US 6,553,760 B1Granted

Control devices of a hydrostatic transmission

OwnerFernando Augusto Baptista, João Manuel Pereira Dias Baptistainventors

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Abstract

The invention refers to control devices applied in a hydrostatic transmission, which includes a motor pump MP, a hydrostatic circuit HC 1 and HC 2 and an impelling pump IP, which is formed by a rotor 1, a stator 2 and a body 3; the fluid debit is infinitely variable and is obtained by the radial and variable decentralisation of the said stator 2, by means of the impulsion of the rods A and B. The devices are constituted by pistons 4 and 5, which impel the rods A and B, and are inserted in cylinders 6 and 7; by springs systems 9, 10 and 11, which regulate the position of the pistons and of the rods, and by a command formed by a valve 8, inserted in a vacuum circuit with ways V1 and V2, which communicate with the cylinder 7. Through way V1 the vacuum effect acts on the piston 5, obtaining the decentralisation of the stator 2 in direction of the rod A; the fluid pressure transmitted by the extension HE to the piston 4, regulates the debit of the impelling pump and the rotation speed of the motor pump, whose rotation direction is the same as the impelling pump, FIG. 1. Through way V2 the decentralisation of the stator 2 is obtained in the inverse direction to the rod A, and the rotation direction of the motor pump is inverse of the rotation direction of the impelling pump, FIG. 2. When the command is not activated, no fluid impulsion is transmitted by the impelling pump and there is no rotation of the motor pump, FIG. 3.

Claims13

Dependent claims

A control device for a hydrostatic transmission,

said transmission including a motor pump, in communication with an impelling pump by means of a fluid circuit, said impelling pump comprising a rotor and a stator contained inside a body;
the fluid debit of said impelling pump is infinitely variable, in accordance with the infinitely variable amplitude of the radial decentralization of said stator, obtained by means of the impulsion of a first and second rod;
the variable work pressures of the fluid which act in each internal side of said stator are compensated and balanced on the corresponding external side, by equal fluid, thus resulting to be small and independent from the said work pressures of the fluid, the needed force applied in the impulsion of said first and second rods;
said control devices of a hydrostatic transmission comprising:
a first cylinder, which communicates with the side of the hydrostatic circuit by means of the hydrostatic extension;
said first cylinder contains a first piston which actuates on said first rod in order to obtain the infinitely variable decentralization of said stator;
a second cylinder communicating with a vacuum feeding circuit, by means of first and second ways;
said first and second ways connected to a valve which commends the direction of actuation of the vacuum;
said second cylinder contains a second piston fastened with said second rod, said second rod acting in order to obtain the variation of the direction of the circulation of the fluid in said transmission;
and
first, second and third spring systems, of laminar type, whose pressure control the reciprocating position of said first and second pistons and the reciprocating position of said first and second rods.

8 more elements

Dependencies are inferred from the claim text.