US 4,090,414 A · Transmission control system for shuttle type vehicles

Abstract

A power transmission control system for vehicles where it is desired to reverse the vehicle direction at full throttle such as vehicles used in mining operations, off road application, or the like. The transmission includes selectively and hydraulically operated friction-type clutches and hydraulic control circuits for actuation thereof. The hydraulically operated output clutches are used to change speed range of the transmission while input clutches are used to change speed and/or direction of the vehicle. The control mechanism permits the vehicle in motion to be shifted to a reverse direction at full throttle and the arrangement is such that when the shift is made, the output speed range clutch disengages or optionally drops to residual torque capacity, the forward clutch remains fully engaged, and the reverse clutch comes on fully to brake the input. Then both forward and reverse clutches are engaged. The input is then locked. The output speed range clutch is then brought to increased "brake mode" torque capacity. The output speed range clutch then functions as a brake to decelerate the vehicle. The static braking reaction torque is held by the locked up direction clutches. When the vehicle speed reaches a predetermined lower value (where it is almost stopped) that situation is sensed by the hydraulic control means and immediately thereafter and simultaneously the forward clutch is released and apply pressure on the braking (output speed range) clutch is permitted to increase to full value. The vehicle then accelerates in the opposite direction under the influence of the torque converter. This control system also provides means for quick and smooth full throttle shifts at and near vehicle stopped condition; that is for either a neutral into range shift or a directional shift.

Claims9

Dependent claims

A shuttle type vehicle having a power transmission including change speed and direction gearing driven by a torque converter, said gearing including forward and reverse direction input clutches and also including output speed range clutches, said clutches being of the selectively and hydraulically actuated friction plate type, a hydraulic control system for said clutches and for permitting reversal of vehicle direction at full throttle, said system comprising:

a pressure fluid source, manually operated hydraulic circuit means for selecting an operating condition of a vehicle direction and gear ratio, second hydraulic circuit means to effect deceleration and acceleration of the vehicle when a selection of opposite direction operating conditions is made, said second hydraulic circuit means including (a) means including an output driven fluid pump to sense speed and direction, (b) means to fully engage said direction clutches simultaneously, and (c) means to simultaneously partially engage a second clutch as a braking means.

a pressure fluid source, manually operated hydraulic circuit means for selecting an operating condition of a vehicle direction and gear ratio and including a direction selector valve, a forward control valve and a reverse control valve, an input clutch range valve, an output clutch range valve, and a speed range selector valve;
second hydraulic circuit means to effect deceleration and acceleration of the vehicle when a selection of opposite direction operating conditions is made, said second hydraulic circuit means including (a) means to sense speed and direction and including an output driven reversible fluid pump fed selectively through an orifice at each side thereof;
(b) means to fully engage said direction clutches simultaneously, and (c) means to simultaneously partially engage a second clutch as a braking means and including a pressure regulator valve for said output clutches.

Dependencies are inferred from the claim text.

Transmission control system for shuttle type vehicles

Life of this patent

Transmission control system for shuttle type vehicles

Life of this patent

Abstract

Claims9