Patent GB-527581-A (GB)
Title: Improvements in or relating to power transmission mechanisms
IPC: F16H61/02
Filed: 1939-04-15
Abstract: 527,581. Variable - speed gearing. MONO-POWER CORPORATION. April 15, 1939, No. 11494. Convention date, July 1, 1938. [Class 80 (ii)] In a variable speed transmission gear a plurality of gear trains are each connected to the driving shaft by a separate clutch operated by pressure fluid and actuated by the selective operation of an equivalent number of relief valves displaced by a centrifugal governor driven by the driving shaft. The transmission comprises a main clutch A centrifugally controlled in response to the speed of an engine flywheel 10. fluid-operated disc clutches B, C, D, E, F, and two sets of planetary gearing. For first speed clutches A, C, E, are engaged and the drive is from flywheel 10, shaft 20, sleeve 40, and the two planetary gears. For the second speed clutches A, C, E, F, are engaged. The clutch F holds the sun wheel 70 and the drive is through cage 61 to the shaft 100. Clutches A, B, E, F are engaged for the third speed direct drive from shaft 20 to drum 118 and cage 61 directly connected to the shaft 100 by an over-running clutch 130. An overdrive fourth speed is provided when clutches A. B. D, F are engaged to drive planet 60 annulus 50 clutch D and drive shaft. For reverse drive clutches A, B, C, are engaged. Main clutch: A disc 35 secured to the shaft 20 is clutched to the flywheel by a pressure plate 134 moved on the admission of pressure to a chamber 33 by a piston 131 and sleeve 133. Fluid in a chamber 140 centrifugally balances the fluid pressure in the chamber 33. Pressure is admitted to the chambers 33, 140, by a valve 146, Fig. 3, controlled by rotating masses 48. Fluid is supplied by pumps to a conduit 145. In the clutch release position fluid is admitted through conduits 145, 147, 43 to the chamber 140. As the speed increases the masses 48 move the valve 146 in opposition to the pressure of a spring 149 and fluid flows from conduits 145, 150, 152, 151, 155. If the speed is increased further, the pressure is built up in the chamber 33 by throttling an escape passage 155 to correspond to the speed. A valve 158, Fig. 3, maintains engagement of the clutch A whenever the transmission is in second speed. When a valve 201 is in the second speed position, pressure is introduced into chamber 160 to move valve 158 fully to the left and the valve 146 to the right, to put chamber 33 under pressure by conduit 161. The fluid pumping system comprises a pump 62 driven by the engine and a pump 63 splined to the driven shaft 100. The clutches B. C are energizd through chambers 166, 168 and the centrifugal forces are balanced by fluid in a chamber 167. The clutches D, E are applied alternately by fluid in chambers 77, 78 respectively. Governor and valve means for automatically controlling clutches : The pump 63 supplies fluid to chambers 171, 174, 175. The chamber 171 is connected to a port 178, Fig. 6, of a plunger 179 connected by a rod 202 to a main automatic valve 201. When the speed of a governor. Fig. 4. increases. a lug 181a operates a plunger 197 to close a port 177 and a pressure determined by a relief valve 183 is built up. This pressure moves the plunger 179, Fig. 6, which is held by detents 188. Further increase of speed moves the plunger 182 against the pressure of a spring 189 to close the chamber of the valve to prevent escape of fluid through a port 185. The pressure of fluid then opposes a relief valve 192 with spring 193 and builds up a higher pressure which moves the plunger 179 to a second position where it is held by the detents 188. At a still higher speed the valve 192 is closed and a higher pressure determined by a main relief valve moves the plunger 179 to an extreme position. The plunger 179 is positively connected to an automatic control valve 201 and is moved to the positions marked 1st, 2nd. 3rd, 4th, Fig. 11. Adjacent and in series with the valve 201 is a manually moved plunger 204 which over-controls the automatic speed-selective action of valve 201. With the manual valve 204 in the highest position and automatic valve 201 in the lowest position fluid enters port 205 and passages 209E, 211C leading to pressure chambers 78, 168 of clutches E; C. The clutches A, C, E are engaged for first speed operation as soon as clutch A is engaged. With the automatic valve in 2nd position, passages 210F, 209E, 211C are under pressure and clutches C, E, F are engaged. Third speed operation with the valve 201 in 3rd position is effected by shutting port 211C and opening port 206B of chamber of clutch B thus engaging clutches A, B. E, F. In the 4th position ports 211C, 209E are both cut off and port 208D of clutch D opened to engage the clutches A, B, D, F. In the passages leading to clutches B, C, D, F ball check valves are inserted to allow slow engagement and rapid disengagement. Fluid from the front pump 62 before entering passages 219, 98 to the chamber 205 passes through a chamber 263 with valve 230 and with relief valve 213. Fluid flows through port 217 to the chamber 205 of valve 201 and through port 218 to operate the main clutch A. Execss fluid is conducted to a second relief valve 214 by passages 222. Manual control means: A lever 235 on sleeve 236 operated from the steering column carries a crank 88 actuating bell-cranks 238 operating valve 204. Movement of the valve 204 actuates the clutches without movement of the valve 201. The circuits are illustrated in Figs. 12-16 (not shown). Reverse operation: For reverse to become effective with the manual valve 204 in its lowest position the vehicle must travel slow enough for the automatic valve 201 to be in its first position. Fluid flows from chambers 205 to ports 92, 82, 210X to clutches B. C and a reversing cylinder, Fig. 8 (not shown). The clutches D. E are deenergized, an overrunning clutch is reversed by a piston. Fig. 8 (not shown), and an overrunning clutch 130 is freed by pressure in cylinders. Fig 9 (not shown). The valve 201 is moved only by pressure from the rear pump 63 an is not moved from its low gear position as the pump is reversed and supplies no pressure. The cylinders of clutch 130 are subjected to pressure concurrently with clutches D, E. When the clutches D, E are de-energized, the cylinder operating the clutch 130 is de-energized to cam the rolls of the clutch to inoperative position. When either of the clutches D, E is de-energized the clutch 130 is not affected. Manual control of main clutch: A lever 234, Fig. 5, connected to a pedal operates a lever 248 which actuates the valve 230 and the plunger 250. The valve 230 renders the automatic second speed lock in for the main clutch inoperative. When the lever 248 is depressed, valve 230 shuts a port supplying valve 158, and clutch is manually controlled through the primary fluid pressure source. Since the clutch engaging pressure in the chamber 33 is dependent upon the relief valve, if the governor has closed the port 155, the lower end of the plunger 250 abuts a smaller spring which opposes a spring 216 and vents the chamber 33 to release the clutch. The main clutch is dependent on the centrifugal force but the clutch may be manually controlled.