CA2063949A1 - Combination of heavy duty pneumatic radial tires for use in winter season - Google Patents
Combination of heavy duty pneumatic radial tires for use in winter seasonInfo
- Publication number
- CA2063949A1 CA2063949A1 CA002063949A CA2063949A CA2063949A1 CA 2063949 A1 CA2063949 A1 CA 2063949A1 CA 002063949 A CA002063949 A CA 002063949A CA 2063949 A CA2063949 A CA 2063949A CA 2063949 A1 CA2063949 A1 CA 2063949A1
- Authority
- CA
- Canada
- Prior art keywords
- tire
- combination
- heavy duty
- width
- pneumatic radial
- 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.)
- Abandoned
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
- B60C11/00—Tyre tread bands; Tread patterns; Anti-skid inserts
- B60C11/03—Tread patterns
- B60C11/11—Tread patterns in which the raised area of the pattern consists only of isolated elements, e.g. blocks
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
- B60C3/00—Tyres characterised by the transverse section
- B60C3/04—Tyres characterised by the transverse section characterised by the relative dimensions of the section, e.g. low profile
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Tires In General (AREA)
Abstract
A COMBINATION OF HEAVY DUTY PNEUMATIC
RADIAL TIRES FOR USE IN WINTER SEASON
Abstract A combination of heavy duty pneumatic radial tires for use in winter season having a negative ratio of not less than 30% is a tire to be mounted on a non-driven steering shaft of a vehicle and a tire to be mounted on a driving shaft thereof, each tire having a ratio of ground contacting width to maximum tire width within a particularly range. In such a combination, the resistance to wondering is largely improved while sufficiently maintaining high performances on snow and ice roads.
RADIAL TIRES FOR USE IN WINTER SEASON
Abstract A combination of heavy duty pneumatic radial tires for use in winter season having a negative ratio of not less than 30% is a tire to be mounted on a non-driven steering shaft of a vehicle and a tire to be mounted on a driving shaft thereof, each tire having a ratio of ground contacting width to maximum tire width within a particularly range. In such a combination, the resistance to wondering is largely improved while sufficiently maintaining high performances on snow and ice roads.
Description
~3~
3-84, 569 A COMBINATION OF E~EAVY DUTY PNEUMATIC
RA~IAL TIRES FOR USl~ IN WINTER SEASON
This invention relates to a combination of heavy duty pneumatic radial tires for use in winter season, and more particularly to a radial tire combination effectively improving resistance to wondering while 05 sufficiently maintaining high running performances on snow and ice road surfaces.
For exampIe, when a vehicle under a heavy duty is provided with a non-driven steering shaft and one or two driving shafts and two tires are mounted on the non-lO driven steering shaft and four tires are mounted on eachof the driving shafts, it has been attempted to improve running performances on snow and ice road surfaces in winter season by rendering all tires into studless tires having a wider ground contacting width as far as 15 possible. In this case, the ratio of ground contacting width to maximum tire width in the tire, for example, a studless tire having a tire size of 10.00 R20 is usually about 0.82.
According to such a conventional technique~
however, the braking performance on snow and ice~road surfaces, traction performance and the like can effectively be improved because the tread width of the tire is wide, but there is caused a problem as to the 20~3~
resistance to wondering during the running on snow road and tracked road. That is, since the tread width of the tire mounted on the steering shaft largely exerting on the wondering is also wide likewise the tire mounted on o~ the driving shaft, it is obliged to degrade the resistance to wonderin~.
It is, therefore, an object of the invention to advantageously solve the above problems of the conventional technigue and to provide a combination of ~0 heavy duty pneumatic radiaI tires for use in winter season capable of ensuring excellent running performances on snow and ice road surfaces while improving the resistance to wondering.
The invention is based on a discovery that the 1~ resistance to wondering is improved by making the ground contacting width of the tire mounted on the steering : shaft narrower than that of the conventional tire, while the reduced amount of the ground contacting width in the tire mounted on the steering shaft is compensated by increasing the ground contacting width of the tire mounted on the driving shaft totally considering the tires mounted on the steering shaft and the driving shaft, whereby excellent running performances on snow and ice road surfaces as a whole of the vehicle can sufficiently be maintained.
