Patent Application
20240218820
The invention generally relates to an exhaust gas control valve.
Conventional exhaust gas control valves are used to regulate a flow of exhaust gas produced from an internal combustion engine. Exhaust gas control valves are used in various applications and can be employed as an exhaust gas recirculation (EGR) valve, a bypass valve, an exhaust tuning valve, and the like.
Typical exhaust gas control valves include a valve member having a valve shaft and a valve body, with the valve member moveable along an axis between an open position and a closed position to regulate the flow of exhaust gas. The valve member is commonly moved through actuation of a gear arrangement. The gear arrangements known in the art often impart a torque multiplication from an actuator to the valve member to assist in overcoming a force exerted on the valve member by the exhaust gas. However, to impart the torque multiplication between the actuator and the valve member necessary to overcome the force of the exhaust gas, particularly on the valve body of the valve member, the gear arrangements known in the art are space consuming, formed of costly materials, or both. As forces exerted by exhaust gas on the valve member, particularly the valve body, continue to increase because of larger valve body requirements to permit higher flow of exhaust gas, higher torque multiplications between the actuator and the valve member are required.
As such, there remains a need to provide an improved exhaust gas control valve.
An exhaust gas control valve for regulating a flow of exhaust gas is provided. The exhaust gas control valve includes a housing having an interior wall defining a housing interior, a pinion gear coupled to the housing and configured to be rotatably driven, and a helical gear configured to receive torque from the pinion gear. The helical gear includes a plurality of helically arranged teeth. The exhaust gas control valve also includes a valve member disposed at least partially in the housing interior of the housing. The valve member includes a valve shaft extending along an axis and having a first shaft end and a second shaft end spaced from the first shaft end along the axis. The valve member also includes a valve body coupled to the valve shaft adjacent to the second shaft end. The valve body is moveable with the valve shaft along the axis between a first valve position of the valve member and a second valve position of the valve member to regulate the flow of exhaust gas. The exhaust gas control valve further includes a motion converter configured to convert rotational motion of the helical gear to linear motion of the valve member.
The helical gear improves a contact ratio between the helical gear and an adjacent gear to increase the amount of torque able to be transmitted. Thus, the helical gear permits a higher relative torque multiplication to assist in overcoming a force exerted on the valve member, particularly the valve body, by the exhaust gas without the need for other space consuming components (e.g. a larger gear), costly materials, or both.
Other advantages of the present invention will be readily appreciated, as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:
With reference to the Figures, wherein like numerals indicate like parts throughout the several views, an exhaust gas control valve 20 for regulating a flow of exhaust gas is shown in
The valve member 34 includes a valve shaft 36 extending along an axis A1 and having a first shaft end 38 and a second shaft end 40 spaced from the first shaft end 38 along the axis A1. The valve member 34 also includes a valve body 42 coupled to the valve shaft 36 adjacent to the second shaft end 40. The valve body 42 is moveable with the valve shaft 36 along the axis A1 between a first valve position of the valve member 34, as shown in
The helical gear 30 improves a contact ratio between the helical gear 30 and an adjacent gear as compared to conventional gears to increase the amount of torque able to be transmitted. Thus, the helical gear 30 permits a greater relative torque multiplication as compared to conventional gears to assist in overcoming a force exerted on the valve member 34, particularly the valve body 42, by the exhaust gas without the need for other space consuming components (e.g., a larger gear), costly materials, or both. In some embodiments, the helical gear 30 generates about a 72% increase in lift force of the valve member 34 in the first valve position against the flow of exhaust gas as compared to another similarly sized gear. Therefore, a larger valve body 42 may be provided and a higher flow rate of exhaust gas is achievable. It is to be appreciated that the force exerted on the valve member 34, particularly the valve body 42, by the exhaust gas may result from a pressure differential on either side of the valve body 42, particularly when the valve member 34 is at or near the first valve position (i.e., closed).
Although not required, the pinion gear 28 may also include a plurality of helically arranged teeth 46. For descriptive purposes, the plurality of helically arranged teeth 46 of the pinion gear 28 is referred to throughout as a second plurality of helically arranged teeth 46. The pinion gear 28 and the helical gear 30 may be in meshed engagement. In other words, the pinion gear 28 and the helical gear 30 may be in direct contact with one another. More specifically, the plurality of helically arranged teeth 32 of the helical gear 30 and the second plurality of helically arranged teeth 46 of the pinion gear 28 may be in meshed engagement with one another. Thus, the pinion gear 28 and the helical gear 30 may form a single stage geartrain. However, it is to be appreciated that torque may be transmitted from the pinion gear 28 to the helical gear 30 through any number of intermediate gear(s). In the embodiments with intermediate gear(s), it is to be appreciated that the helical gear 30 is still configured to receive torque from the pinion gear 28. The plurality of helically arranged teeth 32 of the helical gear 30 and the second plurality of helically arranged teeth 46 of the pinion gear 28 reduce stress and wear on the plurality of helically arranged teeth 32 and the second plurality of helically arranged teeth 46, thus prolonging the life of the exhaust gas control valve 20. Moreover, reduced stress on the plurality of helically arranged teeth 32 permits a relatively smaller center distance of the helical gear 30 and a relatively smaller outer diameter of the helical gear 30, further reducing the packaging space of the exhaust gas control valve 20.
