Internally Cooled Valve Friction Welding Without Stem Twisting
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Solution Overview
Problem
Existing methods for manufacturing internally cooled valves, such as electron beam welding and laser welding, result in suboptimal material properties and are costly, while friction welding poses risks of valve stem twisting due to torque transmission issues, especially when the valve stem is thinner than the weld seam.
Innovation Solution
A method involving friction welding with optimized parameters, including inductive friction welding, engagement structures for torque transmission, and sintering technology to produce valve base elements with cooling ribs and flow-influencing structures, allowing for high material density and uniform structure transition, and enabling the use of sodium as a coolant without repeated opening and closing of the valve.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electron beam welding or laser welding is used to join the valve base to the valve head, then the joining process can be completed, but the material properties are suboptimal and the manufacturing cost is high
Solution Approach 1:
The patent replaces electron beam welding or laser welding (energy-intensive processes) with friction welding (mechanical process). The friction welding process uses mechanical friction and pressure to join the valve base to the valve head, producing superior material properties including high material density and uniform structure transition, while being more cost-effective and easier to implement
Solution Approach 2:
The patent changes the fundamental parameters of the joining process by transitioning from thermal-based welding (electron beam/laser) to mechanical-based friction welding. This parameter change enables controlled friction welding with optimized pressure, speed, and torque parameters that achieve reliable joints with superior material properties without the high costs associated with electron beam or laser welding equipment
2Reliability
If friction welding is used to join the valve base to the valve head, then high material density and uniform structure transition are achieved, but the valve stem may twist off due to torque transmission issues
Solution Approach 1:
The patent segments the torque transmission path by introducing an intermediate engagement structure (such as a drive element with flank toothing or a central borehole engagement structure) between the valve base and valve stem. This segmentation allows the torque to be transmitted through a dedicated engagement mechanism rather than directly through the valve stem, protecting the valve stem from twisting while enabling the friction welding process to proceed with high material density and uniform structure
Solution Approach 2:
The patent introduces an intermediary engagement structure (drive element, toothing, or central borehole feature) that acts as a mediator between the friction welding process and the valve stem. This intermediary component absorbs and transmits the torque required for friction welding without imposing excessive torsional forces on the valve stem, thereby preventing valve stem failure while achieving reliable weld joints
3Quantity of substance
If the cavity is opened at the valve base for coolant filling, then sodium coolant can be introduced, but the valve must be opened and closed repeatedly which increases manufacturing complexity
Solution Approach 1:
The patent applies preliminary action by filling the cavity with sodium coolant before the friction welding operation closes the cavity. The valve base is designed with a temporary opening that allows coolant introduction, and the engagement structure provides access during the welding process. Once welding is complete, the opening is sealed, eliminating the need for subsequent opening and closing operations and reducing manufacturing 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
This method enables the cost-effective and efficient manufacturing of internally cooled valves with improved material properties and heat transfer, reducing the risk of valve stem twisting during friction welding by optimizing torque transmission and using sintered materials for enhanced coolant flow and structural design.
Implementation Method 1
closing the cavity with the valve base element by friction welding the valve base element to the valve head
Implementation Method 2
the friction welding is carried out as inductive friction welding
Implementation Method 3
The valve base element and/or the valve body have/has an engagement structure. The valve base element and/or the valve body may be centrally clamped by the engagement structure. In addition, the engagement structure may be designed in such a way that it allows increased torque transmission
Implementation Method 4
subsequent sintering
Data Source
AI summary
A method for manufacturing an internally cooled valve (2), includes providing a valve body (4) having a valve stem (6) that ends in a valve head (8). The valve body (4) has a cavity (10) that is open toward the valve head (8) and with a valve base element (12) by friction welding the valve base element (12) to the valve head (8). The valve bottom element (12) is preferably a sintered component.