According to the invention, there is the 20~3~Lfq1 According to the invention, at least one sipe is formed in each block constituting each block row whereby excellent performances on ice based on the biting of the sipe edge into ice can be developed.
Ob On the other hand, considering only the performances on ice, it is effective to reduce the negative ratio to increase actual ground contacting area, but if the negative ratio is too small, the block edge component becomes less and the amount of the block bitten into snow during the running on snow road is lacking to lower the running performances on snow road.
According to the invention, therefore, the development of high performances on snow road can be ensured by rendering the negative ratio into not less than 30%.
lb In the invention, the ratio of ground contacting width to maximum tire width (TW/SW)F in the tire to be mounted on the non-driven steering shaft of the vehicle is within a range of 0.66-0.8, which is sufficiently smaller than that of the conventional tire, whereby the excellent resistance to wondering is obtained while ensuring the performances on snow road required on the tire.
: When the ratio (TW/SW)F exceeds 0.8, the resistance to wondering is close to that of the : a6 conventional tire and can not be improved up to an expected extent, while when it is less than 0.66, the , '' ' ~
.~ ' ~$3~
According to the invention, at least one sipe is formed in each block constituting each block row:
whereby excellent performances on ice based on the biting of the sipe edge into ice can be developed.
On the other hand, considering only the performances on ice, it is effective to reduce the negative ratio to increase actual ground contacting area~ but if the negative ratio is too small, the block edge component becomes less and the amount of the block 1~ bittPn into snow during the running on snow road is lacking to lower the running performances on snow road.
According to the invention, therefore, the development of high performances on ~now road can be ensured by rendering the negative ratio into not less than 30%.
lb In the invention/ the ratio of ground contacting width to maximum tire width (TW~SW)F in the tire to be :
~; mounted on the non-driven steerlng shaft of the vehicle is within a range of 0.66-0.8, which is sufficiently smaller than that of the conventional tire, whereby the excellent resistance to wondering is obtained while ensuring the performances on snow road required on the tire.
When~the ratio (~W/SW)F exceeds 0.8, the resistance to wondering is close to that of the 2~ conventional tire and can not be~improved up to an expected extent, while when it~is less than 0.66, the :
, :. `.: ~ , .
'' ~ '' ' '; ' ' 2 ~
friction force of the tire on snow and ice roads is too low and hence the turning performance and other performances are degraded.
In the tire to be mounted on the driving shaft 0~ of the vehicle, in order to make the ground contacting area of the tire as a whole of the vehicle larger than total ground contacting area of the conventional tires to ensure the high performances on snow and ice roads, the ratio of ground contacting width to maximum tire width (TW/SW)D of the tire is not less than 1.21-1/2(TW/SW)F but not more than 1 for preventing the heat generation of the belt portion to enhance the tire durability.
That is, the ground contacting width of the tire 1~ mounted on the non-driven steering shaft is made narrower than that of the conventional tire within a particular range, whereby the resistance to wondering : can largely be improved while ensuring necessary performances on snow and ice roads. On the other hand, the ground contacting width of the tire mounted on the driving shaft is made wider than that of the conven-tional tire within a particular range to compensate the reduced amount of the ground contacting width in the tire mounted on the non-driven steering shaft, whereby : ~ the performances on snow and ice roads as a whole of the vehicle can sufficiently be maintained at a high level.
2~3~49 The invention will be described with reference to the accompanying drawings r wherein:
Fig. 1 is a diagrammatically plan view of a tread pattern used in the tire according to the o~ invention;
Fig. 2 is a graph showing a relation between ground contacting width ratio and resist.ance to wondering; and Fig. 3 is a graph showing a relation between ground contacting width ratio and braking performance on ice road.
In Fig. 1 is shown a plan view of the tread pattern used ln the practice of the invention. This tread pattern is common in the tire mounted on the non-1~ driven steering shaft and the tire mounted on thedriving shaft~
The tire having a ground contacting width TW
comprises a center block row 1, a~pair of shoulder block rows 2 and two pairs of block rows 3, 4 located between the center block row and the shoulder block row at its tread portion. Each of blocks lal 3a, 4a in the respec-tive block rows 1, 3, 4 other than the shoulder block row 2 lS provided with a sipe 5, 6, 7 substantially extend-.ing in the widthwise direction of the tread portion, while each of the blocks 2a in the shoulder block row 2 is pr~vided with two sipes 8 substantially extendlng in '., - ', .
