Patent Application
20250162518
The present disclosure generally relates to sounds generated by vehicle drivelines and more particularly to systems and methods for suppression and avoidance of sounds that may be generated in the vehicle driveline.
A vehicle driveline includes numerous moving parts that transmit torque from the vehicle's powerplant to its wheels. In many applications, such as those involving electrified vehicles, torque is alternatively transferred from the wheels to the powerplant, such as in regenerative braking situations. In addition, due to the inclusion of a steering system and a suspension system through which the wheels may be coupled with the body of the vehicle, the driveline is designed to accommodate a wide range of angles for the expected relative movements.
In operation, the driveline is subjected to significant forces and torques. As a result, many sounds are generated. After multiple cycles, the components involved may wear, corrode, and otherwise change in ways that influence the sounds that are generated. In certain situations, the generated sounds may be perceived by the vehicle occupant(s) as undesirable noises. For example, squeaks, groans, rattles, clicks and other sounds may be described. Diagnosing the source of these sounds and whether corrective action is needed is challenging. In some situations, changes in the generated sounds over time may be normal. In other situations, addressing the perceived sound may be desirable for customer satisfaction or other purposes.
Accordingly, it is desirable to provide vehicle drivelines that avoid undesirable sounds being perceived by the driver, where possible. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing introduction.
Noise suppression systems and methods are provided for a vehicle driveline. In a number of embodiments, the vehicle includes a driveline with a halfshaft. The halfshaft has a surface. A wheel hub and bearing assembly is coupled with the halfshaft. The wheel hub and bearing assembly includes a wall contacting the surface at an interface. The wall and/or the halfshaft define(s) a groove. A ring is compressed in the groove between the halfshaft and the wheel hub and bearing assembly.
In additional embodiments, the ring is made of a compliant, resilient material.
In additional embodiments, a gap is defined between the halfshaft and the wheel hub and bearing assembly. The gap is disposed around, and radially outward from, the ring.
In additional embodiments, a fastener is included to secure the wheel hub and bearing assembly to the halfshaft. The fastener is torqued to a selected torque value that optimizes noise suppression.
In additional embodiments, the selected torque value is selected so that the wall contacts the surface and compresses the ring fully into the groove.
In additional embodiments, the fastener is torqued to a selected torque value, wherein the selected torque value is approximately twenty percent to thirty percent of a conventional torque valve.
In additional embodiments, a splined shaft is included on the halfshaft. The ring seals the interface and the splined shaft.
In additional embodiments, the surface of the halfshaft is disposed normal to a centerline of the halfshaft.
In additional embodiments, the wheel hub and bearing assembly includes a hub assembly with a hub body and a bearing assembly disposed around the hub body. The wall is disposed at an inboard end of the hub body where the inboard end is located inboard relative to the vehicle.
In additional embodiments, the ring has a cross sectional shape that tapers in an axial direction.
In a number of other embodiments, a method of noise suppression for a vehicle includes constructing a halfshaft for a driveline of the vehicle, and providing the halfshaft with a surface. A wheel hub and bearing assembly is coupled with the halfshaft. The wheel hub and bearing assembly includes a wall that contacts the surface at an interface. A groove is formed in at least one of the wall and the halfshaft. A ring is compressed in the groove between the halfshaft and the wheel hub and bearing assembly.
In additional embodiments, a method includes forming the ring from a compliant, resilient material.
In additional embodiments, a method includes defining a gap between the halfshaft and the wheel hub and bearing assembly so that the gap is disposed around, and radially outward from, the ring.
In additional embodiments, a method includes securing, by a fastener, the wheel hub and bearing assembly to the halfshaft; and torquing the fastener to a selected torque value that optimizes noise suppression.
In additional embodiments, a method includes selecting the selected torque value so that the wall contacts the surface and compresses the ring fully into the groove.
In additional embodiments, a method includes torquing the fastener to a selected torque value that is approximately twenty percent to thirty percent of a conventional torque valve to optimize the noise suppression.
In additional embodiments, a method includes forming a splined shaft on the halfshaft; and sealing, by the ring, the interface and the splined shaft.
In additional embodiments, a method includes forming the surface of the halfshaft to be disposed normal to a centerline of the halfshaft.
In additional embodiments, a method includes having, in the wheel hub and bearing assembly, a hub assembly with a hub body and a bearing assembly disposed around the hub body. The wall is formed at an inboard end of the hub body where the inboard end is located inboard relative to the vehicle.
