Hydraulic Actuator Orifice for Jerky Motion Suppression
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Solution Overview
Problem
Hydraulic actuators used to adjust the inclination of outboard motors can experience jerky motion due to excessive pressure changes, which is not effectively suppressed without additional machining operations to create a narrowed orifice in the channel between the upper chamber and the check valve.
Innovation Solution
A pump apparatus with a selector valve that includes an orifice narrower than the channel connected to the second chamber, formed as part of the channel between the actuation valve and the check valve, eliminates the need for additional machining operations to suppress jerky motion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a narrowed orifice is provided in the channel to suppress jerky motion, then jerky motion is restrained, but additional machining operation is required
Solution Approach 1:
The patent combines the orifice function with the existing channel structure by forming the orifice as an integral part of the channel wall through casting or molding processes. This merging eliminates the need for separate machining operations to create the narrowed section, as the orifice is formed during the primary manufacturing process of the housing or manifold.
Solution Approach 2:
The channel structure itself provides the orifice function through its designed geometry. The narrowed section is formed as an inherent feature of the channel during manufacturing, allowing the structure to serve dual purposes: fluid passage and flow restriction, without requiring additional components or post-processing operations.
2Reliability
If the outboard motor weight is larger than expected or air is mixed into the channel, then jerky motion occurs due to excessive pressure changes, but the system should maintain smooth operation
Solution Approach 1:
The narrowed orifice is positioned in the channel leading to the upper chamber to preemptively restrict flow and dampen pressure changes before they can cause jerky motion. This preliminary flow restriction prevents excessive pressure drops that would otherwise occur during rapid cylinder shortening, countering the harmful effects of heavy motor weight or air contamination before they manifest as jerky motion.
Solution Approach 2:
The patent changes the flow resistance parameter by introducing a narrowed orifice section in the channel. This geometric modification alters the pressure-flow characteristics of the hydraulic system, creating a more gradual pressure change profile that suppresses jerky motion regardless of motor weight variations or air contamination in the hydraulic fluid.
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 solution effectively suppresses jerky motion of the hydraulic actuator without requiring additional machining, ensuring smooth operation of the outboard motor inclination adjustments.
Implementation Method 1
the selective valve has, at a channel connected to the second chamber, an orifice that is narrower than a channel connected to the first chamber
Implementation Method 2
Each of the open valves is a combination of an actuation valve and a check valve which slide in a valve chamber
Implementation Method 3
the lower chamber-side actuation valve pressed by the inflow of the hydraulic fluid is displaced inside the valve chamber
Data Source
AI summary
A pump apparatus includes: a pump that ejects a hydraulic fluid; and a selector valve that switches a direction of a flow of the hydraulic fluid to be supplied to one of a first chamber and a second chamber of a cylinder apparatus, which is internally partitioned by a piston into the first chamber extending during an extending stroke of the cylinder apparatus, and the second chamber extending during a shortening stroke of the cylinder apparatus, and the selective valve has, at a channel connected to the second chamber, an orifice that is narrower than a channel connected to the first chamber.