CVT Spider and Nut Fastening Against Shaft Loosening
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Solution Overview
Problem
In continuously variable transmissions (CVTs) used in utility vehicles, the fastening of the spider to the drive shaft can loosen due to torque fluctuations, affecting the speed change function.
Innovation Solution
The spider is secured to the drive shaft using a combination of screws and a nut mechanism that adjusts orientation to counteract centrifugal forces, preventing axial movement and maintaining proper fastening, and additional retaining members or sleeves with stoppers are used to enhance stability and prevent loosening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the spider is fastened to the drive shaft through screwing, then the spider can be simply and effectively fastened, but the fastening may loosen due to torque fluctuations and centrifugal forces
Solution Approach 1:
The nut is pre-positioned on the drive shaft at the location where the spider will be mounted. This preliminary placement allows the nut to be ready to receive and secure the spider's screw, preventing loosening caused by torque fluctuations and centrifugal forces during operation.
Solution Approach 2:
The nut acts as an intermediary component between the spider and the drive shaft. It provides an additional fastening point that reinforces the spider's attachment to the drive shaft, counteracting the loosening effects of centrifugal forces and torque variations.
2Reliability
If the spider is securely fastened to prevent loosening, then fastening reliability improves, but the device complexity increases due to additional components
Solution Approach 1:
The nut serves multiple functions: it fastens the spider to the drive shaft, provides a counterbalance to centrifugal forces, and reinforces the screw connection. This multi-functionality allows reliable fastening without requiring multiple separate components, thereby limiting the increase in device complexity.
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 configuration ensures reliable fastening of the spider to the drive shaft, maintaining appropriate speed changes and providing improved heat resistance and stability against loosening, even under high torque conditions.
Implementation Method 1
a centrifugal weight that is rotatable relative to the movable sheave according to a centrifugal force caused by the rotation of the drive shaft
Implementation Method 2
The spider is screwed to the drive shaft, includes a first screw that advances in one direction of the axial direction of the drive shaft when the spider rotates relative to the drive shaft in one direction of the circumferential direction, and is fastened to the drive shaft by the first screw
Implementation Method 3
The nut is screwed to the drive shaft, includes a second screw that advances in the other direction of the axial direction of the drive shaft when the nut rotates relative to the drive shaft in the one direction of the circumferential direction, and is fastened to the drive shaft by the second screw
Data Source
AI summary
A spider is screwed to a drive shaft, includes a first screw that advances in one direction of an axial direction of the drive shaft when the spider rotates relative to the drive shaft in one direction of a circumferential direction, and is fastened to the drive shaft by the first screw. A nut is screwed to the drive shaft, includes a second screw that advances in the other direction of the axial direction of the drive shaft when the nut rotates relative to the drive shaft in one direction of the circumferential direction, and is fastened to the drive shaft by the second screw.