Swivel Frame Layout for Electric Excavator Balance
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Solution Overview
Problem
The conventional arrangement of a battery above the electric motor and hydraulic pump in a hydraulic excavator leads to a higher center of gravity, making it difficult to maintain balance, especially with large-capacity batteries, which worsens when the battery position is off-center.
Innovation Solution
The battery unit is positioned on a swivel frame in the upper swivel body, with the electric motor and hydraulic pump arranged side by side on the same frame, balancing weight and lowering the center of gravity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the battery is located above the electric motor and hydraulic pump in the upper swivel body, then the battery can be arranged in a compact space, but the center of gravity becomes higher making it difficult to maintain balance
Solution Approach 1:
The patent transitions from a vertical stacking arrangement (battery above motor and pump) to a horizontal side-by-side arrangement on the swivel frame. This dimensional change allows all components to be positioned at a lower, similar elevation, reducing the center of gravity height while maintaining compact arrangement through lateral optimization of space on the swivel frame.
2Quantity of substance
If a large-capacity battery unit is used, then the electric power storage increases, but the center of gravity becomes higher and off-center making it increasingly difficult to maintain balance
Solution Approach 1:
The patent positions the large-capacity battery unit, electric motor, and hydraulic pump side by side on the swivel frame at a lower elevation. This localized arrangement on the same horizontal plane ensures that the heavy battery unit does not create a high or off-center center of gravity, maintaining balance even with increased power storage capacity.
3Adaptability or versatility
If the battery position is off-center in the left-right direction, then the arrangement flexibility increases, but the balance of the machine body deteriorates
Solution Approach 1:
The patent employs asymmetric arrangement of components on the swivel frame, positioning the battery unit, electric motor, and hydraulic pump side by side in optimized locations. This asymmetric layout provides arrangement flexibility for cable routing and maintenance access while maintaining balanced weight distribution through careful positioning of heavy components relative to the swivel frame's center of rotation.
Data Source
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AI summary
[Problem] To provide an electric work machine that can maintain good balance of a machine body during work even when a large-capacity (large-size) battery unit is used. [Solution] A hydraulic excavator as an electric work machine comprises a lower traveling body, an upper swivel body located above the lower traveling body and provided to be swivelable with respect to the lower traveling body, an electric motor arranged in the upper swivel body, a hydraulic pump arranged in the upper swivel body and driven by the electric motor, a battery unit arranged in the upper swivel body and storing electric power to drive the electric motor, and a hydraulic actuator driven by hydraulic oil supplied from the hydraulic pump. The upper swivel body has a swivel frame at a bottom portion thereof. The battery unit is arranged on the swivel frame. The electric motor and the hydraulic pump are arranged on the swivel frame, side by side in a left-right direction of the upper swivel body.