Patent GB-602497-A (GB)
Title: Electromechanical device operating simultaneously as clutch, reverse gear and change-speed gear
IPC: F16H61/02
Filed: 1945-09-12
Abstract: 602,497. Change-speed and reverse gear ; friction clutches. SOC. D'APPLICATION DES BREVETS COTAL. Sept. 12, 1945, No. 23551. Convention date, Dec. 28, 1943. [Class 80 (ii)] An electromagnetically-controlled change-speed epicyclic gear 30, providing four, eight or other number of ratios, is combined with and driven through an epicyclic reversegear 11, also electromagnetically controlled by a forward clutch 4 and reverse brake 13, which are used as a main-clutch and are energized progressively, as for starting a vehicle, and the output member 15 of the reverse-gear is provided with an electromagnetic brake 18, which is energized automatically when the forward-reverse control is moved to the neutral position, whereby the input member 16 of the change-speed gear is held stationary and idle-drag of the clutches or.brakes is avoided. All the clutches and brakes may be energized from a common source, with progressive feed for the reversegear clutch and brake, or the change-speed clutches and brakes may be energized by the vehicle battery, and the reverse-gear clutch and brake by a separate supply such as the usual battery-charging, or a separate, generator, so as to provide automatic declutching at engine-speeds below the generator cut-in speed. The main driving shaft 2 of the unit is connected to the engine through a damped resilient coupling (not shown). The reverse-gear comprises a driving sun 7, a clutched and braked plain or stepped planet-carrier 11 and a driven ring-gear 15 secured to the input sun 16 of the change-speed gear, the clutch 4 providing solid forward drive and the brake 13 a reduced reverse. The brake 18, in addition to preventing idle-drag, also causes the planet-carrier 11 and its armature to rotate in neutral at a geared reduction in relation to engine-speed, whereby the subsequent take-up on the clutch or brake 4, 13 is more progressive. The four-speed gear shown provides three reduced ratios and direct-drive, its first train 16 providing solid and reduced drive by clutching or braking its ring-gear 37 at 22, 23, whilst its second train, the ring gear of which is driven by the planet-carrier 30 of the first and its own planets are carried by the final driven shaft, provides solid and overdrive by clutching or braking its sun 29. In Fig. 2, not shown, the planet-carrier and ring-gear connections of the second train are interchanged to provide two reduced and one overdrive ratios, and direct drive. In Fig. 3, not shown, a simple threeelement clutched and braked train is provided between the reverse and change-speed gear, to provide eight ratios. Fig. 4, not shown, depicts a convenient arrangement for driving a front or rear vehicle-axle from a closelypositioned engine, the reverse and change-speed gears being arranged on opposite sides of the axle and the final driven shaft being a hollow axle-driving worm, through which passes the shaft connecting the reverse to the changespeed gear. To ensure progressive clutching, the clutch and brake members have peripheral friction rings' 19 as described in Specifications 591,091 and 593,987, a hard ring on one member engaging a ring on the complementary member of a material giving smooth friction characteristics. Alternatively, the sliding rings may be on one of the clutch or brake members only and be of flame-hardened or nitrided steel or have an electro-plated or sprayed coating of a suitable metal. To assist disengagement, the clutching surfaces are slightly conical with an outwardly convergent gap when separated. The gear is lubricated by an oil-pump on the driving-shaft.