Hydraulic power transmission apparatus

A power transmitting apparatus, comprising:

• a cylinder block defining a pair of hollow cylinders;
• a pair of pistons disposed for reciprocation in each of said cylinders;
• hydraulic material disposed within said cylinders;
• said cylinder block defining at least one flow passageway connecting said cylinders with one another to permit reciprocating flow of said hydraulic material therethrough in response to reciprocation of said pistons, said cylinder block also defining a plurality of arcuate seating surface within said flow passageway;
• and
• valve means disposed in said flow passageway for variable control of flow between said cylinders, the valve means comprising:
• a cylindrical occluding member having a longitudinal axis extending generally perpendicularly to the flow passageway and engaged by the seating surfaces of the flow passageway for rotational movement of the occluding member about its longitudinal axis, said occluding member being in occluding position within said flow passageway and proportioned in relation to the size of the hydraulic material pathway of the housing so as to divide said flow passageway into a first side and a second side;
• said occluding member having at least one slot therein extending substantially radially inwardly from its periphery, and extending substantially perpendicularly to said longitudinal axis;
• and
• rotating means for rotating said occluding member about its longitudinal axis to move said at least one slot between a first position in which the slot of the occluding member is in fluid communication with both said first and second sides of said housing pathway to allow first and second sides of said housing pathway to allow said hydraulic material to flow between said first and second sides through said slot, and a second position in which the slot of the occluding member is out of fluid communication with at least one of said first and second sides so that said hydraulic material is prevented from flowing between said first and second sides through said slot;
• wherein said one or more slots in said occluding member are defined at least in part by a thermally expanding material which expands in proportion to increased temperature of the hydraulic material to reduce the size of the slots.

In a power transmission apparatus having a housing with surfaces defining a hydraulic material pathway through which hydraulic material flows between a pair of cylinders, said housing surfaces defining a plurality of seating surfaces, a valve for regulating the flow of hydraulic material through the hydraulic material pathway, the valve comprising:

• a circularly cylindrical occluding member having a longitudinal axis extending generally perpendicularly to the direction of flow of hydraulic material through the pathway and engaged by the seating surfaces of the housing for rotational movement of the occluding member about its longitudinal axis, said occluding member being disposed in occluding position within said hydraulic material pathway to divide said pathway into a first side and a second side;
• said occluding member having at least one slot therein;
• and
• rotating means for rotating said occluding member about its longitudinal axis to move said at least one slot between a first position in which the flow of the occluding member is in fluid communication with both said first and second sides of said housing pathway to allow said hydraulic material to flow through said slot between said first and second cylinders, and a second position in which the slot of the occluding member is out of fluid communication with at least one of said first and second sides so that said hydraulic material is prevented from flowing between said first and second cylinders;
• wherein said power transmission apparatus has a housing defining said plurality of seating surfaces and said occluding member is displaceable generally perpendicularly to its longitudinal axis, under the influence of the hydraulic material, from a first position in abutment with a first set of said plurality of seating surfaces to a second position in abutment with a second set of said plurality of seating surfaces.

In a power transmission apparatus having a housing with surfaces defining a hydraulic material pathway through which hydraulic material flows between a pair of cylinders, said housing surfaces defining a plurality of seating surfaces, a valve for regulating the flow of hydraulic material through the hydraulic material pathway, the valve comprising:

• a circularly cylindrical occluding member having a longitudinal axis extending generally perpendicularly to the direction of flow of hydraulic material through the pathway and engaged by the seating surfaces of the housing for rotational movement of the occluding member about its longitudinal axis, said occluding member being disposed in occluding position within said hydraulic material pathway to divide said pathway into a first side and a second side;
• said occluding member having at least one slot therein;
• and
• rotating means for rotating said occluding member about its longitudinal axis to move said at least one slot between a first position in which the slot of the occluding member is in fluid communication with both said first and second sides of said housing pathway to allow said hydraulic material to flow through said slot between said first and second cylinders, and a second position in which the slot of the occluding member is out of fluid communication with at least one of said first and second sides so that said hydraulic material is prevented from flowing between said first and second cylinders;
• wherein said one or more slots in said occluding member are defined at least in part by a thermally expanding material which expands in proportion to increased temperature of the hydraulic material to reduce the size of the slots.

A power transmission apparatus comprising:

• a cylinder block defining a pair of hollow cylinders;
• a pair of pistons disposed for reciprocation in each of said cylinders;
• hydraulic material disposed within said cylinders;
• said cylinder block defining at least one flow passageway connecting said cylinders with one another to permit reciprocating flow of said hydraulic material therethrough in response to reciprocation of said pistons;
• and
• a valve disposed in said flow passageway for variable control of flow between said cylinders;
• each said pair of pistons defining a cylinder space therebetween;
• said cylinder space between each said pair of pistons being substantially filled with hydraulic material.