.
the widthwise direction of the tread portion. 2063 9~ 9 In the illustrated tire having such a tread pattern, the negative ratio is 33% and the tire maximum width SW is 271 mm irrespectively of the non-driven o0 steering shaft and the driving shaft.
Furthermore, the ground contacting width TW of the tire to be mounted on the non-driven steering shaft is 200 mm, and the ground contacting width TW of the tire to be mounted on the driving shaft is 234 mm. ~hat is, the ratio of ground contacting width to maximum tire width (TW/SW)F of the tire mounted on the non-driven steering shaft in the above embodiment is about 0.74 and the ratio of ground contacting width to maximum tire width of the tire mounted on the driving shaft is about 1~ U.86.
In Fig. 2 are shown test results on the resistance to wondering when the tire of the above structure having a tire size of lO.00 R20 and a maximum tire width of 271 mm is mounted on a non-driven steering shaft of a vehicle and run on wondering road by changing the ground contacting width of the tread within a range of 180 mm - 240 mm.
In this test~ the ground contacting width of the tire mounted on the non-driven steerlng shaft is changed, but the ground contacting width of each of four tires mounted on the driving shaft is constant (224 mm).
, . . .
2~39~
The vehicle is straightly run on wondering road over a distance of 5 km, during which the number of handle corrected is measured. In Fig. 2, the measured result is represented by an index value.
0~ As the index value, a case that the straight running is possible with necessitating slight handle correction is 100. The larger the index value, the better the result.
According to the graph shown in ~ig. 2, it is apparent that when the ground contacting width of the tread exceeds 220 mm or the ratio of ground contacting width to maximum tire width (~W/SW)F exceeds 0.81, the improvement of the resistance to wondering can not be expected.
lS On the other hand, when the ratio (TW/SW)F is less than 0.66, or the ground contacting width of the tread is less than 180 mm, it is confirmed from experiments that the friction force of the tire on snow and ice roads is too small as previously mentioned and hence the turning performance and other running performances largely lower.
In the invention, therefore, the ratio (TW/SW)F
in the tire mounted on the non-driven steering shaft is within a range of about 0.66-0.8.
When the resistance to wondering is improved as mentioned above, if the ground contacting width of each g ., .. ~1 of the four tires mounted on the driving shaft is ~3~9 to that of each of the two tires mounted on the non-driven steering shaft, the performances on snow and ice roads as a whole of the vehicle are gradually lowered o~ accompanied with the decrease of the ground contacting width as compared with the resistance to wondering.
This is shown in Fig. 3 relating to the braking performance on ice. In this case, the distance from the starting full braking to the stopping of the vehicle running at 20 km/hr is measured and the performance on ice is represented by an index on the basis that the tire having the stopping distance of 32m, i.e. the tire haviny the ground contacting width of 220 mm i8 100.
According to this graph, when the ground 1~ contacting width of each of the tires mounted on the non-driven steering shaft and the driving shaft i8 224 mm, and when the ground contacting widths of both tlres are 220 mm, the sufficiently large ground contacting width as a while of the vehicle can be 2~ ensured and consequently the performance on ice represented by the index value of not less than 100 can be obtained as shown by white s~uares in Fig. 3 aside from the resistance to wondering. On the other hand, when the ground contacting widths of both tires are gradually decreased to 212 mm, 196 mm and I80 mm for improving the refiistance to wondering, the ground contacting width as a whole of ~he vehicle is too small as shown by black circles in Fig. 3, and hence the performances on ice rapidly lower.
