Rocker Arm Oil Control via Single-Path Spool Valve
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Solution Overview
Problem
Prior hydraulic circuit designs for rocker arms are inefficient due to complexity, leading to high tolerance stack-up and potential device failure, particularly requiring multiple pressure feeds and complex oil passages.
Innovation Solution
A rocker arm design that switches between valve lift profiles using a single supply path for high and low pressure fluids, featuring a spool with notch configurations to communicate fluidly with lash bores and an accumulator path, allowing for simplified oil control and reduced tolerance stack-up by eliminating oil switching at the rocker shaft.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If complex oil passages with multiple pressure feeds are used, then valve lift profile control capability is improved, but device complexity and tolerance stack-up increase
Solution Approach 1:
The patent combines multiple pressure feed functions into a single oil passage that delivers both high-pressure and low-pressure fluid to the spool valve. This merging of functions reduces the number of separate passages and components while maintaining the capability to control different valve lift profiles through pressure variation alone.
Solution Approach 2:
The invention controls different valve lift profiles by changing the pressure parameter of the fluid supplied through the single passage. The spool valve responds to different pressure levels (high and low) to achieve different valve lift events, eliminating the need for multiple separate pressure feeds while maintaining full control capability.
2Adaptability or versatility
If multiple pressure feeds and complex oil passages are used, then valve lift profile switching capability is improved, but manufacturing precision requirements and tolerance stack-up increase
Solution Approach 1:
By merging multiple pressure feed functions into a single passage, the patent reduces the number of interfaces, joints, and alignment requirements that would otherwise accumulate tolerances. The single passage design eliminates the tolerance stack-up associated with multiple separate high-pressure and low-pressure feed lines.
3Adaptability or versatility
If complex oil passages with numerous bores and check valves are used, then valve control functionality is improved, but reliability decreases
Solution Approach 1:
The patent extracts and eliminates numerous check valves and complex internal oil passages from the rocker arm design. By removing these components and replacing them with a simpler spool valve mechanism controlled by a single oil passage, the invention reduces the number of potential failure points while maintaining full valve control functionality.
Solution Approach 2:
The invention merges the functions of multiple check valves and complex passages into a single streamlined oil passage system that works in conjunction with the spool valve. This consolidation reduces the number of moving parts and sealing surfaces that could fail, thereby improving reliability.
4Adaptability or versatility
If oil switching at the rocker shaft is performed, then valve lift profile control is achieved, but reaction time is delayed
Solution Approach 1:
The patent replaces the mechanical oil switching mechanism at the rocker shaft with a spool valve system controlled by pressure variations in a single oil passage. This substitution eliminates the mechanical switching delays and provides faster response time for valve lift profile changes, as the spool valve reacts directly to pressure changes without mechanical switching intermediaries.
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 simplifies oil circuitry, reduces tolerance stack-up, and enhances reaction time by ensuring constant pressurization and minimizing complexity, while allowing for precise control of valve lift profiles without simultaneous pressure supply and venting.
Implementation Method 1
A spool is in the spool bore, the spool comprising a spool notch, the spool configured to reciprocate in the spool bore. At least a first spool path is in fluid communication with the spool and the first lash bore. A second spool path is in fluid communication with the spool and the second lash bore. An accumulator path is in fluid communication with the spool.
Implementation Method 2
A hydraulic lash device is in the first lash bore, the lash device comprising an inner body and an outer body, wherein the outer body is configured to collapse during the first valve lift profile when receiving the low pressure fluid, and wherein the outer body and the inner body are configured to cooperate rigidly when receiving the high pressure fluid
Implementation Method 3
An accumulator path is in fluid communication with the spool
Data Source
AI summary
A rocker arm comprising a supply path that communicates with a first lash bore and a first spool bore. A spool is in the spool bore. A hydraulic lash device is in the first lash bore, wherein an outer body is configured to collapse during a first valve lift profile when receiving a low pressure fluid, and wherein the outer body and the inner body are configured to cooperate rigidly when receiving a high pressure fluid during a second valve lift profile. The spool is movable to a first spool position to align the spool notch with a first spool path and a second spool path, and the spool is movable to a second spool position to align the spool notch with the second spool path and an accumulator path. The supply path in to the rocker arm is the only source of fluid to the spool.