Rotation Sensor Mounting Structure for Hybrid Power Units
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Solution Overview
Problem
In hybrid power units for vehicles like forklift trucks and construction machines, the absence of a bearing for the electric motor reduces the accuracy of rotation sensor detection, as the sensor cannot be disposed adjacent to a bearing.
Innovation Solution
A structure is implemented where the rotation sensor is mounted on an end plate between the engine and electric motor, with a stator fixed on the end plate and a rotor on the rotary shaft, allowing for adjustable angular positioning and minimizing misalignment effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the electric motor uses a cantilever support without a bearing to reduce axial length, then the combined axial length of engine and electric motor is reduced, but the detection accuracy of the rotation sensor decreases
Solution Approach 1:
The end plate serves as an intermediary component between the engine and electric motor. It provides a mounting surface for the rotation sensor on the engine side, allowing the sensor to be positioned close to the rotary shaft without requiring a bearing in the electric motor. This mediator structure enables accurate rotation detection while maintaining the compact cantilever configuration.
2Device complexity
If the rotation sensor is disposed away from the bearing position to accommodate cantilever support, then the electric motor structure is simplified, but the angular misalignment between rotary shaft and crank shaft increases detection error
Solution Approach 1:
The adjust hole is provided in the end plate to enable preliminary adjustment of the stator's angular position before final assembly. This allows the rotation sensor to be pre-aligned to compensate for any angular misalignment between the rotary shaft and crank shaft, ensuring accurate rotation detection even in the simplified cantilever configuration without a bearing.
Data Source
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AI summary
A structure for mounting a rotation sensor (50, 50A) to an electric motor (30) in a hybrid power unit (10) including both an engine (20) and the electric motor is provided. The electric motor includes a rotary shaft (35) that is supported in a cantilever manner by a crank shaft (22) of the engine. The structure includes an end plate (36) defining a boundary between the engine and the electric motor and serving as an outer cover for the electric motor, and the rotation sensor including a stator (51, 51A) fixed on the end plate and a rotor (52, 52A) fixed on the rotary shaft facing the stator.