U.S. patent application number 14/514528 was filed with the patent office on 2015-03-26 for idle air control valve with plastic housing and retention features.
The applicant listed for this patent is Continental Automotive Systems, Inc.. Invention is credited to David Rene Forgeron, Allen Tamman, Calvin Wang, Craig Andrew Weldon.
Application Number | 20150083322 14/514528 |
Document ID | / |
Family ID | 44625789 |
Filed Date | 2015-03-26 |
United States Patent
Application |
20150083322 |
Kind Code |
A1 |
Weldon; Craig Andrew ; et
al. |
March 26, 2015 |
Idle Air Control Valve With Plastic Housing And Retention
Features
Abstract
A method provides a plastic housing for an actuator. The
actuator has a stator assembly coupled to a connector structure and
a rotor assembly that rotates with respect to the stator assembly.
The method inserts the stator assembly with connector structure
connected thereto into an interior of the plastic housing until a
surface of the stator assembly engages a surface of the plastic
housing, with an annular end of the plastic housing extending
beyond an adjacent annular surface of the connector structure. The
annular end of the housing is heated and deformed to capture the
annular surface of the connector structure, thereby coupling the
plastic housing to the connector structure.
Inventors: |
Weldon; Craig Andrew;
(Chatham, CA) ; Wang; Calvin; (Chatham, CA)
; Tamman; Allen; (Chatham, CA) ; Forgeron; David
Rene; (Chatham, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Continental Automotive Systems, Inc. |
Auburn Hills |
MI |
US |
|
|
Family ID: |
44625789 |
Appl. No.: |
14/514528 |
Filed: |
October 15, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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13642677 |
Jan 17, 2013 |
|
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PCT/US2011/031270 |
Apr 5, 2011 |
|
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14514528 |
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61326757 |
Apr 22, 2010 |
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Current U.S.
Class: |
156/303.1 |
Current CPC
Class: |
B29L 2031/3481 20130101;
F16K 31/0644 20130101; B29C 65/02 20130101; F02D 31/003 20130101;
F16K 31/08 20130101; F02M 3/09 20130101; F16K 99/00 20130101; H02K
7/06 20130101; Y10T 137/0491 20150401; H02K 15/14 20130101; H02K
5/08 20130101 |
Class at
Publication: |
156/303.1 |
International
Class: |
B29C 65/02 20060101
B29C065/02; F02M 3/09 20060101 F02M003/09; F16K 31/08 20060101
F16K031/08 |
Claims
1-10. (canceled)
11. A method of providing a plastic housing for an actuator, the
actuator having a stator assembly coupled to a connector structure,
and a rotor assembly constructed and arranged to rotate with
respect to the stator assembly, the method comprising the steps of:
inserting the stator assembly with connector structure connected
thereto into an interior of the plastic housing until a surface of
the stator assembly engages a surface of the plastic housing, with
an annular end of the plastic housing extending beyond an adjacent
annular surface of the connector structure, and heating and
deforming the annular end of the housing to capture the annular
surface of the connector structure, thereby coupling the plastic
housing to the connector structure.
12. The method of claim 11, wherein the deforming step includes
rolling the heated annular end of the plastic housing.
13. The method of claim 11, further comprising: providing tabs in
the interior of the plastic housing and providing associated
pockets in the stator assembly such that upon the inserting step, a
tab interlocks with an associated pocket, thereby preventing
rotation of the stator assembly with respect to the plastic
housing.
14. The method of claim 11, wherein the plastic housing includes an
integral flange, the flange including bolt holes there-through, the
method further comprising: inserting a metal compression limiter in
each bolt hole.
15. The method of claim 11, wherein prior to the inserting step,
the method further comprises: providing ferrous flux ring structure
about a portion of the stator assembly.
16. The method of claim 11, wherein prior to the deforming step,
the method further comprises: orienting the connector structure to
one of 360.degree. positions with respect to the annular wall of
the plastic housing.
Description
[0001] This application claims the benefit of the earlier filing
date of U.S. Provisional Application No. 61/326,757, filed on Apr.
