GB601116A - Improvements in or relating to variable speed power transmission devices - Google Patents

Abstract

601,116. Hydromechanical variable-speed gear. McGILL, D. F. Nov. 8, 1944, No. 21970. Convention date, Oct. 26, 1943. [Class 80 (ii)] [Also in Group XXIX] A hydromechanical variable-speed gear comprises a reaction-housing 14, journalled on aligned input and output shafts 12, 13, and two three-element transmissions, each having first (reaction) elements secured to the housing, second.elements secured together on an aligned intermediate shaft 27, and third elements secured to the input shaft in the case of one transmission and the output shaft in the other. The two transmissions may comprise a hydrokinetic torque-converter in front of (Fig. 1) or behind (Fig. 10, not shown) a planetary gear-train. In Fig. 1, the impeller 23 of the converter is secured to the input shaft 12, its driven member 26 is secured to the intermediate shaft 27 carrying the driving sun 31 of the planetary train, whilst its reactionmember 25 is integral with the reactionhousing 14 carrying stepped planets 32, 34 of the train, the other sun 35 of which is secured to the final output shaft 13. Forward drive is through the stepped planets 32, 34, and reverse is by sliding a planetary idler 41, permanently meshing the driven sun 35, into mesh with a wheel 40 of a secondary stepped-planet pair 39, 40. In reverse the common reactionhousing 14 is held by a brake 48, and, in forward drive, either by the brake or by a one-way detent 19, which allows the reactionmember to rotate forwardly when conditions permit, the drive ultimately becoming one-toone. A spring-engaged friction-clutch 72, actuated through a collar 85, connects together the converter driving and reaction members 23, 25 for unit-ratio fluid-coupling drive. To prevent idle-drag, the converter has a flowarresting' ring-valve 81, operated through a collar 79. In Fig. 10 (not shown) the planetary train is arranged ahead of the converter, the driving and driven shafts in Fig. 1 being, in effect, interposed, and the clutch 72 and reverse are omitted. The planetary gear may impart speed increase or reduction to the converter impeller. Various modified torque-converters are shown, in some of which the driven member initially rotates in the reverse direction, the reverse idler 41, Fig. 1, then being used in forward drive. The Specification as open to inspection under Sect. 91 states also that the friction-clutch 72, for changing from converter to coupling drive, may be governor-controlled. This statement does not appear in the Specification as accepted.