure 9 (A) shows the ground contact profile diagram when the applied load is 945 kg, and Figure 9 (B)
is the ground contact profile diagram when the applied load is 1500 kg, and Figure 9 (C) is the ground contact profile diagram when the applied load is 1720 kg.
FIG. 9(D) shows the ground contact profile diagram when the applied load is 2165 kg. From these FIGS. 9(A) to 9(D), it can be seen that the ground contact shape becomes non-uniform as the load increases.

[Purpose of the invention]

An object of the present invention is to provide a pneumatic tire that can maintain a uniform ground pressure distribution on the tread surface regardless of changes in usage conditions such as air pressure and load when paving a road surface, and a method for manufacturing the same.

[Structure of the invention]

To achieve this objective, the present invention provides 5% of the normal internal pressure.
In the shape of the tire when it is filled with the internal pressure of The gist is a pneumatic tire characterized by satisfying the following relationship between the distance P of the tread surface to the intersection of R+ and Rz.

Furthermore, when the tire is vulcanized and molded in a mold, the present invention has a cavity corresponding to the shape of the tire, and the tread radius of the region from the circumferential center line of this cavity to the shoulder portion is defined as R and R2. The air is characterized by using a mold that satisfies the following relationship between the distance P of the tread surface from the circumferential center line to the intersection of these R, and R2, and R, , R2. The gist is the method for manufacturing tires. Here, W represents the tread width of the tire when filled with an internal pressure of 5% of the normal internal pressure, and R represents the tread radius of the tire when the vulcanized tire is filled with the normal internal pressure.

P< (w/2)X (315) R+ =Rx (1,5~3.0)R2=RX
(0,5-1.0) Hereinafter, the configuration of the present invention will be explained in detail with reference to the drawings.

FIG. 1 is an explanatory cross-sectional view showing the shape of a tire when it is filled with an internal pressure of 5% of the normal internal pressure and fixed to a rim (hereinafter referred to as 5% internal pressure shape).

The 5% internal pressure shape is substantially equal in shape and size to mold shape 3 described above.

In FIG. 1, the tread radius in the area from the tire circumferential center line m to the shoulder portion 6 is divided into R8 and R2, and these R1 and Rz satisfy the following relationship.

R+ = RX (1,5~3.0) R2=Rx (0,5~1.0) Here, R is the tire shape shown in Figure 2 when filled with the normal internal pressure after vulcanization, that is, the product shape. This is the tread radius at 4.

If R, is less than RXl,5, the ground pressure in a part of the crown center will be larger than in the shoulder part, and conversely, if R1 is less than R
X3. If it exceeds 0, a buckling phenomenon will occur. R2
The same applies when R2 is RXo, less than 5, and R2 is RXl, greater than 0.

In addition, in FIG. 1, the distance P of the tread surface from the tire circumferential center line m to the intersection of these R1 and R2 is
The following relationships are satisfied.

P < (w/2) X (3/5) where W is the tread width of the tire when filled with an internal pressure of 5% of the normal internal pressure. The reason for defining P in this way is that P
≧ (W/2) This is because the pressure will lack uniformity.

When the pneumatic tire of the present invention thus constructed is used under a high load, the ground contact pressure of the crown center part 5 and the shoulder part 6 increase as shown in the ground contact profile diagram 10 of FIG. The ground pressure becomes substantially equal. Therefore, during pavement construction, the ground pressure distribution becomes uniform, as shown in Figure 3 (B).
As shown in the figure, since the tread surface 12 of the tire 11 and the road surface 2 are in uniform contact with each other, no waving phenomenon occurs.

Furthermore, the graph in Figure 3 (B) is a measurement of the ground pressure distribution from the crown center part to the shoulder part of the tire tread, and it shows that it is very uniform from the crown center part to the shoulder part. I understand.

