Normally rising variable force solenoid

Details Normally rising variable force solenoid Normally rising variable force solenoid

2000-04-25

2001-08-21

Lee, Kevin (Department: 3753)

Valves and valve actuation

Electrically actuated valve

With means to bias valve open

C251S129170, C335S237000, C335S279000

Reexamination Certificate

active

06276663

ABSTRACT:

BACKGROUND
This disclosure relates generally to a solenoid in a hydraulic pressure management system, and more particularly, to a normally rising variable force solenoid interfaced between the electronic logic and hydraulic fluid controls of such a system.
Solenoids have been used to provide hydraulic pressure management in situations where hydraulic output pressure must be independent of hydraulic supply pressure. Output pressure is proportional to the closing force of the solenoid. If the closing force can be varied, the solenoid is said to be a variable force solenoid, and if output pressure increases proportionally with applied closing force, the solenoid is said to be normally rising.
Some previous solenoid designs included springs, either as a closing force or as balance springs in combination with another closing force. However, springs are undesirable for several reasons, for example, decreased performance with wear. Moreover, decreasing the number of components to facilitate manufacture is a major concern in the industry.
One type of closing force used presently is magnetic flux applied to actuate an armature. The magnetic flux is produced by application of an electrical input current to a coil. However, the performance of these solenoids are often negatively impacted by hysteresis, a lagging in the values of resulting magnetization in a magnetic material due to a changing magnetizing force. In practical terms, hysteresis makes the solenoid less responsive to opening or closing commands by resisting movement of the armature. Furthermore, solenoids of this type must be calibrated to provide a predetermined output pressure. In the past, calibration has been a relatively arduous undertaking.
Therefore, what is needed is a normally rising variable force solenoid that is easily calibrated, and has relatively fewer components while minimizing hysteresis.
SUMMARY
Accordingly, an embodiment of the present invention provides a variable force solenoid for controlling the flow of a fluid in a housing having a bore for receiving the fluid flow, at least one port for exhausting the fluid flow, and a seat extending between the port and the bore. The solenoid includes a valve member disposed in the housing. In a closed position, the valve member is engaged with the seat, preventing fluid flow from the bore to the port. In an open position, the valve member is not engaged with the seat, allowing fluid flow from the bore to the port. A subassembly is disposed in the housing and surrounds a portion of the valve member for moving the valve member to its closed position. The subassembly has a movable armature for engaging the valve member, an annular member for attracting the armature, and a gap defined between the armature and the annular member. The gap is maintained by engagement of the armature by the valve member. A coil is disposed in the housing radially outward from the subassembly. Reception of electric current by the coil produces magnetic flux, thereby attracting the armature to the annular member, and thus moving the valve member to the closed position.
One advantage of the embodiments described herein is that hysteresis is minimized by creating a gap between the armature and the annular member. Another advantage of the embodiments is that the subassembly greatly simplifies calibration, as the subassembly is adjusted as a singular component, providing more consistent and accurate output pressure. Yet another advantage is that fewer components are used when compared to previous designs.


REFERENCES:
patent: 2911183 (1959-11-01), Matthews et al.
patent: 4556085 (1985-12-01), Warrick
patent: 4570904 (1986-02-01), Mullally
patent: 4595035 (1986-06-01), Warrick
patent: 4617961 (1986-10-01), Lichtenberg
patent: 4617968 (1986-10-01), Hendrixon
patent: 4674536 (1987-06-01), Warrick
patent: 4753263 (1988-06-01), Warrick
patent: 4863142 (1989-09-01), Hendrixon et al.
patent: 4932630 (1990-06-01), Kumar et al.
patent: 4951703 (1990-08-01), Brehm et al.
patent: 4989564 (1991-02-01), Cook et al.
patent: 5000420 (1991-03-01), Hendrixon et al.
patent: 5000421 (1991-03-01), Hendrixon et al.
patent: 5050840 (1991-09-01), Kondo et al.
patent: 5051631 (1991-09-01), Anderson
patent: 5075584 (1991-12-01), Hendrixon et al.
patent: 5076323 (1991-12-01), Schudt
patent: 5110087 (1992-05-01), Studtmann et al.
patent: 5467962 (1995-11-01), Bircann et al.
patent: 5593132 (1997-01-01), Hrytzak
patent: 5685519 (1997-11-01), Bircann et al.

Affiliated with

Also associated with

Rating

Normally rising variable force solenoid does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Normally rising variable force solenoid, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Normally rising variable force solenoid will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2490956