Controllable Shock Absorber Valve Segmentation for Independent Damping Control
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Solution Overview
Problem
Existing controllable shock absorbers for motor vehicles face challenges in independently setting the damping characteristic for compression and rebound stages, particularly when the magnet actuator fails, as the valve body's switchover to the failsafe function inadvertently closes the regular outflow path, limiting the setting capability of the damping characteristic.
Innovation Solution
A controllable shock absorber design featuring a separate closing element for the first outflow path, allowing for independent selection and actuation of outflow paths, with active faces loaded differently during each stage to manage the valve body's position and maintain the first outflow path open even when the valve body is at its stop position, utilizing a magnetic closing element and a common restoring spring to manage the magnetic flux and fluid pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the valve body is used for both setting pilot control pressure and switching between outflow paths, then the device complexity is reduced, but the setting capability of damping characteristic for individual stages is limited
Solution Approach 1:
The patent divides the valve body into two functionally independent parts: a first valve body for setting pilot control pressure in the first stage, and a second valve body for switching between first and second outflow paths in the second stage. This segmentation allows each valve body to be optimized for its specific function without interfering with the other, thereby achieving independent setting capability for different stages while maintaining manageable device complexity.
2Reliability
If the valve body is moved to upper stop position to switch to failsafe function, then the reliability is improved, but the first outflow path is inadvertently closed, limiting the setting capability
Solution Approach 1:
By separating the failsafe switching function (second valve body) from the pilot control pressure setting function (first valve body), the patent ensures that when the second valve body moves to the upper stop position to activate the failsafe function, it does not interfere with the first outflow path controlled by the first valve body. This allows the first outflow path to remain open and functional even during failsafe operation.
Solution Approach 2:
The patent introduces a pilot control valve as an intermediary component that controls the first outflow path independently of the valve body's position. This intermediary mechanism ensures that the first outflow path can be maintained open through active control, decoupling it from the automatic switchover mechanism of the second valve body.
3Ease of manufacture
If the same valve body is used for both pilot control and outflow path switching, then the ease of manufacture is improved, but the operational flexibility is reduced
Solution Approach 1:
The patent segments the valve assembly into multiple valve bodies, each dedicated to a specific function. While this increases manufacturing complexity compared to a single integrated valve body, it provides significant operational flexibility by allowing independent control of pilot pressure and outflow paths, enabling the shock absorber to adapt to different operating conditions and failure modes.
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 design enables independent setting of damping characteristics for both stages, maintaining the first outflow path open during failures, thus enhancing the shock absorber's operational flexibility and reliability by separating the pilot control pressure setting from the switchover between outflow paths.
Implementation Method 1
a magnetic actuator (40) which can be supplied with electrical current and generates a magnetic flux (M)
Implementation Method 2
a common restoring spring (53) for restoring the valve body (32) and the closing element (37) into their initial position
Implementation Method 3
a hydraulic fluid which is received in a sealed manner in the cylinder tube (10)
Data Source
AI summary
A controllable shock absorber may include a cylinder tube with hydraulic fluid, a movable piston that divides the cylinder tube into two working spaces, and a piston rod connected to the piston. Two fluid leadthroughs in the piston may connect the two working spaces. Valve assemblies for damping piston movement in actuating directions may be arranged on the leadthroughs. Each valve assembly may have a pilot control chamber and a valve plate movable between open and closed positions. The valve plate can be prestressed into the closed position by pressure loading the pilot control chamber. Pressures in the pilot control chambers can be set by a pilot control valve having a valve body that is movable between open and closed positions. An outflow cross section between the pilot control chambers and the working spaces is settable. First and second outflow paths may adjoin the valve body on the outflow side, the first outflow path being closed when an actuator for actuating the position of the valve body is inactive. A closing element separate from the valve body may be provided for closing the first outflow path.