Clutch Unit with Slide Gear for Seat Lifter Locking
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Solution Overview
Problem
The existing clutch unit for automobile seat lifters fails to reliably lock the output shaft when rotational torques in forward and backward directions are reversely input in an alternate and continuous manner, leading to seat lowering during vehicle vibrations on rough roads.
Innovation Solution
Incorporating a gear member mounted to a stationary member that meshes with the output member to prevent gradual rotation, with a cam mechanism and elastic member to control meshing and release, ensuring reliable locking of the output shaft.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cylindrical rollers are used to control torque transmission through engagement and disengagement in wedge gaps, then the clutch unit can transmit and interrupt rotational torque, but the output shaft cannot be reliably locked when rotational torques are reversely input in an alternate and continuous manner
Solution Approach 1:
A gear member is introduced as an intermediary element between the stationary member and the output member. The gear member meshes with the output member to provide additional locking capability, preventing gradual rotation that occurs with cylindrical rollers alone under continuous reverse torque conditions.
Solution Approach 2:
The locking mechanism combines two different engagement methods: cylindrical rollers for normal torque transmission control and gear meshing for reliable locking under reverse torque. This composite approach leverages the strengths of both mechanisms to achieve reliable locking without excessive complexity.
2Reliability
If a gear member is added to mesh with the output member for reliable locking, then locking reliability improves, but device complexity increases
Solution Approach 1:
The gear member is designed to serve multiple functions: it meshes with the output member to prevent gradual rotation, works in conjunction with the cylindrical rollers for torque transmission control, and integrates with the existing clutch structure. This multi-functionality justifies the added complexity by providing enhanced locking reliability.
3Reliability
If the gear member is always engaged with the output member, then locking reliability is maximized, but the clutch unit cannot properly transmit torque during operation
Solution Approach 1:
The gear member is designed to be movable relative to the output member, allowing it to dynamically engage and disengage as needed. During normal operation, the gear member is disengaged to allow torque transmission; during locking conditions, it engages to prevent reverse rotation. This dynamic behavior maintains both reliability and ease of operation.
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 prevents seat lowering during vehicle vibrations by reliably locking the output shaft, even with contact position displacements and elastic deformation, ensuring stable torque transmission and seat adjustment.
Implementation Method 1
The plurality of cylindrical rollers are configured to control the transmission and interruption of the rotational torque from the outer ring through engagement and disengagement in wedge gaps between the outer ring and the inner ring
Implementation Method 2
The two centering springs are configured to accumulate elastic forces with the rotational torque from the outer ring, and return the cage and the outer ring to respective neutral states by the accumulated elastic forces when the input of the rotational torque is lost
Implementation Method 3
The plate springs are configured to apply a separating force to the pairs of cylindrical rollers
Implementation Method 4
The friction ring is configured to apply a rotational resistance to the output shaft
Data Source
Figure 1
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Figure 3
AI summary
Provided is a clutch unit, including: a lever-side clutch part (11) configured to control transmission and interruption of a rotational torque input through a lever operation; and a brake-side clutch part (12) configured to transmit the rotational torque from the lever-side clutch part (11) to an output side, and interrupt a rotational torque reversely input from the output side, wherein the brake-side clutch part (12) includes: an outer ring (23) which is constrained in rotation; an output shaft (22) configured to output the rotation; a cage (15c), which is arranged between the outer ring (23) and the output shaft (22), and is configured to receive the rotational torque input from the lever-side clutch part (11); and a cylindrical roller (27) configured to control the interruption of the rotational torque reversely input from the output shaft (22) and the transmission of the rotational torque input from the cage (15c) through engagement and disengagement between the outer ring (23) and the output shaft (22), and wherein the outer ring (23) includes a slide gear (32), which meshes with the output shaft (22) during interruption of the rotational torque and is released from the meshing state with the output shaft 22) during transmission of the rotational torque.