JPH07125506A - Hollow pneumatic-type solid tire and manufacture thereof - Google Patents

Abstract

PURPOSE:To maintain performance of a solid tire, so as to improve traveling stability and durability by providing a specific groove opening in the axial center part, and continuing in the circumferential direction or a groove part having the groove depth on the inner peripheral surface of a tire base body. CONSTITUTION:A groove part 6 opening in the axial center part and continuing in the circumferential direction is provided on the inner peripheral surface 3, to the attached to a rim base 19, of a rim 16. The sectional shape in the tire radial direction of this groove 6 is formed into a rectangle or a trapezoid, and a projecting shape where groove wall surfaces 7 are folded like a step, and the groove width WD is 0.1 to 0.7 times of the axial length WB of the inner peripheral surface 3, and the groove depth HD is 0.1 to 0.7 times of the tire sectional height HT from a bead line H to the radial outermost end of a tread surface 5. Moreover, they are connected to each other by a joint member 9 extended across the groove wall surfaces 7. Accordingly, rolling resistance can be decreased, fuel consumption can be saved, and riding comfort and durability can be improved.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a hollow pneumatic solid tire which is excellent in running performance including riding comfort and durability, and a vulcanization time which can be shortened economically when manufacturing the tire. The present invention relates to a manufacturing method that can be manufactured.

[0002]

2. Description of the Related Art Forklift trucks used for transportation in factories or warehouses are generally required to use solid tires rather than pneumatic tires because the posture stability is a requirement. To be

By molding a rubber composition into a solid tire, a solid tire has less bending than a pneumatic tire and has the advantage of stabilizing the posture of the vehicle when the vehicle is stopped, but it is heavy and solid. Therefore, there is a drawback that heat generation and rolling resistance are large and riding comfort is inferior to that of a pneumatic tire.

Further, the solid tire has a larger rubber volume than a pneumatic tire of the same size, which requires time for the vulcanization process and also causes a bad appearance such as a bear.

For these reasons, the spread of solid tires has been hindered, and there has been a restriction on increasing the size of solid tires.

As a result of intensive studies to solve the above-mentioned problems, the inventors have provided a groove portion that opens on the inner peripheral surface of the tire, and have the groove width and groove depth of the groove portion function as a solid tire. In order to eliminate the above-mentioned defects without impairing the above, it is necessary to regulate the dimensions thereof, and the groove width,
It has been found that it is preferable to control the groove depth dimension in proportion to the outer shape of the tire, and the hollow pneumatic solid tire of the present invention has been completed.

On the other hand, in manufacturing the tire having the above-mentioned structure, particularly in molding the groove portion, it has been found that the accuracy cannot be maintained by the hollow molding method using high pressure air as in the conventional pneumatic tire. It has been found that the tire can be manufactured with high accuracy by using a core made of a segment having a novel structure, which has not been used in a filled tire.

An object of the present invention is to provide a hollow pneumatic solid tire having excellent running performance and durability while maintaining the performance of the conventional solid tire, and a manufacturing method capable of economically manufacturing the tire. There is.

[0009]

The first invention of the present application is a hollow pneumatic solid tire, which has 1 on both sides.
Pneumatic comprising a base rubber layer having an inner peripheral surface fitted to a rim base surface of a rim having a pair of rim flanges, and a tread rubber layer arranged on a radially outer side of the base rubber layer to form a tread surface. Type solid tire, on the inner peripheral surface of the tire base having a cross-sectional shape, open in the axial center portion of the inner peripheral surface and continuous in the circumferential direction, and in the axial direction of the inner peripheral surface of the base rubber layer. A groove portion having a groove width WD that is 0.1 to 0.7 times the sectional length WB and a groove depth HD that is 0.1 to 0.7 times the tire sectional height HT is provided.

Further, the groove portion may be provided with a joint member which is mounted on the inner peripheral surface side between the groove wall surfaces facing each other so as to extend across the groove wall surfaces.

It is preferable that the groove has a stepped groove shape with a wide inner peripheral side, and the joint material is an annular body fitted into the step and sealing the groove.

