GB2383195A

GB2383195A - Solenoid actuated valve

Info

Publication number: GB2383195A
Application number: GB0227498A
Authority: GB
Inventors: Michel Marechal; Christophe Cardon
Original assignee: Delphi Technologies Inc
Current assignee: Delphi Technologies Inc
Priority date: 2001-12-14
Filing date: 2002-11-26
Publication date: 2003-06-18
Also published as: GB0227498D0; GB0129821D0

Abstract

A solenoid actuated valve (10) in accordance with the present invention comprises a housing (12); an electrical solenoid (20) positioned inside the housing and having an annular configuration; a magnetic plunger (24) positioned at least partially inside the solenoid and capable of sliding movement in an axial direction (A) relative to the solenoid; a push rod (30) secured to the plunger; and a valve member secured to the push rod; wherein the solenoid comprises two or more coils (32) which have the same number of turns, and which are electrically connected in parallel. Allows the valve size to decrease without decreasing valve performance.

Description

SOLENOID ACTUATED VALVE Technical Field The present invention relates to a solenoid actuated valve, and in particular to a solenoid actuated hydraulic valve.

Background of the Invention It is known to provide a solenoid actuated valve in which the solenoid coil consists of a predetermined number of turns. Such a solenoid has limitations in terms of size and packaging.

Summary of the Invention The present invention aims to overcome the above mentioned problem.

A solenoid actuated valve in accordance with the present invention comprises a housing; an electrical solenoid positioned inside the housing and having an annular configuration; a magnetic plunger positioned at least partially inside the solenoid and capable of sliding movement in an axial direction relative to the solenoid; a push rod secured to the plunger; and a valve member secured to the push rod; wherein the solenoid comprises two or more coils which have the same number of turns, and which are electrically connected in parallel.

The present invention replaces a solenoid made of N turns by a solenoid made of X coils, each of N/X turns, connected in parallel. This allows the overall size of the coil to be decreased without decreasing the performance of the valve. Also, using X coils with the same number of turns connected in parallel leads to a decrease in the electrical resistance of the solenoid (the new resistance is equal to the initial resistance divided by the square of the number of windings). This allows the use of a smaller wire diameter (which is better for packaging) even when the power supply (battery) delivers a low tension.

The design of a solenoid is limited by the maximum electrical resistance Rmax of the wire. Rmax is defined by the minimum supply voltage Vmm and the maximum supply current Iman.

Rmax imposes the use of a wire with the following minimum cross-section Smm

where Rho is the copper resistivity, and L is the wire length.

Smm leads to a minimum solenoid size. The present invention allows a reduction in the solenoid size.

If X coils (with N/X turns) are connected in parallel, a new resistance R'max can be calculated

It is now possible to use a smaller wire cross-section and then have a solenoid with a smaller dimension to generate the same magnetic force.

For example, for a solenoid having one winding, R = 3 ohms, Imax = 3 amps, then the required tension is Vmm = 9 volts. For a solenoid in accordance with the present invention having three coils each of 1 ohm resistance, R'= 0.33 ohms, I'max = 3x3 = 9 amps (same magnetic force), then the minimum required tension is 0.33 x 9 = 3 volts.

It is therefore possible to have a higher wire resistance, with a smaller wire diameter, which leads to a smaller packaging for the same efficiency.

The present invention has particular application in a motor vehicle, for example, for creating a magnetic force for piloting hydraulic valves of a vehicle roll control system.

Brief Description of the Drawings The present invention will now be described, by way of example, with reference to the accompanying drawings, in which :- Figure 1 is a cross-sectional view of a solenoid actuated valve in accordance with the present invention.

Description of the Preferred Embodiment Referring to the drawing, the solenoid actuated valve 10 in accordance with the present invention includes a housing 12 (preferably formed from magnetic material) which is substantially cup-shaped with an open end 14 and an integral intumed lip 16 at the other end. The intumed lip 16 defines an opening 18. Secured inside the housing 12 is a solenoid 20 (described in more detail below). The solenoid 20 is substantially annular and is secured between the intumed lip 16 and a washer 22 secured in the open end 14 of the housing 12. A magnetic plunger 24 is positioned inside the solenoid 20 and is capable of movement in an axial direction A relative to the solenoid. The plunger 24 is covered by a cup-shaped magnetic casing 26 and an annular non-magnetic casing 28. The non-magnetic casing 28 is located adjacent the solenoid 20. The magnetic casing 26 extends through the opening 18 defined by the intumed lip 16 of the housing 12. A push rod 30 is secured to the plunger 24 and extends through the open end 14 of the housing 12. A valve member (not shown) is attached to the push rod 30 which opens and closes the valve 10 on actuation of the solenoid 20.

The solenoid 20 comprises a number of coils 32 which are wound on a common spool 34. In this embodiment, three coils 32 are provided, but any number of (two or more) coils may be provided in accordance with the present invention. The coils 32 are substantially identical and each have the

same number of turns. The coils 32 are electrically connected in parallel. Electrical power for the coils 32 is supplied by a power source (not shown) by way of wire guides 36 formed in the intumed lip 16 of the housing 12.

Claims

1. A solenoid actuated valve comprising a housing; an electrical solenoid positioned inside the housing and having an annular configuration; a magnetic plunger positioned at least partially inside the solenoid and capable of sliding movement in an axial direction relative to the solenoid; a push rod secured to the plunger; and a valve member secured to the push rod; wherein the solenoid comprises two or more coils which have the same number of turns, and which are electrically connected in parallel.

2. A solenoid actuated valve as claimed in Claim 1, wherein the solenoid comprises three coils.

3. A solenoid actuated valve as claimed in Claim 1 or Claim 2, wherein the coils are wound on a common spool.

4. A solenoid actuated valve as claimed in any one of Claims 1 to 3, wherein the magnetic plunger has a cup-shaped magnetic casing which is positioned outside of the coils; and an annular non-magnetic casing which is positioned adjacent the coils.

5. A solenoid actuated valve as claimed in any one of Claims 1 to 4, wherein the solenoid is secured between an intumed lip of the housing, and a washer secured in one end of the housing.

6. A solenoid actuated valve substantially as herein described with reference to, and as shown in, the accompanying drawing.