WO2018034648A1

WO2018034648A1 - Unitary solenoid fluxcore

Info

Publication number: WO2018034648A1
Application number: PCT/US2016/047044
Authority: WO
Inventors: Garrett R. Holmes; Ken Morgan; Jerome Fisher; Steven J. Roskowski
Original assignee: Borgwarner Inc.
Priority date: 2016-08-15
Filing date: 2016-08-15
Publication date: 2018-02-22

Abstract

A solenoid actuator (20) includes an armature (24) movable within a flux core bore (42) of a unitary flux core (30); a housing (22) electrically communicating magnetic flux through the armature (24); and a unitary flux core (30), which includes a mandrel portion (34) for receiving a bobbin (26) that supports a coil (28) carrying electrical current from an electrical connector (32); an upper annular shoulder (36) at one end of the mandrel portion (34); and a lower annular shoulder (38) at another end of the mandrel portion (34). The unitary flux core (30) is constructed as a single component.

Description

UNITARY SOLENOID FLUXCORE

TECHNICAL FIELD

[001] The present application relates to solenoid actuators and, more particularly, to flux core design within solenoid actuators.

BACKGROUND

[002] Solenoid actuators are used to control physical elements in a variety of systems. These physical elements could be the control of fluid or the actuation of a mechanical switch, for example. The solenoids use the selective application of electrical current to bias an armature of the solenoid from a resting position to an extended position. The electrical current flows through a coil of wire that surrounds a multi-component core and, based on the principles of induction, moves the armature in a desired direction. The solenoid can actuate valves in many different environments. For example, hydraulic solenoid valves can regulate the flow of fluid in a vehicle transmission, while other solenoid valves can be used to open and close valves to the combustion chamber of a vehicle engine. As components within a vehicle— including engines— become increasingly compact, the solenoids used within a vehicle have become increasingly compact as well. Despite this reduction in size, the solenoids are asked to produce the same amount of force— if not more— than they did when implemented in a larger package.

SUMMARY

[003] In one embodiment, a unitary flux core of a solenoid includes a mandrel portion for receiving a bobbin that supports a coil carrying electrical current from an electrical connector! an upper annular shoulder at one end of the mandrel portion,' and a lower annular shoulder at another end of the mandrel portion. The unitary flux core is constructed as a single component.

[004] In another embodiment, a control valve includes a solenoid portion and a hydraulic portion. The solenoid portion includes a unitary flux core constructed as a single component having a flux core bore that receives an armature; a bobbin supported by the unitary flux core carrying a coil through which electrical current flows; and the armature that is slidably received in the flux core bore moving axially in response to the application of current and opposably biased by a solenoid spring. The hydraulic portion includes a valve actuated by the solenoid portion.

BRIEF DESCRIPTION OF THE DRAWINGS

[005] Figure 1 depicts a cross sectional view of an embodiment of a control valve and a solenoid;

[006] Figure 2 depicts a cross sectional view of an embodiment of a unitary flux core used in the solenoid.^"

[007] Figure 3 depicts a perspective view of an embodiment of a bobbin used with a unitary flux core;

[008] Figure 4 depicts a perspective view of an embodiment of a bobbin and a unitary flux core,^' and

[009] Figure 5 a perspective view of an embodiment of a bobbin assembled with a unitary flux core.

DETAILED DESCRIPTION

[010] A reduction in solenoid size along with a desire to maintain or even increase the force the solenoid generates creates a need for more efficient components within the solenoid. The flux core of the solenoid is one of those components that can benefit from increased efficiency. In the past, the flux core has been assembled from a plurality of components that are joined together. The bobbin of the solenoid has been a unitary structure that is generally annularly shaped and receives a coil of wire on an exterior annular surface. A multi-piece flux core would then be axially inserted into an opening in the unitary bobbin as separate components. One component of the flux core, a pull piece, is inserted into one side of the bobbin opening and another piece of the flux core, a flux tube or flux core, is inserted in an opposite side of the bobbin opening such that the components of the flux core are concentrically positioned with respect to the bobbin, contact an inner annular surface of the bobbin, and connect with each other after insertion. This can present a number of problems. First, the area(s) of the flux core where the components join can create undesirable magnetic force output variation. The joint areas where the components meet can create a weakened magnetic force or a magnetic force exerting away from a desired direction. That is, the magnetic properties of a multi— piece flux core may not be uniform or easily predictable where its components meet or join. Second, the area where components of a multi-piece flux core join creates a crevice where magnetic debris, such as ferritic micropowder, can lodge itself during solenoid operation. Often, solenoids are used in engines and transmissions where friction between moving metal parts may occasionally create a metallic byproduct (e.g., the ferritic micropowder) that circulates in a lubrication medium contacting both the internal components of the engines/transmissions as well as solenoid components.