The second invention of the present application relates to the manufacture of the hollow pneumatic solid tire.
A base rubber layer having an inner peripheral surface fitted to a rim base surface of a rim having a pair of rim flanges on both sides, and a tread rubber layer arranged radially outside the base rubber layer to form a tread surface. On the inner peripheral surface of the tire base body having a pneumatic solid tire-shaped cross-sectional shape consisting of
A groove width WD that is open at the central portion in the axial direction of the inner peripheral surface and is continuous in the circumferential direction, and that is 0.1 to 0.7 times the axial sectional length WB of the inner peripheral surface of the base rubber layer. A hollow pneumatic solid tire having a groove portion having a groove depth HD of 0.1 to 0.7 times the tire cross-sectional height HT and a method for manufacturing the hollow pneumatic solid tire, the tire being divided at an equatorial plane,
And an outer die for forming a cavity having a pneumatic solid tire shape in cross section by combining, and at least four segments that are divided in the circumferential direction and can be extracted inward in the radial direction, and a segment that forms the groove. A hollow pneumatic solid tire having a groove portion is vulcanized by a vulcanization mold made of a metal core.

In the above manufacturing method, unvulcanized rubber may be cast or injected into the cavity of the outer mold, and unvulcanized rubber may be arranged on the outer peripheral surface of the core to form a green cover tire. Then, it may be vulcanized by inserting it into the cavity of the outer mold together with the core.

[0014]

In the first aspect of the invention, since the rim has the rim flanges on both sides and the tire has the cross-sectional shape of a pneumatic solid tire, the tire can be assembled firmly and accurately. .

Further, the tire base body is provided with a groove portion which opens on the inner peripheral surface, and the groove width and groove depth are regulated. As a result, compared to a solid tire of the same size, the rigidity of the tire base body is softened and the riding comfort is improved, and the heat generated during running is dissipated to the groove portion, so that the temperature rise of the tire is suppressed and the tire is continuously operated for a long time. It is possible to drive and improve durability. Moreover, since it is lighter than the conventional solid tire, rolling resistance is reduced and fuel consumption can be reduced.

When the groove width WD of the groove portion is less than 0.1 times the cross-sectional length WB of the inner peripheral surface or the groove depth HD is less than 0.1 times the tire cross-sectional height HT, the above temperature rise suppression, The above-mentioned actions such as improvement of durability and reduction of rolling resistance cannot be exhibited, and conversely, the groove width WD exceeds 0.7 times the section length WB, or the groove depth HD is the tire section height. This is because if it exceeds 0.7 times the HT, the rubber thickness of the tire base becomes thin and external damage such as side cuts and tread cuts occurs and the durability is reduced.

Further, in the case where the groove portion is provided with a spanning joint material between the groove wall surfaces, the tire rim assembling accuracy is enhanced, the deflection can be easily adjusted, and the riding comfort and durability can be further enhanced. Further, the fitting pressure with the rim is increased and rim slip is prevented.

In the second aspect of the present invention, an unvulcanized rubber is arranged on the outer peripheral surface of the core divided in the circumferential direction, and the core is vulcanized together with the core in the cavity of the outer mold divided on the tire equatorial plane. Is. Therefore, the shape of the groove can be accurately maintained during vulcanization.

Further, since the core is formed by segments that are divided in the circumferential direction and can be extracted inward in the radial direction, the core after vulcanization can be removed without deforming the tire, The dimensional accuracy of is maintained.

Further, since the core is made of metal, the green cover tire can be heated through the core. As a result, the tire base body can be heated and vulcanized more quickly and evenly as compared with the conventional solid tire to improve the vulcanization quality, and the vulcanization time can be shortened, so that the work efficiency can be increased and the economical production can be achieved. .

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, a hollow pneumatic solid tire 1 has a base rubber layer 12 having an inner peripheral surface 3 that fits into a rim 16, a radially outer side of the base rubber layer 12, and an outer peripheral surface of which is a tread surface 5. Forming tread rubber layer 13
It has a cross-sectional shape of a pneumatic solid tire formed by and.

The hollow pneumatic solid tire 1 extends radially outward along the inner peripheral surface 3 fitted to the rim base 19 of the rim 16 and the rim flanges 17, 17 of the rim 16. The tire base body 2 is surrounded by a pair of side wall surfaces 4 and 4 and a tread surface 5 connecting the outer ends of the side wall surfaces 4 and 4 in the radial direction.

In the present embodiment, the inner peripheral surface 3 is formed as a tapered hole surface whose diameter is expanded on both sides in the axial direction with the equatorial plane C of the tire as the center.

