Parallel Link Mechanism Motor Offset Assembly
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Solution Overview
Problem
Industrial robots face challenges in maintaining cleanliness and assembly ease due to the use of bellows in vertical movement shaft mechanisms, which lead to dust generation and grease leakage, and the complexity of aligning drive motors with rotational axes.
Innovation Solution
A parallel link mechanism with a drive motor fixed to either the first arm or connection shaft, allowing the motor to rotate with the arm and offsetting the motor shaft from the rotational axis, enabling easy assembly and internal wiring without a hollow motor, thus maintaining cleanliness and reducing assembly complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a bellows is used as a protecting member in the vertical movement shaft mechanism, then cleanliness is improved by preventing dust generation and grease leakage, but the pressure change in the mechanism induces dust generation and grease leakage again, and the material selection is limited
Solution Approach 1:
The invention removes the bellows from the vertical movement shaft mechanism entirely. Instead of using a bellows as a protecting member, the patent employs a different structural approach where the connection base and link mechanisms provide protection without requiring bellows, thereby eliminating the pressure-induced dust generation and grease leakage problems while expanding material selection freedom.
Solution Approach 2:
Rather than using a bellows to contain and protect the internal components, the invention inverts the approach by designing the connection base and link mechanisms themselves to provide the protective function. The structural arrangement of the parallel link mechanism and connection base creates a protected environment without relying on bellows containment.
2Reliability
If the drive motor is fixed to the fixed base with the rotational axis coinciding with the arm's rotational axis, then the mechanism can function properly, but the assembly process becomes complicated
Solution Approach 1:
The invention segments the drive system by separating the drive motor from the fixed base and attaching it to the movable base instead. This segmentation allows the motor to be positioned independently, eliminating the need for complex alignment between the motor shaft and arm rotational axes during assembly, while still achieving the required functional performance through the parallel link mechanism.
Solution Approach 2:
The movable base acts as an intermediary component that carries the drive motor and transmits its motion to the arms through the parallel link mechanism. This intermediary arrangement decouples the motor positioning from the fixed base, simplifying assembly by allowing the motor to be mounted on the movable base without requiring precise alignment with the arm's rotational axis.
3Object-affected harmful factors
If cables are arranged in the fixed base or arms for internal wiring, then cleanliness is maintained, but a hollow motor is required which enlarges the device sizes
Solution Approach 1:
The invention addresses the wiring issue by utilizing the spatial arrangement of the parallel link mechanism and movable base. Instead of routing cables through the fixed base or arms which would require hollow motors, the wiring can be arranged in the dimensional space created by the movable base's position and the link mechanism's configuration, eliminating the need for hollow motors and reducing device size while maintaining cleanliness.
Data Source
AI summary
A parallel link mechanism includes a first arm, a second arm, a first auxiliary link, a second auxiliary link, and a drive motor. A cylindrical connection shaft having a first rotational axis is provided near the proximal portion of the first arm. The proximal portion of the first arm is rotatably connected to a fixed base through the connection shaft. The distal portion of the second arm is rotatably connected to a movable base. The proximal portion of the second arm is rotatably connected to the distal portion of the first arm through a connecting portion connected to a transmission mechanism. The first auxiliary link forms a first parallel link together with the first arm, the connecting portion, and the fixed base. The second auxiliary link forms a second parallel link together with the second arm, the connecting portion, and the movable base. The drive motor drives the transmission mechanism to pivot the first arm and the second arm. The drive motor includes a motor shaft having a second rotational axis. The drive motor is fixed to either the first arm or the connection shaft with the second rotational axis being offset from the first rotational axis in a radial direction of the connection shaft in such a manner that, when the first arm rotates about the first rotational axis, the drive motor is allowed to rotate about the first rotational axis together with the first arm.