[011] A unitary flux core can provide a more efficient solenoid component comprising a smaller structure while minimizing undesirable magnetic force output variation and unwanted crevices. Unlike the multi-piece flux core described above, the unitary flux core can be constructed from one material, such as bar stock metal. Rather than fitting the multi-piece flux core into a unitary bobbin, a multi-piece bobbin can be formed around the unitary flux core. By forming the flux core without joints or crevices, the unitary flux core can eliminate variations in magnetic force and direction. And the lack of joint(s) can also eliminate locations that attract magnetic debris, which could alter the magnetic force generated by the solenoid.

[012] Turning to Figure 1, there is shown an exemplary embodiment of a control valve 10 using a solenoid actuator having a unitary flux core. The control valve 10 includes two portions, a solenoid portion 20 and a hydraulic portion 60, that can be physically joined together in an coaxial relationship. The solenoid portion 20 comprises a housing 22, an armature assembly 24, a bobbin 26, a coil 28, a unitary flux core 30, and an electrical receptacle 32 for electiically communicating current to the coil 28.

[0 3] The unitary flux core 30, also referred to as a monocore, can include an annularly shaped mandrel portion 34 as well as an upper annular shoulder 36 and a lower annular shoulder 38 that are each a larger diameter than the mandrel portion 34. The mandrel portion 34 can include a flux choke 40 having a smaller diameter than other sections of the mandrel portion 34. The unitary flux core 30 also includes a flux core bore 42 that provides an opening passing through the upper annular shoulder 36 and the lower annular shoulder 38. One end of the unitary flux core 30 can be referred to as a pole attraction portion 44 through which magnetic force flows and attracts the armature assembly 24. Another end of the unitary flux core 30 can be referred to the flux return portion 46 that returns the flow of magnetic flux to the armature assembly 24.

[014] The armature assembly 24 can be made of a ferric material and slidably located within the flux core bore 42 of the unitary flux core 30. The flux core bore 42 receives the armature assembly 24 such that the assembly 24 is located concentrically within the bore 42 and can move in a coaxial relationship with respect to the unitary flux core 30 when current is applied to the coil 28. The armature assembly 24 can include an armature 48 and a pushrod 50 that are fit together. The armature assembly 24 and collectively receives electrically- created magnetic flux and acts on an element to be controlled.

[015] The bobbin 26 can also be annularly shaped and sized so that it has a larger diameter than an outer diameter 52 of the mandrel portion 34 of the unitary flux core 30 and able to at least substantially cover an outside surface of the mandrel portion 34. The bobbin 26 can have a length allowing the bobbin 26 to fit between the upper annular shoulder 36 and lower annular shoulder 38 of the unitary flux core 30. It is also possible for the bobbin 26 to include an upper annular bobbin shoulder 54 and a lower annular bobbin shoulder 56 that each abuts the upper annular shoulder 36 and lower annular shoulder 38, respectively. The coil 28 can then be wound around an outside surface of the bobbin 26 such that it surrounds the mandrel portion 34 and the flux core bore 42. The housing 22 can enclose the coil 28 and unitary flux core 30 as well as support the electrical receptacle 32. In this implementation, the housing 22 can conduct electrical flux to and from the unitary flux core 30 as part of a flux circuit. [016] The hydraulic portion 60 comprises a valve sleeve 62 that includes a plurality of apertures 64, a hydraulic bore 66, and a spring 68. The hydraulic bore 66 can be closed on one end by a cap 70 that attaches to the hydraulic bore 66 and slidably receives a valve 72 that moves axially to open and close the apertures 64. The valve 72 includes an annularly recessed portion 74 along one or more sections of the length of the valve 72 that has a reduced diameter. The spring 68 can be positioned in the hydraulic bore 66 in between the valve 72 and the cap 70. In the absence of current through the coil 28, the spring 68 can bias the valve 72 into a first position when an outer surface 76 of the valve 72 blocks the flow of fluid through one or more apertures 64. When current flows through the coil 28, the armature assembly 24 moves toward the cap 70 into a second position compressing the spring 68 and positioning the valve 72 coaxially with respect to the hydraulic bore 66 so that the outer surface 76 of the valve 72 no longer blocks passage through one or more of the aperture(s) 64. The apertures 64 are instead then aligned with the annularly recessed portion 74 such that the valve 72 no longer blocks the flow of fluid through the aperture(s) 64. The valve 72 moves in concert with the armature assembly 24 in response to the selective application of current to the coil 28 and force from the hydraulic spring 68. The apertures 64 can be isolated from each other during operation via an overmold 78 and a plurality of Orings 80.