The inner peripheral surface 3 is provided with a groove portion 6 which is open at the axial center of the inner peripheral surface 3 and is continuous in the circumferential direction. The cross-sectional shape of the groove portion 6 in the tire radial direction is not only a rectangular cross-section but also a trapezoidal cross-section, and further, two groove wall surfaces 7 facing each other have a convex shape in which they are bent stepwise, or the groove wall surface 7 is formed by a curved surface. May be

However, the groove width WD is set to 0.1 times or more of the axial length WB of the inner peripheral surface 3 at the minimum position, and 0.7 times or less of the length WB even at the maximum position. .
On the other hand, the groove depth HD is set in the range of 0.1 to 0.7 times the tire section height HT, which is the distance from the bead base line L of the tire to the radially outermost end of the tread surface 5.

In the present embodiment, in the groove portion 6, a joint material 9 is provided between the groove wall surfaces 7, 7 of the groove portion 6 facing each other so as to extend over the groove wall surfaces 7, 7. In order to fit the joint material 9, a step portion 10 having a wide inner peripheral surface 3 is provided on the groove wall surface 7 of the groove portion 6.

In the present example, the groove 6 is wide on the inner peripheral surface 3 side, and the wide portion 6A is connected to the wide portion 6A through the step 10 and is narrower than the wide portion 6A. Middle part 6B
And located radially outward of the intermediate portion 6B,
Wide groove portion 6C extending in an arc shape from B and widening in the axial direction
Formed by and.

The tire base 2 is, in this embodiment,
A base rubber layer 12 forming the inner peripheral surface 3 and a tread rubber layer 13 arranged on the outer side in the radial direction of the base rubber layer 12 and having an outer peripheral surface forming the tread surface 5.

The base rubber layer 12 is formed such that its height HC is higher than the height HF of the rim flange 17 of the rim 16 and is in the range of 15 to 50% of the radial cross sectional height TH of the tire. The base rubber layer 12 is, for example, as a short fiber cord, a reinforcing rubber composition containing a short fiber cord obtained by cutting an organic fiber tire cord such as nylon or polyester into a length of 3 to 30 mm, preferably 5 to 10 mm. Is used. 30-40% by weight of these short fiber cords
By using the mixed rubber composition for the base rubber layer 12, its rigidity and compression elastic modulus can be increased. The base rubber layer 12 may be formed of a hard rubber material alone without being reinforced with the short fibers.

The tread rubber layer 13 is made of a rubber composition having a JIS (A) hardness of about 60 to 75 degrees, and has a wear resistance,
A rubber composition having excellent cut resistance is used. If the hardness is 60 degrees or less, the cut resistance and abrasion resistance are poor, and if the JIS hardness exceeds 75 degrees, the grip performance is deteriorated.

The joint material 9 has a base portion whose inner surface 11 is substantially flush with the inner peripheral surface 3 when it is fitted into the step portion 10 of the groove portion 6, and has a wall thickness which is the height in the radial direction. G is preferably in the range of 0.5 to 2.0 times the flange height HF of the rim flange 17.

When such a joint material 9 is provided, the air intervening in the groove portion 6 can be blocked from the outside air, and the cushioning property of the hollow pneumatic solid tire can be further enhanced.

The wall thickness G is less than the flange height HF of 0.
If it is less than 5 times, the rigidity of the base rubber layer 12 is insufficient and the rim 1
This is because there is a risk of the tire idling between the groove 6 and the groove 6, and if the tire exceeds 2.0 times, the effective gap of the groove 6 becomes too small and the effect of providing the groove 6 does not occur.

In the present embodiment, the joint material 9 is formed of a relatively hard rubber composition having a JIS A hardness of 60 to 85 degrees. As a result, when fitted in the groove portion 6, the dimension in the tire width direction can be accurately maintained, and the airtightness of the void formed in the groove portion 6 can be maintained. Further, the fitting pressure with the rim 16 can be increased and rim slip can be prevented.

Next, a manufacturing method of the hollow pneumatic solid tire 1 (hereinafter referred to as a manufacturing method) will be described.

Hollow pneumatic type solid tire 1
Is an outer mold and a core 21 that forms the groove 6 of the tire 1.
It is manufactured using a vulcanization molding die 27 composed of. The gist thereof is to vulcanize the raw tire 2A made of unvulcanized rubber on the outer peripheral surface 22 of the core 21 together with the core 21 in the cavity 24 formed in the outer mold 23.

As shown in FIGS. 2 and 3, the core 21 has an outer peripheral surface 22 conforming to the shape of the groove portion 6 and is formed by four or more segments 21A, 21B, ... Further, these segments 21A, 21B ... Can be extracted one by one by using a pulling tool 31 as appropriate inward in the radial direction. Further, each segment of the core 21 is formed by using a metal having high heat conductivity such as steel or aluminum alloy.

