Valve Plate Cooling Concave Portion for Axial Piston Pump Thermal Management
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Solution Overview
Problem
Existing axial piston hydraulic pumps and motors face issues with temperature increase at the valve plate due to frictional heat, which can lead to seizure or thermal cracks, and increasing leakage oil for cooling reduces efficiency.
Innovation Solution
A valve plate design with a cooling concave portion and grooves that allow operating oil to flow between the valve plate and the cylinder block, as well as between the valve plate and the housing, to effectively dissipate frictional heat without relying on leakage oil adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the amount of leakage oil is increased to enhance cooling effect, then the cooling effect is improved, but the efficiency of the pump or motor decreases
Solution Approach 1:
The valve plate is segmented into multiple functional regions: a cooling concave portion for heat dissipation, a sliding supporting surface for load bearing, and multiple ports for oil flow control. This segmentation allows different areas to perform specialized functions, enabling effective cooling without requiring excessive leakage oil that would reduce overall system efficiency.
Solution Approach 2:
Different regions of the valve plate are given different properties: the cooling concave portion is designed to receive and retain cooling oil for thermal management, while the sliding supporting surface maintains appropriate clearance for hydrodynamic lubrication. This localized differentiation allows each region to optimize its function without compromising the other, achieving cooling efficiency without excessive leakage.
2Power
If the internal pressure of the cylinders is increased to improve performance, then the output is improved, but the risk of seizure or thermal crack increases
Solution Approach 1:
Cooling oil is supplied to the cooling concave portion in advance of potential thermal problems, establishing a thermal management system that prevents temperature buildup before it can cause seizure or thermal cracking. This preliminary cooling action allows the system to operate at higher pressures with improved reliability.
3Productivity
If the rotation speed of the cylinder block is increased to improve productivity, then the output is improved, but the frictional heat generation increases
Solution Approach 1:
The cooling oil supply to the cooling concave portion is continuous, ensuring constant thermal management as the cylinder block rotates at high speeds. This continuous cooling action counteracts the continuous generation of frictional heat, enabling sustained high-speed operation without excessive temperature rise.
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 design effectively cools the valve plate, preventing seizure and thermal issues while maintaining or improving efficiency by using operating oil as a cooling medium, allowing for increased cylinder block revolution and oil pressure without decreasing pump or motor efficiency.
Implementation Method 1
a cooling concave portion into which an operating oil flows is formed in a region except for the ports on the back surface
Implementation Method 2
frictional heat is generated on sliding surfaces of the valve plate 65 and the cylinder block 64
Implementation Method 3
Since the cylinder block 64 rotates in this state, frictional heat is generated on sliding surfaces of the valve plate 65 and the cylinder block 64
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
To provide a valve plate to be effectively cooled and used in a hydraulic motor and a hydraulic pump. A valve plate (5) is used in a swash plate type motor (1) including a motor shaft (4) and a cylinder block (3) in a motor housing (2) and includes: a sliding supporting surface (5f) contacting a rear end surface (3r) of the cylinder block (3) to support the cylinder block (3); a supporting surface (5s) that is a surface corresponding to and opposite to the sliding supporting surface (5f); a central through hole (5a) through which the motor shaft (4) penetrates; and a plurality of ports (10L) and (10R) formed around the central through hole (5a) as inlets and outlets of operating oil so as to penetrate the valve plate (5), and a cooling concave portion (12) into which the operating oil flows is formed in a region except for the ports (10L) and (10R) on the supporting surface (5s).