Hydraulic vehicle speed limiting system

摘要

A speed limiting system for a vehicle with a hydraulic transmission comprising pump 12 driving motor 13 through discharge 41, forward 46F and reverse 46R circuits and a pilot operated reversing valve 21. The system has pump capacity control means 12C controlling the pump swash plate12a via control cylinder 12CC subject to control valve 12CLS which exposes the cylinder to either tank 12A or discharge pressure 12B according to a control valve balance of discharge pressure LS2 plus a spring 12CP and motor load pressure LS1 plus solenoid reaction 12CS. A speed detecting pump 17, motor 18 set plus sensor 31 supply controller 30 with vehicle speed and when a set speed is exceeded the controller changes the solenoid reaction to alter the pressure balance to reduce pump capacity. The set speed may be changed by replacing removable module 39 in the controller.