Signal Accumulator Piston Sleeve Assembly for Worn Valve Body Bores
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Solution Overview
Problem
Wear in signal accumulator piston bores of control solenoid valves in vehicle transmissions leads to loss of variable force solenoid signal pressure, resulting in poor shift control, hydraulic-related converter warnings, and burnt clutches.
Innovation Solution
A drop-in signal accumulator piston assembly comprising a cylindrical sleeve, piston, and plug is installed in the valve body bore, with a spring positioned in the piston and enclosed by a plug, allowing for seamless replacement without modifying the valve body.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the original equipment signal accumulator piston is used in the valve body bore, then the transmission operates normally, but wear in the piston bore leads to loss of signal pressure and poor shift control
Solution Approach 1:
The replacement assembly is divided into separate components: a sleeve that fits into the worn valve body bore, a new piston that fits into the sleeve, and a plug that seals the assembly. This segmentation allows the new piston to be protected from direct contact with the worn bore, while the sleeve absorbs the wear. The components can also be independently replaced in the future.
Solution Approach 2:
The sleeve acts as an intermediary component between the worn valve body bore and the new piston. It provides a fresh mating surface for the piston while protecting the piston from direct contact with the worn bore. The sleeve can be pressed into the existing bore without modifying the bore itself, and provides a renewed interface for the piston to operate against.
2Reliability
If a replacement piston assembly is installed to restore hydraulic control, then proper fluid line pressure control is maintained, but the assembly requires multiple components (sleeve, piston, spring, plug) instead of a single piston
Solution Approach 1:
The assembly uses a nested structure where the piston is inserted into the sleeve, and the spring is positioned within the piston cavity. The plug then seals the entire assembly from the valve body. This nesting consolidates multiple functional elements into a compact package that fits within the existing valve body bore space, managing complexity through hierarchical organization.
Solution Approach 2:
The sleeve serves multiple functions: it provides a mating surface for the piston, absorbs wear from the valve body bore, and can be removed as a unit with the piston and spring for maintenance. The plug serves both as a seal and as a structural closure. This multi-functionality reduces the need for additional separate components.
3Manufacturing precision
If the valve body bore is modified to accommodate a new piston, then a fresh mating surface is created, but modification of the valve body is required
Solution Approach 1:
Instead of modifying the worn valve body bore, the invention extracts the problematic worn surface by pressing a sleeve into the existing bore. The sleeve provides a fresh mating surface without requiring any machining or modification of the valve body itself. The worn bore is effectively bypassed rather than repaired.
Solution Approach 2:
The sleeve is pre-formed with the correct dimensions and surface finish required for proper piston operation. Rather than attempting to restore the worn bore through machining or other procedures, the suitable mating surface is prepared in advance as a separate component that can be directly installed into the existing bore.
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 assembly maintains proper fluid line pressure control, ensuring smooth transmission operation and preventing issues like soft shifts and hydraulic warnings, functioning equivalently to the original equipment piston.
Implementation Method 1
A spring is positioned in part in the piston and in part extends beyond an end of the piston
Implementation Method 2
Control solenoids in a vehicle transmission supply control fluid for the proper operation, e.g., shifting, of the vehicle transmission
Data Source
AI summary
A drop-in signal accumulator piston assembly to replace an original equipment (OE) signal accumulator piston in a vehicle transmission hydraulic circuit, the OE signal accumulator piston positioned in a bore in a valve body having an open end and a fluid port. The drop-in signal accumulator piston assembly has a sleeve having open first and second ends. The sleeve is configured to be positioned within the bore of the valve body. A piston is positioned in the sleeve. A spring biases the piston towards the fluid port. A plug is positioned to removably retain the sleeve, the piston, and the spring within the bore and to prevent the sleeve from moving axially within the bore.