GB825709A - Improvements in or relating to friction clutches - Google Patents

Abstract

825,709. Friction clutches. MONKS, H. June 18, 1957 [April 28, 1956], No. 13080/56. Class 80 (2). In a fluid pressure operated friction clutch a main pressure space 11 is formed between an axially movable clutch disc 6 and a carrier 1 carrying a clutch member 5, an initial pressure space 19 is also formed between the carrier and the disc, and valve means are provided whereby pressure is first admitted to the initial pressure space for light engagement and then to the main pressure space for full engagement, the initial pressure space being closed at one side by an internal annular flange 7 on the clutch disc sliding on a sleeve 8. Two clutches according to the invention are mounted on a shaft 2 to provide alternate drives to gears 9 of a twospeed gear. Each gear 9 has a sleeve 8 with teeth 14 engaged by teeth 13 on the clutch discs 6 which are urged to the disengaged position by springs 15 until the discs abut a spring ring 12. Fluid pressure is fed from bores 20 in the shaft 2 to passages 22 in the carrier 1, and by passages 23 to the initial pressure space 19 which is sealed by the flange 7 to the sleeve 8 and by an annular surface 18 and a spigot 3 on the carrier. On initial engagement the clutch surfaces 16, 17 engage, after which pressure builds up in the passage 22 to open a spring-loaded valve 25, housed in a counterbore 24 in the carrier, to allow pressure to enter the main pressure space 11 through a passage 30 for full clutch engagement. The valve 25 comprises a roller in a square passage 31 the passage being tangential to a circle concentric with the carrier 1 to obviate the effects of centrifugal force, though the passage may be given a slight inclination if it is desired to aid or oppose the spring 26. When the valve 25 is closed the space 11 is vented through a passage 29.