Fluid handling – Systems – Multi-way valve unit
Patent
1995-03-02
1997-02-25
Michalsky, Gerald A.
Fluid handling
Systems
Multi-way valve unit
25112915, F15B 13044
Patent
active
056051786
DESCRIPTION:
BRIEF SUMMARY
This invention relates to an hydraulic control valve, wherein the spool is driven by a linear force motor. The valve is for controlling the flow of hydraulic fluid, particularly for use in electronically controlled suspensions and gearboxes on motor vehicles.
Hydraulic control valves for motion control are typically used for the control of an actuator in two directions, and with a requirement for a neutral or null position to hold the actuator in a specific position. Conventionally the valve is designed such that the neutral position is between the two positions used for the control of motion, and that the spool of the valve returns to that position when there is no electrical power. The use of a linear force motor to drive the spool provides this configuration, and uses one set of windings to provide the two directions of movement. In order to maintain a satisfactory level of cleanliness in the armature chamber, typically seals are provided in the valve body around the spool, in order to prevent the ingress of debris (particularly magnetic debris) into the armature chamber. The provision of such seals increases the friction when the spool moves, to the detriment of the valve performance.
In the valve described in EP-A-0157630 a magnetic pin is disposed at the entry to the armature chamber to collect magnetic debris in fluid. This adds to the expense of the valve, does not provide a particular large magnetic surface area for attracting magnetic debris and if the magnetic debris escape there is no second chance.
We have now devised a valve for controlling the flow of hydraulic fluid (which valve is hereinafter referred to for convenience as a "linear motor valve") which is less susceptible to the ingress of foreign debris, which has fewer components and tends to have a smaller envelope size than the aforementioned conventional such valves.
According to the present invention, there is provided a linear motor valve adapted to be controlled by a reversible electrical current comprising a valve body defining a valve chamber, an armature defining a magnetic bore disposed in the valve chamber, a valve spool extending into the bore, a stator which is rigidly mechanically linked to but not in magnetic connection with the valve body, characterised in that the spool and armature are arranged so that only a minor part of flow through the valve enters the chamber containing the armature and that minor is in fluid flow connection with the bore of the armature whereby magnetic debris in that minor part is retained in the magnetic bore.
In the linear motor valve according to the present invention substantially the only fluid flow into the armature chamber is that due to spool leakage, and typically this leakage would not be more than 2% of the full flow of the valve. The leakage from the spool is directed towards a midpoint within the armature bore, thereby positioning the fluid such that it has to pass through the magnetic field of the armature before it can reach either end of the armature. It will be appreciated that the fluid within the armature will reciprocate from end to end of the chamber as the valve operates, and that during each reciprocal movement the said fluid will be subjected to the magnetic force within the armature. By this means the fluid within the armature chamber will achieve a high level of cleanliness from magnetic debris. The magnetic debris will be retained within the bore of the armature, thereby precluding its movement to other parts of the hydraulic circuit in which the linear motor valve is used. The adjustment mechanism, to position the spool in relation to the valve body to give the required characteristics in null, is designed and positioned such that there is still free flow of fluid between the two ends of the armature, whilst utilising a design of adjustment mechanism that provides fine control, and is clear of the part that directs the leakage from the spool towards a mid-point within the armature bore, as aforementioned.
While we do not exclude the possibility that the electrical curr
REFERENCES:
patent: 4140152 (1979-02-01), Budzich
patent: 4525695 (1985-06-01), Sheng et al.
patent: 4635683 (1987-01-01), Nielsen
patent: 4655254 (1987-04-01), Hafner et al.
patent: 4664136 (1987-05-01), Everett
patent: 4744389 (1988-05-01), Ichihashi
patent: 4809749 (1989-03-01), Ichihashi
patent: 4947893 (1990-08-01), Miller et al.
patent: 5036885 (1991-08-01), Miura
patent: 5156184 (1992-10-01), Kolchinsky
patent: 5249603 (1993-10-01), Byers
Electro Hydraulic Technology Limited
Michalsky Gerald A.
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