According to the invention, therefore, the 0~ ground contacting width of the tire mounted on the non~
driven steering shaft is maintained at the narrow value for improving the resistance to wondering, while the ratio of ground contacting width to maximum tire width ~TW/SW)D of each of the tires mounted on the driving 1~ shaft is limited to a range of 1.21-1/2(TW/SW)F~
(TW/SW)D~1, whereby the decreased quantity of ground contacting width viewing the whole of the vehicle is sufficiently compensated while improviny the resistance to wondering, whereby the effective improvement of the 1~ performances on ice is obtained.
As shown by white circles in Fig. 3, when the ratio (TW/SW)F is constant or the ground contacting width of the tire mounted on the non-driven steering shaft is constant and the ground contacting width of the tire mounted on the driving shaft is changed from 212 mm to 224 mm, from 196 mm to 232 mm and 240 mm or from 180 mm to 240 mm, the high performances represented by an index value of not less than lO0 can be obtained.
As seen from the above, according to the invention, the resistance to wonderlng can effectively be improved by narrowing the ground contacting width of the tire mounted on the non~driven steering shaft within a constant range as compared with the conventional tire, and also the high performances on snow and ice roads as a whole of the vehicle can suficiently be maintained by widening the ground contacting width of the tire mounted on the driving shaft to sufficiently compensate the decreased quantity of the ground contacting width of the tire mounted on the non-driven~steering shaft.
When two t.ires are mounted on the single non-driven steering shaft~ four tires are mounted on the single driving shaft and four tires are mounted on the single non-driven and non-steering shaft located behind the driving sha~t, the relation among the ground contacting width, the resistance to wondering and the braking per~ormances on ice is shown in Table 1.
Table l _ ~i ~ .h ~ . '. . .~ ~t. . 7. ~ ~d~ t .;. . Res ist- ~aiting steering on driving non-driven wondering on ice sha~t shaft shat _ . _ _ _ . .
Com~ar-tire I220 mm 220 mm 220 mm 100 100 Com~ar-: atlve196 mm 196 mm 196 mm 130 90 : : Invention 196 mm 232 mm 232 mm 130 102 _ tire ~196 mm 240 mm 240 mm 130 105 As seen from Table 1, even when the constructio2n~ 3 ~9 of the inventlon is applied to the vehicle provided with the non-driven and non~steering shaft, the resistance to wondering can efectively be improved while maintaining o~ high performances on snow and ice roads.
Thus, according to the invention, the ratio of ground contacting width to maximum tire width (TW/SW)F
of the tire mounted on the non-driven steering shaft is within a range of 0.66-0.8 smaller than that of the conventional tire, and the ratio of ground contacting width to maximum tire width (TW/SW)D of the tire mounted on the driving shaft is within a range of 1.21-l/2(TW/SW)FS(TW/SW)D~l larger than that of the conventional tire, whereby the performances on snow and 1~ ice roads are sufficiently developed and further the resistance to wondering can effectively be improv~d.
ao ':
:: ~ ~
3-84, 569 A COMBINATION OF E~EAVY DUTY PNEUMATIC
RA~IAL TIRES FOR USl~ IN WINTER SEASON
This invention relates to a combination of heavy duty pneumatic radial tires for use in winter season, and more particularly to a radial tire combination effectively improving resistance to wondering while 05 sufficiently maintaining high running performances on snow and ice road surfaces.
For exampIe, when a vehicle under a heavy duty is provided with a non-driven steering shaft and one or two driving shafts and two tires are mounted on the non-lO driven steering shaft and four tires are mounted on eachof the driving shafts, it has been attempted to improve running performances on snow and ice road surfaces in winter season by rendering all tires into studless tires having a wider ground contacting width as far as 15 possible. In this case, the ratio of ground contacting width to maximum tire width in the tire, for example, a studless tire having a tire size of 10.00 R20 is usually about 0.82.
According to such a conventional technique~
however, the braking performance on snow and ice~road surfaces, traction performance and the like can effectively be improved because the tread width of the tire is wide, but there is caused a problem as to the 20~3~
resistance to wondering during the running on snow road and tracked road. That is, since the tread width of the tire mounted on the steering shaft largely exerting on the wondering is also wide likewise the tire mounted on o~ the driving shaft, it is obliged to degrade the resistance to wonderin~.