In a number of additional embodiments, a noise suppression system is provided for a vehicle that includes a driveline with a halfshaft that includes a surface defining an annular shape around the halfshaft. A wheel hub and bearing assembly is coupled with the halfshaft. The wheel hub and bearing assembly includes a hub body that has a wall contacting the surface at an interface. The wall and/or the surface defines a groove. A fastener retains the wheel hub and bearing assembly to the halfshaft. A compliant ring is compressed, by a torquing of the fastener, in the groove between the halfshaft and the wheel hub and bearing assembly.
The exemplary embodiments will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements, and wherein:
The following detailed description is merely exemplary in nature and is not intended to limit the application and uses. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding introduction, brief summary or the following detailed description.
With reference to
Propulsion of the vehicle 20, such as on a roadway 32, is provided by a propulsion system 34 including a powerplant 36. The powerplant 36 may be any of various types such as electric, internal combustion, hybrid, or others. Torque generated by the powerplant 36 is transferred to the wheel assemblies 28 through the driveline 24. The driveline 24 includes a number of torque transfer elements that may be coupled with any number of the wheel assemblies 28. In this embodiment, the powerplant 36 is coupled with the front wheel assemblies 28 through a pair of halfshafts 40 and 42 of the driveline 24.
The vehicle 20 is propelled by transferring torque from the powerplant 36 through the driveline 24 and uses forces generated as a result of traction due to friction between the wheel assemblies 28 and a roadway 32. In embodiments, the wheel assemblies 28 may also operate to transfer torque to the powerplant 36. For example, in a regenerative braking mode the momentum of the vehicle 20 may be used to drive the powerplant 36 by the wheel assemblies 28 and through the driveline 24. As a result, torque may act bi-directionally on the various component interfaces of the driveline 24.
Referring additionally to
The halfshaft 40 is configured, while rotating, to allow the outboard end 46 to pivot at various angles relative to the inboard end 44, such as to accommodate suspension travel and steering angles. Adjacent to the outboard end 46, or nearer to the inboard end 44 than the inboard end 44, the halfshaft 40 includes a joint assembly 52, such as a tripod joint, covered by a boot 54. Adjacent to, or relatively nearer to, the outboard end 46, the halfshaft 40 includes a joint assembly 56, such as a constant velocity joint, covered by a boot 58. The halfshaft 40 includes a shaft 60 interconnecting the joint assemblies 52, 56. As a result, torque is transferable between the inboard end 44 and the outboard end 46 and suspension and steering travels are accommodated.
Referring to
Referring to
The bearing assembly 66 is shown schematically and in general, includes an outer race configured, such as through the flange 70 of
Various interfaces with the halfshaft 40 exist. For example, one interface 77 is a splined connection between the splined shaft 50 and the hub body 78. Another interface is between the nut 84 and the threaded section 86. Another interface is between the nut 84 and the hub assembly 68. Another interface 79 is between the wall 82 and the halfshaft 40 at the surface 88. Various other interfaces may exist.
Regarding the interfaces, those between the nut 84 and other components are generally not of concern for noise generation because the nut 84 is typically secured in position on the threaded section 86 by a pin, such as a cotter pin (not shown), by a clip (not shown), or by other means.
As part of the current disclosure, the interface between the wall 82 and the halfshaft 40 at the surface 88 has been found to be the source of sounds that may be considered noise or that may develop into a noise over time. Due to intermittent and variable torque transfers including in both propulsion modes and regenerative braking modes, which may be described as fatigue cycles, the surface 88 and/or the wall 82 may wear over time or may experience a changed clamp load. In addition, the wall 82 and/or the surface 88 at the interface may be subject to corrosion. As a result, sounds that may be described as a click may develop.
Also as part of the current disclosure, the interface between the hub body 78 and the splined shaft 50 of the halfshaft 40 has been found to be the source of sounds that may be considered noise or that may develop into a noise over time. This interface is also subjected to intermittent and variable torque transfers including in both propulsion modes and regenerative braking modes, which may be described as fatigue cycles. Oxidation/corrosion of the spline surfaces in the interface may occur, oxides may wear off, and new corrosion may occur in a repetitive fashion. As a result, outcomes such as fretting may occur that may lead to changes in the sounds generated and that may become classified as noise.
