Dual-Stage Pump Tappet Mechanism for High Pressure
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Dual-stage pumps for hydraulic systems are limited by a maximum limit pressure of 100 to 140 bar due to the spring element required to open the switching valve, and they are costly to produce, making it difficult to achieve high flow rates at pressures above 140 bar and are expensive.
Innovation Solution
The dual-stage pump design incorporates a movable tappet with a smaller effective diameter than the piston, allowing the control pressure to be applied indirectly, reducing the force required to open the switching valve, enabling higher limit pressures and using spring elements with lower spring constants, which are simpler and cost-effective. Additionally, the use of a cutting edge for valve sealing eliminates the need for additional sealing elements, reducing production costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If a spring element with high spring constant is used to enable higher limit pressures, then the limit pressure increases, but the space requirement increases and the spring element becomes more complex
Solution Approach 1:
The patent introduces a tappet as an intermediary component between the control pressure chamber and the piston. The control pressure acts on the tappet, which then transmits the force to the piston. This intermediary mechanism allows the use of spring elements with lower spring constants while still achieving high limit pressures, thereby reducing structural complexity and space requirements.
2Stress or pressure
If direct control pressure application to piston is used, then the structure is simple, but high limit pressures cannot be achieved
Solution Approach 1:
The tappet serves as a mechanical intermediary that decouples the direct relationship between control pressure and piston. By introducing this intermediate component, the system achieves higher pressure multiplication capability without proportionally increasing overall structural complexity.
3Reliability
If conventional sealing elements are used for valves, then sealing is reliable, but production costs increase
Solution Approach 1:
The patent removes conventional sealing elements (O-rings, sealing rings) from the valve mounting structure. Instead, the valves are directly caulked into the housing, extracting the sealing function from separate components and integrating it into the valve-housing interface itself, thereby eliminating additional sealing elements and reducing production costs.
Solution Approach 2:
The sealing function is merged with the valve mounting structure. The valve body itself forms the sealing interface with the housing through caulking, combining the mounting and sealing functions into a single integrated solution rather than using separate sealing components.
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
This design allows for higher limit pressures above 140 bar while being more cost-effective, as it reduces the force needed to open the switching valve and simplifies the spring structure, and the cutting edge sealing method reduces production costs and simplifies mounting, achieving efficient and economical operation.
Implementation Method 1
control pressure in the control chamber exceeds the limit pressure adjusted via the spring element the piston is moved
Implementation Method 2
piston that is movable against the force of the spring element relative to the housing
Data Source
AI summary
The present invention relates to a dual-stage pump for a hydraulic system with a housing, a high and low-pressure pump element, a common pressure outlet and a switching valve that is arranged between a tank connection and the low-pressure pump element. The switching valve has a spring element and a piston being movable against a force of the spring element relative to the housing and having a closing member that can be lifted from a valve seat by a control pressure that is tapped on the pressure outlet and applied in a control pressure chamber. On the one hand, the invention is characterized in that the switching valve comprises a tappet that is movable relative to the housing and configured to move the piston and arranged between the control pressure chamber and the piston and has a smaller effective diameter than the piston. On the other hand, the invention is characterized in that the dual-stage pump comprises at least one valve that can be screwed into the housing, wherein a cutting edge of the valve is sealingly cut into the housing.