Rotating Housing Actuator for Heavy Loads With Lower Friction
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Solution Overview
Problem
Existing electro-mechanical actuators are not suitable for heavy loads due to their configuration, which results in reduced outer dimensions and increased friction leading to heat generation, limiting their ability to handle heavy loads efficiently.
Innovation Solution
An electro-mechanical actuator design featuring a load-carrying cylindrical housing that rotates around a concentric actuating rod, maximizing load-carrying surfaces and using threaded rolling members to reduce friction, allowing for large force generation and heat dissipation while maintaining small outer dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the space within the outer static cylinder is occupied by motor components and threaded nuts, then the actuator can be compact, but the dimensions of the nut, screw and threads must be reduced, resulting in inability to handle heavy loads
Solution Approach 1:
Instead of having a stationary outer cylinder with internal components, the patent inverts the configuration by making the outer cylindrical housing rotatable while the actuating rod remains relatively stationary. This inversion allows the load-carrying surfaces to be maximized at the outer radius, enabling heavy load handling while maintaining compact dimensions. The rotatable housing engages with threaded rolling members that convert rotational motion to linear motion of the actuating rod.
Solution Approach 2:
The patent utilizes the radial dimension effectively by positioning the load-carrying threaded surfaces at the maximum outer radius of the rotatable housing. This dimensional arrangement allows the load-carrying surfaces to extend further from the center, increasing the effective lever arm and load capacity without increasing the axial length of the actuator, thus maintaining compactness while handling heavy loads.
2Area of stationary object
If the outer dimensions such as the outer diameter of the static cylinder are restricted, then the actuator fits within equipment constraints, but the load carrying capacity is reduced
Solution Approach 1:
The patent maximizes the utilization of the available outer diameter by positioning the load-carrying threaded surfaces at the maximum outer radius of the rotatable housing. This allows the full outer diameter to contribute to load capacity, enabling the actuator to handle heavy loads within restricted dimensional constraints.
3Device complexity
If traditional electro-mechanical actuator components are used, then the structure is simple, but friction between components generates heat that reduces functionality
Solution Approach 1:
The patent replaces traditional sliding friction mechanisms with rolling friction by introducing threaded rolling members that engage with the rotatable housing. This substitution of sliding contact with rolling contact significantly reduces friction and heat generation while maintaining the electro-mechanical conversion function. The rolling members rotate along the threaded surfaces, minimizing frictional heat compared to traditional screw mechanisms.
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 actuator effectively handles heavy loads, reduces material usage and weight, and dissipates friction heat, making it suitable for replacing hydraulic cylinders in working equipment while maintaining capacity and stability.
Implementation Method 1
the actuating rod comprises the second end part of the actuator and is arranged in connection with the cylindrical housing, such that when the electric motor assembly rotates the cylindrical housing, the rotational movement of the cylindrical housing is transformed into linear movement of the actuating rod in relation to the cylindrical housing along the longitudinal axis
Implementation Method 2
The rolling contact between the actuating rod and the cylindrical housing will this way be achieved at maximum radius, which will maximise the load carrying surfaces
Implementation Method 3
The working surfaces of the electro-mechanical actuator are lubricated for reducing friction and wear between said surfaces
Implementation Method 4
Since the rotatably arranged cylindrical housing is the outermost load-carrying member and also provides encapsulation, friction heat generated in the electro-mechanical actuator may be effectively dissipated from the cylindrical housing
Data Source
Figure 1
Figure 2a~2b
Figure 3~4
AI summary
The disclosure relates to an electro-mechanical actuator (10) for working equipment, the actuator (10) extending along a longitudinal axis (A) and comprising: a first end part (11) and a second end part (12); an actuating rod (20) comprising outer threads (22); a load-carrying cylindrical housing (30) concentrically arranged outside the actuating rod (20), the housing (30) comprising inner threads (32); and an electric motor assembly (40) connected to the outside of the cylindrical housing (30) to rotate the cylindrical housing (30) around the longitudinal axis (A); wherein the actuating rod (20) comprises the second end part (12) of the actuator and is arranged in connection with the cylindrical housing (30), such that when the electric motor assembly (40) rotates the cylindrical housing (30), the rotational movement of the cylindrical housing (30) is transformed into linear movement of the actuating rod (20) in relation to the cylindrical housing (30) along the longitudinal axis (A), whereby the distance between the first and second end parts (11,12) increases or decreases depending on the rotational direction of the cylindrical housing (30). The disclosure further relates to a working equipment.