Swashplate leveling device
AssigneeSauer Inc.
InventorsRonald J. Sporrer, Scott D. Meyer
Life of this patent
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Abstract
A swashplate leveling device has a reciprocative leveling follower movable along a fixed axial pin. The cam is biased into engagement with a swashplate of an axial piston variable displacement hydraulic unit to position the swashplate in a zero displacement orientation when there is no control input to the hydraulic unit. The leveling device has a pair of contact points, one positioned on each side of the swashplate tilt axis in a manner that both contact points engage the swashplate when it is leveled to its zero displacement orientation.
Claims6
A swashplate leveling device for a variable displacement hydraulic unit which has a housing, a cylinder block rotatable in the housing about a first axial centerline and having pistons axially movable therein, a swashplate tiltable about a transverse axis perpendicular to the first centerline and having a surface engageable by the pistons to control the stroke of the piston within the cylinder block, the leveling device comprising:
- an elongated pin fixedly mounted on the housing and having a longitudinal axis defining a second axial centerline offset from and extending substantially parallel to the first axial centerline;
- a reciprocal follower slidably mounted on the pin for movement between a first position for engaging the swashplate to maintain the swashplate in an orientation representative of a zero displacement of the hydraulic unit, and a second position wherein the swashplate tilted under the influence of an external force.
A swashplate leveling device for a variable displacement hydraulic unit which has a housing, a cylinder block rotatable in the housing about a first axial centerline and having pistons axially movable therein, a swashplate tiltable about a transverse axis perpendicular to the first centerline and having a surface engageable by the pistons to control the stroke of the piston within the cylinder block, the leveling device comprising:
- an elongated pin fixedly mounted on the housing and defining a second axial centerline offset from and extending substantially parallel to the first axial centerline;
- a reciprocal follower slidably mounted on the pin for movement between a first position for engaging the swashplate to maintain the swashplate in an orientation representative of a zero displacement of the hydraulic unit, and a second position wherein the swashplate tilted under the influence of an external force;
- and
- a coil spring interposed between said reciprocal follower and the housing, surrounding the pin and having a stiffness sufficient to maintain the swashplate in the zero displacement orientation in the absence of an external control force, the spring stiffness permitting the retention of a prescribed non-zero displacement orientation of the swashplate in the absence of an external control force.
A swashplate leveling device for a variable displacement hydraulic unit which has a housing, a cylinder block rotatable in the housing about a first axial centerline and having pistons axially movable therein, a swashplate tiltable about a transverse axis perpendicular to the first centerline and having a surface engageable by the pistons to control the stroke of the piston within the cylinder block, the leveling device comprising:
- said housing including a pocket and a cavity formed therein having parallel longitudinal axes, said cylinder block being rotatable in said cavity and a pin being press fitted into said pocket whereby said pin and cylinder block have parallel longitudinal axes, and
- a reciprocal follower slidably mounted on the pin for movement between a first position for engaging the swashplate to maintain the swashplate in an orientation representative of a zero displacement of the hydraulic unit, and a second position wherein the swashplate is tilted under the influence of an external force.
Dependencies are inferred from the claim text.