Fig. 4 (A) to (D) show the tire of the present invention (900-20
-10PR) various ground contact profile diagrams are shown. Figure 4 (A)
Figure 4 (
B) is the ground contact profile diagram when the applied load is 1500 kg, Figure 4 (C) is the ground contact profile diagram when the applied load is 1720 kg, and Figure 4 (D) is the ground contact profile diagram when the applied load is 2165 kg. represent These Figures 4 (A) to (D)
From this, it can be seen that even if the load increases, the ground contact shape does not become uneven.

The tire of the present invention described above has a cavity corresponding to the tire shape, and the tread radius of the region from the circumferential center line of the cavity to the shoulder portion is divided into R and R2, and the tread radius of the region from the circumferential center line to the shoulder portion is divided into R and R2. It can be manufactured by vulcanization molding using a mold in which the distance P of the tread surface to the intersection of R8 and R2 and R1 + R2 satisfy the above-mentioned relationship described in FIGS. 1 and 2.

[Brief explanation of the drawing]

Figure 1 is an explanatory cross-sectional view showing the shape of the tire when it is filled with an internal pressure of 5% of the normal internal pressure and fixed to the rim, Figure 2 is an explanatory cross-sectional view showing the shape of the tire when it is filled with the normal internal pressure, and Figure 3
Figure (A) is an explanatory diagram showing the ground contact shape of the tread portion of the tire of the present invention, Figure 3 (B) is an explanatory diagram showing the ground contact pressure distribution and ground pressure measurement values during paving work, and Figure 4 ( A) ~ (D
) is an explanatory diagram showing the ground contact shape of the tire (900-20-10PR) of the present invention under various loads. Figure 5 is an explanatory diagram showing how paving work is performed using a rolling pressure machine;
Figure 6 is a cross-sectional explanatory diagram showing the tire shape when vulcanized in a mold and the tire shape when filled with the normal internal pressure, Figure 7 is an explanatory diagram showing the concape profile, and Figure 8 (A)
is an explanatory diagram showing the contact shape of the tread of a tire manufactured with a concape profile, and Figure 8 (B) shows the ground pressure distribution and ground pressure measurement when performing paving work with a tire manufactured with a concape profile. FIGS. 9A to 9D are explanatory diagrams showing the values, and FIGS. 9A to 9D are explanatory diagrams showing the ground contact shape under various loads of a tire (900-20-10PR) manufactured with a concave profile. 1... Roller, 2... Road surface, 3... Mold shape,
4...Product shape, 5...Part of crown center, 6.
...Shoulder part, 10...Grounding shape diagram, 11...
Tire, 12...tread.

Claims (1)

[Claims] 1. In the tire shape when the tire is filled with an internal pressure of 5% of the normal internal pressure and fixed to the rim, the tread radius in the area from the tire circumferential center line to the shoulder part is R_1 and R_
2, and these R_1 and R from the tire circumferential center line.
The distance P of the tread surface to the intersection with _2 and R_1,
A pneumatic tire characterized by satisfying the following relationship with R_2. P<(w/2)×(3/5) R_1=R×(1.5-3.0) R_2=R×(0.5-1.0) Here, w is 5% of the normal internal pressure. R represents the tread width of the tire when filled with internal pressure, and R represents the tread radius of the tire when filled with normal internal pressure. 2. When vulcanizing a tire in a mold, it has a cavity corresponding to the shape of the tire, and the tread radius of the area from the circumferential center line of this cavity to the shoulder part is divided into R_1 and R_2, and Distance P of the tread surface from the direction center line to the intersection of these R_1 and R_2
A method for manufacturing a pneumatic tire, comprising using a mold that satisfies the following relationship for R_1 and R_2. P<(w/2)×(3/5) R_1=R×(1.5-3.0) R_2=R×(0.5-1.0) Here, w is 5% of the normal internal pressure. R represents the tread width of the tire when filled with internal pressure, and R represents the tread radius of the tire when the vulcanized tire is filled with the normal internal pressure.