초록 ▼

A geared steering system, which is capable of actuating rightside and leftside driving mechanisms to ensure efficient operation of a crawler vehicle, has a geared steering device (30) and a control system. The geared steering device (30) has one power input shaft (31), leftside and rightside steerin

A geared steering system, which is capable of actuating rightside and leftside driving mechanisms to ensure efficient operation of a crawler vehicle, has a geared steering device (30) and a control system. The geared steering device (30) has one power input shaft (31), leftside and rightside steering brakes (38L, 38R) and leftside and rightside direct-coupled clutches (36, 44), one turn clutch (46), three planet gear trains (40, 43, 48), leftside and rightside power output shafts (32L, 32R) coupled to leftside and rightside steering brake hubs (34L, 34R), and a hydraulic turning motor (83) coupled to the turn clutch (46) with gears. The control system has a controller (56) which compares an actual steering ratio of the geared steering device (30) and a designated steering ratio, and outputs a correction signal for approximating the actual steering ratio to the designated steering ratio to solenoid valves (60-64) for controlling the leftside and rightside direct-coupled clutches (36, 44), the turn clutch (46) or the leftside and rightside steering brakes (38L, 38R), an engaging signal to a direct-coupled clutch for an opposite direction to the steering direction to be entered by an operation lever (57), and, in a low speed large radius turn, a signal for controlling an amount of discharge of a variable capacity hydraulic pump (87).

대표청구항 ▼

A geared steering device for a crawler vehicle having a prime mover, a rightside track shoe, a leftside track shoe, and rightside and leftside output shafts, for selectively operating the rightside and leftside output shafts at high speed rotation and low speed rotation, and for selectively braking

A geared steering device for a crawler vehicle having a prime mover, a rightside track shoe, a leftside track shoe, and rightside and leftside output shafts, for selectively operating the rightside and leftside output shafts at high speed rotation and low speed rotation, and for selectively braking said output shafts, to control steering of the rightside and leftside track shoes of the crawler vehicle, said geared steering device comprising: a power input drive element adapted to receive driving power from the prime mover; a fixed housing; a first steering brake for selectively engaging and releasing a first one of the output shafts with respect to the fixed housing; a first rotatable housing coupled to the first one of said output shafts; a first direct-coupled clutch for selectively engaging and releasing said first rotatable housing with respect to said power input drive element; a center shaft; a first planet gear train having a first sun gear, a first carrier gear, and a first ring gear; each of said first sun gear, said first carrier gear, and said first ring gear being connected to a respective different one of said center shaft, said power input drive element, and said first rotatable housing; a second steering brake for selectively engaging and releasing a second one of said output shafts with respect to a fixed housing; a second rotatable housing coupled to the power input drive element; a drive hub coupled to the second one of the output shafts; a second planet gear train having a second sun gear, a second carrier gear, and a second ring gear; each of said drive hub and said center shaft being connected to a respective different one of the second sun gear, the second carrier gear, and the second ring gear; a second direct-coupled clutch for selectively engaging and releasing said second rotatable housing with respect to the second carrier gear; a third planet gear train having a third sun gear, a third carrier gear, and a third ring gear; a turn clutch for selectively engaging and releasing a turn clutch hub which is connected to one of the gears of the third planet gear train; a variable capacity hydraulic pump having a discharge control device; and a hydraulic turning motor for driving said turn clutch hub via the turn clutch; wherein each of the second rotatable housing and the turn clutch hub is connected to a respective different one of the third sun gear, the third carrier gear, and the third ring gear; wherein the gear of said second planet gear train other than the gears connected to the center shaft and the drive hub is coupled with a gear of the third planet gear train other than the gears of the third planet gear train which are connected to the turn clutch hub and the second rotatable housing.