Abstract: Disclosed is a friction welding apparatus in which electricity is supplied to a servo motor to rotate a spindle to thereby impart a fixed relative rotational motion to one workpiece and another workpiece, and, while doing so, the one workpiece and the other workpiece are brought into contact with each other and imparted a frictional thrust thereto to soften a bonding interface between the two workpieces. After this, the friction welding apparatus undergoes speed reduction until the RPM of the spindle becomes a phase adjustment RPM; when the RPM of the spindle attains the phase adjustment RPM, a clutch device is engaged with the spindle, and the electricity supply to the servo motor is cut off to stop the rotation of the spindle.

Abstract: A friction welding device allows one work (5) and the other work (9) to be in contact with each other and gives friction thrust thereto, giving a fixed relative rotation operation to the one work (5) and the other work (9) by energizing a servo motor (15) and rotating a main shaft (3), and thereby softens a connection interface between the works (5, 9). Then, the friction welding device decelerates the main shaft (3) until the number of the rotation of the main shaft (3) is set to the number of phase focusing rotation, and when the number of the rotation of the main shaft reaches the number of the phase focusing rotation, allows a clutch device (19) to be engaged with the main shaft, shuts off the energization to the servo motor (15), and thereby stops the rotation of the main shaft (3).

Abstract: A process for producing an olefin oligomer by the polymerization of an olefin in the presence of boron trifluoride as a catalyst, and further in the co-presence of water and/or an alcohol and a carboxylic acid anhydride as a co-catalyst. The process has advantages that (i) olefin oligomers having a low viscosity can be produced at high yields, (ii) the production efficiency can be improved by decreasing the time required for the reaction, (iii) the amount of the co-catalyst required can be decreased, and (iv) the viscosity of an olefin oligomer to be obtained can be freely controlled by changing the amounts of the olefin, the catalyst, the co-catalyst, etc.