JPS6348727B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a tubeless tire running on snowy roads. (Prior Art) Although so-called snowmobiles are known for driving on snowy roads, they are used exclusively for snowy roads and are impossible or difficult to run on general roads, lack versatility, and are expensive. In addition, for so-called large vehicles such as regular passenger cars and trucks, there are snow tires with a so-called block pattern tread pattern and a large groove depth, but this function becomes less effective when the amount of snow becomes large. If it is severely damaged or frozen, it will no longer be possible to drive it, so it is common practice to install spikes or wrap a chain around it. On the other hand, a so-called angular tubeless tire whose entire body including the tire body is made of an elastic material and whose tread portion has triangular lugs with a hollow cross section projecting at equal intervals in the circumferential direction is disclosed in Japanese Patent Publication No. 52-37845 and Japanese Patent Application Laid-Open No. 55-47904. Although publications and the like are known, all of these are for wetlands, and their properties are completely different from the snowy roads that are the object of the present invention. In other words, in order to drive through wetlands, the tire pattern's ability to remove dirt is a very important factor;
On snowy roads, buoyancy is an important factor, and the driving mechanisms of tires are fundamentally different between wetlands and snowy roads. In other words, while in wetlands you have to drag your feet through the mud, on snowy roads you have to ride on top of the snow. Therefore, for wetland tires, it is desirable to have a pattern that does not deform in the mud and grips the mud easily, and has good soil removal once it leaves the contact surface, whereas tires for snowy roads are designed to compact the snow surface. It is very important to keep the surface intact. (Problem to be Solved by the Invention) In a rectangular tubeless tire for wetlands, the height of the triangular lugs is too high, making it impossible to use it for driving on snowy roads. Furthermore, if the height of the triangular lugs of square tubeless tires for wetlands is reduced, the ability to compact the snow surface will be reduced, and the snow surface will be crushed, making it impossible to drive on snowy roads. The present invention provides a tubeless tire that can run on snowy roads regardless of the amount of snow and the quality of the snow, and can also run stably and smoothly on general roads according to its purpose, and in particular has a small load capacity. Weight 200~
The purpose of the present invention is to provide a tubeless tire for snowy roads for so-called ultra-small buggy vehicles weighing about 300 kg. (Means for Solving the Problems) The present invention provides a triangular lug with a hollow cross section, which is made up of a first slope portion serving as a kick surface and a second slope portion on the opposite side of the kick surface, on the outer peripheral surface of a tire body in the circumferential direction. The triangular lug protrudes radially outward with a spacing of The following technical measures have been taken in order to achieve the stated purpose of the tubeless tires for use in the market. That is, in the present invention, the height from the bead part 4 of the tire body 1 to the top part 15 of the triangular lug 14 is
H1, when the height from the bead part 4 to the connecting part 19 connecting between the triangular lugs 14 is H2, H1/
H2 is set to be 1.3 or more and less than 2.0, and the first slope part 17 and the top part 15 of the triangular lug 14
Each of these is extended outward in the tire axial direction from the lug elevation wall 20 to form a compaction wing body 21,
The wing body 21 is connected to the tire shoulder 6, and the top part of the wing body 21 on the extended end side and the lug elevation wall 20 on the second slope portion 18 side of the triangular lug 14 are connected to each other. It is characterized in that a support portion 22 is formed. (Embodiments and Effects) Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the basic configuration examples shown in FIGS. 1 to 6,
1 is a tire body, which is entirely made of flexible elastic rubber or other similar materials. A rim 2 is usually made of metal and has an axle mounting portion 3 in its center. Note that the rim 2 may be made of resin, and a so-called split rim structure is desirable. The tire body 1 is composed of a pair of left and right bead portions 4, each sidewall portion 5 rising from each bead portion 4, and a tread portion 7 in which each sidewall portion 5 is connected via a shoulder 6. The surface is a tread portion 8. Each bead portion 4 of the tire body 1 is fitted into a rim bead seat 9 and a rim flange 10 of a rim 2, thereby forming a substantially tubeless hollow tire. In order to assemble the body 1 and rim 2, each bead portion 4 can be sufficiently elastically deformed and has a structure that ensures sufficient airtightness after assembly. That is, as particularly shown in FIG. 3, a bulge 11 is integrally formed to protrude from the tip of each bead portion 4 and located inside the sidewall portion 5.
