Hydrostatic variable displacement pump having springs arranged outside the servocylinder pressure chamber

A hydrostatic variable displacement pump,

• comprising, a variable-displacement pump housing (6),
• a cylinder block (2) in the pump housing (6),
• displacement pistons (1) in the cylinder block,
• a swash plate pivotally mounted in the pump housing in operational contact with the displacement pistons (1) and which can have its pivotal position in relation to a stroke direction of the displacement pistons set by means of a servosystem (4) fitted on the pump housing;
• a tank chamber in the pump housing;
• the servosystem (4) having a servosystem housing (15) and at least one servopiston (7) in a pressure cylinder (18) in the tank chamber (5) which forms a servocylinder pressure chamber (8) within the cylinder (18),
• the servopiston (7) having at least two servopiston surfaces (11, 12) subjected to the action of fluid pressure,
• a spring assembly (9, 10) mounted in the servosystem housing (15) on the outside of the servocylinder pressure chamber (8) to subject the two servopiston surfaces (11, 12) to compressive loading, wherein a spring plate (13, 14) is arranged between the servopiston (7), and the servosystem housing (4).

A hydrostatic variable displacement pump,

• comprising, a variable-displacement pump housing (6),
• a cylinder block (2) in the pump housing (6),
• displacement pistons (1) in the cylinder block,
• a swash plate pivotally mounted in the pump housing in operational contact with the displacement pistons (1) and which can have its pivotal position in relation to a stroke direction of the displacement pistons set by means of a servosystem (4) fitted on the pump housing;
• a tank chamber in the pump housing;
• the servosystem (4) having a servosystem housing (15) and at least one servopiston (7) in a pressure cylinder (18) in the tank chamber (5) which forms a servocylinder pressure chamber (8) within the cylinder (18),
• the servopiston (7) having at least two servopiston surfaces (11, 12) subjected to the action of fluid pressure,
• a spring assembly (9, 10) mounted in the servosystem housing (15) on the outside of the servocylinder pressure chamber (8) to subject the two servopiston surfaces (11, 12) to compressive loading, wherein a spring plate having an angled portion (14) is positioned between the servosystem housing (15) and the spring assembly (9, 10).

A hydrostatic variable displacement pump,

• comprising, a variable-displacement pump housing (6),
• a cylinder block (2) in the pump housing (6),
• displacement pistons (1) in the cylinder block,
• a swash plate pivotally mounted in the pump housing in operational contact with the displacement pistons (1) and which can have its pivotal position in relation to a stroke direction of the displacement pistons set by means of a servosystem (4) fitted on the pump housing;
• a tank chamber in the pump housing;
• the servosystem (4) having at least one servopiston (7) located within a servosystem housing (15) and in a pressure cylinder (18) which forms a servocylinder pressure chamber (8) within the cylinder (18),
• the servopiston (7) having at least two servopiston surfaces (11, 12) subjected to the action of fluid pressure,
• a spring assembly (9, 10) mounted in the servosystem housing (15) about the exterior of the servopiston (7) to subject the two servopiston surfaces (11, 12) to compressive loading.