摘要:
The present invention provides a method for estimating a tire wear life which enables estimation of the tire wear life accurately in a short time. In this method, a rubber index Gi of a rubber test piece which is made of the same material as the material used in the tire tread portion of the tire whose tire wear life is to be estimated is measured using an abrasion tester which can be operated under a slip ratio of about 0.5 to 5% (step 100). Then, friction energies of the tire in free rolling, in a state in which the tire is provided with a toe angle, in a state in which a side force is applied to the tire, in a state in which a driving force is applied to the tire and in a state in which a braking force is applied to the tire are measured (step 102), respectively. An expected value of the tire wear life T1 is calculated from the rubber index Gi and the friction energies obtained above (step 104). The tire wear life is estimated from the expected value of the tire wear life T1 thus obtained (step 106).
摘要:
A wear resistance index G1 of a tire whose wear life is to be estimated is measured by the Lambourn abrasion tester. Then, friction energies in free rolling, when the tire is fitted with a toe angle, under application of a side force, under application of a braking force and under application of a driving force of the tire are measured. An expected value of the wear life T1 is calculated using the wear resistance index G1 and the friction energies thus obtained and the wear life of the tire is estimated on the basis of the expected value of the wear life T1. The wear life of a tire can be estimated accurately in a short time in accordance with the method for estimating a tire wear life of the present invention.
摘要:
A pneumatic tire maintaining excellent traction performance for the entire life of the tire. The tire (10) has blocks (18) each demarcated by both a circumferential groove formed in the tread and lateral grooves crossing the circumferential groove, and also has recessed parts (20). Each recessed part (20) is formed in at least one of those both wall surfaces of each block (18) that are oriented to the lateral direction of the tire, and the circumferential width (C) of each recessed part (20) is increased from the tread side of the block (18) toward the radially inside of the tire. Because the edge effect of the blocks (18) at the portions between the lateral grooves and the recessed parts (20) can be maintained in an excellent state even if the wear of the tire (10) progresses, the edge effect of the entire blocks can be maintained in an excellent state, and excellent traction performance can be maintained for the entire life of the tire.
摘要:
A motor-driven welding gun has a servomotor for displacing a movable electrode tip toward and away from a fixed electrode tip. The servomotor has a motor housing with a copper pipe which is inserted therein when the motor housing is cast. The copper pipe provides a coolant passage in the motor housing for supplying a coolant therethrough. When the coolant passage is supplied with the coolant, the motor housing is forcibly cooled, reducing the amount of heat generated by the servomotor.
摘要:
Provided is a tire exhibiting improved wear resistance, partial wear resistance, and traction performance on the wet road surface. The tire has block land portion arrays 5 defined on a tread portion 1. Between two block land portion arrays 5 located adjacent to each other while sandwiching a circumferential groove 2, a block land portions 4 constituting the block land portion arrays are arrange so as to be positionally displaced from each other, and a groove portion 6 located between the block land portions adjacent in the tire width direction extends obliquely with respect to tire width direction and the tire circumferential direction. At this time, a distance d2 between the block land portions adjacent in the tire width direction is shorter than a distance d1 between the block land portions adjacent in the circumferential direction. In the block land portion arrays 5 adjacent in the tire width direction, an inclined angle α of a side wall 9 of the block land portion 4 located on the groove portion 6 side with respect to the tire circumferential direction is larger than an inclined angle β of the other side wall 10 located on the opposite side to said groove portion 6 with respect to the tire circumferential direction.
摘要:
An object of the present invention is to provide a tire possessing improved wear resistance by optimizing configurations of block land portions. The tire is configured such that, in at least two adjacent block land portion arrays 5 sandwiching a circumferential groove 2, adjacent block land portions 4 constituting the block land portion arrays 5 are arranged so as to be positionally displaced from each other in the tire circumferential direction; and a distance d2 between the block land portions adjacent in the tire width direction is shorter than a distance d1 between the block land portions adjacent in the tire circumferential direction. A groove portion 8 between the block land portions adjacent in the tire width direction extends obliquely with respect to the tire width direction and the tire circumferential direction. Further, plural sets each formed by at least two adjacent block land portion arrays 5 sandwiching the circumferential groove 2 are arranged; and, among the block land portions arrays 5, an inclination angle θ1 of an extending direction of the groove portion 8B between the block land portions adjacent in the tire width direction of block land portion arrays 5 located closest to a tire equatorial plane CL side with respect to the tire circumferential direction is larger than an inclination angle θ2 of an extending direction of the groove portion 8A between the block land portions adjacent in the tire width direction of block land portion arrays 5 located at the outermost side in the tire width direction with respect to the tire circumferential direction.
摘要:
A copolymer of ethylene and an alpha-olefin having an ethylene content of from 30 to 90 mole %, a number average molecular weight of from 300 to 30,000 and a molecular weight distribution defined by a Q value (the ratio of the weight average molecular weight to the number average molecular weight) of not more than 3 and a Z value (the ratio of the maximum value of the molecular weight to the minimum value of the molecular weight when the molecular weight is measured by gel permeation chromatography) of from 15 to 200. The said copolymer can be produced by a process comprising copolymerizing ethylene with an alpha-olefin in the liquid phase in the presence of a polymerization catalyst composed of a combination of a soluble vanadium compound and an organoaluminum compound in the co-presence of hydrogen, characterized in that (a) the copolymerization is carried out in a continuous manner, (b) the concentration of the vanadium compound in the polymerization system is maintained at 0.3 to 30 millimoles/liter, and (c) the vanadium compound is supplied to the polymerization system as a solution in a polymerization medium in a concentration which is 1 to 5 times the concentration of the vanadium compound in the liquid phase. This compound is useful as a synthetic lubricant oil, a fuel oil additive and a lubricant oil additive.
摘要:
An object of the present invention is to provide a tire possessing improved wear resistance by optimizing configurations of block land portions. The tire is configured such that, in at least two adjacent block land portion arrays 5 sandwiching a circumferential groove 2, adjacent block land portions 4 constituting the block land portion arrays 5 are arranged so as to be positionally displaced from each other in the tire circumferential direction; and a distance d2 between the block land portions adjacent in the tire width direction is shorter than a distance d1 between the block land portions adjacent in the tire circumferential direction. A groove portion 8 between the block land portions adjacent in the tire width direction extends obliquely with respect to the tire width direction and the tire circumferential direction. Further, plural sets each formed by at least two adjacent block land portion arrays 5 sandwiching the circumferential groove 2 are arranged; and, among the block land portions arrays 5, an inclination angle θ1 of an extending direction of the groove portion 8B between the block land portions adjacent in the tire width direction of block land portion arrays 5 located closest to a tire equatorial plane CL side with respect to the tire circumferential direction is larger than an inclination angle θ2 of an extending direction of the groove portion 8A between the block land portions adjacent in the tire width direction of block land portion arrays 5 located at the outermost side in the tire width direction with respect to the tire circumferential direction.
摘要:
A component Fin toward an axial inner direction of the tire which is an opposite direction from an axial outer direction of the tire is applied to a force acting on a kicking end 16B of a land portion 16. With this, abrasion of the kicking end of the land portion can be moderated, and a biased abrasion resistance can be enhanced. A groove wall 20 of a lug groove 14 is provided with a step portion 22, a tread side groove width WA in a tread side of the step portion is widened toward an axial outer side of the tire, and a width WS of the step portion 22 is increased toward the axial outer side of the tire, thereby suppressing the lift from the road surface 26 at the tread-in end 16A of the land portion 16.