Motor Unit Oil Pump and Cooler Layout for Balanced Cooling
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Solution Overview
Problem
The existing motor units in electric automobiles suffer from weight imbalance due to the pump being positioned below the motor chamber and the cooler being vertically aligned, leading to undesirable deterioration in cooler cooling performance.
Innovation Solution
The motor unit design includes an oil pump mounted on the first end surface of the reducer, an oil cooler attached to the opposite side of the electric motor, and a housing with integrated oil paths and storage units to facilitate balanced weight distribution and efficient cooling oil circulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the pump is positioned below the motor chamber and the cooler is positioned vertically below the motor chamber, then the motor unit structure is simplified, but weight balance shifts toward the motor chamber undesirably
Solution Approach 1:
The patent repositions the pump and cooler from a vertical arrangement (below motor chamber) to a horizontal arrangement (on opposite sides of reducer), changing the spatial dimension of component layout. This dimensional shift resolves the weight balance issue while maintaining structural simplicity
2Volume of moving object
If the contact surface of the cooler and the first side wall surface are provided overlapping each other, then the motor unit structure is compact, but the cooler is directly affected by heat generated from the motor, causing deterioration in cooling performance
Solution Approach 1:
The patent extracts the cooler from the heat-affected zone by positioning it on the first end surface of the reducer, separated from the motor chamber. This isolation removes the harmful thermal influence from the cooler while maintaining compact overall structure through integrated reducer mounting
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 weight imbalance and minimizes the impact of motor heat on the oil cooler, enhancing cooling performance and facilitating easier assembly and downsizing of the motor unit.
Implementation Method 1
an oil pump that is mounted on a first end surface of the reducer, and to draw up the cooling oil accumulated in the storage unit in the gear case
Implementation Method 2
an oil cooler that is mounted on the first end surface of the reducer, has an inlet port which is connected to a cooling oil outlet port of the oil pump, cools the cooling oil from the outlet port of the oil pump
Implementation Method 3
the oil accumulated in the oil reservoir is scooped up by the differential apparatus, is introduced into a rotor, is dispersed evenly toward a stator due to centrifugal force generated by the rotation of the rotor
Data Source
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AI summary
A motor unit includes: an electric motor (10) including: a rotor (11); a stator (12); and a housing (13) that internally houses the rotor (11) and the stator (12), the housing (13) having: an upper portion where an oil path (61) where a cooling oil flows and outlet paths (71) to (74) where the cooling oil is discharged from the oil path (61) toward the stator (12) are formed; and a lower portion having a cooling oil storage unit (81); a reducer (20) including: a reducer mechanism (22) including a plurality of gears (22a) (22b); and a gear case (23) that internally houses the reducer mechanism (22), and has a lower portion having a cooling oil storage unit (82) communicating with the storage unit (81) in the housing (13), the reducer (20) having a second end surface on which a first end surface of the electric motor (10) is mounted, and transmitting power from the electric motor (10) at a reduced rotation speed; an oil pump (30) that is mounted on a first end surface of the reducer (20), draws up the cooling oil accumulated in the storage unit (82) in the gear case (23), and causes the cooling oil to circulate through the oil path (61) in the housing (13); and an oil cooler (40) that is mounted on the first end surface of the reducer (20), has an inlet port (40a) which is connected to a cooling oil outlet port (30b) of the oil pump (30), cools the cooling oil from the outlet port (30b) of the oil pump (30), and has an outlet port (40b) where the cooled cooling oil is discharged into a cooling oil flow path between the outlet port (40b) and an inlet port of the oil path (61) in the housing (13).