1 has a ring-shaped locking part 1 toward the inner diameter of the tire.
2 is recessed, and a rigid ring 13 made of steel wire or the like is engaged and fitted into the locking portion 12. Therefore, if air or a pressurized medium is directly injected into the body 1 through a valve device (not shown) provided on the rim, the bulges 11 will flow and deform outward due to the internal pressure, and the rim bead seat 9 and the rigid ring The body 13 is wedge-shaped and is tightly and firmly assembled here. In addition, although the illustration shows one locking portion 12 and one rigid ring body 13, they may be arranged side by side in the axial direction. Reference numeral 14 designates triangular lugs with a hollow cross section, which substantially constitute the tread portion 7, and eight of which in the figure are projected on radial lines at equal intervals in the circumferential direction. The apex 15 of each lug 14 is located at the same circumferential position on the radial line, and as shown in FIG. It shows. That is, as shown by the symbol R in FIG.
It is said to be ~2R. Reference numerals 17 and 18 indicate slope parts on both sides of the lug, and the leading side in the rotational direction (kick surface) is the first slope part 17 which essentially becomes a tread surface for compacting snow, and the trailing side in the rotation direction (reverse kick surface) is substantially used as a support surface for the tread surface, and is designed to generate buoyancy and drive force here regardless of the amount of snow accumulated or the quality of the snow. Therefore, as shown in FIG.
In this example, θ1 is set to 15° to 30° (preferably 25°),
The minimum angle of θ2 is limited to 5 degrees, and the first slope part 17 increases the tread area and thereby improves the buoyancy.In order to carry out this function of the first slope part 17, the second slope part 18 is configured to prevent excessive deformation of the slope portion 17. In addition, in order to better achieve this function, the thickness t1 of the first slope portion 17, the thickness t2 of the second slope portion 18, and the thickness t3 of the tire crown portion are set such that t2≧t1≧t3. . The thickness of the sidewall portion 5 may be equal to or slightly different from the thickness t3. Further, the root portions of the lug slope portions 17 and 18 are connected to each other at a tire crown, that is, a connecting portion 19 between substantially circumferentially adjacent lugs, and a polygonal tread portion 8 is formed here. There is. Furthermore, the height of the triangular lug 14 from the bead portion 4 is
When H1 is the height of the joint 19 and H2 is the height of the connecting part 19, H1/H2 is set to be 1.3 or more and less than 2.0 in consideration of the buoyancy on the snow and the driving force, and the tire width W1
In relation to this, H2/W1 is 0.63 and 0.41, as is clear from the examples described later. That is, if the height of the triangular lug 14 becomes higher than this, although it is excellent for use in wetlands such as wet fields, it will not be able to achieve the function of compacting the snow and improving the floating of the snow on the snow. , lag 14
The pitch is preferably greater than 2 (H1-H2), and the number of lugs in the snow is preferably 4 at most, preferably 3. Further, both ends of the triangular lug 14 in the tire axial direction are closed by vertical walls 20 connected to the tire shoulder 6, and the vertical walls 20 extend outward in the radial direction as shown in FIG. Therefore, it is an inclined elevation facing outward in the tire axial direction. Reference numeral 21 denotes a compaction wing body, which is formed by extending the first slope portion 17 and the top portion 15 of the triangular lug 14 outward in the tire axial direction from the lug elevation wall 20. Pressing surface portion 21A of
is connected to the tire shoulder 6 via a curved constriction 21C. Reference numeral 22 denotes a support portion, which is formed by connecting the top portion 21B of the wing body 21 on the extending end side and the lug elevation wall 20 on the second slope portion 18 side of the triangular lug 14, and the support portion 22 is connected to one end thereof. 22A is located in the middle of the tire axial direction length of the top portion 21B, and the other end 22B is located in the middle of the lug elevation wall 20 in the height direction, and both ends are connected as a curved edge 22C ( (See Figure 5). Here, behind the compaction wing body 21 (rear side)
is a recessed part 23 which allows elastic deformation of the wing body 21 and also allows the vertical wall 20 and the supporting part 22
The blade body 21 is configured to prevent excessive deformation of the wing body 21 and promote elastic recovery after deformation. Here, the wing body 21 assists or enhances the insufficient driving force and levitation force due only to the first slope portion 17, and the elastic deformation of the wing body 21 is suitably achieved by forming the recessed portion 23 behind it. However, together with the constriction portion 21C, the wing body 21 itself does not become a significant obstacle to turning during cornering, ensuring stable running on snow. Next, Examples of a wetland polygonal tire (outer diameter 558 mm) A, an invention tire (outer diameter 690 mm) B, and an invention tire (outer diameter 730 mm) C are shown below. In addition, it is advantageous for the tire of the present invention to have a static ground contact pressure of 0.10 Kg/cm ² or less, preferably 0.05 Kg/cm ² or less.

