Cycloidal Robot Speed Reducer With Elastic Backlash Compensation
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Solution Overview
Problem
Existing robot speed reducers, particularly those using harmonic and RV designs, suffer from poor rigidity, high vibration noise, heat generation, and large back clearance due to gear transmission and small bearings, limiting their ability to handle higher input speeds and reducing their lifespan.
Innovation Solution
A low-back-clearance robot speed reducer design featuring a central crankshaft with a double-cross-shaped slider structure and elastic compensation, utilizing a cycloidal pin gear mechanism with trapezoidal grooves and protrusions for automatic clearance adjustment, and deep groove ball bearings to reduce heat and enhance rigidity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a gear transmission is used as the first stage transmission in conventional RV reducer, then the structure is compact, but there is great vibration noise at high speed
Solution Approach 1:
The patent removes the gear transmission component from the first stage of the speed reducer, replacing it with a direct crankshaft-cycloidal wheel connection. This extraction of the harmful gear element eliminates the source of vibration and noise while maintaining the speed reduction function through the cycloidal mechanism.
Solution Approach 2:
The patent substitutes the gear transmission mechanical system with a cycloidal pin joint mechanical system. The crankshaft directly drives the cycloidal wheel through eccentric rotation, replacing the gear engagement mechanism with a different mechanical principle that avoids high-speed vibration and noise.
2Speed
If small pin bearings are used in double crankshaft structure, then the structure is compact, but the end play creates large back clearance
Solution Approach 1:
The patent converts the harmful effect of bearing clearance into a beneficial automatic compensation mechanism. The elastic member is pre-compressed to store elastic energy, which then automatically pushes the cycloidal wheel against the pin bearing, eliminating back clearance without requiring larger or more complex bearing structures.
Solution Approach 2:
The elastic member provides self-service by automatically compensating for bearing clearance through its elastic force. The system self-regulates the back clearance issue without external intervention or complex adjustment mechanisms, maintaining precision through the inherent elastic properties of the component.
3Duration of action of stationary object
If small pin bearings are used in double crankshaft structure, then the structure is compact, but heat generation increases affecting lifetime
Solution Approach 1:
The patent removes the double crankshaft structure with small pin bearings and replaces it with a single central crankshaft configuration. This structural extraction eliminates the multiple small bearings that generate heat, reducing thermal load and extending the lifetime of the speed reducer.
Solution Approach 2:
The patent changes the bearing configuration parameter from multiple small pin bearings to fewer larger bearings on a single crankshaft. This parameter change reduces the total surface area of bearing contacts, thereby reducing friction and heat generation while maintaining structural integrity.
4Ease of manufacture
If gear transmission is used with certain clearance, then the assembly is easier, but the bearing is affected by clearance reducing precision
Solution Approach 1:
The patent converts the clearance that would normally harm precision into a beneficial feature by using the elastic member to intentionally create a pre-loaded contact condition. The clearance allows for easy assembly while the elastic force ensures precise bearing engagement, transforming the harmful clearance into a useful design feature.
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
This design allows for increased running speed, reduced heat generation, and improved rigidity by enabling larger bearings and automatic clearance compensation, addressing the limitations of conventional RV reducers.
Implementation Method 1
the clearance of the cross-shaped slider may be axially and automatically compensated through an elastic member
Implementation Method 2
select a deep groove ball bearing with good rotation characteristics as the eccentric portion bearing used therein, thereby facilitating the reducing of heat generation
Data Source
AI summary
A low-back-clearance robot speed reducer includes a wheel holder (16), a pin gear shell (1), a first cycloidal wheel (6), a roller pin (8), a second cycloidal wheel (11), a gland (2), an elastic member (9), a first cross-shaped slider (5), a second cross-shaped slider (13) and a crankshaft (10). The first cycloidal wheel (6) and the second cycloidal wheel (11) are in a phase relation of 180 degrees and have a multi-point engagement transmission relationship with the pin gear shell (1) and the roller pin (8). The first cross-shaped slider (5) and the second cross-shaped slider (13) form a double cross-shaped slider structure, in which the groove profile of the sliders is of a trapezoidal groove structure. A clearance is automatically axially compensated by the elastic member (9). The center of rotation of the crankshaft (10) is coaxial with the wheel holder (16) and the gland (2).