Torque-Transmitting Assembly with Hydrostatic Damper
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Solution Overview
Problem
Dog clutches in electrically-variable transmissions face challenges due to large inertia and random torque inputs, which prevent effective synchronization and result in uncontrolled motion and noise, as traditional synchronizers are inadequate to align the teeth for smooth engagement.
Innovation Solution
A torque-transmitting assembly with a selectively engageable dog clutch in series with a rotary hydrostatic damper, where the damper provides variable resistance to relative rotation, isolating the torque input and output members and allowing for synchronization before engagement, and a synchronizer ensures aligned tooth engagement, enabling smooth and reliable operation even with large inertia and random torque inputs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a dog clutch is used in an electrically-variable transmission with heavy components, then torque transmission capability is improved, but synchronization difficulty increases due to large inertia and random torque inputs
Solution Approach 1:
A hydrostatic damper is introduced as an intermediary component between the dog clutch and the torque input/output members. The damper isolates the clutch from random torque inputs and inertia effects, allowing the teeth to synchronize and engage smoothly despite the heavy components and variable loading conditions in electrically-variable transmissions.
Solution Approach 2:
The synchronization function is extracted from the traditional synchronizer mechanism and achieved through the hydrostatic damper's inherent damping properties. The damper removes the harmful effects of random torque inputs and inertia, creating the conditions necessary for successful tooth engagement without requiring complex synchronizing mechanisms.
2Object-generated harmful factors
If the teeth of a dog clutch are closely set to minimize uncontrolled motion, then noise is reduced, but the alignment precision required for engagement increases
Solution Approach 1:
The hydrostatic damper provides beforehand cushioning by dampening random torque inputs and speed variations before they reach the dog clutch. This pre-cushioning effect ensures that the teeth remain closely aligned during the engagement process, minimizing uncontrolled motion and noise while reducing the stringency of alignment precision requirements.
3Ease of operation
If a traditional synchronizer is used to synchronize dog clutch speeds, then engagement smoothness is improved, but the system becomes inadequate under random torque inputs from bumpy surfaces
Solution Approach 1:
The traditional mechanical synchronizer system is replaced with a hydrostatic damper that uses fluid-based damping to achieve synchronization. This substitution provides superior adaptability to random torque inputs from bumpy surfaces while maintaining smooth engagement, as the hydrostatic damper can dynamically respond to varying loading conditions without the rigid constraints of mechanical synchronizing mechanisms.
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 allows for reliable and smooth engagement of the dog clutch teeth, reducing uncontrolled motion and noise, and enables operation in electrically-variable transmissions by damping random torque inputs and maintaining low resistance during disengagement, facilitating efficient mode shifts between operating modes.
Implementation Method 1
The damper dampens random torque inputs to provide a variable resistance to relative rotation of the first and second components of the dog clutch
Implementation Method 2
a spring is connected between the two members to urge them to a substantially centered orientation within the range of permitted relative rotation
Data Source
AI summary
A torque-transmitting assembly is provided that includes a dog clutch isolated by a device such as a rotary hydrostatic damper from relative loading on the torque input member and torque output member that it is to connect for common rotation and torque transmission. Although its use is not limited to electrically-variable transmissions, the torque transmitting assembly is able to function even with the large inertia and potentially random torque inputs associated with theses types of transmissions.