Robot Joint Driving Device Axial Wiring Routing
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Solution Overview
Problem
Existing joint driving devices in vertical multi-joint robots face issues with increased joint size, weight, and limited operation speed due to the placement of wiring and tubes at the center of the motor and reduction gears, leading to friction and torque consumption, which is exacerbated in smaller robots.
Innovation Solution
The joint driving device incorporates a motor frame as part of the transmission shaft, housing the wire body in the outer circumference of the reduction gear output shaft and transmission shaft, with a U-shaped folded-back wire body design to distribute bending stress and prevent friction, allowing for a compact and durable configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the hole through which the wiring lines and tubes pass is provided at the center of the input-output shaft of the reduction gears and the motor shaft, then the wiring lines and tubes can be routed through the joint, but the size of the joint in radial direction increases so that the arm becomes thicker and the arm weight increases
Solution Approach 1:
The patent moves the wiring routing from the radial dimension (through the center hole of the shaft) to the axial dimension (along the surface of the shaft in the shaft direction). This dimensional change allows wiring to be routed without increasing the radial size of the joint, thereby preventing arm thickening and weight increase.
Solution Approach 2:
The patent introduces a cable guide as an intermediary component that facilitates wiring routing along the shaft surface. This cable guide acts as a mediator between the wiring lines and the shaft, enabling efficient routing without requiring modifications to the shaft structure that would increase joint size or weight.
2Ease of operation
If the hole through which the wiring lines and tubes pass is provided at the center of the input-output shaft of the reduction gears and the motor shaft, then the wiring can be routed through the joint, but the outer diameter of the motor shaft and input-output shaft increase, causing increased circumferential speed that spills grease and lubricant and increases friction heat
Solution Approach 1:
The patent relocates wiring routing from the radial center hole to the axial surface of the shaft. This dimensional relocation prevents any increase in shaft outer diameter, thereby maintaining safe circumferential speeds that prevent grease and lubricant spillage and reduce friction heat generation.
Solution Approach 2:
The cable guide serves as an intermediary that enables wiring routing along the shaft surface without requiring enlargement of the shaft. This preserves the original shaft dimensions and lubrication system integrity, preventing lubricant spillage and excessive heat generation.
3Ease of operation
If the hole through which the wiring lines and tubes pass is provided at the center of the input-output shaft of the reduction gears and the motor shaft, then the wiring can be routed through the joint, but the torque generated by the motor is consumed by increased frictional resistance, limiting joint operation speed
Solution Approach 1:
The patent changes the wiring routing path from radial (through center hole) to axial (along shaft surface). This prevents shaft diameter increase, thereby minimizing frictional resistance and preserving motor torque for productive work, which maintains high joint operation speed.
Solution Approach 2:
The cable guide acts as an intermediary that enables wiring routing without shaft enlargement. This prevents increased frictional resistance, ensuring that motor torque is not wasted on overcoming friction, thereby maintaining high joint operation speed and productivity.
4Ease of operation
If the hole through which the wiring lines and tubes pass is provided at the center of the input-output shaft of the reduction gears and the motor shaft, then the wiring can be routed through the joint, but the inertia on the side of the input-output shaft of the reduction gears increases, limiting joint acceleration
Solution Approach 1:
The patent relocates wiring routing from the radial center to the axial surface of the shaft. This prevents any increase in shaft mass and moment of inertia, thereby preserving joint acceleration performance and responsiveness.
Solution Approach 2:
The cable guide serves as an intermediary that enables wiring routing along the shaft surface without requiring shaft enlargement or added mass. This prevents increased inertia, allowing the joint to accelerate and decelerate rapidly with minimal torque consumption.
5Ease of operation
If the cable guide is located at the outer circumference of the servomotor with the cable folded back to the motor side, then the wiring can be routed, but a space is required between the motor and motor cover, increasing the outer diameter of the joint
Solution Approach 1:
The patent routes wiring along the shaft surface in the shaft direction rather than folding cables back at the motor circumference. This eliminates the need for additional space between the motor and motor cover, thereby preventing joint outer diameter increase and volume expansion.
Solution Approach 2:
The cable guide acts as an intermediary that enables efficient wiring routing along the shaft surface without requiring the motor-cable guide-motor cover arrangement. This eliminates the need for additional clearance space, maintaining compact joint dimensions and minimizing volume.
6Ease of operation
If the cable is arranged along with the cable guide in the shaft direction, then the wiring can be routed, but another space for arranging the cable in the shaft direction is required, increasing the width of the joint
Solution Approach 1:
The patent merges the cable guide function with the shaft surface itself, routing the cable along the shaft in the shaft direction without requiring separate dedicated space. This integrated approach allows wiring routing while minimizing joint width increase.
Solution Approach 2:
The cable guide serves as an intermediary that enables cable routing along the shaft surface. By positioning the cable guide on the shaft surface and routing the cable in the shaft direction, the design efficiently utilizes available space without significantly increasing joint width.
Data Source
AI summary
A joint driving device includes: a reduction gear output shaft that transmits a torque to a second link; a transmission shaft that transmits reaction of the torque to a first link; a transmission shaft outer cylinder arranged on the outer circumference of the transmission shaft and connected to the transmission shaft; a reduction gear output shaft outer cylinder arranged in the outer circumference of the reduction gear output shaft and connected to the reduction gear output shaft; and a wire body arranged between the first link and the second link and including at least one of a wire and a pipe. The transmission shaft includes the motor frame as at least a part. The wire body is housed in a space between the transmission shaft outer cylinder and the transmission shaft, and a space between the reduction gear output shaft outer cylinder and the reduction gear output shaft.