One of the plurality of helically arranged teeth 32 of the helical gear 30 and the second plurality of helically arranged teeth 46 of the pinion gear 28 may have a right-handed helical configuration, and the other one of the plurality of helically arranged teeth 32 of the helical gear 30 and the second plurality of helically arranged teeth 46 of the pinion gear 28 has a left-handed helical configuration. In other words, in one embodiment, the plurality of helically arranged teeth 32 of the helical gear 30 has a right-handed helical configuration, and the second plurality of helically arranged teeth 46 of the pinion gear 28 has a left-handed helical configuration, and in another embodiment, the plurality of helically arranged teeth 32 of the helical gear 30 has a left-handed helical configuration and the second plurality of helically arranged teeth 46 of the pinion gear 28 has a right-handed helical configuration.
The plurality of helically arranged teeth 32 of the helical gear 30 may have a helix angle of about 1 degree to about 10 degrees. It is also to be appreciated that the plurality of helically arranged teeth 32 of the helical gear 30 may have a helix angle of about 2 degrees to about 9 degrees, of about 3 degrees to about 7 degrees, of about 4 degrees to about 6 degrees, of about 1 degree to about 9 degrees, of about 1 degree to about 8 degrees, of about 1 degree to about 7 degrees, of about 1 degree to about 6 degrees, of about 1 degree to about 5 degrees, of about 1 degree to about 4 degrees, of about 1 degree to about 3 degrees, of about 1 degree to about 2 degrees, of about 1 degree, of about 2 degrees, of about 3 degrees, of about 4 degrees, of about 5 degrees, of about 6 degrees, of about 7 degrees, of about 8 degrees, of about 9 degrees, and of about 10 degrees. However, it is also to be appreciated that the plurality of helically arranged teeth 32 of the helical gear 30 may even have a helix angle of more than 10 degrees, or ranging to more than 10 degrees, such as about 1 degree to about 15 degrees, about 1 degree to about 14 degrees, about 1 degree to about 13 degrees, about 1 degree to about 12 degrees, and about 1 degree to about 11 degrees.
A helix angle of about 1 degree to about 10 degrees is relatively small among helical gears known in the art. The helix angle may be limited to about 1 degree to about 10 degrees to obtain the benefits associated with an improved contact ratio (e.g. higher torque resulting from a higher gear ratio) without generating thrust loads which may damage other components of the exhaust gas control valve 20, including the helical gear 30 itself and/or the pinion gear 28. High thrust loads may negate the benefits associated with the improved contact ratio. The helix angle being limited to about 1 degree to about 10 degrees permits the use of the helical gear 30 in the exhaust gas control valve 20 where otherwise a helical gear with a large helix angle would be considered inappropriate and/or unfeasible.
Although not required, a gear ratio between the pinion gear 28 and the helical gear may be at least 6:1. Moreover, the gear ratio between the pinion gear 28 and the helical gear 30 may be at least 7:1, may be at least 8:1, may be at least 9:1, or may be at least 10:1. The gear ratio between the pinion gear 28 and the helical gear 30 may also be at least 4:1, at least 5:1, or may be between about 5:1 and about 10:1, may be between about 5:1 and about 8:1, may be between about 6:1 and about 8:1, and may be between about 6:1 and about 7:1.
The helical gear 30 may be further defined as a helical cam gear 48 having a helical cam gear surface 50 defining a central opening 52 therethrough. The helical cam gear 48 may also have a cam feature 54 extending away from the helical cam gear surface 50. The cam feature 54 may be disposed about the central opening 52. The helical cam gear 48 may be rotatable in either a first rotational direction RD1 or a second rotational direction RD2 opposite the first rotational direction RD1. The motion converter 44 may include a link 56 coupled to the first shaft end 38 of the valve shaft 36, and the motion converter 44 may include a bearing 58 rotatably supported by the link 56. The bearing 58 may be engageable with the cam feature 54 of the helical cam gear 48 to move the valve member 34 toward the second valve position as the helical cam gear 48 rotates in the first rotational direction RD1. It is to be appreciated that rotation of the helical cam gear 48 in the first rotational direction RD1 may move the valve member toward the first valve position (e.g., closed) and that rotation of the helical cam gear 48 in the second rotational direction RD2 may move the valve member toward the second valve position (e.g. open). Moreover, the bearing 58 may define a bore 60, and the motion converter 44 may further include a bearing shaft 62 rotatably supported by the link 56. The bearing shaft 62 may be disposed in the bore 60 of the bearing 58.
