Cycloid Motor Output Shaft Intermittent Oil Grooves
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Solution Overview
Problem
The existing cycloid hydraulic motors face limitations in radial bearing capacity due to their structure, which restricts their ability to handle larger radial forces and can lead to increased leakage, even with the addition of radial needle or ball bearings.
Innovation Solution
The output shaft of the cycloid hydraulic motor is modified by processing intermittent oil grooves with an eccentric arc bottom, allowing for improved radial bearing capacity and enhanced sealing, while maintaining a compact structure. This is achieved through a specific processing method using a four-jaw chuck and the arrangement of needle bearings and a plane thrust bearing, which enhances the motor's ability to handle radial forces and maintain a reliable seal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If circumferential annular oil grooves are disposed on the output shaft to ensure lubrication and form flow-distribution oil film, then sealing and lubrication are improved, but radial bearing capacity deteriorates
Solution Approach 1:
The continuous circumferential annular oil groove is segmented into intermittent oil grooves distributed along the axial direction. This segmentation prevents the groove from forming a complete circular path that would compromise structural integrity, while still providing adequate lubrication and sealing at multiple locations along the output shaft.
Solution Approach 2:
Different sections of the output shaft are given different properties: the dynamic engaging portion has intermittent oil grooves for lubrication, while the portions requiring high radial bearing capacity maintain solid structure without grooves. The oil grooves are localized to specific axial positions rather than forming a complete circle.
2Force
If radial needle bearing or ball bearing is added to improve radial bearing capacity, then force bearing capability is improved, but leakage increases
Solution Approach 1:
The harmful element (radial needle bearing or ball bearing) is extracted from the system. Instead of adding bearings that would increase leakage, the patent removes the need for such bearings by optimizing the output shaft structure with intermittent oil grooves that provide lubrication without compromising sealing.
3Manufacturing precision
If complicated milling process is adopted to process equi-depth circumferential intermittent oil grooves, then manufacturing precision is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
Instead of using complicated milling processes to create precise equi-depth circumferential intermittent oil grooves, the patent uses a simpler copying approach where the oil grooves are formed by direct machining methods that replicate the required pattern without complex tooling or multi-step processes.
Solution Approach 2:
The oil groove design transitions from equi-depth circumferential grooves requiring precise milling to intermittent grooves with varying depths that can be machined more simply. The groove parameters (depth, position, shape) are optimized to achieve the required precision through simpler manufacturing processes.
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 modifications result in a significant improvement of nearly 40% in radial bearing capacity and axial bearing capacity, along with improved processability and cost performance, while reducing manufacturing complexity and costs.
Implementation Method 1
enabling oil contained in the oil groove flowing from both ends of the oil groove to the excircle area of the dynamic engaging portion of the main body between adjacent oil grooves, and then further diffusing to both sides, so that better oil film can be formed to ensure the lubrication and seal
Data Source
AI summary
Disclosed are an output shaft (1) of a cycloid hydraulic motor and an axle valve flow-distribution cycloid hydraulic motor having same, belonging to the technical field of mechanical transmission. The main body of the output shaft includes a larger-diameter section (1-2) assembled in a casing (10) of the cycloid hydraulic motor and a smaller-diameter section (1-1) extending out of the casing. An engaging structure transmissibly connected with a linkage shaft (21) of the cycloid hydraulic motor is disposed in an inner hole of the larger-diameter section (1-2), and a dynamic engaging portion (1-2-1) is disposed on an external surface of the larger-diameter section for dynamically engaging with the casing (10), the dynamic engaging portion (1-2-1) includes at least two circumferential intermittent oil grooves (1-2-2); a groove bottom of each intermittent oil groove is formed by an eccentric arc about the center O' that deviates from the center O of an excircle of the dynamic engaging portion by a process eccentricity e, the radius R of the eccentric arc is greater than the radius r of the excircle of the dynamic engaging portion. The output shaft and the cycloid hydraulic motor can improve the working efficiency and reduce the manufacture cost, and can form a better oil film, enhance the radial bearing capacity, and ensure the lubrication and seal.