[017] The magnetic flux circuit flowing through the armature assembly

24, the unitary flux core 30, and the housing 22 is shown using arrows identified by the symbol <j>. As electrical current flows from the electrical receptacle 34 through the coil 28, magnetic flux flows through the magnetic flux circuit φ. The arrows identify a path followed by magnetic flux when current flows starting from the flux return portion of the core 30, to the housing 22, and received by the pole attraction portion of the core 30. The unitary flux core 30 can then direct the magnetic flux to the armature assembly 24 via the flux choke 44; the armature assembly 24 can then return the flux to the flux return portion. The force (F) vector generated by this flux circuit φ is shown. It should be understood that the control valve 10 shown in Figure 1 is merely one implementation of a solenoid using a unitary flux core and that the unitary flux core can be implemented by solenoids configured differently that is shown in Figure 1.

[018] Turning to Figure 2, an assembly 200 is shown depicting a cross- sectional view of an embodiment of the bobbin 26 and the unitary flux core 30. The bobbin 26 and the unitary flux core 30 are shown separately in Figure 2 but are later joined in an assembled state. As can be appreciated from Figure 2, the unitary flux core 30 includes the mandrel portion 34, the upper annular shoulder 36, the lower annular shoulder 38, the flux choke 40, and the flux core bore 42. The upper annular shoulder 36 and the lower annular shoulder 38 can have a exterior diameter 82 that is larger than the diameter 50 of the mandrel portion 34. The unitary flux core 30 is formed as one piece without joints that normally result from assembling a multi-piece flux core using a pull piece and a flux tube joined together inside of a one-piece bobbin. In one implementation, the unitary flux core 30 is formed out of metal bar stock. The bar stock can be forged or machined into the desired shape of the unitary flux core 30 having the upper annular shoulder 36 and the lower annular shoulder 38. In another implementation, the unitary flux core 30 can be cast out of a ferric material using a mold cut to the desired shape of the unitary flux core 30.

[019] Rather than using unitary bobbins made from one piece of material, the bobbin 26 can be designed such that it can be applied to or assembled around the unitary flux core 30. The bobbin 26 can be a resin-based carrier that cushions the coil 28 from the unitary flux core 30. Given the one-piece construction of the unitary flux core 30, the bobbin 26 can comprise a multi- component assembly that couples with the core 30 after both the bobbin 26 and the unitary flux core 30 have been formed. In one implementation shown in Figure 3, the bobbin 26 can include a hinge 84 that permits the bobbin 26 to open and close in a clamshell-like way around the mandrel portion 34 of the unitary flux core 30. One or more deflectable tabs 86 can secure the bobbin 26 around the unitary flux core 30 after assembly. In another implementation shown in Figure 4, the bobbin 26 is formed in a plurality of segments that later join at one or more axial joint(s) 88 found along the length of the mandrel portion 38. Apart from being previously-formed, the bobbin 26 can be applied in situ to the unitary flux core 30. In this implementation, an electrically-insulating material can initially exist in a liquid state and be sprayed on to the unitary flux core 30 via an aerosol spray that deposits the material such that it covers the mandrel portion 34 as well as at least a portion of the upper annular shoulder 40 and the lower annular shoulder 38. The applied electrically-insulating material can dry or harden into a resilient coating that forms the bobbin 26 over a portion of the unitary flux core 30. After applying the bobbin 26 to the unitary flux core 30, the coil 28 can be wound around the bobbin 26 and electrically connected to the electrical receptacle 32 such that electrical current can selectively flow through the coil 28. An assembly that includes the bobbin 26 and unitary flux core 30 as they are joined is shown in Figure 5.