In general, the noise suppression system 22 may include various aspects including of a resilient element in the form of a ring 90 and including of the nut 84 as further described below. In embodiments, the ring 90 may be referred to as a noise suppression ring or a resilient element or as a compliant element. In embodiments, the ring 90 encircles the halfshaft 40 and/or the centerline thereof. In embodiments, the ring 90 may be annular in shape or may have another shape, such as a non-circular shape, an undulating shape, or an irregular shape. In embodiments, the ring 90 may have a circular cross sectional shape or another cross sectional shape.
Referring to
The ring 90 is annular in shape and is sized to be compressed between the wall 82 and the surface 88 when the nut 84 is torqued. The resilient element/ring 90 is made of a material that is compressible and/or deformable or is otherwise compliant and that is selected for the application's environment with a sufficient toughness and temperature compatibility. For example, the ring 90 has a physical strength and the ability to retain its properties after long term exposure to heat, lubricants and forces. For example, a material that is able to withstand 80 degrees Celsius with excursions to 130 degrees Celsius may be selected. An example is a rubber-like material such as a hydrogenated nitrile butadiene rubber material, although other materials are contemplated.
Prior to torquing the fastener/nut 84, the resilient element/ring 90 extends out of the groove 92. When the nut 84 is torqued, the ring 90 moves into the groove 92 and metal-to-metal contact is established between the wall 82 and the surface 88 of the halfshaft 40. A gap 93 may be provided between the wall 82 and the halfshaft 40 at the surface 88 radially outward from the ring 90. The gap 93 provides space between the wall 82 and the surface 88 in the area radially outside the ring 90, which isn't provided with the benefits of the ring 90. In some embodiments, a washer (not shown) may be added between the wall 82 and the surface 88/ring 90.
In a number of embodiments, to optimize the foregoing features, the ring 90 may have a configuration as shown in
Inclusion of the ring 90 provides a number of benefits. The presence of the ring 90 changes the acoustic properties of the interfacing elements, such as by changing the natural frequency. In embodiments, the ring 90 may provide damping of vibrations. Also adding the ring 90 changes how energy is radiated providing attenuation, especially at higher frequency ranges where sound may be undesirable. In addition to changing the vibrations before they occur, the ring 90 may block sound from emanating/radiating out of the interface acting as a type of barrier. In addition, the ring 90 seals the interface from outside elements preventing liquid and other corrosive elements form entering the interface between the wall 82 and the halfshaft 40 and from entering the interface between the hub body 78 and the splined shaft 50, avoiding noise generation.
In addition to inclusion of the ring 90 in the noise suppression system 22, torque on the nut 84 may be tailored to reduce/avoid noise as a part of methods for the noise suppression system 22. Torque for the fastening together of the wheel hub and bearing assembly 64 and the halfshaft 40 is, without use of the current disclosure, set a level (conventional torque value) that is maximized for retention purposes and is below an upper threshold. The upper threshold is a torque value that would compress the bearing assembly 66 to a point of distortion/damage. Accordingly, torque is conventionally maximized to the extent possible. In a number of embodiments of this disclosure, torque is selected (a selected torque value) above but approximately at, a lower threshold. The lower threshold is a torque value where the ring 90 is compressed into the groove 92 and the wall 82 contacts the surface 88, which has been discovered to provide optimized and secure noise suppression. It has been found that higher torque levels may decrease the noise suppression properties. In this case the torque is set at a selected torque value of approximately 20%-30% of the standard torque value. A non-limiting specific example includes a conventional torque value of 250 Nm and a selected torque value of 50 Nm. In this way, torque is reduced from what would be expected and optimizes the noise suppression properties.
With use of the ring 90, the torque on the nut 84 may be reduced to the selected torque value, which has been discovered to help eliminate undesirable sound. In embodiments, the torque is selected at a level that is at, or just above, where the wall 82 contacts (metal-to-metal) the surface 88, and the ring 90 is fully compressed into the groove 92. Testing may be conducted to determine the optimal torque on the fastener(s)/nut 84 to avoid undesirable sound generation.
Accordingly, noise suppression systems and methods are provided that address potential driveline 24 sounds. Undesirable sounds may be reduced or eliminated, with the benefits surviving over extended periods of time with repeated fatigue cycles. While at least one exemplary embodiment has been presented in the foregoing detailed description, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the disclosure in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing the exemplary embodiment or exemplary embodiments. It should be understood that various changes can be made in the function and arrangement of elements without departing from the scope of the disclosure as set forth in the appended claims and the legal equivalents thereof.
