CA1324070C - Pneumatic tire - Google Patents
Pneumatic tireInfo
- Publication number
- CA1324070C CA1324070C CA 579763 CA579763A CA1324070C CA 1324070 C CA1324070 C CA 1324070C CA 579763 CA579763 CA 579763 CA 579763 A CA579763 A CA 579763A CA 1324070 C CA1324070 C CA 1324070C
- Authority
- CA
- Canada
- Prior art keywords
- tire
- sipes
- block
- blocks
- tread surface
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Landscapes
- Tires In General (AREA)
Abstract
TITLE OF THE INVENTION
"PNEUMATIC TIRE"
ABSTRACT OF THE DISCLOSURE
A tread surface of a pneumatic tire comprises a plurality rows of blocks arranged in the circumferential direction of the tire and separated from one another by a plurality of circumferentially extending zigzag grooves and a plurality of transversely extending grooves, each of the blocks of inner rows being formed with a plurality of sipes each oriented toward the direction of rotation of the tire and each inclined with respect to the circumferential direction of the tire and each arranged so that, when the tire rolls on the road, an inner end of the sipe located in a central portion of the block is brought into contact with the ground earlier than an outer end of the sipe located in an edge of the block.
"PNEUMATIC TIRE"
ABSTRACT OF THE DISCLOSURE
A tread surface of a pneumatic tire comprises a plurality rows of blocks arranged in the circumferential direction of the tire and separated from one another by a plurality of circumferentially extending zigzag grooves and a plurality of transversely extending grooves, each of the blocks of inner rows being formed with a plurality of sipes each oriented toward the direction of rotation of the tire and each inclined with respect to the circumferential direction of the tire and each arranged so that, when the tire rolls on the road, an inner end of the sipe located in a central portion of the block is brought into contact with the ground earlier than an outer end of the sipe located in an edge of the block.
Description
FIELD OF THE INVENTION
The present invention relates in general to pneumatic tires, and in particular to tread patterns of pneumatic tires for heavy-duty vehicles which travel on frozen road.
The invention is especially directed to pneumatic tires wherein travelling performance on ~ce and snow is enhanced, without the use of spikes or studs, by improving water absorption performance and drainage performance, particularly on travel on ice.
DESCRIPTION OF THE PRIOR ART
In order to ensure travelling performance on ice and travelling performance on snow, there have been used snow spike tires with spikes in the tread. However, damage to roads and dust caused by the spikes of the snow tires become important problems lately and there is therefore a tendency that snow spike tires has been replaced by studless tires using no spikes. The studless tire does not have better travelling performance on ice, as compared with the spike tire.
A pneumatic studless tire 1 of the block type as shown in FIG. 3 has been proposed to improve the faults mentioned above. The conventional tire 1 has in its tread surface 2 a plurality of blocks 6 separated from one another by a plurality of circumferentially extending grooves 3 and transversely extending grooves 4. Each block 6 is provided - with a pluralit~ of sipes 7 arranged in the same direction at a substantially constant angle to the circumferential :, , ' direction of the tire. By arranging these sipes 7, the ; pneumatic tire 1 has better drainage performance as the ends 7a of the sipes 7 thereof cut water film occurring when the tire is travelling on the frozen road.
However, in the case of pneumatic tires for heavy duty vehicles having higher ground pressure, there is a drawback that drainage performance and travelling performance ; on frozen road are insufficient as a large amount of ice melt by the high ground pressure and thick water film is formed.
Accordingly, it is an object of the present invention to an improved pneumatic tire wherein travelling performance on ice and travelling performance on snow are enhanced. The object is achieved by provision of a plurality of sipes each oriented toward the direction of rotation of the ` 15 tire and each inclined with respect to the circumferential ; direction of the tire and each arranged so that, when the tire ~' rolls on the road, an inner end of the sipe located in a - central portion of the block is brought into contact with the ground earlier than an outer end of the sipe located in an edge of the block.
SUMMARY OF THE INVENTION
In accordance with an important aspect of the present invention, there is provided a tread surface of a pneumatic tire comprising: a plurality rows of blocks arranged ~ 25 in the circumferential direction of the tire and separated from one another by a plurality of circumferentially extending zigzag grooves and a plurality of transversely extending grooves; each of the blocks of inner rows being formed with a _ 4 _ 1 324070 plurality of sipes each oriented toward the direction of rotation of the tire and each inclined with respect to the circumferential direction of the tire and each arranged so that, when the tire rolls on the road, an inner end of the sipe located in a central portion of the block is brought into contact with the ground earlier than an outer end of the sipe located in an edge of the block.
