Patent GB-1458026-A (GB)
Title: Synchronously shiftable dual range planetary transmission with coaxial input shafts
IPC: F16H47/04
Filed: 1973-12-19
Abstract: 1458026 Hydromechanical variable-speed gear G M DELALIO 19 Dec 1973 [22 Dec 1972] 58798/73 Heading F2D A continuously variable power transmission comprises an arrangement of low and high speed planetary gear means connected to the driving means through coaxial input shafts and an infinitely variable hydrostatic drive. In one embodiment an input shaft 12, Fig. 1, driven, e.g. by a vehicle engine, drives an adjustable swashplate 28 of the pump 24 of a hydrostatic unit 18 and extends through the hydraulic motor 30 and planetary gearing to the driving element 40 of a clutch C of which the driven element 42 is connected to a ring gear 44. Planets 64 on a carrier 50, which drives the output shaft 14, mesh with the ring gear 44 and with a sun 48 mounted on a quill shaft 38 which is coaxial with the shaft 12 and driven by the motor 30. The quill shaft also carries a further sun 46 in mesh with planets 56 on the carrier 50 and these planets mesh with planets 58 which mesh in turn with a ring gear 60 controlled by a brake B. The swashplate 34 of the motor may be fixed, as shown, or adjustable. Low range is established when the clutch C is disengaged and the brake B applied. In this condition, the transmission is in neutral when the swashplate is positioned for zero stroke of the pump 24 and in reverse when the swashplate is positioned as shown by the dotted line. The motor 30 rotates in the same direction as the pump when the swashplate is in the dotted line position but the output is reversed due to the intermeshing planets 56, 58. When the swashplate is moved from neutral towards the full line position the motor rotates in the reverse direction to drive the output in the forward direction, and when the pump is at maximum displacement the driving and driven elements of the clutch C will be rotating at the same speed and in the same direction so that the clutch may then be engaged and the brake B released to establish high range in which the drive is effected through the train 44, 48, 64. Further increase of output speed is then effected by progressive adjustment of the swashplate 28 through zero displacement to the dotted line position. In a modification the pump swashplate is driven at a higher or lower speed than the shaft 12. Another modification has only one sun 80, Fig. 4, and the carrier 50<SP>11</SP> supports planetary gears 82 in mesh with the sun and with the ring gear 44<SP>11</SP>, and planetary gear clusters 74 of which gears 78 mesh with the gears 82 and gears 76 with the ring gear 83. In Fig. 9 the carrier 50<SP>111</SP> is connected to the ring gear 96 and output shaft 14<SP>111</SP>, and the driven element 90 of the clutch C<SP>111</SP> is connected to a carrier which supports intermeshing planets 92, 94 meshing respectively with the sun 93 and the ring gear 96. Fig. 11 illustrates an arrangement in which a shaft 110, in place of the shaft 12 of Fig. 1, is driven at a lower speed than the input shaft 100, and the pump swashplate 130 at a higher speed. The planetary gearing comprises planets 136 in mesh with both the sun 122 and the ring gear 134, and planets 146 in mesh with both the sun 124 and the ring gear 148. Also described is a control arrangement in which a fluid-pressure actuator operates cams which actuate valves to provide sequential operation of the pump swashplate and the clutch and brake of the planetary gearing.