Pressure Control Valve Compensating Chamber
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Solution Overview
Problem
In automatic transmissions, hydraulically actuated pressure control valves face issues with dirt particles, particularly ferromagnetic particles, affecting the axial movement and electromagnetic actuation of the control piston, leading to functional impairments.
Innovation Solution
A pressure control valve design featuring a magnet chamber hydraulically connected to a compensating chamber via a compensating channel, which allows particles to settle and adhere to the magnetized inner wall, combined with a multi-part housing configuration and a ventilating compensating channel to prevent 'pumping' and ensure undamped movement of the control piston.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the control piston is directly exposed to hydraulic oil in the oil sump, then the pressure control valve can be installed in the hydraulic oil reservoir, but ferromagnetic particles and dirt accumulate in the magnetic pole area, adversely affecting guidance and electromagnetic actuation
Solution Approach 1:
The patent divides the hydraulic system into separate zones: a clean magnet chamber housing the electromagnetic actuator and pole tube, and a dirty compensating chamber exposed to the oil sump. This segmentation isolates the sensitive magnetic components from ferromagnetic particles while maintaining pressure control functionality through the control piston that operates at the interface between these zones.
Solution Approach 2:
The control piston acts as an intermediary element between the clean magnet chamber and the dirty compensating chamber. It transmits electromagnetic force from the protected magnetic components to the hydraulic system while being exposed to particles on its rod side, thus shielding the magnetic poles from contamination.
2Manufacturing precision
If the control piston moves axially to regulate pressure, then pressure control is achieved, but pumping of hydraulic oil occurs through the control piston, causing damped movement
Solution Approach 1:
The control piston serves as a mediator that separates the magnetic force transmission function from the hydraulic pressure control function. By positioning the magnetic poles in the clean magnet chamber and allowing only the control piston rod to extend into the compensating chamber, the system achieves undamped movement while maintaining precise pressure regulation.
3Object-affected harmful factors
If a sealing arrangement is provided between the magnet chamber and compensating chamber, then dirt entry is minimized, but the control piston cannot perform axial movement for pressure regulation
Solution Approach 1:
The patent segments the sealing arrangement into two distinct interfaces: a dynamic seal around the control piston rod where controlled leakage is permitted to enable movement, and static seals at the magnet chamber boundary that prevent particle ingress. This segmentation allows simultaneous achievement of contamination protection and operational mobility.
Solution Approach 2:
Different sealing qualities are applied to different locations: the seal at the control piston rod interface is designed with local quality characteristics that permit minimal leakage for movement freedom, while seals at the magnet chamber boundaries have different local quality characteristics optimized for contamination exclusion.
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 prevents dirt particles from impacting the pressure control valve's function, ensuring a largely undamped movement of the control piston and maintaining the pressure control function by filtering out particles and ventilating the magnet chamber, thus reducing the risk of 'pumping' and maintaining operational precision.
Implementation Method 1
a control piston (40) situated in a housing (28) and actuatable by an armature (78) situated in a magnet chamber (76) of a pole tube (72)
Implementation Method 2
ferromagnetic particles may adhere in the area of the magnetized inner wall of the housing
Implementation Method 3
the magnet chamber is hydraulically connected via a compensating channel to a compensating chamber in the housing
Implementation Method 4
particles are able to settle due to gravity
Data Source
AI summary
A pressure control valve, in particular for an automatic transmission in a motor vehicle, including a housing and including a control piston situated in the housing, the control piston being actuatable by an armature situated in a magnet chamber of a pole tube, the magnet chamber being hydraulically connected to a compensating chamber provided in the housing, which is delimited, in particular by a lateral surface of a solenoid coil and the housing.