It is, therefore, an object of the invention to advantageously solve the above problems of the conventional technigue and to provide a combination of ~0 heavy duty pneumatic radiaI tires for use in winter season capable of ensuring excellent running performances on snow and ice road surfaces while improving the resistance to wondering.
The invention is based on a discovery that the 1~ resistance to wondering is improved by making the ground contacting width of the tire mounted on the steering : shaft narrower than that of the conventional tire, while the reduced amount of the ground contacting width in the tire mounted on the steering shaft is compensated by increasing the ground contacting width of the tire mounted on the driving shaft totally considering the tires mounted on the steering shaft and the driving shaft, whereby excellent running performances on snow and ice road surfaces as a whole of the vehicle can sufficiently be maintained.
According to the invention, there is the 20~3~Lfq1 According to the invention, at least one sipe is formed in each block constituting each block row whereby excellent performances on ice based on the biting of the sipe edge into ice can be developed.
Ob On the other hand, considering only the performances on ice, it is effective to reduce the negative ratio to increase actual ground contacting area, but if the negative ratio is too small, the block edge component becomes less and the amount of the block bitten into snow during the running on snow road is lacking to lower the running performances on snow road.
According to the invention, therefore, the development of high performances on snow road can be ensured by rendering the negative ratio into not less than 30%.
lb In the invention, the ratio of ground contacting width to maximum tire width (TW/SW)F in the tire to be mounted on the non-driven steering shaft of the vehicle is within a range of 0.66-0.8, which is sufficiently smaller than that of the conventional tire, whereby the excellent resistance to wondering is obtained while ensuring the performances on snow road required on the tire.
: When the ratio (TW/SW)F exceeds 0.8, the resistance to wondering is close to that of the : a6 conventional tire and can not be improved up to an expected extent, while when it is less than 0.66, the , '' ' ~
.~ ' ~$3~
According to the invention, at least one sipe is formed in each block constituting each block row:
whereby excellent performances on ice based on the biting of the sipe edge into ice can be developed.
On the other hand, considering only the performances on ice, it is effective to reduce the negative ratio to increase actual ground contacting area~ but if the negative ratio is too small, the block edge component becomes less and the amount of the block 1~ bittPn into snow during the running on snow road is lacking to lower the running performances on snow road.
According to the invention, therefore, the development of high performances on ~now road can be ensured by rendering the negative ratio into not less than 30%.
lb In the invention/ the ratio of ground contacting width to maximum tire width (TW~SW)F in the tire to be :
~; mounted on the non-driven steerlng shaft of the vehicle is within a range of 0.66-0.8, which is sufficiently smaller than that of the conventional tire, whereby the excellent resistance to wondering is obtained while ensuring the performances on snow road required on the tire.
When~the ratio (~W/SW)F exceeds 0.8, the resistance to wondering is close to that of the 2~ conventional tire and can not be~improved up to an expected extent, while when it~is less than 0.66, the :
, :. `.: ~ , .
'' ~ '' ' '; ' ' 2 ~
friction force of the tire on snow and ice roads is too low and hence the turning performance and other performances are degraded.
In the tire to be mounted on the driving shaft 0~ of the vehicle, in order to make the ground contacting area of the tire as a whole of the vehicle larger than total ground contacting area of the conventional tires to ensure the high performances on snow and ice roads, the ratio of ground contacting width to maximum tire width (TW/SW)D of the tire is not less than 1.21-1/2(TW/SW)F but not more than 1 for preventing the heat generation of the belt portion to enhance the tire durability.
That is, the ground contacting width of the tire 1~ mounted on the non-driven steering shaft is made narrower than that of the conventional tire within a particular range, whereby the resistance to wondering : can largely be improved while ensuring necessary performances on snow and ice roads. On the other hand, the ground contacting width of the tire mounted on the driving shaft is made wider than that of the conven-tional tire within a particular range to compensate the reduced amount of the ground contacting width in the tire mounted on the non-driven steering shaft, whereby : ~ the performances on snow and ice roads as a whole of the vehicle can sufficiently be maintained at a high level.
