Two-Stage Shock Absorber Valve for Low-Loss Damping Control
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Solution Overview
Problem
Conventional valves in shock absorbers generate strong damping forces at low piston speeds due to pressure losses, leading to uncomfortable vehicle ride quality, and attempts to reduce damping force by lowering sub-disc flexural rigidity compromise durability.
Innovation Solution
A valve design featuring a first valve body with a fixed inner circumference, a second valve body with adjustable biasing, and a communication passage to maintain hydraulic oil flow efficiency, allowing independent damping force setting on both extension and compression sides.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the sub-disc has high flexural rigidity to maintain structural stability, then the gap between the sub-disc and main disc becomes narrow when opening the orifice hole, but this causes pressure loss in hydraulic oil flow and generates strong damping force
Solution Approach 1:
The valve body is divided into two separate components: a first valve body that opens/closes the annular window and a second valve body that opens/closes the hole forming the throttle. This segmentation allows each component to be optimized independently - the first valve body can have high rigidity for reliable sealing while the second valve body can be designed with a larger opening area to reduce pressure loss and damping force.
Solution Approach 2:
The second valve body acts as an intermediary element between the first valve body and the main disc. It provides a controlled passage for hydraulic oil through its hole that faces the annular window, mediating the flow between the port and the throttle while reducing the negative effects of narrow gaps through its specific geometric design.
2Loss of energy
If the sub-disc is made thin to lower flexural rigidity and reduce damping force, then pressure loss decreases, but the durability of the sub-disc deteriorates due to large warping under pressure
Solution Approach 1:
By segmenting the valve body into two separate valve bodies, the patent eliminates the need for a thin, fragile sub-disc. The first valve body can be made with sufficient thickness and rigidity to withstand pressure without warping, while the second valve body is designed specifically to control the throttle opening area and minimize damping force generation.
Solution Approach 2:
The patent changes the geometric parameters of the valve bodies, specifically designing the hole in the second valve body with dimensions and positioning that optimize the balance between opening area (to reduce pressure loss) and structural integrity (to prevent warping under pressure).
3Device complexity
If hydraulic oil flows through the same orifice hole regardless of shock absorber direction, then the valve structure is simple, but it becomes difficult to independently set damping force characteristics on extension and compression sides
Solution Approach 1:
The valve body is segmented into a first valve body with the annular window and a second valve body with the hole, allowing independent control of flow paths for extension and compression directions. This enables different damping force characteristics to be set for each direction by adjusting the geometry and positioning of the respective valve bodies.
Solution Approach 2:
The valve design enables dynamic control of the flow paths - the first and second valve bodies can move independently to open or close their respective passages (annular window and hole) based on the direction of piston movement, allowing adaptive damping force characteristics for extension and compression sides.
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 valve design attenuates damping force, improves durability, and maintains efficient hydraulic oil flow, enhancing vehicle ride quality by reducing unnecessary resistance and pressure losses.
Implementation Method 1
When the upstream pressure of the port reaches a valve opening pressure, the main disc becomes warped and then comes off an annular valve seat
Implementation Method 2
a pressure loss occurs in the hydraulic oil when the hydraulic oil flows through the orifice hole. Likewise, a pressure loss also occurs in the hydraulic oil when the hydraulic oil flows between the sub-disc and the main disc
Implementation Method 3
the damping force becomes strong. As described above, a conventional valve disadvantageously generates strong damping force due to its orifice hole
Data Source
AI summary
A valve of the present invention includes: a valve seat member that has a port, an annular window which communicates with an outlet end of the port, an inner-circumferential valve seat provided on an inner-circumferential side of the annular window, and an outer-circumferential valve seat of the annular window; a first valve body that are stacked on a valve seat member, that can seat on or come off the outer-circumferential valve seat to open or close the annular window, and that has a hole; a second valve body that is contained in the annular window so as to be movable in an axial direction and that closes the hole when abutting on a valve seat member side surface of the first valve body; a second valve body biasing member that is contained in the annular window and that biases the second valve body toward the first valve body; a regulating portion that restricts a movement of the second valve body in a direction in which the second valve body moves away from the first valve body; and a communication passage that secures communication between the hole and the port even when the second valve body abuts on the regulating portion.