This invention relates to an idle air control valve (IACV) and, more particularly, to an IACV for use in a small engine with the IACV having a shroud for protecting the cap nut and having an improved valve seat.
The IACV is a digital linear actuator (DLA) that accurately controls throttle airflow in an engine system. The need for using an IACV is that pollution emission control regulations require more precise air/fuel ratios in engines so as to produce cleaner emissions. Alternative flow control uses for a DLA are for a fuel cell or Positive Crankcase Ventilation (PCV).
IACVs are being developed for the small engine market such as, for use in two and three-wheeled motorcycles, off-road recreational vehicles, marine outboard motors, portable generators, lawn and garden power tools, etc., to reduce emissions. A throttle valve seat diameter, in the throttle body, for these small engines typically ranges between 3-6 mm. The capnut shape of the IACV determines the airflow profile in the throttle body. For an IACV with 8.5 mm linear travel, the capnut becomes very needle-like in shape. Such needle-like capnut is weak and subject to handling damage before final assembly into the throttle body, which may occur after cross-continent travel.
Thus, there is a need to provide a shroud for protecting the capnut of an IACV for use in a small engine, with the shroud also defining the valve seat.
An object of an embodiment is to fulfill the need referred to above. In accordance with the principles of an embodiment, this objective is obtained by providing a linear actuator that includes a stator assembly and a rotor assembly operatively associated with the stator assembly and mounted for rotation with respect to the stator 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 capnut is associated with a distal end of the shaft for movement therewith. A shroud is coupled to the stator assembly and substantially surrounds the capnut. The shroud includes a valve seat, and an inlet communicating with an outlet through a throttle opening adjacent to the valve seat. The shaft and associated capnut are constructed and arranged to move relative to the valve seat to control air flow between the inlet and the outlet.
In accordance with another aspect of an embodiment, a method protects a capnut of a linear actuator. The actuator includes a stator assembly and a rotor assembly operatively associated with the stator assembly and mounted for rotation with respect to the stator 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 capnut is associated with a distal end of the shaft for movement therewith. The method couples a shroud to the stator assembly so as to substantially surround the capnut. The shroud provides a valve seat, and an inlet communicating with an outlet through a throttle opening adjacent to the valve seat so that the shaft and associated capnut can move relative to the valve seat to control air flow between the inlet and the outlet.
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.
The invention will be better understood from the following detailed description of the preferred embodiments thereof, taken in conjunction with the accompanying drawings, wherein like reference numerals refer to like parts, in which:
With reference to
The motor 11 is of the type disclosed in US Patent Application Publication No. 20080121833, the content of which is hereby incorporated by reference into this specification. Thus, with reference to
An electrical connector 18 is employed for providing a source of electrical current to the coil windings 20, 22. In the embodiment of motor 11 as a stepper motor, introduction of a current in the coil windings 20, 22 of the stator assembly 12 causes rotational movement of the rotor assembly 14. The rotor assembly 14 has a threaded portion 24 for engagement with a threaded portion 26 of shaft 28. The shaft 28 is restricted from rotating via a front bearing 30. Therefore, rotational motion of rotor assembly 16 is converted into linear motion of shaft 28 via the threaded interface, making this stepper motor 11 a linear actuator. The shaft 28 is constructed and arranged to have a linear travel of about 8.5 mm. One skilled in the art will appreciate that the present embodiment could be utilized in various alternative embodiments of magnetic devices regardless of whether such devices are of single or multiple phase construction. Moreover, in response to an electrical input, such alternative embodiments could be constructed to provide a different output such as in a rotary stepper motor, or in a motor which provides continuous rotary motion or the like.
As shown in
The shroud 34 has a body 35 that includes an inlet port connector 36, defining an inlet 37 of the IACV 10, and an outlet port connector 38, defining an outlet 39 of the IACV 10. The inlet 37 communicates with the outlet 39 through a throttle opening 46 in the body 35 and adjacent to the valve seat 40. The capnut 32 is moveable with respect to the valve seat 40 to control airflow from the inlet 37, through opening 46, past the valve seat 40, to the outlet 39. The surface defining the valve seat 40 is a hard radius surface communicating with opening 46 so the radius surface can be engaged annularly by the tapered portion 42 of the capnut 32 to form an annular seal. Preferably, the outlet 39 is disposed transversely with respect to the inlet 37, with the inlet 37 being disposed along the axis X. As noted above, since the engine is a small engine, a diameter of a throttle opening 46 is between about 3-6 mm.
Each of the inlet port connector 36 and the outlet port connector 38 includes a flange 44 defining a barb that can engage and retain a hose (not shown) so as that the IACV 10 can be coupled remotely with a mechanical throttle body to control airflow to an engine. The IACV 10 also includes a mounting flange 41 for coupling to a member associated therewith.
With reference to
Thus, the shroud 34, 34′ provides protection of the capnut 32 from handling during shipping and assembly and also advantageously incorporates the valve seat 40 that would otherwise need to be machined into the mechanical throttle body.
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.
Number | Name | Date | Kind |
---|---|---|---|
4346728 | Sulzer | Aug 1982 | A |
4412517 | Kobashi | Nov 1983 | A |
4650156 | Kawahira | Mar 1987 | A |
4725041 | Chauvin | Feb 1988 | A |
4789132 | Fujita | Dec 1988 | A |
4844339 | Sayer | Jul 1989 | A |
4948091 | Satoh | Aug 1990 | A |
5239961 | Neidhard | Aug 1993 | A |
5364066 | Dorste | Nov 1994 | A |
5419531 | Hoehn | May 1995 | A |
5692723 | Baxter | Dec 1997 | A |
6016832 | Vars | Jan 2000 | A |
6076803 | Johnson | Jun 2000 | A |
6460567 | Hansen, III | Oct 2002 | B1 |
6492751 | Ineson | Dec 2002 | B1 |
6561480 | Komiya | May 2003 | B1 |
6674208 | Ineson | Jan 2004 | B2 |
7325780 | Arai | Feb 2008 | B2 |
7608952 | Weldon | Oct 2009 | B2 |
20040188650 | Nalini | Sep 2004 | A1 |
20060261302 | Inoue | Nov 2006 | A1 |
20070018128 | Arai | Jan 2007 | A1 |
20080121833 | Weldon et al. | May 2008 | A1 |
Entry |
---|
Dian et al., Idle Air control Valve for the Small Engine Market, JSAE 20139163/SAE 2013-32-9163, Jul. 25, 2013. |
Weldon et al., Optimization of an Automotive Grade Stepper Motor Idle Air control Valve for the Small Engine Market, SAE 2012-32-0040/JSAE 201290490, 2012. |
Number | Date | Country | |
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20160061122 A1 | Mar 2016 | US |