2~3~49 The invention will be described with reference to the accompanying drawings r wherein:
Fig. 1 is a diagrammatically plan view of a tread pattern used in the tire according to the o~ invention;
Fig. 2 is a graph showing a relation between ground contacting width ratio and resist.ance to wondering; and Fig. 3 is a graph showing a relation between ground contacting width ratio and braking performance on ice road.
In Fig. 1 is shown a plan view of the tread pattern used ln the practice of the invention. This tread pattern is common in the tire mounted on the non-1~ driven steering shaft and the tire mounted on thedriving shaft~
The tire having a ground contacting width TW
comprises a center block row 1, a~pair of shoulder block rows 2 and two pairs of block rows 3, 4 located between the center block row and the shoulder block row at its tread portion. Each of blocks lal 3a, 4a in the respec-tive block rows 1, 3, 4 other than the shoulder block row 2 lS provided with a sipe 5, 6, 7 substantially extend-.ing in the widthwise direction of the tread portion, while each of the blocks 2a in the shoulder block row 2 is pr~vided with two sipes 8 substantially extendlng in '., - ', .
.
the widthwise direction of the tread portion. 2063 9~ 9 In the illustrated tire having such a tread pattern, the negative ratio is 33% and the tire maximum width SW is 271 mm irrespectively of the non-driven o0 steering shaft and the driving shaft.
Furthermore, the ground contacting width TW of the tire to be mounted on the non-driven steering shaft is 200 mm, and the ground contacting width TW of the tire to be mounted on the driving shaft is 234 mm. ~hat is, the ratio of ground contacting width to maximum tire width (TW/SW)F of the tire mounted on the non-driven steering shaft in the above embodiment is about 0.74 and the ratio of ground contacting width to maximum tire width of the tire mounted on the driving shaft is about 1~ U.86.
In Fig. 2 are shown test results on the resistance to wondering when the tire of the above structure having a tire size of lO.00 R20 and a maximum tire width of 271 mm is mounted on a non-driven steering shaft of a vehicle and run on wondering road by changing the ground contacting width of the tread within a range of 180 mm - 240 mm.
In this test~ the ground contacting width of the tire mounted on the non-driven steerlng shaft is changed, but the ground contacting width of each of four tires mounted on the driving shaft is constant (224 mm).
, . . .
2~39~
The vehicle is straightly run on wondering road over a distance of 5 km, during which the number of handle corrected is measured. In Fig. 2, the measured result is represented by an index value.
0~ As the index value, a case that the straight running is possible with necessitating slight handle correction is 100. The larger the index value, the better the result.
According to the graph shown in ~ig. 2, it is apparent that when the ground contacting width of the tread exceeds 220 mm or the ratio of ground contacting width to maximum tire width (~W/SW)F exceeds 0.81, the improvement of the resistance to wondering can not be expected.
lS On the other hand, when the ratio (TW/SW)F is less than 0.66, or the ground contacting width of the tread is less than 180 mm, it is confirmed from experiments that the friction force of the tire on snow and ice roads is too small as previously mentioned and hence the turning performance and other running performances largely lower.
In the invention, therefore, the ratio (TW/SW)F
in the tire mounted on the non-driven steering shaft is within a range of about 0.66-0.8.
When the resistance to wondering is improved as mentioned above, if the ground contacting width of each g ., .. ~1 of the four tires mounted on the driving shaft is ~3~9 to that of each of the two tires mounted on the non-driven steering shaft, the performances on snow and ice roads as a whole of the vehicle are gradually lowered o~ accompanied with the decrease of the ground contacting width as compared with the resistance to wondering.
This is shown in Fig. 3 relating to the braking performance on ice. In this case, the distance from the starting full braking to the stopping of the vehicle running at 20 km/hr is measured and the performance on ice is represented by an index on the basis that the tire having the stopping distance of 32m, i.e. the tire haviny the ground contacting width of 220 mm i8 100.
According to this graph, when the ground 1~ contacting width of each of the tires mounted on the non-driven steering shaft and the driving shaft i8 224 mm, and when the ground contacting widths of both tlres are 220 mm, the sufficiently large ground contacting width as a while of the vehicle can be 2~ ensured and consequently the performance on ice represented by the index value of not less than 100 can be obtained as shown by white s~uares in Fig. 3 aside from the resistance to wondering. On the other hand, when the ground contacting widths of both tires are gradually decreased to 212 mm, 196 mm and I80 mm for improving the refiistance to wondering, the ground contacting width as a whole of ~he vehicle is too small as shown by black circles in Fig. 3, and hence the performances on ice rapidly lower.
