| 摘要 |
831,196. Motor vehicle hydraulic driving gear. DOWTY HYDRAULIC UNITS Ltd. July 8, 1957 [July 9, 1956], No. 21237/56. Class 79(2) In a vehicle with ground engaging elements such as wheels or endless tracks 2, Fig. 1, separately driven by independent hydraulic motors 6 the speed control members 19, 21 for each motor are interlinked so that they are moved in unison for normal speed control and moved oppositely for steering by differentially driving the tracks. In one example the motors 6 are supplied from two swash-plate pumps 9, 11 having variable outputs controlled by push rods 19, 21 of servo units 17, 18 attached to the pump bodies. The push rods 19, 21 are controlled from a gear lever 36 and steering wheel 37, the arrangement being such that when the gear lever 36 is moved to drive the vehicle in reverse by cross-wise movement in a slot 72 of a plate 69 the linkage automatically reverses the sense of the steering so that the vehicle moves in the same curved path according to the setting of the steering wheel as when moving in forward direction. The lever 36 is coupled through links 46, 47 to a pin 45 interconnecting a pair. of cross links 51, 52 attached by pivots 53, 54 to the push rods 19, 21. The cross-links 51, 52 are also pivoted at 41, 42 to a T- shaped member 38 which is pivoted at 39 to the vehicle frame and is swung about the pivot by the steering wheel 37 through the steering arm 65, push rods 63, 56 and an intermediate T-shaped lever 58 which is pivoted at 59 to the vehicle. A push rod 68 connects the gear lever 36 to the push rod 63 to move its end 62 from side to side in a slot 61 of the lever 58 to reverse its direction of rotation by the steering wheel 37 according to the sideways movement of the gear lever 36. In the hydraulic system for the control of the two motors 5, 6, Fig. 3, the supply for the servo units 17, 18 is taken from the supply lines through valve casings 24 containing opposed non-return valves 26, 27 so that the servo units are under pressure irrespective of in which direction the pumps are operating. A priming pump 28 is also incorporated in the circuit and supplies sufficient pressure through non- return valves 31, 32, 34, 35 to operate the servos when the gear lever is set at neutral and no pressure is supplied by the main pumps 9, 11. In a modification the gear lever 36, Fig. 2, operates the control rods 19, 21 through push rods 87, 88, interconnected links 101, 102 and crank arms 103,104 pivoted to the vehicle. A pin 89 interconnecting the links 88, 101, 102, engages a longitudinal slot 91 in a geared sector 94 rotatable by the steering wheel 37 through gears 95, 96. With this arrangement the opposed movements of the control rods 19, 21 by the steering wheels 37 is progressively increased with the speed of the vehicle as determined by the lever 36 so that the vehicle steers on the same curve irrespective of speed according to the setting of the steering wheel as in conventional steering. |