22, 2010, which is hereby incorporated by reference into this
specification.
FIELD
[0002] This invention relates to a linear actuator such as a
vehicle idle air control valve (IACV) and, more particularly, to an
improved IACV having a plastic housing and retention features.
BACKGROUND
[0003] The IACV is a digital linear actuator (DLA) mounted
externally to the intake manifold of automotive engines that
accurately controls throttle airflow in an engine system. Axial
alignment of the IACV ensures that a pintle/capnut thereof
maintains proper alignment with a throttle body or manifold valve
seat. The IACV is needed since vehicle pollution emission control
regulations require more precise air/fuel ratios and thus cleaner
tailpipe emissions.
[0004] The conventional IACV is an automotive grade can-stack style
stepper motor which has been in production for 10-15 years. The
conventional IACV has a metal housing for stringent environmental
standards requiring that Hexavalent (Cr6) plating replaced by
Trivalent (Cr3) plating. This housing met the environmental
standards but failed to provide sufficient duration for corrosion
protection which may result in a cosmetic annoyance to end
customers.
[0005] Thus, there is a need to provide an improved IACV having a
plastic housing that will meet warranty requirements and that can
provide a measure of cosmetic appeal due to use of non-corrosive
materials.
SUMMARY
[0006] An object of the invention is to fulfill the need referred
to above. In accordance with the principles of the present
invention, this objective is obtained by providing a linear
actuator including a plastic housing having an integral flange for
mounting the actuator. A stator assembly is disposed in the plastic
housing, with the stator assembly having windings. A rotor
assembly, having a permanent magnet, is mounted for rotation with
respect to the stator assembly such that when the windings are
energized, a magnetic field is generated to cause rotation of the
rotor assembly. A shaft is restricted from rotation and is
associated with the rotor assembly such that rotation of the rotor
assembly causes linear movement of the shaft. Connector structure
houses leads for powering the windings. The plastic housing has an
annular end that captures an annular surface of the connector
structure coupling the plastic housing to the connector
structure.
[0007] In accordance with another aspect of the invention, an idle
air control valve for a vehicle includes a plastic housing having
an integral flange for mounting the actuator. A stator assembly is
disposed in the plastic housing with the stator assembly having
windings. A rotor assembly, having a permanent magnet, is mounted
for rotation with respect to the stator assembly such that when the
windings are energized, a magnetic field is generated to cause
rotation of the rotor assembly. A shaft is restricted from rotation
and is associated with the rotor assembly such that rotation of the
rotor assembly causes linear movement of the shaft. A pintle is
associated with a distal end of the shaft for linear movement
therewith. Connector structure houses leads for powering the
windings. The plastic housing has an annular end that captures an
annular surface of the connector structure, coupling the plastic
housing to the connector structure.
[0008] In accordance with yet another aspect of the invention, a
method provides a plastic housing for an actuator. The actuator has
a stator assembly coupled to a connector structure, and a rotor
assembly constructed and arranged to rotate with respect to the
stator assembly. The method includes inserting the stator assembly
with connector structure connected thereto into an interior of the
plastic housing until a surface of the stator assembly engages a
surface of the plastic housing, with an annular end of the plastic
housing extending beyond an adjacent annular surface of the
connector structure. The annular end of the housing is then
deformed to capture the annular surface of the connector structure,
thereby coupling the plastic housing to the connector
structure.
[0009] Other objects, features and characteristics of the present
invention, as well as the methods of operation and the functions of
the related elements of the structure, the combination of parts and
economics of manufacture will become more apparent upon
consideration of the following detailed description and appended
claims with reference to the accompanying drawings, all of which
form a part of this specification.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The invention will be better understood from the following
detailed description of the preferred embodiments thereof, taken in
conjunction with the accompanying drawing, wherein like reference
numerals refer to like parts, in which:
[0011] FIG. 1 is an axial sectional view of an embodiment of a
digital linear actuator in the form of an idle air control valve
(IACV) in accordance with an embodiment of the invention.