FIG. 3 shows an example in which the core 21 is divided into 12 segments. In this example, the trapezoidal first segments 21A ...
, And the second segments 21B ... Which are fan-shaped outward in the radial direction are arranged in the circumferential direction at a ratio of 1: 2.

As shown in FIG. 3, the first segment 21
By sequentially extracting A, a gap g is formed in the core 21 in the circumferential direction, and the second segment 21B can also be extracted without deforming the tire base body 2 vulcanized by the gap g. Of.

When there is a wide groove portion 6C that widens at the groove bottom of the groove portion 6 as in this embodiment, the core 21 is further divided into a plurality of portions in the axial direction, in this example, three divisions are made. After vulcanization, the bulging segment 26, 2
6 can be taken out from the tire base 2.

The outer mold 23 forms a molding and vulcanizing mold 27 together with the core 21. The outer die 23 is a hollow tread surface 5 of the pneumatic solid tire 1, a side wall surface 4,
4 along with 4 and divided into two at tire equatorial plane C
A pair of outer mold pieces 33, 33 and a projection 35 along the inner peripheral surface 3 and engaging with a locking groove 34 provided on the side surface of the core 21.
And a pair of inner mold pieces 36, 36 protruding from each other.

These outer mold pieces 33, 33 and inner mold piece 3
Cavity 2 having a donut shape like a pneumatic solid tire inside by combining 6 and 36
4 is formed and the core 21 is engaged with the inner mold piece 36, the core 21 is positioned and protrudes in the tire cavity 24.

However, as shown in FIG.
A raw cover tire 2A is formed by superposing the unvulcanized rubber 12A for the base rubber layer and the unvulcanized rubber 13A for the tread rubber layer on the outer peripheral surface of the inside 1 and the outside.

The raw cover tire 2A is filled in the tire cavity 24 of the outer mold 23 together with the core 21, and the engaging groove 34 of the core 21 and the projection 3 of each inner mold piece 36 are filled.
By coupling with 5, the core 21 is correctly positioned in the tire molding cavity 24.

After that, the green cover tire 2A is pressure-molded by the outer peripheral mold 23 into a shape of a pneumatic solid tire, and vulcanized to form a hollow pneumatic solid tire 1. 2 is formed. By vulcanizing together with the core 21 in this way,
The raw cover tire 2A can also absorb heat from the core 21, can shorten the vulcanization time, and can improve the quality of the finished tire by uniformly heating.

The vulcanized and molded hollow pneumatic solid tire 1 has an outer mold 2 as shown in FIG. 5 (A).
3 is divided, and then the core 21 is removed as shown in FIG. 5 (B). The core 21 is formed by at least four segments 21A ..., 21B ... As described above, and the segments are taken out radially inward and removed from the hollow pneumatic solid tire 1. When the groove 6 has a bulging portion as in this embodiment, the segment 26 of the bulging portion is finally taken out. The hollow pneumatic type solid tire 1 can be manufactured through such steps.

FIG. 6 shows another manufacturing method. In this example, the outer die 23A is formed by the outer die pieces 33A and 33A and the inner die pieces 36A and 36A, and the outer die 23A is formed.
The core 29 in the cavity 24A of the inner mold piece 36A,
The vulcanization molding die 27 is formed by being sandwiched by 36A.

The cavity 24A has an outer mold 23A.
The unvulcanized rubber 14 can be loaded by injection or injection through an injection port 30 that is transparently provided in the raw cover tire 2A.
Is formed. The tire base 2 is formed by vulcanizing the raw cover tire 2A together with the core 29. Then, the core 29 is pulled out, and the hollow pneumatic solid tire 1 is completed. As described above, the manufacturing method of the present invention can be modified into various embodiments.

[0049]

INDUSTRIAL APPLICABILITY As described above, the hollow pneumatic solid tire of the present invention has a pneumatic solid tire-like outer peripheral shape and has a regulated groove width and groove depth that open at the inner peripheral surface. Since the groove portion is provided, rolling resistance is reduced as compared with a conventional pneumatic solid tire, so that fuel consumption can be reduced, and riding comfort is improved and durability is excellent.

In the second aspect of the present invention, the method is characterized in that the raw cover tire is vulcanized together with the groove forming core in the cavity of the outer mold. In the above, heat is transferred to the green cover tire not only through the outer mold but also through this core, so that uniformity of tire quality can be improved and vulcanization time can be shortened, and economical production can be achieved.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a tire of the present invention.