According to the invention, therefore, the 0~ ground contacting width of the tire mounted on the non~
driven steering shaft is maintained at the narrow value for improving the resistance to wondering, while the ratio of ground contacting width to maximum tire width ~TW/SW)D of each of the tires mounted on the driving 1~ shaft is limited to a range of 1.21-1/2(TW/SW)F~
(TW/SW)D~1, whereby the decreased quantity of ground contacting width viewing the whole of the vehicle is sufficiently compensated while improviny the resistance to wondering, whereby the effective improvement of the 1~ performances on ice is obtained.
As shown by white circles in Fig. 3, when the ratio (TW/SW)F is constant or the ground contacting width of the tire mounted on the non-driven steering shaft is constant and the ground contacting width of the tire mounted on the driving shaft is changed from 212 mm to 224 mm, from 196 mm to 232 mm and 240 mm or from 180 mm to 240 mm, the high performances represented by an index value of not less than lO0 can be obtained.
As seen from the above, according to the invention, the resistance to wonderlng can effectively be improved by narrowing the ground contacting width of the tire mounted on the non~driven steering shaft within a constant range as compared with the conventional tire, and also the high performances on snow and ice roads as a whole of the vehicle can suficiently be maintained by widening the ground contacting width of the tire mounted on the driving shaft to sufficiently compensate the decreased quantity of the ground contacting width of the tire mounted on the non-driven~steering shaft.
When two t.ires are mounted on the single non-driven steering shaft~ four tires are mounted on the single driving shaft and four tires are mounted on the single non-driven and non-steering shaft located behind the driving sha~t, the relation among the ground contacting width, the resistance to wondering and the braking per~ormances on ice is shown in Table 1.
Table l _ ~i ~ .h ~ . '. . .~ ~t. . 7. ~ ~d~ t .;. . Res ist- ~aiting steering on driving non-driven wondering on ice sha~t shaft shat _ . _ _ _ . .
Com~ar-tire I220 mm 220 mm 220 mm 100 100 Com~ar-: atlve196 mm 196 mm 196 mm 130 90 : : Invention 196 mm 232 mm 232 mm 130 102 _ tire ~196 mm 240 mm 240 mm 130 105 As seen from Table 1, even when the constructio2n~ 3 ~9 of the inventlon is applied to the vehicle provided with the non-driven and non~steering shaft, the resistance to wondering can efectively be improved while maintaining o~ high performances on snow and ice roads.
Thus, according to the invention, the ratio of ground contacting width to maximum tire width (TW/SW)F
of the tire mounted on the non-driven steering shaft is within a range of 0.66-0.8 smaller than that of the conventional tire, and the ratio of ground contacting width to maximum tire width (TW/SW)D of the tire mounted on the driving shaft is within a range of 1.21-l/2(TW/SW)FS(TW/SW)D~l larger than that of the conventional tire, whereby the performances on snow and 1~ ice roads are sufficiently developed and further the resistance to wondering can effectively be improv~d.
ao ':
:: ~ ~
Claims (8)
1. A combination of heavy duty pneumatic radial tires for use in winter season to be mounted on a non-driven steering shaft and a driving shaft of a vehicle, each tire having a negative ratio of not less than 30%
and comprising plural block rows located in a surface of a tread portion and separated from each other in a widthwise direction of the tread, in which each block constituting each of the block rows is provided with at least one sipe, characterized in that a ratio of ground contacting width to maximum tire width (TW/SW)F in the tire mounted on the non-driven steering shaft is within a range of 0.66-0.8, and a ratio of ground contacting width to maximum tire width (TW/SW)D in the tire mounted on the driving shaft is within a range of 1.21-1/2(TW/SW) F?(TW/SW)n?1.
and comprising plural block rows located in a surface of a tread portion and separated from each other in a widthwise direction of the tread, in which each block constituting each of the block rows is provided with at least one sipe, characterized in that a ratio of ground contacting width to maximum tire width (TW/SW)F in the tire mounted on the non-driven steering shaft is within a range of 0.66-0.8, and a ratio of ground contacting width to maximum tire width (TW/SW)D in the tire mounted on the driving shaft is within a range of 1.21-1/2(TW/SW) F?(TW/SW)n?1.