[0012] FIG. 2 is view of a portion of an end of a plastic housing
of the IACV prior to heat forming thereof.
[0013] FIG. 3 is a view of a portion of the end of the plastic
housing of FIG. 2, shown after heat rolling to capture a portion of
a connector structure.
[0014] FIG. 4 is a partial sectional view of the end of the plastic
housing prior to heat rolling thereof.
[0015] FIG. 5 is a partial sectional view of the end of the plastic
housing after heat rolling and shown capturing a portion of the
connection structure.
[0016] FIG. 6 is a view of the plastic housing of the IACV showing
tabs of anti-rotate structure.
[0017] FIG. 7 is a view showing the anti-rotate structure with a
tab engaged in a pocket of the stator assembly of the IACV.
DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS
[0018] For illustrative purposes, throughout the following
discussion the invention is described as it is incorporated into a
particular magnetic device used in a specific product assembly,
namely an electric motor, generally indicated at 10, in the form of
a stepper motor that provides linear actuation for an idle air
control valve assembly 11 for a vehicle. However, the invention is
equally applicable to other linear actuator devices that are
employed in harsh environment.
[0019] With reference to FIG. 1, a motor, generalty indicated at
10, of an Idle Air Control Valve (IACV) for use in a vehicle is
shown in accordance with an embodiment of the present invention.
The motor 10 includes a plastic housing 12 with integral flange 14
extending outwardly of the housing 12. A stator assembly, generally
indicated at 16, is disposed in the housing 12. The stator assembly
16 includes the conventional windings 18, field cups, pole plates,
and bobbins.
[0020] As shown in FIG. 1, a rotor assembly, generally indicated at
20, is associated with the stator assembly 16. The rotor assembly
20 has the conventional permanent magnet 22 generally adjacent to
the windings 18. Bearing structure, including a rear, sealed ball
bearing 24 and a front eyelet bearing 26 supports the rotor
assembly 20 to permit rotation of the rotor assembly 20 relative to
the stator assembly 16. In the embodiment of motor 10 as a stepper
motor, introduction of a current in the coil windings 18 of the
stator assembly 16 causes rotational movement of the rotor assembly
20. The rotor assembly 20 has a passage 28 there-through including
a threaded portion 30 for engagement with a threaded portion of
shaft 32. The distal end of the shaft 32 is associated with a front
bearing 33, preventing shaft rotation. Therefore, rotational motion
of rotor assembly 20 is converted into linear motion of shaft 32,
making this stepper motor a linear actuator.
[0021] In the embodiment of the motor 10 used in an idle air
control valve, the shaft 32 has an integral pintle 34 at its distal
end. A spring 36 tends to bias the pintle 34 in an extended
position. The pintle 34 receives a cylindrical grime shield 38 to
protect against contamination of the motor 10. With the example of
the idle air control valve shown in FIG. 1, the motor 10 can be
fitted within a bore of an intake manifold or throttle body. To
control airflow into the manifold.
[0022] Since the housing is made of plastic instead of metal, to
ensure that the flux path is not disrupted, additional,
compensating flux ring structure 40 is provided at the perimeter of
the stator assembly 16. In the embodiments the flux ring structure
40 includes a pair of ferrous material flux rings disposed about
the stator assembly 16, generally adjacent to the windings 18.
[0023] The flange 14 provides bolt holes 42 there-through for the
mounting hardware to the manifold. Since the material of the flange
14 is plastic (instead of metal), M4 and M5 mounting bolts could
damage the plastic flange 14 when torqued to the prescribed
installation torque. Thus, metal, preferably split-ring compression
limiters 44 are provided in the bolt holes 42 to prevent damage to
the flange 14. The limiters 44 frictionally engage the surfaces
defining the bolt holes 42.
[0024] An important retention feature of the motor 10 is heat
rolling of the plastic housing 12 to capture a connector structure
46 of the motor 10 and thus capture the stator assembly 16 and
rotor assembly 20 that are coupled to the connector structure 46.