FIG. 2 is a tire axial direction cross-sectional view showing an outer mold for manufacturing the tire together with a core.

FIG. 3 is a plan view showing an example of a core segment configuration.

FIG. 4 is a cross-sectional view schematically showing a manufacturing method, (A) shows a state in which a green cover tire is formed on the outer peripheral surface of the core, and (B) shows a state during vulcanization.

FIG. 5A is a cross-sectional view showing a state where an outer peripheral die is removed and FIG. 5B is a state where a core is removed.

FIG. 6 is a cross-sectional view showing another example of the outer peripheral die.

[Explanation of symbols]

 2 Tire Base Material 2A Raw Cover Tire 3 Inner Circumferential Surface 6 Groove 7 Groove Wall 9 Joint Material 10 Step 11 Inner Surface 12, 12A Base Rubber Layer 13, 13A Tread Rubber Layer 14 Unvulcanized Rubber 16 Rim 17 Rim Flange 19 Rim Base Surface 21 , 29 Core 22 Outer peripheral surface 23, 23A Outer peripheral mold 24, 24A Cavity 27 Vulcanization mold C Tire equatorial plane G Wall thickness HD Groove depth HF Flange height HT Tire cross section height WB Axial length of inner peripheral surface WD groove width

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Claims (8)

[Claims] 1. A base rubber layer having an inner peripheral surface fitted to a rim base surface of a rim having a pair of rim flanges on both sides, and a tread surface arranged radially outside of the base rubber layer. And a base rubber which is continuous with the inner peripheral surface of the tire base body having a pneumatic solid tire-shaped cross-sectional shape and which is open at the central portion in the axial direction of the inner peripheral surface and is continuous in the circumferential direction. Groove width WD of 0.1 to 0.7 times the axial section length WB of the inner peripheral surface of the layer
And a groove depth H of 0.1 to 0.7 times the tire sectional height HT
Hollow pneumatic type solid tire provided with a groove portion having D. 2. The hollow pneumatic cylinder according to claim 1, wherein the groove portion has a joint member which is mounted on the inner peripheral surface side between the groove wall surfaces facing each other and extends across the groove wall surfaces. Type solid tire. 3. The groove portion has a stepped groove shape with a wide inner peripheral surface side, and the joint material is an annular body fitted into the step portion and sealing the groove portion. The hollow pneumatic solid tire according to claim 2. 4. The joint material has a flange height HF of 0.5 from an inner surface fitted to the rim base surface.
3. Having a wall thickness G of .about.2.0 times.
The hollow pneumatic type solid tire described. 5. The joint material has a JISA hardness of 60 to 85.
3. The hollow pneumatic solid tire according to claim 2, wherein the hollow pneumatic solid tire is composed of a rubber composition having a degree of hardness. 6. A base rubber layer having an inner peripheral surface fitted to a rim base surface of a rim having a pair of rim flanges on both sides, and a tread surface arranged radially outside of the base rubber layer. And a base rubber which is continuous with the inner peripheral surface of the tire base body having a pneumatic solid tire-shaped cross-sectional shape and which is open at the central portion in the axial direction of the inner peripheral surface and is continuous in the circumferential direction. Groove width WD of 0.1 to 0.7 times the axial section length WB of the inner peripheral surface of the layer
And a groove depth H of 0.1 to 0.7 times the tire sectional height HT
A hollow pneumatic solid tire having a groove portion with D and a method for manufacturing the same, wherein a cavity having a sectional shape forming a pneumatic solid tire is formed by dividing the tire equatorial plane and combining them. The groove portion is provided by a vulcanization molding die comprising an outer die and a metal core which is divided in the circumferential direction and can be extracted inward in the radial direction and which is made of a segment forming the groove portion. A method for producing a hollow pneumatic solid tire, characterized by vulcanizing and molding a hollow pneumatic solid tire. 7. The core is arranged in the cavity of an outer mold, and unvulcanized rubber is arranged on the outer peripheral surface of the core by casting or injecting unvulcanized rubber into the cavity. 7. The method for producing a hollow pneumatic solid tire according to claim 6. 8. An unvulcanized rubber is arranged on the outer peripheral surface of the core to form a raw cover tire, and then the raw cover tire is inserted together with the core into the cavity of the outer mold for vulcanization. 7. The method for producing a hollow pneumatic solid tire according to claim 6.