[Table] The above is a basic embodiment of the present invention, but the structure of the present invention can be improved as shown in FIGS. 8 to 10. In the embodiments shown in FIGS. 8 to 10, compaction or buoyancy promotion parts including the aforementioned wing body 21 are provided on both outer end surfaces of the triangular hollow lug 14, which further enhances the buoyancy promotion function. play. In addition, the first
A second slope portion 18 that supports the slope portion 17
A support rib 24 is provided at the support rib 24, and when the support rib 24 is provided, the thickness of the second slope portion 18 can be made thinner, contributing to weight reduction. Although the supporting ribs 24 are shown outside in the figure, they may be provided on the inner surface of the second slope portion 18, and in this case, the support ribs 24 may be provided in a so-called hollow space between the first slope portion 17 and the second slope portion 18. The triangular lugs 14 may be provided so as to be partitioned. In any case, the number of supporting ribs 24 may be more than one as shown in the figure, and the supporting ribs 24 of the first embodiment shown in FIG.
4 can also be provided. Next, its operation will be explained with reference to FIG.
The tubeless tire of the present invention has an internal tire pressure of 0.2Kg/
It has a low pressure of about ^cm2 , and is applied to the driving wheels (which may be steering wheels) of so-called micro passenger vehicles (weighing 200 to 300 kg), such as three-wheel buggies and four-wheel buggies, through the axle mounting part 3. It will be installed. If the vehicle rotates in the direction of arrow D in FIG.
7 and the wing body 21 will hit the snow surface S, but the first slope portion 17 is hollow inside,
Further, the wing body 21 has a recessed portion 23 and is elastically deformable, and the first sloped portion 17 has a recessed portion 23 and the second sloped portion 18
Since the wing body 21 is supported by the support portion 22 and the vertical wall 20, the snow surface S
A large buoyant force is generated by the reaction force that hits the snow layer, and the snow layer is successively compacted.By providing the wing body 21, the first slope portion 17, that is, the area of the first slope portion 17 can be increased without increasing the lug height. This makes it possible to form a tread surface, which in turn allows the vehicle to run on general roads without excessive vibration. In this way, the snow layer is successively compacted, and when the lug 14 separates from the snow surface S, it is elastically restored to its previous position by the first slope part 17 and the support part 22. Furthermore, when the running speed increases, that is, when the tire rotational speed becomes large, the first slope part 17 and the second slope part 18 press the so-called snow layer at the front and rear of the snow surface S, and the surface travels while floating. According to experiments, even when the amount of snow is large and the axle sinks almost to the top of the snow surface S, it is possible to run the vehicle. Furthermore, when the vehicle is turning while driving, the wing body can be easily moved because the top portion 15 of the lug 14 is arc-shaped and the surface portion 21A of the wing body 21 is connected to the tire shoulder portion 6 via the constriction portion 21C. 21 is elastically deformed during turning without becoming a hindrance to turning, making it possible to turn extremely safely and easily. In addition, since the lug height is substantially reduced by the wing body 21, the vehicle can run on general roads without excessive vibration, and together with the hollow triangular lugs 14, it is possible to ensure that the vehicle can run on general roads. . (Effects of the Invention) The present invention is as described above, and has the following effects. From the bead part 4 of the tire body 1 to the triangular lug 14
H1 is the height to the top 15 of the
When H2 is set, H1/H2 is set to be 1.3 or more and less than 2.0, so the height of the triangular lug 14 is not too high and the vehicle can be driven on snowy roads and ordinary roads. In other words, in the conventional tubeless tire with hollow triangular lugs (Japanese Patent Application Laid-Open No. 1983-47904), the lug height is increased to allow for running on wetlands.
