Lock-up Device Torsional Vibration Absorber
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Solution Overview
Problem
In lock-up devices, the close contact between coiled parts of second coil springs during torsional vibration absorption leads to abrasion and damage, reducing the durability of both first and second coil springs, and existing configurations face similar drawbacks across multiple torsional characteristics.
Innovation Solution
A lock-up device design featuring an input rotary member, an output rotary member, first and second elastic members, a float member, and an activation restricting mechanism, where the second elastic members have a shorter free length and are disposed within the first elastic members, and the activation restricting mechanism prevents close contact by engaging the float member with either the output or input rotary member, allowing for multistage torsional characteristics without direct contact between coiled parts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the coiled parts of second coil springs are configured to be closely contacted to form multistage torsional characteristics, then the torsional vibration absorption capability is improved, but the durability of first coil springs and second coil springs deteriorates due to abrasion and damage
Solution Approach 1:
The patent introduces a third coil spring as an intermediary element between the first and second coil springs. The third coil spring is disposed inside the first coil spring and works in conjunction with the second coil spring to provide the third stage torsional characteristic without requiring close contact between coiled parts of the second coil spring, thereby preventing abrasion and damage while maintaining vibration absorption capability
Solution Approach 2:
The patent segments the torsional vibration absorption function into three distinct stages using three separate coil springs (first, second, and third coil springs). Each spring group provides a specific stage characteristic, allowing the system to achieve multistage torsional characteristics without the harmful close contact that would occur in a two-spring system
2Adaptability or versatility
If the lock-up device is activated in the condition that the coiled parts of the second coil springs are closely contacted, then the multistage torsional characteristics are achieved, but the ends of second coil springs may move onto the outer periphery of the receiver part causing damage or breakage
Solution Approach 1:
The third coil spring acts as a mediator that enables the lock-up device to achieve multistage torsional characteristics and activated state without requiring the harmful close contact of second coil spring coiled parts. The third spring absorbs the additional compression that would otherwise force the second spring ends onto the receiver part
Solution Approach 2:
The third coil spring provides beforehand cushioning by being positioned to engage before the second coil spring ends would contact the receiver part. This prevents damage or breakage of the second coil spring ends while still enabling the lock-up device to reach its activated state with multistage torsional characteristics
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 design enhances the durability of elastic members by preventing close contact and allowing flexible setting of bent points between torsional characteristics, thereby improving the device's durability and design flexibility without increasing the number of components.
Implementation Method 1
the first elastic members in each group are configured to be circumferentially compressed in series by relative rotation between the input rotary member and the output rotary member
Implementation Method 2
when each pair of first coil springs and each pair of second coil springs begin to be compressed, torsional vibration is absorbed and attenuated in accordance with torsional stiffness of each pair of first coil springs and each pair of second coil springs
Implementation Method 3
The float member restricts radial movement of the plurality of groups of the first elastic members
Implementation Method 4
The activation restricting mechanism is configured to restrict and bring one of the first elastic members in each group and the second elastic member disposed in the inner peripheral part of the one of the first elastic members in each group to a deactivated state by at least either of engagement of the float member with the output rotary member and engagement of the input rotary member with the float member
Data Source
AI summary
A lock-up device includes a drive plate, a driven plate, first torsion springs, second torsion springs, a spring holder and a rotation restricting unit. The rotation restricting unit is configured to restrict and bring the first torsion spring in each group and the second torsion spring in each group to a deactivated state by at least either of engagement of the spring holder with the driven plate or engagement of the drive plate with the spring holder.