BRIEF DESCRIPTION OF THE DRAWINGS
The drawbacks of a conventional pneumatic tire and the features and advantages of a pneumatic tire according to the present invention will be more clearly understood from the following description taken in conjunction with the accompanying drawings:
FIG. 1 is a plan view, partly broken away, showing the tread surface of a pneumatic tire constructed in - accordance with an embodiment of the present invention;
- FIG. 2 is a view similar to FIG. 1 showing the tread surface of a pneumatic tire constructed in accordance with a ` another embodiment of the present invention; and FIG. 3 is a plan view, partly broken away, showing the tread surface of a conventional pneumatic tire.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
i Referring now in greater detail to the drawings and initially to FIG. 1, there is shown a pneumatic tire 11 constructed in accordance with a preferred embodiment of the present invention. The pneumatic tire 11 has in the tread surface 12a of a tread 12 five rows of blocks 16a, 16b, 16c, 16d and 16e which are arranged in the circumferential - s - 1 324 0 70 direction of the tire and separated from one another by four circumferentially extending zigzag grooves 13 and a plurality of transversely extending grooves 14. Each block 15 of the three rows of blocks 16b, 16c and 16d in the tread central region is formed with a plurality of pairs of sipes 18 symmetrical with respect to the central portion 15a of the block 15 and oriented toward the direction of rotation R of the tire. Each sipe 18 in the inner rows of blocks 16b and 16d extends from the edge 15b of the corresponding block lS at an angle of e with respect to the circumferential direction and terminates short of the central portion 15a of the block 15, and has an open end 18a open to the circumferential groove 13 or traverse groove 14. In the central row of blocks 16c, a pair of the sipes 18 and 18 are interconnected at the block ` 15 central portion 15a.
` Each sipe 18 is arranged so that, when the tire ` rolls on the road, the inner end 18b of the sipe 18 located in the block central portion 15a is brought into contact with the ground earlier than the outer end 18c of the sipe 18 located in the block edge 15b. The reason is that the drainage speed of water is greatly increased. The width of the sipe 18 ranges from 0.3 mm to 2 mm. In the case of the sipe width of less than 0.3 mm, the water drainage performance by the sipes and the travelling performance on ice cannot be obtained satisfactorily, while in the case of the sipe width of more than 2 mm, the rigidity of the blocks is decreased and the ` edge effect of the block ends is reduced, thereby resulting in reduction in the travelling performance on snow. ~he depth of - 6 - l 32407 0 the sipe 18 ranges from 25% to 120% of the depth of the circumferential groove 13. The reason is that in the case of being less than 25%, the the water drainage performance and the travelling performance on ice cannot be obtained satisfactorily, and in the case of being more than 120%, the rigidity of the blocks is decreased and the edge effect of the block ends is reduced, thereby resulting in reduction in the travelling performance on snow. The construction not mentioned above is the same as that of normal pneumatic tires.
If the pneumatic tire 11 of the present invention travels on the frozen road, a thick water film will occur between the blocks 15 and the road. The thick water film is cut by the sipe ends of a plurality of the sipes 18 provided in the blocks 15, and therefore water enters into the sipes 18 and is effectively discharged as the tire rolls on the road.
As a pair of the sipes 18 are oriented toward the direction of - rotation of the tire and symmetrical with respect to the block central portion 15a, the water in the blocks 15 flows from the block central portions 15a to the block edges 15b and into the circumferentially extending grooves 13 from the open ends 18a of the sipes 18. This flow cau~es the water to be discharged rapidly. In addition, as no water flows back to the sipes 18, travelling performance on frozen road is greatly enhanced.
- Further, as the blocks 15 have suitable block rigidity, travelling performance on snow is also maintained satisfactorily.
- FIG. 2 illustrates a pneumatic tire 21 constructed in accordance with another embodiment of the present invention. The same constructions as the embodiment of FIG. 1 will be designated by like reference numerals. In the embodiment of FIG. 2, the pneumatic tire 21 comprises five circumferentially extending grooves 13 and six rows of blocks 16a through 16f, and only the blocks 15 located in the two rows of blocks 16c and 16d of the tread central region are with a plurality of sipes 18. Unlike the embodiment shown in FIG. 1, the sipes 18 comprise a plurality of pairs of symmetrical sipes 18A and a plurality of azygous sipes 18A'.
