Vehicle Drive Device Axial Layout and Coupling
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Solution Overview
Problem
The existing vehicle drive devices with an engine, torque converter, and electric motor in series result in an elongated axial length, particularly problematic for FF vehicles where space is limited, leading to difficulties in mounting and potential fuel economy issues due to increased fluid resistance.
Innovation Solution
A vehicle drive device configuration where the engine and hydraulic transmission device rotate around one axial center, with the electric motor having a different axial center, coupled to the input-side rotating element of the hydraulic transmission device, allowing for a shorter overall axial length and improved fuel efficiency by reducing fluid resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the engine, hydraulic transmission device, and electric motor are disposed in series around one axial center, then the power transmission path is simplified, but the entire axial length becomes elongated
Solution Approach 1:
The patent transitions from a one-dimensional series arrangement (all components on one axial center) to a two-dimensional layout (electric motor on a parallel axial center). This spatial reconfiguration reduces the axial length while maintaining power transmission functionality through the coupling mechanism between the two axial centers.
2Length of moving object
If the electric motor is disposed on a different axial center, then the entire axial length is reduced, but the coupling mechanism becomes more complex
Solution Approach 1:
The input-side rotating element of the hydraulic transmission device serves as an intermediary component that couples the electric motor (on a different axial center) to the power transmission system. This mediator enables power transfer between offset axial centers while maintaining structural compactness.
3Ease of manufacture
If the axial length is elongated, then all components can be simply arranged in series, but the fuel economy deteriorates due to increased fluid resistance
Solution Approach 1:
By reconfiguring the component layout from a longitudinal series arrangement to a compact two-dimensional arrangement with parallel axial centers, the patent reduces the axial length and consequently shortens the duct line, reducing fluid resistance and improving fuel economy while maintaining manufacturing feasibility.
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 configuration reduces the entire axial length of the vehicle drive device, facilitating easier mounting on FF vehicles and enhancing fuel economy by minimizing fluid resistance in the duct line.
Implementation Method 1
a hydraulic pump rotationally driven by the input-side rotating element of the hydraulic transmission device
Implementation Method 2
a torque converter that is a hydraulic transmission device
Data Source
AI summary
A vehicle drive device comprising: an engine; a hydraulic transmission device constituting a portion of a power transmission path between the engine and drive wheels; and an electric motor, the engine and the hydraulic transmission device disposed to rotate around one axial center, the electric motor disposed with a rotation axial center different from the one axial center, the electric motor coupled to an input-side rotating element of the hydraulic transmission device receiving input of a drive force from the engine, the input-side rotating element being rotatable around the one axial center, the electric motor coupled to the input-side rotating element via an electric motor coupling rotating element coupled relatively non-rotatably to the input-side rotating element, a hydraulic pump rotationally driven by the input-side rotating element of the hydraulic transmission device disposed such that a rotor of the hydraulic pump rotates around the one axial center, and a coupling portion of the electric motor coupling rotating element for the input-side rotating element inserted into a pump-cover through-hole formed on an internal side of the pump-cover through-hole of the hydraulic pump in a radial direction, along with a portion of the input-side rotating element, and coupled relatively non-rotatably to the input-side rotating element in the pump-cover through-hole, in order to couple the input-side rotating element to the rotor.