A hydrostatic transmission system includes a hydraulic motor and at least one proportional control valve and at least one pump connected to the hydraulic motor to provide fluid to operate the hydraulic motor. The at least one pump includes at least one fluid driver having a prime mover and a fluid displacement assembly to be driven by the prime mover such that fluid is transferred from the pump inlet to the pump outlet. The hydrostatic transmission system also includes a controller that establishes at least one of a speed and a torque of the at least one prime mover and concurrently establishes an opening of the at least one proportional control valve to adjust at least one of a flow and a pressure in the hydrostatic transmission system to an operational set point.

Various downhole tools, such as drilling motors, drilling tools, reamer tools, casing reamer shoes, and related methods of installation, assembly and use. Casing reamer shoes and drilling reamers or motors may have internal impellers, progressive cavity pumps, hollow rotors and other parts, universal joints, and other features. A progressive cavity section may have a rotor and a stator. Rotor contacting surfaces of the stator, and stator contacting surfaces of the rotor, may be rigid during use. The stator contacting surfaces and the rotor contacting surfaces may be made of metal. After the casing is run, the casing is cemented and the reamer shoe drilled out.

Various downhole tools, such as drilling motors, drilling tools, reamer tools, casing reamer shoes, and related methods of installation, assembly and use. Casing reamer shoes and drilling reamers or motors may have internal impellers, progressive cavity pumps, hollow rotors and other parts, universal joints, and other features. A progressive cavity section may have a rotor and a stator. Rotor contacting surfaces of the stator, and stator contacting surfaces of the rotor, may be rigid during use. The stator contacting surfaces and the rotor contacting surfaces may be made of metal. After the casing is run, the casing is cemented and the reamer shoe drilled out.

A hydrostatic transmission system includes a hydraulic motor and at least one proportional control valve and at least one pump connected to the hydraulic motor to provide fluid to operate the hydraulic motor. The at least one pump includes at least one fluid driver having a prime mover and a fluid displacement assembly to be driven by the prime mover such that fluid is transferred from the pump inlet to the pump outlet. The hydrostatic transmission system also includes a controller that establishes at least one of a speed and a torque of the at least one prime mover and concurrently establishes an opening of the at least one proportional control valve to adjust at least one of a flow and a pressure in the hydrostatic transmission system to an operational set point.

A hydrostatic transmission system includes a hydraulic motor and at least one proportional control valve and at least one pump connected to the hydraulic motor to provide fluid to operate the hydraulic motor. The at least one pump includes at least one fluid driver having a prime mover and a fluid displacement assembly to be driven by the prime mover such that fluid is transferred from the pump inlet to the pump outlet. The hydrostatic transmission system also includes a controller that establishes at least one of a speed and a torque of the at least one prime mover and concurrently establishes an opening of the at least one proportional control valve to adjust at least one of a flow and a pressure in the hydrostatic transmission system to an operational set point.

A hybrid elastomer/metal on metal motor for a helical gear device includes a rotor and stator comprising a hydraulic motor that produces work when a working fluid is pumped therethrough. The improvement involves the stator being, for part of its length, a conventional or even wall stator, using an elastomer to form a seal against the moving rotor. The stator's remaining length comprises a profiled rigid surface that forms a seal directly with the moving rotor. This gives the motor the high efficiency of the elastomer sealing against the rotor, and simultaneously provides a backup of the stator's rigid section allowing continued motor operation at reduced efficiency, if the elastomer part failed in service. The invention also includes combinations of a regular disk stack with a rubber lining, a rigid material disk stack (or unitized element) and a circular rigid sleeve which react to rotor sideloading while permitting proper rotor orbiting.

A hybrid elastomer/metal on metal motor for a helical gear device includes a rotor and stator comprising a hydraulic motor that produces work when a working fluid is pumped therethrough. The improvement involves the stator being, for part of its length, a conventional or even wall stator, using an elastomer to form a seal against the moving rotor. The stator's remaining length comprises a profiled rigid surface that forms a seal directly with the moving rotor. This gives the motor the high efficiency of the elastomer sealing against the rotor, and simultaneously provides a backup of the stator's rigid section allowing continued motor operation at reduced efficiency, if the elastomer part failed in service. The invention also includes combinations of a regular disk stack with a rubber lining, a rigid material disk stack (or unitized element) and a circular rigid sleeve which react to rotor sideloading while permitting proper rotor orbiting.

Techniques involve a motor assembly including a rotor and a stator. The stator includes a contact surface for contacting an outer surface of the rotor. The contact surface includes a rigid material. The motor assembly also includes at least one constraint disposed along a length of the motor assembly, where the constraint constrains a radial and/or tangential movement of the rotor relative to the stator. The at least one constraint may be disposed at one or more proximate ends of the motor assembly, and/or along the length of the motor assembly. The contact surface of the stator may have a profile including peaks and valleys, and in some embodiments, the contact surface may be treated to reduce friction and/or wear.

Techniques involve a motor assembly including a rotor and a stator. The stator includes a contact surface for contacting an outer surface of the rotor. The contact surface includes a rigid material. The motor assembly also includes at least one constraint disposed along a length of the motor assembly, where the constraint constrains a radial and/or tangential movement of the rotor relative to the stator. The at least one constraint may be disposed at one or more proximate ends of the motor assembly, and/or along the length of the motor assembly. The contact surface of the stator may have a profile including peaks and valleys, and in some embodiments, the contact surface may be treated to reduce friction and/or wear.

A progressive cavity positive displacement motor having a solid metal stator and a rotor having an elastomeric seal layer on its outer surface, as well as a method of manufacturing the motor. The elastomeric seal layer on the rotor can be formed by extruding the uncured elastomer, applying the extrusion to the metal rotor core and machining the cured elastomer to produce a uniform thickness seal layer. The elastomer can be made from a high molecular weight elastomer compound. Graphene additives can further enhance the performance characteristics of the elastomer.