From the foregoing description, it will be seen that an improved pneumatic tire is provided wherein travelling performance on ice and travelling performance on snow are , enhanced by arranging a plurality of sipes each oriented ` toward the direction of rotation of the tire and each inclined with respect to the circumferential direction of the tire and ~; each arranged so that, when the tire rolls on the road, an inner end of the sipe located in a central portion of the block is brought into contact with the ground earlier than an outer end of the sipe located in an edge of the block.
t 20 While certain representative embodiments and details have been shown for the purpose of illustrating the invention, it will be apparent to those skilled in this art that various changes and modifications may be made therein without departing from the scope of the invention.
The present invention relates in general to pneumatic tires, and in particular to tread patterns of pneumatic tires for heavy-duty vehicles which travel on frozen road.
The invention is especially directed to pneumatic tires wherein travelling performance on ~ce and snow is enhanced, without the use of spikes or studs, by improving water absorption performance and drainage performance, particularly on travel on ice.
DESCRIPTION OF THE PRIOR ART
In order to ensure travelling performance on ice and travelling performance on snow, there have been used snow spike tires with spikes in the tread. However, damage to roads and dust caused by the spikes of the snow tires become important problems lately and there is therefore a tendency that snow spike tires has been replaced by studless tires using no spikes. The studless tire does not have better travelling performance on ice, as compared with the spike tire.
A pneumatic studless tire 1 of the block type as shown in FIG. 3 has been proposed to improve the faults mentioned above. The conventional tire 1 has in its tread surface 2 a plurality of blocks 6 separated from one another by a plurality of circumferentially extending grooves 3 and transversely extending grooves 4. Each block 6 is provided - with a pluralit~ of sipes 7 arranged in the same direction at a substantially constant angle to the circumferential :, , ' direction of the tire. By arranging these sipes 7, the ; pneumatic tire 1 has better drainage performance as the ends 7a of the sipes 7 thereof cut water film occurring when the tire is travelling on the frozen road.
However, in the case of pneumatic tires for heavy duty vehicles having higher ground pressure, there is a drawback that drainage performance and travelling performance ; on frozen road are insufficient as a large amount of ice melt by the high ground pressure and thick water film is formed.
Accordingly, it is an object of the present invention to an improved pneumatic tire wherein travelling performance on ice and travelling performance on snow are enhanced. The object is achieved by provision of a plurality of sipes each oriented toward the direction of rotation of the ` 15 tire and each inclined with respect to the circumferential ; direction of the tire and each arranged so that, when the tire ~' rolls on the road, an inner end of the sipe located in a - central portion of the block is brought into contact with the ground earlier than an outer end of the sipe located in an edge of the block.
SUMMARY OF THE INVENTION
In accordance with an important aspect of the present invention, there is provided a tread surface of a pneumatic tire comprising: a plurality rows of blocks arranged ~ 25 in the circumferential direction of the tire and separated from one another by a plurality of circumferentially extending zigzag grooves and a plurality of transversely extending grooves; each of the blocks of inner rows being formed with a _ 4 _ 1 324070 plurality of sipes each oriented toward the direction of rotation of the tire and each inclined with respect to the circumferential direction of the tire and each arranged so that, when the tire rolls on the road, an inner end of the sipe located in a central portion of the block is brought into contact with the ground earlier than an outer end of the sipe located in an edge of the block.
BRIEF DESCRIPTION OF THE DRAWINGS
The drawbacks of a conventional pneumatic tire and the features and advantages of a pneumatic tire according to the present invention will be more clearly understood from the following description taken in conjunction with the accompanying drawings:
FIG. 1 is a plan view, partly broken away, showing the tread surface of a pneumatic tire constructed in - accordance with an embodiment of the present invention;
- FIG. 2 is a view similar to FIG. 1 showing the tread surface of a pneumatic tire constructed in accordance with a ` another embodiment of the present invention; and FIG. 3 is a plan view, partly broken away, showing the tread surface of a conventional pneumatic tire.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
i Referring now in greater detail to the drawings and initially to FIG. 1, there is shown a pneumatic tire 11 constructed in accordance with a preferred embodiment of the present invention. The pneumatic tire 11 has in the tread surface 12a of a tread 12 five rows of blocks 16a, 16b, 16c, 16d and 16e which are arranged in the circumferential - s - 1 324 0 70 direction of the tire and separated from one another by four circumferentially extending zigzag grooves 13 and a plurality of transversely extending grooves 14. Each block 15 of the three rows of blocks 16b, 16c and 16d in the tread central region is formed with a plurality of pairs of sipes 18 symmetrical with respect to the central portion 15a of the block 15 and oriented toward the direction of rotation R of the tire. Each sipe 18 in the inner rows of blocks 16b and 16d extends from the edge 15b of the corresponding block lS at an angle of e with respect to the circumferential direction and terminates short of the central portion 15a of the block 15, and has an open end 18a open to the circumferential groove 13 or traverse groove 14. In the central row of blocks 16c, a pair of the sipes 18 and 18 are interconnected at the block ` 15 central portion 15a.