Vehicles are driven by scraping the snowy road rather than compacting it, making it virtually impossible to compact the snow layer, making it impossible to drive on snowy roads, and also making it impossible to drive on general roads due to the extreme vibrations that occur. It is advantageous compared to Furthermore, in the present invention, although the height of the triangular lug 14 is kept as low as possible to reduce vibration when running on general roads, the first slope part 17 and the top part 15 of the triangular lug 14 are
Each of these is extended outward in the tire axial direction from the lug elevation wall 20 to form a compaction wing body 21,
Since the wing body 21 is connected to the tire shoulder 6, the first slope portion 17 of the triangular lug 14 and the wing body 21
You can drive on snowy roads by compacting them on both sides,
In order to compact the snowy road, the supporting portion 22 of the wing body 21 is formed by connecting the top of the wing body 21 on the extended end side and the lug elevation wall 20 on the second slope portion 18 side of the triangular lug 14. As a result, excessive elastic deformation of the wing body 21 is suppressed, and driving through the snowy road while compacting it is ensured. Further, the wing body 21 has the first slope portion 1 of the triangular lug 14.
7 and the apex 15 extending outward in the tire axial direction, and the second slope portion 18 of the triangular lug 14 is also not extended, the wing body 21 is formed by a slight difference when cornering on a general road. Since the elastic restoring force is ensured by the supporting portion 22 and the lug elevation wall 20, the vehicle can run on both snowy roads and ordinary roads. Here, it is possible to drive while compacting the snow regardless of the amount of snow or the quality of the snow, and it is easy to manufacture due to its lightweight and one-piece structure. It is advantageous in that it can also be used for driving.

[Brief explanation of the drawing]

Fig. 1 is a front view of the tire of the present invention, Fig. 2 is a rear view thereof, Fig. 3 is an enlarged cross-sectional view taken along line A-A in Fig. 1, and Fig. 4 is an enlarged cross-sectional view taken along line B-B in Fig. 1, showing the right half of the tire. FIG. 5 is an enlarged plan view of the main parts, FIG. 6 is an explanatory perspective view of the main parts, FIG. 7 is an explanatory operating diagram of an example of a driving situation, and FIG. 8 is a second embodiment of the present invention. Front view showing,
FIG. 9 is an enlarged cross-sectional view taken along the line CC in FIG. 8, and FIG. 10 is a plan view of the main parts thereof. 1... Tire body, 6... Tire shoulder,
8...Tread portion, 14...Triangular hollow lug, 15...
Top of lug, 17, 18...first and second slope parts, 20
... Lug elevation wall, 21 ... Wing body, 22 ... Support part.

Claims (1)

[Scope of Claims] 1. A triangular lug having a hollow cross section and consisting of a first slope portion serving as a kick surface and a second slope portion on the opposite side of the kick surface is spaced apart in the circumferential direction on the outer peripheral surface of the tire body. A tubeless tire for snowy roads in which the tire body and the triangular lugs are made of an elastic material, the triangular lugs protruding outward in the radial direction, and both ends of the triangular lugs in the tire axial direction are closed by vertical walls connected to the tire shoulder. From the bead part 4 of the tire body 1 to the triangular lug 14
H1 is the height to the top 15 of the
When H2 is assumed, H1/H2 is 1.3 or more and less than 2.0, and the first slope part 17 and the top part 15 of the triangular lug 14
Each of these is extended outward in the tire axial direction from the lug elevation wall 20 to form a compaction wing body 21,
The wing body 21 is connected to the tire shoulder 6, and the top part of the wing body 21 on the extended end side and the lug elevation wall 20 on the second slope portion 18 side of the triangular lug 14 are connected to each other. A tubeless tire for snowy roads, characterized in that a supporting portion 22 is formed.