Rotary Swash Plate Pump Spool Layout for Variable Capacity
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Solution Overview
Problem
Existing rotary swash plate piston pumps have a fixed discharge capacity and are not compact in size, necessitating a solution that allows for variable discharge capacity while maintaining a compact design.
Innovation Solution
A rotary swash plate hydraulic pump with a variable capacity mechanism that includes a spool to adjust the effective stroke length of the piston, positioned within a cylinder block to minimize space requirements, and check valves that eliminate the need for separate ports and allow compact placement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a variable capacity mechanism is added to change discharge capacity, then the discharge capacity becomes variable, but the device size increases
Solution Approach 1:
The spool is inserted into the spool hole within the cylinder block, nesting the variable capacity mechanism inside the existing pump structure. This allows the discharge capacity to be variable while minimizing the increase in overall pump size by utilizing internal space efficiently.
Solution Approach 2:
The spool hole is positioned in the axial direction of the cylinder block, utilizing the existing axial space rather than expanding radially. This dimensional arrangement allows the variable capacity mechanism to be integrated without significantly increasing the pump's external dimensions.
2Adaptability or versatility
If the spool hole is positioned in the casing outside the cylinder block, then the variable capacity mechanism can be implemented, but the pump size increases
Solution Approach 1:
The spool hole is integrated into the cylinder block structure rather than being separate in the casing. This merging of the variable capacity mechanism with the cylinder block eliminates the need for additional external housing space, thereby reducing the overall pump size while maintaining variable discharge capacity.
3Productivity
If cylinder ports are used to connect inlet passage to cylinder bore, then fluid flow is enabled, but the device complexity increases
Solution Approach 1:
The inlet check valve is inserted directly into the other axial end portion of the cylinder bore, extracting the need for separate cylinder ports. This direct integration simplifies the structure by eliminating unnecessary ports while maintaining the fluid flow function from the inlet passage to the cylinder bore.
4Volume of moving object
If discharge check valve is positioned radially inward, then compactness is achieved, but the inlet check valve and discharge check valve interfere with each other
Solution Approach 1:
The inlet check valve and discharge check valve are positioned asymmetrically in the axial direction, with the discharge check valve radially outward of the inlet check valve. This asymmetric arrangement prevents interference between the two valves while maintaining compactness, as each valve has its own dedicated radial position without overlapping functional zones.
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
The pump achieves a variable discharge capacity while being compact in size, utilizing a spool mechanism and check valves to optimize space utilization and reduce overall dimensions.
Implementation Method 1
a spool that changes the effective stroke length of the piston by adjusting opening and closing of the cylinder bore that corresponds to the spool
Implementation Method 2
an inlet check valve that allows a flow of a working fluid in one direction to the cylinder bore and blocks an opposite flow of the working fluid
Implementation Method 3
a discharge check valve that allows a flow of the working fluid in one direction discharged from the cylinder bore and blocks an opposite flow of the working fluid
Implementation Method 4
a rotary swash plate that is housed in the casing so as to be rotatable about an axis and reciprocates the piston
Data Source
AI summary
This rotary swash plate hydraulic pump includes: a casing; a cylinder block including a cylinder bore and disposed in the casing so as to prevent relative rotation of the cylinder block; a piston that is inserted into the cylinder bore; a rotary swash plate that is housed in the casing so as to be rotatable about an axis and reciprocates the piston; and a variable capacity mechanism that changes an effective stroke length of the piston. The variable capacity mechanism includes a spool that changes the effective stroke length of the piston by adjusting opening and closing of the cylinder bore that corresponds to the spool. The cylinder block includes a spool hole into which the spool is inserted.