Electromagnetically energized actuator
a technology of actuators and actuators, applied in the direction of valve details, valve operating means/release devices, non-fuel substance addition to fuel, etc., can solve the problems of wide tolerances, adversely affecting the over-all reliability of pneumatic valves, and reducing durability, etc., to achieve low friction, low impact, and low wear
Inactive Publication Date: 2005-03-03
DELPHI TECH INC
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Benefits of technology
The present invention is an improved electromagnetically energized actuator featuring low friction, low wear, low impact and low noise attributes.
The tube is composed of a polymer which (relative to a conventional brass tube) allows tighter tolerances between the plunger and the tube resulting in lower wear, less sliding noise, reduction in corrosion, and elimination of thinned end of the tube. The preferred tube polymer is VESPEL® (a polyimide material) with TEFLON® (a fluoropolymer resin material) mixture (most preferred), or VESPEL, both are trademarks of and available through The DuPont Company of Wilmington, Del. 19880. These polymers have very good mechanical and chemical properties, including a favorable wear rate and thermal coefficient of expansion, as detailed in “Using Advanced Materials to Improve Automotive Part Life by Richard Van Ryper, The DuPont Company, August, 1996, hereby incorporated herein by reference. For example, an advantage of these polymers, particularly the VESPEL with TELFLON mixture, is self lubrication which tends to protect the plunger in such a manner that the existing plunger coating material could be changed to nickel resulting in tighter tolerances capability, lower friction forces resulting in less plunger wear and higher corrosion resistance, with the attendant advantage of long term failure-free performance. The reduced clearance between the tube and the plunger also improves alignment of the plunger with the valve seat, reducing wear and noise.
The polymer tube is partly received into a recess formed at an opening of the first plate, wherein the non-recessed portion of the opening is proximally spaced from the plunger when it is located at its first position. Because of the recess, a compound secondary air gap is thus formed at the opening, including a first gap component at the non-recessed portion of the opening across a small spacing separating the first plate from the plunger, and a second gap component between the first plate and the plunger at the recess portion of the opening across the thickness of the sidewall of the tube. At the first position, the magnetic energy through the plunger is large when the solenoid is energized, thereby delivering an initially high magnetic force on the plunger to overcome the spring biasing. However, as the plunger moves toward the stop, the area of the plunger proximate the first plate at the compound secondary air gap becomes smaller, whereupon the reluctance of the magnetic circuit increases at the compound secondary air gap even as the reluctance between the plunger and the stop at the primary air gap is rapidly decreasing as the plunger comes into proximity with the stop. The moderation of the magnetic circuit reluctance keeps the magnetic energy from increasing rapidly and thereby dampens the plunger impact at the stop, for example by 35% over the conventional electromagnetically energized actuator shown at FIG. 2. This also has the benefit that duty cycles of the solenoid energization will be more efficient: more magnetic force initially will ensure a rapid, firm start of reciprocation of the plunger when at the first position, whereas as the magnetic circuit energy dissipates with increasing secondary air gap reluctance as the plunger reaches the second position. Accordingly, the spring response time is improved, whereby the plunger is returned more quickly upon de-energization of the solenoid.
Accordingly, it is an object of the present invention to provide an electomagnetically energized actuator featuring low friction, low wear, low impact and low noise attributes.
Problems solved by technology
As plunger moves back and forth (reciprocates) while operating, two main problems emerge.
This wear leads to reduced durability and adversely affects the over-all reliability of the pneumatic valve.
However, this is an extra manufacturing step which does not eliminate the problem.
The second problem relates to plunger impact.
This impacting results in undesirable noise generation and undesirable wear when the plunger hits the valve seat and the stop.
Related to this problem is the excessive amount of magnetic energy stored in the solenoid.
Method used
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Referring now to the Drawing, FIGS. 3 through 6 depict an example of an electromagnetically energized actuator 100 according to the present invention. The electromagnetically energized actuator 100 may, for example, be used in a pneumatic valve as depicted at FIGS. 1 and 1A in substitution for the conventional electromagnetically energized actuator thereof (as also shown at FIG. 2), or may be used in other device applications.
The electromagnetically energized actuator 100 includes a plunger 102, a stop 104, a first plate 106 having a first plate opening 106a, a second plate 108 having a second plate opening 108a, and a polymer tube 110 extending between the first and second plate openings and into which is reciprocally situated the plunger and stationarily situated the stop. The plunger 102, the stop 104, the first plate 106 and the second plate 108 are each composed of highly permeable material (i.e., ferromagnetic material). The plunger 102 and the stop 104 are preferably of cy...
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An electromagnetically energized actuator featuring low friction, low wear, low impact and low noise attributes. The actuator includes a polymer tube, a stop fixedly disposed in the tube and composed of a highly permeable material, a plunger reciprocably disposed within the tube and composed of a highly permeable material, a spring assembly including a spring which is formed at the facing ends the stop and the plunger which spring serves to bias the plunger away from the stop, a first plate composed of a highly permeable material which is connected to a first end of the tube, and a second plate composed of a highly permeable material which is connected to a second end of the tube. The tube is composed of a polymer which (relative to a conventional brass tube) allows tighter tolerances between the plunger and the tube resulting in lower wear, less sliding noise, reduction in corrosion, and elimination of thinned end of the tube. The preferred tube polymer is VESPEL® with TEFLON® mixture.
Description
TECHNICAL FIELD The present invention relates to electromagnetically energized actuators, and more particularly to an electromagnetically energized actuator configured for minimization of plunger friction and plunger impact. BACKGROUND OF THE INVENTION A conventional pneumatic valve 10 is depicted at FIGS. 1 through 2 in which an electromagnetically energized actuator used to control flow of fuel vapors from a canister to the engine intake manifold. The conventional pneumatic valve 10 includes a housing 12, an electromagnet assembly 14 which includes a solenoid 14a wound on a spool 14b, a brass tube 16 concentrically disposed relative to the spool, a stop 18 fixedly disposed in the tube and composed of a highly permeable material, a plunger 20 reciprocally disposed within the tube and composed of a highly permeable material, a spring 22 of a spring assembly 24 formed at the facing ends 18f, 20f of the stop and the plunger which biases the plunger away from the stop, and a valve se...
Claims
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IPC IPC(8): F02M25/08F16K31/06
CPCF02M25/0836F16K31/0686F16K31/0658F02M2025/0845
InventorBURROLA, SANTOSPELKA, JEAN-FRANCOISRAD, MAHMOOD
OwnerDELPHI TECH INC