Swash Plate Tilt Control for Low-Torque Hydraulic Pump Starting
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Solution Overview
Problem
Conventional hydraulic pumps require high starting torque, especially in low-temperature environments due to high fluid viscosity, necessitating large batteries and starter motors.
Innovation Solution
A hydraulic pump design featuring a swash plate with a first pressing unit to reduce tilt angle and a second pressing unit controlled by external pressure to increase tilt angle, allowing for reduced starting torque through adjustable tilt angle control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the swash plate tilt angle is maximized for high flow rate output, then the hydraulic pump delivers maximum discharge flow, but the starting torque requirement becomes excessively large
Solution Approach 1:
The swash plate tilt angle is made dynamically adjustable rather than fixed. The control piston moves the swash plate between a maximum tilt angle (for high flow rate during operation) and a minimum tilt angle (for reduced starting torque), allowing the system to adapt its displacement characteristics to different operational phases.
Solution Approach 2:
The control piston is pre-loaded with a spring that automatically positions the swash plate at the minimum tilt angle during the starting phase before hydraulic pressure is applied. This preliminary positioning reduces starting torque requirements before the system begins operation.
2Quantity of substance
If the swash plate tilt angle is increased to improve fluid discharge, then the flow rate increases, but the torque required to rotate the cylinder block increases significantly
Solution Approach 1:
The system changes the tilt angle parameter of the swash plate based on operational requirements. During starting, the tilt angle is maintained at minimum to reduce torque. During operation, the control piston increases the tilt angle to maximize fluid discharge volume, thus optimizing the parameter at different phases.
3Productivity
If a conventional hydraulic pump design is used with fixed maximum tilt angle, then the pump achieves high flow output, but large batteries and starter motors are required for starting
Solution Approach 1:
The fixed tilt angle design is replaced with a dynamic tilt angle control mechanism. The swash plate can be positioned at minimum tilt during starting (reducing starting torque and allowing smaller batteries/starter motors) and at maximum tilt during operation (maintaining high flow output), thus resolving the contradiction between productivity and device complexity.
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
Enables starting the hydraulic pump with minimal torque, even in low-temperature conditions, reducing the need for large batteries and contributing to a downsized hydraulic drive system.
Implementation Method 1
a first pressing unit for pressing the swash plate in such a direction as to reduce the tilt angle of the swash plate
Implementation Method 2
a second pressing unit for pressing the swash plate in such a direction as to increase the tilt angle of the swash plate by a pressure supplied from an outside
Data Source
AI summary
A hydraulic pump that allows a drive source to be started with a small torque includes a cylinder block having a plurality of cylinder bores and disposed so as to be rotatable. Pistons are each movably retained in an associated one of the cylinder bores. A swash plate controls the amount of movement of the pistons in accordance with the size of the tilt angle. A first pressing unit is configured for pressing the swash plate in such a direction as to reduce the tilt angle of the swash plate, and a second pressing unit is configured for pressing the swash plate to increase the tilt angle of the swash plate by the pressure supplied from the outside.