[020] It is to be understood that the foregoing is a description of one or more embodiments of the invention. The invention is not limited to the particular embodiment(s) disclosed herein, but rather is defined solely by the claims below. Furthermore, the statements contained in the foregoing description relate to particular embodiments and are not to be construed as limitations on the scope of the invention or on the definition of terms used in the claims, except where a term or phrase is expressly defined above. Various other embodiments and various changes and modifications to the disclosed embodiment(s) will become apparent to those skilled in the art. All such other embodiments, changes, and modifications are intended to come within the scope of the appended claims.

[021] As used in this specification and claims, the terms "e.g.," "for example," "for instance," "such as," and "like," and the verbs "comprising," "having," "including," and their other verb forms, when used in conjunction with a listing of one or more components or other items, are each to be construed as open-ended, meaning that the listing is not to be considered as excluding other, additional components or items. Other terms are to be construed using their broadest reasonable meaning unless they are used in a context that requires a different interpretation.

Claims

CLAIMS What is claimed is:

1. A solenoid actuator (20), comprising:

an armature (24) movable within a flux core bore (42) of a unitary flux core (30);

a housing (22) electrically communicating magnetic flux through the armature (24); and the unitary flux core (30) comprising a mandrel portion (34) for receiving a bobbin (26) that supports a coil (28) carrying electrical current from an electrical connector (32); an upper annular shoulder (36) at one end of the mandrel portion (34); and a lower annular shoulder (38) at another end of the mandrel portion (34), wherein the unitary flux core is constructed as a single component.

2. The solenoid actuator (20) recited in claim 1, wherein the unitary flux core (30) is constructed from a ferric material.

3. The solenoid actuator (20) recited in claim 1, further comprising a multiple -component bobbin (26) that is received by the unitary flux core (30).

4. The solenoid actuator (20) recited in claim 1, further comprising a hinged bobbin (26) that is received by the unitary flux core (30).

5. The solenoid actuator (20) recited in claim 1, further comprising a bobbin (26) comprised of a sprayed on material that adheres to the unitary flux core (30).

6. The solenoid actuator (20) recited in claim 1, further comprising a bobbin (26) that is wrapped or wound around the unitary flux core (30).

7. The solenoid actuator (20) recited in claim 1, wherein the unitary flux core (30) further comprises a pole attraction portion (44) and a flux return portion

(46).

8. The solenoid actuator (20) recited in claim 7, wherein the unitary flux core (30) further comprises a flux choke (40) that connects the pole attraction portion (44) and the flux return portion (46).

9. A control valve (10), comprising:

a solenoid portion (20) including:

a unitary flux core (30) constructed as a single component having a flux core bore (42) that receives an armature (24);

a bobbin (26) supported by the unitary flux core (30) carrying a coil (28) through which electrical current flows,^'

the armature (24) that is slidably received in the flux core bore (42) moving axially in response to the application of current and opposably biased by a solenoid spring (68); and

a hydraulic portion (60) including a valve (72) actuated by the solenoid portion (20).

10. The control valve (10) recited in claim 9, wherein the unitary flux core (30) is constructed from a ferric material.

11. The control valve (10) recited in claim 9, wherein the bobbin (26) comprises a multiple-component bobbin (26) that is received by the unitary flux core (30).

12. The control valve (10) recited in claim 9, wherein the bobbin (26) further comprises a hinged bobbin (26) that abuts the unitary flux core (30).

13. The control valve (10) recited in claim 9, wherein the bobbin (26) further comprises a sprayed on material that adheres to the unitary flux core (30).

14. The control valve (10) recited in claim 9, further comprising a bobbin (26) that is wrapped or wound around the unitary flux core (30).

15. The control valve (10) recited in claim 9, wherein the unitary flux core (30) comprises a pole attraction portion (44) and a flux return portion (46).

16. The unitary flux core (10) recited in claim 9, further comprising a flux choke (40) that connects the pole attraction portion (44) and the flux return portion (46).