The connector structure houses leads 47 (FIG. 4) for powering the
windings 18 in the conventional manner. Alternative methods of
coupling the plastic housing 12 to the connector structure 46 were
attempted. For example, molding snap fingers on the inner surface
of the housing 12 was not possible. Further, ultrasonic welding of
the core of the motor 10 to a plastic housing 12 had mixed results.
After thermal cycling, the ultrasonic weld retention load was
compromised. Secondary, contamination of the ultrasonic weld
surfaces were found unpredictable. Thus, the heat rolling process,
explained below, was developed.
[0025] In accordance with the embodiment and with reference to
FIGS. 2-4, the connector structure 46 is inserted axially into the
interior 49 of the plastic housing 12 until a planar surface 51 of
the stator assembly 16 contacts a planar surface 53 (FIG. 4) of the
plastic housing 12. As seen in FIGS. 2 and 4, after such insertion,
a distal, annular end 48 of the housing 12 extends beyond an
annular surface 50 of the connector structure 46. Thereafter, a
heat rolling process heats and deforms the end 48 to capture the
annular surface 50 (FIGS. 1, 3 and 5) of the connector structure 46
thereby coupling the plastic housing 12 to the connector structure
46. This heat deformation process of the plastic housing 12
functionally replicates a swaged metal housing. Thus, in the
embodiment, the end 48 is deformed to have a radius R of
approximately 1.9 mm.
[0026] The heat roll formation of the plastic is more difficult
than the conventional metal swage. Functional requirements for the
heat roll connection are, a static 90 N axial load test and also to
retain structural integrity after thermal life cycling and thermal
vibration. The plastic housing 12 provides sufficient flexure that
ensures alignment throughout the range of thermal exposure (e.g.,
-40 to +125C manifold ambient environment). This flexure, in
addition to axial support, provides additional tolerance to
manifold vibration since excess vibration can damage the internal
motor of the IACV. The heat roll connection between the housing 12
and the connector structure 46 can be air leak tested as witnessed
by IACV on the engine manifold.
[0027] Another important retention feature of the motor 10 is
anti-rotate structure created between the plastic housing 12 and
the stator assembly 16. As seen in FIG. 6, a plurality of tabs 52,
preferably molded into the hosing 12, extend in spaced relation
about an interior surface 54 of the plastic housing 12. As shown in
FIG. 7, the stator assembly 16 includes a plurality of pockets 56,
with one pocket 56 being associated with one tab 52. Thus, upon
assembly of the housing 12 with the stator assembly 16, each tab 52
engages an associated pocket 56. The configuration is such that the
interference between the pocket 56 and tab 52 is sufficient that
the plastic of the tabs 52 and plastic of the surfaces defining the
pocket 56 yield or deform creating a tongue and groove anti-rotate
interlock structure. The functional requirement for this
anti-rotate structure is a 5.5 N-m resistance of the core of the
motor turning without violating the angle location requirement of
the electrical connector of the connector structure 46.
[0028] The plastic used for the housing can by any plastic material
suitable for the environment of an idle air control valve. Features
of the plastic housing 12 include: [0029] unique external heat
forming the plastic housing end 48 after assembly to retain the
core motor [0030] external heat form allows for 360.degree.
connector orientation with respect to the housing 12 whereas
conventional internal snap retention configurations are location
sensitive [0031] heat form method less expensive solution to
ultrasonic welding with existing jointing issues [0032] molded
internal anti-rotation interlock structure [0033] flange/housing
integration eliminates existing jointing issues [0034] flange
compression limiters allow use of existing hardware (manifold)
[0035] weight savings [0036] the plastic housing exterior
eliminates corrosion plating and associated cosmetics rejects
[0037] motor efficiency is higher due to provision of the flux ring
structure [0038] utilizes existing production core motor with
minimal refinements
[0039] The foregoing preferred embodiments have been shown and
described for the purposes of illustrating the structural and
functional principles of the present invention, as well as
illustrating the methods of employing the preferred embodiments and
are subject to change without departing from such principles.
Therefore, this invention includes all modifications encompassed
within the spirit of the following claims.
* * * * *