Planetary Roller Screw Cage Reset for Axial Offset Prevention
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Solution Overview
Problem
In forced seal ball valves, particularly in large-diameter high-pressure applications, the planetary roller screw device experiences axial offset due to manufacturing precision issues and environmental factors, leading to contact between the cage and thread members, causing operational difficulties and reduced working life.
Innovation Solution
A cage reset planetary roller screw device is introduced, featuring a cage with convex ends and limit blocks that maintain the planetary rollers in the correct position between male and female threads, ensuring accurate alignment and preventing axial offset through one-way rotational loads during non-load rotation strokes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If planetary roller screw device is used in forced seal ball valve, then the mechanical seal between ball and valve end-connection is achieved, but axial offset occurs due to manufacturing precision issues and environmental factors, causing cage contact with thread members
Solution Approach 1:
The patent applies preliminary action by providing limit blocks on the cage that engage with the planetary rollers before axial offset can occur. These limit blocks pre-establish boundaries to prevent the rollers from moving out of position, addressing the manufacturing precision and environmental factor issues before they cause cage contact
Solution Approach 2:
The patent implements feedback through the limit block mechanism that continuously monitors and corrects the positional relationship between planetary rollers and cage. When rollers tend to move out of position due to manufacturing tolerances or environmental factors, the limit blocks provide immediate feedback by engaging to restore proper alignment
2Force
If planetary roller screw device operates under high pressure, then forced seal is achieved, but frictional force at thread contact surface increases, causing increased operation torque
Solution Approach 1:
The patent applies dynamics by introducing a reset mechanism that allows the planetary roller screw device to dynamically adjust and reset its position during operation. The limit blocks enable the system to periodically return to its initial state, preventing cumulative friction effects and maintaining ease of operation under high pressure conditions
Solution Approach 2:
The patent implements periodic action through the reset mechanism where the planetary rollers are periodically returned to their initial position by the limit blocks. This periodic resetting prevents continuous friction buildup during forced sealing operations, reducing overall operation torque
3Productivity
If planetary roller screw device undergoes repeated reciprocating rotations, then the valve operation is achieved, but accumulation of roller position changes causes axial offset between planetary roller and cage
Solution Approach 1:
The patent applies preliminary action by pre-positioning limit blocks on the cage that define the maximum allowable displacement of planetary rollers. Before repeated reciprocating rotations can cause significant axial offset, the limit blocks are already in place to prevent excessive position changes and maintain stability
Solution Approach 2:
The patent implements feedback through the limit block mechanism that provides continuous positional monitoring during repeated valve operations. Each time the planetary rollers approach their maximum displacement, the limit blocks provide feedback by engaging, ensuring the positional relationship between rollers and cage remains stable across multiple operation cycles
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 solution effectively resets the planetary rollers to their initial working position, ensuring proper operation and extending the working life of the device by preventing contact between the cage and thread members, thus maintaining the mechanical seal and reducing operational torque.
Implementation Method 1
a number of planetary rollers are disposed between the male thread and the female thread
Implementation Method 2
The limit block is in contact with the convex end of the cage in the circumferential direction of the cage
Data Source
AI summary
The present disclosure relates to a cage reset planetary roller screw device comprising a male thread member provided with a male thread and a female thread member provided with a female thread, a number of planetary rollers disposed between the male thread and the female thread. The planetary rollers are disposed between the male thread and the female thread through a cage, and the planetary rollers are disposed in roller retaining pockets of the cage. The side surfaces of the cage are provided with convex ends. The male thread member and/or the female thread member are provided with limit blocks that are in contact with the convex ends of the cage in the circumferential direction of the cage.