Fixing resin composition for use in rotor

A fixing thermosetting resin composition used for forming a fixing member in a rotor provided with

• a rotor core fixed and installed over a rotating shaft, in which a plurality of hole portions arranged along the peripheral portion of the rotating shaft are formed,
• a magnet inserted in the hole portion, and
• the fixing member, composed of a cured product of a fixing thermosetting resin composition, that fixes the magnet, the fixing member provided in a separation portion between the hole portion and the magnet and on at least a side wall on an inner peripheral side of the rotor core out of side walls of the magnet,
• wherein the fixing thermosetting resin composition comprises:
• a thermosetting resin (A) containing an epoxy resin,
• a curing agent (B), and
• an inorganic filler (C),
• wherein a content of the inorganic filler (C) is equal to or more than 50% by mass, based on 100% by mass of a total content of the fixing thermosetting resin composition,
• the fixing thermosetting resin composition further includes a low-stress agent, and
• the low-stress agent contains a polybutadiene compound, an acrylonitrile-butadiene copolymerization compound, or a silicone compound,
• wherein a total concentration of sodium ions and chlorine ions in the fixing thermosetting resin composition is equal to or less than 500 ppm, and
• when a cure torque of the fixing thermosetting resin composition is measured over time at a measurement temperature of 175° C. using a curelastometer, the cure torque value at 60 seconds after measurement initiation is defined as T60 and the maximum cure torque value up to 300 seconds after measurement initiation is defined as Tmax, the ratio of the cure torque value at 60 seconds after measurement initiation to the maximum cure torque value up to 300 seconds after measurement initiation, T60/Tmax(%), is equal to or more than 50%.