Lens Barrel Lead Screw Drive With Backlash-Reducing Ring Support
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing focus lens drive mechanisms using lead screws and nuts face performance limitations in precision and efficiency, particularly in reducing backlash and improving movement accuracy.
Innovation Solution
A lens barrel design incorporating a ring-shaped member with grooves that contacts the lead screw's thread grooves, supported by a movement portion and biased by a spring, allowing rotational movement and reducing friction, thereby enhancing the drive mechanism's performance by minimizing backlash and improving position control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a lead screw and nut mechanism is used to drive the focus lens, then the lens can be moved along the optical axis, but backlash and movement accuracy deteriorate
Solution Approach 1:
The ring-shaped member is configured to rotate together with the lead screw while simultaneously moving in the axial direction. This dynamic coupling allows the groove contact surfaces to maintain continuous contact without backlash, as the rotational movement compensates for any gaps that would exist in a traditional nut-lead screw interface.
Solution Approach 2:
The invention transitions from a purely linear sliding contact (traditional nut-lead screw) to a combined rotational and linear contact. The ring-shaped member's groove contacts the lead screw's thread groove both radially and axially, utilizing two-dimensional contact to eliminate backlash while maintaining precise axial movement control.
2Force
If a traditional lead screw and nut mechanism is used, then the structure is simple, but friction and drive load increase
Solution Approach 1:
By allowing the ring-shaped member to rotate with the lead screw, the mechanism converts static sliding friction into dynamic rolling-like contact. This reduces the coefficient of friction significantly, lowering the drive load on the motor while the added rotational degree of freedom does not substantially increase structural complexity.
Solution Approach 2:
The invention changes the contact parameters between the drive elements by using groove-to-groove contact instead of thread-to-thread contact. This geometric parameter change reduces the contact pressure and friction coefficient, thereby reducing the force required to drive the system while maintaining structural simplicity.
3Measurement precision
If a ring-shaped member with groove contact is used, then backlash is reduced and accuracy improves, but the device complexity increases
Solution Approach 1:
The ring-shaped member serves multiple functions simultaneously: it acts as the moving element that carries the lens, provides the contact surface that eliminates backlash through groove engagement, and rotates with the lead screw to maintain continuous contact. This multi-functionality achieves high precision without proportionally increasing the number of separate components.
Solution Approach 2:
The invention merges the functions of the traditional nut body and the contact element into a single ring-shaped member. The groove is formed directly on the ring-shaped member, combining the support structure and the precision contact surface into one integrated component, thereby achieving high accuracy without excessive 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
The design improves the accuracy and speed of lens movement, reduces the load on the drive motor, and allows for a more compact and efficient drive source unit, enabling the handling of heavier lens frames with less power and faster operation.
Implementation Method 1
a biasing portion that biases the ring-shaped member toward the lead screw in a direction orthogonal to the axial direction of the lead screw
Implementation Method 2
a lead screw that has a first thread groove formed thereon and is rotationally driven by the drive source; a movement member that is connected to the lens holding frame, rotatably holds the ring-shaped member, and moves in an axial direction of the lead screw as the lead screw rotates
Data Source
AI summary
A lens barrel includes a lens holding frame that holds a lens, a drive source, a lead screw that has a first thread groove formed thereon and is rotationally driven by the drive source, a ring-shaped member that has a groove on an inner periphery thereof, the groove being in contact with the first thread groove, a movement member that is connected to the lens holding frame, rotatably holds the ring-shaped member, and moves in an axial direction of the lead screw as the lead screw rotates, and a biasing portion that biases the ring-shaped member toward the lead screw in a direction orthogonal to the axial direction of the lead screw.