Sliding Shoe Joining With Capacitor Discharge Welding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing methods for producing sliding shoes for hydrostatic displacement machines, particularly axial piston machines, face challenges such as high reject rates and high costs due to inhomogeneous heating and temperature distribution during gas soldering processes, leading to solder defects and excessive silver solder usage.
Innovation Solution
The method involves locally welding a steel base body to a titanium-free copper-zinc alloy brass plate using capacitor discharge welding, with circular ring-shaped weld projections to minimize heat input and structural changes, eliminating the need for silver solder and flux, and allowing for precise control of the welding process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gas soldering process is used to join brass plate to steel body, then joining is achieved, but inhomogeneous heating and temperature distribution occur leading to solder defects
Solution Approach 1:
The patent replaces the thermal field (gas flames) with an electrical field (capacitor discharge) to join the brass plate to the steel body. This substitution eliminates the inhomogeneous heating problem inherent in gas soldering, as capacitor discharge provides concentrated, controllable energy delivery at the joint location without the temperature distribution issues of flame heating.
Solution Approach 2:
The patent changes the fundamental parameter of the joining process from thermal energy (gas flames with temperatures exceeding solder melting points) to electrical energy (capacitor discharge). This parameter change allows for precise control of energy input, avoiding the temperature-related defects such as solder phase separation and incomplete melting that occur with gas soldering.
2Ease of manufacture
If gas flames are used for heating during soldering, then joining is achieved, but high gas consumption occurs during non-productive times
Solution Approach 1:
The patent replaces the continuous gas combustion system with a capacitor-based electrical discharge system. Capacitors store electrical energy and release it in controlled discharges only when needed for welding, eliminating the continuous gas consumption that occurs during non-productive times in flame soldering. This substitution transforms the energy delivery from continuous to on-demand.
Solution Approach 2:
The patent employs periodic capacitor discharge instead of continuous gas burning. The capacitor charges during non-productive times (storing energy without consumption) and discharges only when welding is required. This periodic action eliminates wasteful continuous energy consumption while maintaining manufacturing capability.
3Strength
If silver solder with high silver content is used, then joining strength is achieved, but procurement costs increase
Solution Approach 1:
The patent replaces the material-intensive approach (using expensive silver solder) with a process-intensive approach (using capacitor discharge welding). The electrical discharge directly joins the brass plate to the steel body through localized melting and fusion, eliminating the need for silver solder entirely. This substitutes material cost with process control.
Solution Approach 2:
The patent replaces the expensive silver-based hard solder with a cheaper joining method that uses the base materials themselves (brass and steel) joined through electrical discharge. The capacitor discharge creates a metallurgical bond without requiring expensive filler materials, effectively using the workpieces themselves as the joining medium.
4Extent of automation
If solder wire feed control is used, then solder supply is attempted, but fluctuation up to +/- 20% occurs compared to target value
Solution Approach 1:
The patent replaces the mechanical wire feed control system with an electrical field-based joining process. Capacitor discharge welding melts and fuses the brass plate and steel body directly at the joint location through controlled electrical energy delivery. This substitution eliminates the entire solder wire feed mechanism and its associated precision problems, achieving joining through field control rather than material delivery control.
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 approach reduces reject rates and production costs, enhances the resilience and tribological properties of the sliding shoes, and simplifies the manufacturing process by eliminating the need for silver solder and flux, while ensuring a stable and defect-free joint.
Implementation Method 1
the steel base body is only locally welded to the brass plate by means of capacitor discharge welding
Implementation Method 2
capacitor discharge welding
Implementation Method 3
with at least one welding projection in the form of a circular ring-shaped projection being produced on the steel base body in the area of contact with the brass plate, and with the brass plate being made of a titanium-free copper-zinc alloy
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
The invention relates to a method for producing a sliding shoe (6) of a hydrostatic displacement machine (1), in particular an axial piston machine, which can be fastened in an articulated manner to a pressurized piston (5) and supports the piston (5) on a stroke-generating running surface (7), wherein the slide shoe (6) consists of a steel base body (6a) and a brass plate (6b) which interacts with the running surface (7) and is joined to the steel base body (6a) of the slide shoe (6). According to the invention, the steel base body (6a) is only locally welded to the brass plate (6b) by means of capacitor discharge welding, with at least one welding projection (40; 41; 42; 43) in the form of a circular ring being made on the steel base body (6a) in the area in contact with the brass plate (6b). Buckels is made and the brass plate (6b) consists of a titanium-free copper-zinc alloy.