` Each sipe 18 is arranged so that, when the tire ` rolls on the road, the inner end 18b of the sipe 18 located in the block central portion 15a is brought into contact with the ground earlier than the outer end 18c of the sipe 18 located in the block edge 15b. The reason is that the drainage speed of water is greatly increased. The width of the sipe 18 ranges from 0.3 mm to 2 mm. In the case of the sipe width of less than 0.3 mm, the water drainage performance by the sipes and the travelling performance on ice cannot be obtained satisfactorily, while in the case of the sipe width of more than 2 mm, the rigidity of the blocks is decreased and the ` edge effect of the block ends is reduced, thereby resulting in reduction in the travelling performance on snow. ~he depth of - 6 - l 32407 0 the sipe 18 ranges from 25% to 120% of the depth of the circumferential groove 13. The reason is that in the case of being less than 25%, the the water drainage performance and the travelling performance on ice cannot be obtained satisfactorily, and in the case of being more than 120%, the rigidity of the blocks is decreased and the edge effect of the block ends is reduced, thereby resulting in reduction in the travelling performance on snow. The construction not mentioned above is the same as that of normal pneumatic tires.
If the pneumatic tire 11 of the present invention travels on the frozen road, a thick water film will occur between the blocks 15 and the road. The thick water film is cut by the sipe ends of a plurality of the sipes 18 provided in the blocks 15, and therefore water enters into the sipes 18 and is effectively discharged as the tire rolls on the road.
As a pair of the sipes 18 are oriented toward the direction of - rotation of the tire and symmetrical with respect to the block central portion 15a, the water in the blocks 15 flows from the block central portions 15a to the block edges 15b and into the circumferentially extending grooves 13 from the open ends 18a of the sipes 18. This flow cau~es the water to be discharged rapidly. In addition, as no water flows back to the sipes 18, travelling performance on frozen road is greatly enhanced.
- Further, as the blocks 15 have suitable block rigidity, travelling performance on snow is also maintained satisfactorily.
- FIG. 2 illustrates a pneumatic tire 21 constructed in accordance with another embodiment of the present invention. The same constructions as the embodiment of FIG. 1 will be designated by like reference numerals. In the embodiment of FIG. 2, the pneumatic tire 21 comprises five circumferentially extending grooves 13 and six rows of blocks 16a through 16f, and only the blocks 15 located in the two rows of blocks 16c and 16d of the tread central region are with a plurality of sipes 18. Unlike the embodiment shown in FIG. 1, the sipes 18 comprise a plurality of pairs of symmetrical sipes 18A and a plurality of azygous sipes 18A'.
From the foregoing description, it will be seen that an improved pneumatic tire is provided wherein travelling performance on ice and travelling performance on snow are , enhanced by arranging a plurality of sipes each oriented ` toward the direction of rotation of the tire and each inclined with respect to the circumferential direction of the tire and ~; each arranged so that, when the tire rolls on the road, an inner end of the sipe located in a central portion of the block is brought into contact with the ground earlier than an outer end of the sipe located in an edge of the block.
t 20 While certain representative embodiments and details have been shown for the purpose of illustrating the invention, it will be apparent to those skilled in this art that various changes and modifications may be made therein without departing from the scope of the invention.
Claims (4)
1. A tread surface of a pneumatic tire comprising:
a plurality rows of blocks arranged in the circumferential direction of said tire and separated from one another by a plurality of circumferentially extending zigzag grooves and a plurality of transversely extending grooves;
each of said blocks of inner rows being formed with a plurality of sipes each oriented toward the direction of rotation of said tire and each inclined with respect to the circumferential direction of said tire and each arranged so that, when said tire rolls on the road, an inner end of said sipe located in a central portion of said block is brought into contact with the ground earlier than an outer end of said sipe located in an edge of said block.
a plurality rows of blocks arranged in the circumferential direction of said tire and separated from one another by a plurality of circumferentially extending zigzag grooves and a plurality of transversely extending grooves;
each of said blocks of inner rows being formed with a plurality of sipes each oriented toward the direction of rotation of said tire and each inclined with respect to the circumferential direction of said tire and each arranged so that, when said tire rolls on the road, an inner end of said sipe located in a central portion of said block is brought into contact with the ground earlier than an outer end of said sipe located in an edge of said block.
