Valves and valve actuation – Electrically actuated valve – Including solenoid
Reexamination Certificate
2000-04-17
2001-10-23
Kaufman, Joseph A. (Department: 3754)
Valves and valve actuation
Electrically actuated valve
Including solenoid
C251S331000, C251S362000
Reexamination Certificate
active
06305664
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of Invention
This invention relates generally to a fluid control valve and, more particularly, to a proportional variable bleed solenoid valve that includes a working air gap adjustment feature to provide magnetic calibration.
2. Discussion of the Related Art
Most vehicles generally incorporate a large number of electronically controlled systems, such as an automatic transmission controller. Automatic transmission controllers typically include several solenoid operated fluid control valves that independently act to control fluid pressure in the vehicle's transmission to operate various components of the transmission. For example, solenoid operated fluid control valves are known that use transmission fluid pressure to engage and disengage the transmission clutch. One particular known solenoid valve used for this purpose is referred to as a proportional bleed solenoid valve. The proportional bleed solenoid valve provides a particular control pressure that is directly proportional to the current applied to the solenoid coil in the valve. In other words, the output control pressure is nearly linear to the current applied to the solenoid coil. These types of solenoid valves are referred to as bleed valves because they use a relatively low flow of fluid through the hydraulic portion of the valve. Solenoid operated fluid control valves are also used in other vehicle controllers besides transmission controllers.
As the controllers become more sophisticated, it is necessary that the solenoid operated fluid control valves also include advancements and improvements over the state of the art. In this regard, it becomes important to increase the operating efficiency, reduce the cost, reduce the weight, reduce the complexity, etc. of the existing solenoid operated fluid control valves. Therefore, advancements in size, part reduction, component simplification, etc. of the control valves is advantageous.
One area of improvement for proportional valves is providing a consistent control pressure. Because the component tolerances in the control valves may vary from valve to valve, the control pressure may also vary from valve to valve at the same coil current. This may be important for modern automatic transmission controllers that need to provide a consistent control pressure for a particular operation. Therefore, it is important to provide some kind of calibration of the valve at the manufacturing level of the valve so that the valve control is consistent. One area where the control pressure of a proportional solenoid valve can be calibrated is the magnetic force adjustment, where an armature position driven by the coil of the solenoid can be calibrated.
U.S. Pat. No. 5,218,999 issued Jun. 15, 1993 to Tanimoto discloses a solenoid valve that provides a mechanical adjustment of the air gap between an armature and a pole piece so the gap is consistent from valve to valve to provide a constant performance. To provide the mechanical adjustment, an elastic wave washer is interposed between the pole piece and the casing of the valve. When a lid member is fixedly attached to the casing, the wave washer is compressed to a degree depending on the dimensions of the pole piece, the coil bobbin, and a magnetic holder to set the air gap at a constant dimension.
Although the solenoid valve described in the '999 patent offers one technique for adjusting the air gap between the armature and the pole piece to provide magnetic calibration, this technique is also susceptible to the tolerances of the elastic washer, as well as including other disadvantages. Therefore, there is still room for improvement in solenoid valves to provide a magnetic force adjustment for magnetic calibration.
SUMMARY OF THE INVENTION
In accordance with the teachings of the present invention, a proportional variable bleed solenoid valve is disclosed that includes a mechanism for magnetic force adjustments to provide magnetic calibration. The control valve includes a housing or can defining a chamber, where an electromagnetic coil is wound on a bobbin and is coaxially mounted within the housing. A movable armature is coaxially positioned within the bobbin in the chamber and has an armature poppet valve extending from a bottom end of the armature. An armature spring is in contact with an upper end of the armature and a top wall of the bobbin, where the spring positions the armature in an initial position when the coil is not energized. A pole piece is mounted to the housing and is positioned adjacent to the lower end of the armature to define an air gap between the pole piece and the armature. The pole piece includes a flux shunt portion that is an extended annular ring positioned below the lower end of the armature such that the armature poppet valve extends through the flux shunt ring. A mounting bracket is secured to the housing adjacent to the pole piece and a valve sleeve is connected to the mounting bracket. The valve sleeve includes a central bore axially aligned with the armature. A control ball is positioned in the bore adjacent to a bottom seal surface of the poppet valve. When the coil is energized, the poppet valve is forced against the control ball and the control ball is forced against a valve seat surface to seal off an exhaust port so that a supply pressure orifice in fluid communication with the bore of the valve sleeve provides a control pressure at a control pressure opening in the valve sleeve.
In order to provide magnetic force adjustments for magnetic calibration, the valve sleeve is selectively positionable relative to the bracket so that the distance between the armature poppet valve and the seat surface is adjustable. In one particular embodiment, the valve sleeve is secured to the bracket by a threaded connection so that its position can be readily changed.
Additional objects, advantages and features of the present invention will become apparent from the following description and appended claims, taken in conjunction with the accompanying drawings.
REFERENCES:
patent: 4411289 (1983-10-01), Walters
patent: 4532951 (1985-08-01), Fermanich
patent: 4662605 (1987-05-01), Garcia
patent: 5051631 (1991-09-01), Anderson
patent: 5069420 (1991-12-01), Stobbs et al.
patent: 5127624 (1992-07-01), Domke
patent: 5218999 (1993-06-01), Tanimoto
patent: 5289841 (1994-03-01), Maranzano
patent: 5301921 (1994-04-01), Kumar
patent: 5307774 (1994-05-01), Hammer
patent: 5617890 (1997-04-01), Brehm et al.
patent: 5707039 (1998-01-01), Hamilton et al.
patent: A12041593 (1991-05-01), None
Holmes Garrett R.
McKenna Michael D.
Bonderer David A.
Borg-Warner Inc.
Dziegielewski Greg
Kaufman Joseph A.
Warn, Burgess & Hoffmann, P.C.
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