Two-Speed Transmission Single Actuator Dog Clutch
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Solution Overview
Problem
Existing two-speed transmissions for electric vehicles require two actuators for electromagnetic clutches, increasing size and power consumption, and leading to inefficiencies in both low and high vehicle velocity regions.
Innovation Solution
A two-speed transmission system using a planetary gear mechanism with a single actuator, employing a dog clutch and friction clutch configuration that switches engagement states via an armature moved by electromagnetic and elastic forces, allowing efficient gear shifting without torque interruption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If two electromagnetic clutches are installed to ensure engagement in both large and small reduction ratios, then the transmission can operate in both low and high vehicle velocity regions, but the electric power consumption increases and the load on the battery increases
Solution Approach 1:
The patent merges the functions of two separate electromagnetic clutches into a single electromagnetic clutch system. The first and second clutches are combined such that one clutch engages for large reduction ratio (low velocity region) while the other engages for small reduction ratio (high velocity region), allowing the transmission to operate in both velocity regions while using only one electromagnetic actuator, thereby reducing power consumption compared to using two separate electromagnetic clutches.
Solution Approach 2:
The single electromagnetic clutch system is designed to perform multiple functions: it can engage the first clutch for large reduction ratio transmission in low velocity regions, and engage the second clutch for small reduction ratio transmission in high velocity regions. This multi-functional design eliminates the need for two separate electromagnetic clutches, reducing overall power consumption while maintaining adaptability across different velocity regions.
2Adaptability or versatility
If two actuators are installed for the respective clutches, then the transmission can switch between reduction ratios, but the size of the transmission increases and layout restriction occurs
Solution Approach 1:
The patent combines two separate actuator systems into a single electromagnetic clutch assembly. The first and second clutches share a common electromagnetic actuator that can selectively engage either clutch based on the required reduction ratio. This merging of actuator functions significantly reduces the overall transmission size and eliminates the layout restrictions that would result from installing two separate actuators.
3Reliability
If electromagnetic force is used to maintain clutch engagement in both reduction ratios, then reliable transmission engagement is achieved, but the electric power consumption amount increases
Solution Approach 1:
The patent merges the electromagnetic engagement mechanism into a single unified system that controls both clutches. By using one electromagnetic coil to actuate both the first and second clutches through a shared armature mechanism, the system maintains reliable engagement in both reduction ratios while consuming less electrical power than would be required by two independent electromagnetic clutch systems.
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 system reduces power consumption, enhances efficiency in both low and high vehicle velocity regions, and minimizes shift shock, enabling improved energy efficiency and increased maximum vehicle velocity.
Implementation Method 1
an armature which is movable along an input axis, is rotated with the input axis, is moved to and is urged to a first direction by the elastic body, and is moved to and is urged to a second direction which is opposite to the first direction by an electromagnetic force generated from the electromagnetic coil
Implementation Method 2
an armature which is movable along an input axis, is rotated with the input axis, is moved to and is urged to a first direction by the elastic body
Data Source
AI summary
The present invention relates to a two-speed transmission for an electric driving vehicle and the two-speed transmission for an electric vehicle has only one actuator. The transmission comprises a planetary gear mechanism (12), an elastic body (44), an armature (26) to integrally rotate with an input axis, an electromagnetic coil (46) and a multi-plate friction clutch (30). A ring gear (20) is fixed to a housing. The armature (26) comprises clutch projection portions (26-1). A dog clutch is constituted by the clutch projection portions (26-1) and recess portions (18-2) of a sun gear (18). When the electromagnetic coil (46) is not electrically energized, the dog clutch is engaged. The rotation of the input axis is reduced and is transmitted to an output axis via the sun gear (18) and a carrier (16). When the electromagnetic coil (46) is electrically energized, the armature (26) is displaced against elastic force, the dog clutch becomes a non-engaging state, a multi-plate friction clutch (30) becomes an engaging state by pressing flange portions (26-4) of the armature (26) and the rotation of the input axis is transmitted to the output axis with a one-to-one relationship. The transmission can comprise a one-way clutch to prevent torque interruption when switching the gear ratio.