2. A tread surface as set forth in claim 1, wherein said plurality of sipes comprise a plurality of pairs of sipes symmetrical with respect to said central portion of said block.
3. A tread surface as set forth in claim 1, wherein said plurality of sipes comprise a plurality of pairs of sipes symmetrical with respect to said central portion of said block and a plurality of azygous sipes.
4. A tread surface as set forth in claim 1, wherein each of said sipes has a width ranging from 0.3 mm to 2 mm and a depth ranging from 25% to 120% of the depth of said circumferentially extending groove.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62-257,986 | 1987-10-12 | ||
| JP62257986A JP2545099B2 (en) | 1987-10-12 | 1987-10-12 | Pneumatic tire |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1324070C true CA1324070C (en) | 1993-11-09 |
Family
ID=17313960
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 579763 Expired - Lifetime CA1324070C (en) | 1987-10-12 | 1988-10-11 | Pneumatic tire |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JP2545099B2 (en) |
| CA (1) | CA1324070C (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US11059330B2 (en) | 2018-03-23 | 2021-07-13 | Hankook Tire Co., Ltd. | Tire having V-shaped kerfs |
| US20220371375A1 (en) * | 2019-10-25 | 2022-11-24 | Bridgestone Corporation | Tire |
Families Citing this family (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH03182814A (en) * | 1989-12-11 | 1991-08-08 | Sumitomo Rubber Ind Ltd | Snow tire |
| DE19700101A1 (en) | 1997-01-03 | 1998-07-09 | Pirelli Reifenwerke | Tread pattern for a vehicle tire |
| US6571844B1 (en) * | 1999-07-19 | 2003-06-03 | Bridgestone Corporation | Pneumatic tire having tread including pairs of sipes |
| JP4780816B2 (en) * | 1999-08-31 | 2011-09-28 | 株式会社ブリヂストン | Pneumatic tire |
| JP4323623B2 (en) * | 1999-07-19 | 2009-09-02 | 株式会社ブリヂストン | Pneumatic tire |
| DE60022473T2 (en) * | 1999-12-01 | 2006-04-13 | Pirelli Pneumatici S.P.A. | AIR TIRES FOR VEHICLE WHEELS |
| JP3517404B2 (en) * | 2001-06-29 | 2004-04-12 | 住友ゴム工業株式会社 | studless tire |
| JP4589719B2 (en) * | 2004-12-28 | 2010-12-01 | 住友ゴム工業株式会社 | Pneumatic tire |
| FR2928866B1 (en) * | 2008-03-20 | 2010-03-19 | Michelin Soc Tech | SCULPTURE FOR TIRE TREAD |
| JP7437909B2 (en) * | 2019-10-25 | 2024-02-26 | 株式会社ブリヂストン | tire |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS60255506A (en) * | 1984-05-31 | 1985-12-17 | Yokohama Rubber Co Ltd:The | Pneumatic tire |
| JPS6116111A (en) * | 1984-06-30 | 1986-01-24 | Yokohama Rubber Co Ltd:The | Pneumatic tyre |
| JPS6136002A (en) * | 1984-07-27 | 1986-02-20 | Bridgestone Corp | Motorcycle belted tire excellent in grounding characteristic |
| JPS61261109A (en) * | 1985-05-14 | 1986-11-19 | Bridgestone Corp | Pneumatic tire excellent in traction and brake performance |
| JPS6238161A (en) * | 1985-08-14 | 1987-02-19 | 松下電工株式会社 | Stress elimination apparatus |
-
1987
- 1987-10-12 JP JP62257986A patent/JP2545099B2/en not_active Expired - Fee Related
-
1988
- 1988-10-11 CA CA 579763 patent/CA1324070C/en not_active Expired - Lifetime
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US11059330B2 (en) | 2018-03-23 | 2021-07-13 | Hankook Tire Co., Ltd. | Tire having V-shaped kerfs |
| US20220371375A1 (en) * | 2019-10-25 | 2022-11-24 | Bridgestone Corporation | Tire |
| EP4049859A4 (en) * | 2019-10-25 | 2022-12-14 | Bridgestone Corporation | Tire |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2545099B2 (en) | 1996-10-16 |
| JPH01101204A (en) | 1989-04-19 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |
Effective date: 20101109 |