GB674030A - Torque and speed changing and reversing unit - Google Patents

Abstract

674,030. Change-speed gear; friction clutches. DUYCK, G. Nov. 24, 1947 [Nov. 23, 1946], No. 31086/47. Class 80 (ii). [Also in Group XXXIV] A change-speed and reverse gear, which constitutes its own main-clutch, comprises two planetary trains in series, each controlled by electromagnetic friction clutches and brakes, those for the output train 26, being of the electromagnetically - initiated torque - assisted type, whilst the brake (or clutch) of the speedreducing input train 5, which is used as the starting clutch on a vehicle, is operated by two axially spaced magnets 10, 11, one, 11, of which serves to attract the armature 9, whilst the other, 10, produces the friction pressure, its energisation being gradually increased from zero whilst the magnet 11 is de-energised. (Economy in current results.) The reducing input-train shown comprises a ring gear 2 fast to the input shaft 1; a reaction sun 4, fast with an armaturedisc 9, which, for solid drive, is frictionally clutched to the driving ring-gear 2 by an electromagnet 7, or, for reduced starting drive is gradually braked by the stationary magnets 10, 11; and a driven planet-carrier integral with an intermediate shaft 5 on which is fast the driving sun 21 of the output train. The sun 21 meshes planets 25 carried by the output shaft 27 and meshing further planets 23, meshing on one side a ring gear 24 having claw teeth 29 held positively by a magnet 28 to provide two reverse ratios, and on the other side a reaction sun 15 which is clutched by a magnet 13 to the intermediate shaft 5 for solid drive, or braked by a magnet 16 for reduced drive in the output train. The direct drive clutch in the output train may be of the double magnet type, Fig. 4 (not shown), like the brake 10, 11 of the input train, but, as shown, comprises a coil-spring 18 secured at one end to the driving intermediate shaft 5 and expanded into self-tightening frictional engagement with a surrounding drum 17, rotationally fast with the reaction sun 15, by the initial friction drag provided by the magnet 13. The reduced drive brake comprises a band 19, contracted into self-tightening engagement with an underlying drum 20 by the initial friction drag of the magnet 16. Fig. 6, not shown, has the input shaft arranged inside a concentric hollow output shaft driving, through a gear-pair, an underlying parallel axle-driving bevel shaft on a front-drive or rear-engined vehicle. The friction surfaces of the clutches and brakes may be coated with powdered steel sintered with graphite or the armatures may be made entirely of this material. Reference is made to Specification 647,832 and French Specifications 936,561 and 936,563 for clutch and brake details. The Specification as open to inspection under Sect. 91, states also that the input train may multiply instead of reduce speed. This subjectmatter does not appear on the Specification as accepted.