Abstract: Provided is a lubricating oil composition, which has low viscosity but also prolonged anti-shudder life without reduction of intermetallic friction coefficient. The lubricating oil composition is characterized in comprising (A) a lubricating base oil, and (C) (C-1) a borated succinimide compound with a mass average molecular weight of 4,000-7,000 and (C-2) a borated succinimide compound with a mass average molecular weight of greater than 7,000-10,000.

Abstract: A lubricating oil composition which achieves extended anti-shudder durability without causing a decrease in the metal-to-metal friction coefficient, even when the viscosity of the composition is reduced. The lubricating oil composition includes (A) a lubricant base oil, (C) (C-1) a succinimide compound or boronated succinimide compound having a weight-average molecular weight of 4,000 to 7,000, (C-2) a succinimide compound or boronated succinimide compound having a weight-average molecular weight of more than 7,000 to 10,000, and (D) a phosphorus-based extreme pressure agent, the lubricating oil composition does not include zinc dithiophosphate and may optionally include a sulfur-based extreme pressure agent, provided that the content of sulfur-based extreme pressure agent is no more than 0.1 percent by weight of the lubricating oil composition.

Abstract: In a frictional coupling device of a vehicular power transmitting system, includes: first and second rotary members; a frictional coupling portion, and a piston disposed movably in a direction of the axis to press the frictional coupling portion, a spacing distance between adjacent spline teeth of the radially outer splined portion in a rotating direction thereof decreases along the direction of the axis in which the friction discs are brought into the spline engagement with the radially outer splined portion during assembling of the friction discs with respect to the first rotary member, and/or a spacing distance between adjacent spline teeth of the radially inner splined portion in a rotating direction thereof decreases along the direction of the axis in which the friction plates are brought into the spline engagement with the radially inner splined portion during assembling of the friction plates with respect to the second rotary member.

Abstract: The present disclosure is directed to a lubricant composition that achieves extended anti-shudder durability without causing a decrease in the metal-to-metal friction coefficient, even when the viscosity of the composition is reduced. A lubricant composition comprises (A) a lubricant base oil, (C) (C-1) a succinimide compound or boronated succinimide compound having a weight-average molecular weight of 4,000 to 7,000, (C-2) a succinimide compound or boronated succinimide compound having a weight-average molecular weight of more than 7,000 to 10,000, and (D) (D-1) an amide-based friction modifier.

Abstract: Provided is a lubricating oil composition, which has low viscosity but also prolonged anti-shudder life without reduction of intermetallic friction coefficient. The lubricating oil composition is characterized in comprising (A) a lubricating base oil, and (C) (C-1) a borated succinimide compound with a mass average molecular weight of 4,000-7,000 and (C-2) a borated succinimide compound with a mass average molecular weight of greater than 7,000-10,000.

Abstract: A support structure for supporting a brake, as a frictional coupling device, includes a snap ring, a friction plate, and a back plate. The snap ring fits in a groove that extends in a circle. The back plate is disposed between the friction plate and the snap ring. The back plate is pressed against the snap ring. The snap ring has a first end face that faces the back plate and a second end face that faces the opposite side from the first end face and is in contact with a sidewall of the groove. The back plate has an end face that is in contact with the first end face. The static friction coefficient between the first end face of the snap ring and the end face of the back plate is smaller than that between the second end face of the snap ring and the sidewall of the groove.

Abstract: A support structure for supporting a brake, as a frictional coupling device, includes a snap ring, a friction plate, and a back plate. The snap ring fits in a groove that extends in a circle. The back plate is disposed between the friction plate and the snap ring. The back plate is pressed against the snap ring. The snap ring has a first end face that faces the back plate and a second end face that faces the opposite side from the first end face and is in contact with a sidewall of the groove. The back plate has an end face that is in contact with the first end face. The static friction coefficient between the first end face of the snap ring and the end face of the back plate is smaller than that between the second end face of the snap ring and the sidewall of the groove.