GB726544A - Improvements in and relating to bushings - Google Patents

Abstract

726,544. Making bushes. AEROQUIP CORPORATION. Jan. 22, 1953 [Nov. 25, 1952], No. 1922/53. Classes 83 (2) and 83 (4). Assembling force fits.-A force fit between a bushing and a hole in another member is effected by providing the bushing with a leading pilot portion of a diameter approximating the hole in said member and a hole broaching portion adjacent said pilot portion, said broaching portion having an external surface defined by longitudinal splines which provide leading ends with cutting teeth. To form a bushing 10 a metal blank is first machined to a diameter equal to the hole in which the bushing is to be inserted and annular chip grooves 14 are cut in the machined blank. Stepped broaching portions 16 and 18 having splines 20 are formed by a broaching operation which increases the diameter of the blank across the splines by approximately 0.003 to 0.005 inch. The blank is drilled and reamed and cut to length and finally accurately ground to provide the required difference in diameter between the pilot 12 and the broaching portions 16 and 18. The recesses 22 are of greater cross-sectional area than the splines 20 and the diameter across the recesses is less than the diameter of the hole. The pilot accurately aligns the bush in the hole and also provides a retaining wall for the chips resulting from the broaching operation of the splines 20. A wedging accumulation of chips is thus provided by the pilot and the wall of the reamed hole for assisting in the self-staking of the bushing in the hole. Several broaching portions may be provided if necessary and the bush may have a helical chip groove 14<SP>1</SP> (Fig. 4).