Compact Rotary Electrohydraulic Actuator for Shock Load Handling
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Solution Overview
Problem
Conventional rotary electrohydraulic actuators for top drives in drilling operations face challenges such as large size, high mass due to hydraulic hoses, difficulty in handling, and poor performance in shock-loading situations, especially when using electric motors with gear sets.
Innovation Solution
A rotary electrohydraulic actuator design featuring a hydraulic motor with a gear-free connection, a compact power plant integrated with close-coupled electric motors and hydraulic pumps, eliminating the need for long hoses and providing a direct drive configuration that handles shock loads effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If electric motors with gear sets are used to generate required power, then rotational speed can be provided, but the device size and mass increase and performance in shock-loading situations deteriorates
Solution Approach 1:
The patent replaces the electromechanical gear set system with a hydraulic transmission system. The electric motor drives a hydraulic pump that generates pressurized fluid, which then actuates a hydraulic motor to drive the output shaft. This substitution eliminates mechanical gears while maintaining speed control capability through hydraulic means, thereby improving shock-load performance.
Solution Approach 2:
The patent employs a hydraulic transmission system where an electric motor drives a hydraulic pump to generate pressurized fluid. This hydraulic fluid is then directed to a hydraulic motor that converts hydraulic pressure back to mechanical rotation. The hydraulic system provides smooth torque delivery and shock absorption, replacing the problematic mechanical gear set.
2Reliability
If hydraulic motors are used, then shock loads are handled effectively and control is improved, but the device requires lengthy and large hoses that add mass and complexity
Solution Approach 1:
The patent integrates the electric motor, hydraulic pump, and hydraulic motor into a single compact unit. The electric motor is directly coupled to the hydraulic pump, which is in turn coupled to the hydraulic motor, eliminating the need for external hydraulic hoses. This merging of components reduces system complexity while maintaining the shock load handling capabilities of hydraulic motors.
Solution Approach 2:
The patent employs a nested arrangement where the electric motor is positioned within or adjacent to the hydraulic motor assembly. The hydraulic pump is integrated into the same housing structure, creating a compact nested configuration that eliminates external hydraulic connections and reduces overall system complexity.
3Weight of moving object
If a compact integrated design is used, then mass and installation space are reduced, but manufacturing complexity may increase
Solution Approach 1:
The patent creates a multi-functional integrated unit where a single assembly performs the functions of an electric motor, hydraulic pump, and hydraulic motor. This universal design consolidates multiple components into one manufacturable unit, reducing overall mass while managing manufacturing complexity through standardized integration protocols.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution results in a smaller, lighter, and more reliable actuator that can handle shock loads and provide variable speed and torque, reducing maintenance and installation space while eliminating leak points and long conveyance lines.
Implementation Method 1
an electric motor configured to drive the hydraulic pump, wherein operation of the electric motor causes the hydraulic pump to supply pressurized fluid
Implementation Method 2
operation of the electric motor causes the hydraulic pump to supply pressurized fluid to one of the fluid inlet and fluid outlet of the hydraulic motor
Implementation Method 3
a hydraulic motor including a hydraulic motor housing having a fluid inlet and a fluid outlet. The hydraulic motor includes a rotor disposed in the hydraulic motor housing so as to rotate about a rotational axis
Data Source
AI summary
A rotary electrohydraulic actuator includes a direct drive hydraulic motor having an output shaft through opening that is concentric with a rotational axis of a rotor of the hydraulic motor. The actuator includes a power plant mounted on the hydraulic motor via a manifold. The power plant includes an electric motor driven hydraulic pump. Operation of the electric motor causes the hydraulic pump to supply pressurized fluid to the hydraulic motor. The power plant is compactly mounted to the manifold so that a longitudinal axis of the electric motor is parallel to and spaced apart from the rotational axis of the hydraulic motor.