An improved hydrostatic power transmission is disclosed including first, second and third fluid displacement units, of which the first and second fluid displacement units are constructed as variable-displacement and constant-displacement units, respectively, while the third fluid displacement unit may be constructed either as a variable-displacement or as a constant-displacement unit as the case may be. The transmission system features split-power characteristics in which the second fluid displacement unit acts not only as a hydrostatic unit but as a mechanical reaction unit whereby the input power is split into two input and/or output components. The transmission efficiency is consequently increased to a significant extent in spite of the simple and small-sized construction of the transmission system. A typical practical application of the transmission system is motor vehicles including heavy-duty industrial vehicles in which powerful braking actions are required when they are to be stopped.
A hydrostatic machine including a casing 1 containing a rotary member 12 having radial cylinders 20 each with a piston 21 engaging a track ring 23. Both input 6 and output shafts 7 are connected either hydraulically through the transmission rotary members 12 or mechanically through a bypass shaft 10 and clutch 50 for reducing machine heat losses. Hydraulic ram 106,110 assistance for cushioning out pressure transients when transmission power returns from mechanical to hydraulic. Internal oil ducts 72,80.90 included for providing further temperature control for the main internal transmission component parts 14.24 said ducts 72,80,90 feed from a auxiliary fluid pump 8,9.
A vibration reducing shoe for biasing a cam ring of a variable displacement ball pump into engagement with a surface of the pump housing. In a hydrostatic transmission having a variable displacement pump and a fixed displacement motor a pair of shoes are located within bores in the pintle. The shoes are slidably received in the bores and exert a force against the cam ring which is proportional to the pressure of the fluid used to rotate the motor. Since the pump is reversible, one shoe is in fluid communication with one of the passages directing fluid to the motor and the other shoe is in fluid communication with the other passage. Accordingly, the force exerted on the cam ring by the shoes increases and decreases with increases and decreases in the pressure of the fluid from the pump to the motor.
Devices for adjustably controlling a flow of fluid through a common passage and through first and second auxiliary passages are disclosed. The flow control devices may be used for controlling the steering of a vehicle having independently controlled driven structures, such as wheels. Various other applications of these devices and related methods are also disclosed.