The helical cam gear 48 may also have a return feature 64 extending away from the helical cam gear surface 50. The return feature 64 may extend about the central opening 52, and the return feature 64 may be spaced between the cam feature 54 and the plurality of helically arranged teeth 32. The bearing shaft 62 may include an extended portion 66 engageable with the return feature 64 of the helical cam gear 48 to move the valve member 34 toward the first valve position as the helical cam gear 48 rotates in the second rotational direction RD2.
The cam feature 54 of the helical cam gear 48 may be configured to provide a non-linear cam ramp rate. The valve member 34 may be configured to move a distance D1 from the first valve position to the second valve position, and the cam feature 54 of the helical cam gear 48 may be configured to provide the non-linear cam ramp rate such that mechanical advantage is maximized when the valve member 34 is within about 0 percent to about 10 percent of the distance D1 from the first valve position. A non-linear cam ramp rate permits a smaller gear ratio to provide the same initial force when moving from the first valve position toward the second valve position against the flow of exhaust gas. It is to be appreciated that where the cam ramp rate is lower there is increased mechanical advantage, thus allowing the valve member 34 to have a targeted lift force increase. Moreover, a non-linear cam ramp rate increases force output of the valve member 34 when the valve member 34 is near the first valve position (e.g. within about 0 percent to about 10 percent of the distance D1 from the first valve position) when force output is most needed to successfully move to the valve member 34 to the second valve position.
The non-linear cam ramp rate may be characterized as the rate at which the relative distance between the cam feature 54 and the central opening 52 changes as the cam feature 54 rotates. As such, the non-linear camp ramp rate may be characterized in terms of millimeters per degree of rotation of the cam feature 54, or in terms of percentage change of the relative distance between the cam feature 54 and the central opening 52 per degree of rotation of the cam feature 54. It is to be appreciated that, under either characterization, the non-linear cam ramp rate is not constant throughout all possible degrees of rotation of the cam feature 54. It is also to be appreciated that the non-linear cam ramp rate may alternatively be characterized as a non-linear lift rate.
As shown in
The resilient shaft shield 70 protects the valve shaft 36 from contact with the soot, debris, and other contamination in, or suspended by, the exhaust gas which may cause the valve member 34 to move more slowly between the first valve position and the second valve position or which may cause the valve member 34 to become completely stuck. The resilient shaft shield 70 requires no staking or other mechanical fastening to be retained in position relative to the housing 22. Instead, the resilient shaft shield 70 engages the interior wall 24 of the housing 22 through a spring-lock, similar to a sealing push-in cap or a cup plug. Moreover, the resilient shaft shield 70 provides a dependable seal completely circumferentially about the valve shaft 36, and thus does not rely upon discrete points of staking or other mechanical fastening which may leave gaps between discrete points. Gaps between discrete points of staking or other mechanical fastening permit exhaust gas, soot, debris, or other contamination to leak through and contact the valve shaft 36, which reduces the lifespan of the exhaust gas control valve 20 through corrosive effects. As such, the resilient shaft shield 70 prolongs the lifespan of the exhaust gas control valve 20 by reducing corrosion of various components protected by the resilient shaft shield 70. Moreover, the resilient shaft shield 70 requires less time to assemble as compared to shaft shields which rely upon staking or other mechanical fastening because a step of staking, or a step of fastening, is not required to engage the resilient shaft shield 70 to the interior wall 24 of the housing 22. Additionally, engagement of the resilient shaft shield 70 and the interior wall 24 of the housing 22 is easily monitored during manufacturing to ensure a quality of the seal formed therebetween.
An exhaust gas control assembly 78 is further provided. The exhaust gas control assembly 78 includes the exhaust gas control valve 20 and an actuator 80 coupled to the housing 22 of the exhaust gas control valve 20. The actuator 80 is configured to rotatably drive the pinion gear 28. An assembly 82 for controlling a flow of exhaust gas from an engine is also provided. The assembly 82 includes an exhaust gas manifold 84 adapted to be coupled to the engine, and the exhaust gas control valve 20. It is also to be appreciated that the assembly 82 may include the exhaust gas control assembly 78, which then incorporates the actuator 80.
The invention has been described in an illustrative manner, and it is to be understood that the terminology which has been used is intended to be in the nature of words of description rather than of limitation. Many modifications and variations of the present invention are possible in light of the above teachings, and the invention may be practiced otherwise than as specifically described.
The present application claims priority to and all the benefits of U.S. Provisional Patent Application No. 63/437,011, filed on Jan. 4, 2023, which is hereby expressly incorporated herein by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 63437011 | Jan 2023 | US |