2. A combination of heavy duty pneumatic radial tires according to claim 1, wherein said combination further comprises a tire to be mounted on a non-driven and non-steered shaft of a vehicle and having a ratio of ground contacting width to maximum tire width (TW/SW)N
of 1.21-1/2(TW/SW)F?(TW/SW)N?1.
of 1.21-1/2(TW/SW)F?(TW/SW)N?1.
3. A combination of heavy duty pneumatic radial tire according to claim 1, wherein said sipe formed in said block extends substantially in the widthwise direction of the tread.
4. A combination of heavy duty pneumatic radial tires according to claim 1, wherein said blocks in one of said block rows are arranged at a given shifting amount with respect to blocks in another adjoining block row in the circumferential direction.
5. A combination of heavy duty pneumatic radial tires according to claim 1, wherein each block constituting a block row located at an outermost side of the tread is provided with two sipes extending substantially in the widthwise direction.
6. A combination of heavy duty pneumatic radial tires according to claim 1, wherein each of said tires comprises at least five block rows.
7. A combination of heavy duty pneumatic radial tires according to claim 1, wherein said plural block rows are defined by plural circumferential main grooves each extending zigzag in the circumferential direction and plural circumferential narrow grooves having width narrower than that of the circumferential main groove and extending zigzag in the circumferential direction.
8. A combination of heavy duty pneumatic radial tires according to claim 7, wherein a pair of said circumferential narrow grooves are arranged between a pair of said circumferential main grooves in a central portion of the tread and a pair of said circumferential narrow grooves are arranged outside said pair of the circumferential main grooves toward the tread ends.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3084569A JPH04297305A (en) | 1991-03-26 | 1991-03-26 | Combinated structure of heavy duty radial tire used in winter |
| JP3-84,569 | 1991-03-26 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2063949A1 true CA2063949A1 (en) | 1992-09-27 |
Family
ID=13834300
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002063949A Abandoned CA2063949A1 (en) | 1991-03-26 | 1992-03-25 | Combination of heavy duty pneumatic radial tires for use in winter season |
Country Status (5)
| Country | Link |
|---|---|
| JP (1) | JPH04297305A (en) |
| CA (1) | CA2063949A1 (en) |
| FI (1) | FI921276A (en) |
| NO (1) | NO921115L (en) |
| SE (1) | SE9200924L (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6435237B1 (en) * | 2000-06-14 | 2002-08-20 | The Goodyear Tire & Rubber Company | Pneumatic tire having generally rounded footprint shape |
| US6446689B1 (en) * | 2000-06-14 | 2002-09-10 | The Goodyear Tire & Rubber Company | Pneumatic tire having 80 to 105 pitches |
| US6439285B1 (en) * | 2000-06-14 | 2002-08-27 | The Goodyear Tire & Rubber Company | Pneumatic tire having 98 pitches |
-
1991
- 1991-03-26 JP JP3084569A patent/JPH04297305A/en active Pending
-
1992
- 1992-03-20 NO NO92921115A patent/NO921115L/en unknown
- 1992-03-25 FI FI921276A patent/FI921276A/en not_active Application Discontinuation
- 1992-03-25 CA CA002063949A patent/CA2063949A1/en not_active Abandoned
- 1992-03-25 SE SE9200924A patent/SE9200924L/en not_active Application Discontinuation
Also Published As
| Publication number | Publication date |
|---|---|
| SE9200924L (en) | 1992-09-27 |
| SE9200924D0 (en) | 1992-03-25 |
| FI921276A (en) | 1992-09-27 |
| NO921115D0 (en) | 1992-03-20 |
| NO921115L (en) | 1992-09-28 |
| JPH04297305A (en) | 1992-10-21 |
| FI921276A0 (en) | 1992-03-25 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDE | Dead |