Vehicle driveline noise suppression system and method

Abstract

A noise suppression system and method for a vehicle having a driveline with a half axle. The half shaft has a surface. A hub and bearing assembly is coupled with the axle shaft. The hub and bearing assembly includes a wall that contacts the surface at the interface. The wall and / or the half shaft define a groove. The ring is compressed in a recess between the axle shaft and the hub and bearing assembly.

Description

Technical Field

[0001] The present disclosure relates generally to sounds generated by a vehicle powertrain, and more particularly to systems and methods for suppressing and avoiding sounds that may be generated in a vehicle powertrain. Background Art

[0002] The vehicle driveline includes many moving parts that transmit torque from the vehicle's powerplant to its wheels. In many applications, such as those involving electrified vehicles, torque may alternatively be transferred from the wheels to the powerplant, such as in regenerative braking situations. In addition, by including the steering and suspension systems through which the wheels may be coupled to the body of the vehicle, the driveline is designed to accommodate a wide range of angles for expected relative motion.

[0003] In operation, the drivetrain is subjected to significant forces and torques. As a result, many sounds are generated. After multiple cycles, the components involved may wear, corrode, or otherwise change, affecting the generated sounds. In some cases, the generated sounds may be perceived by vehicle occupants 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 cases, changes in the generated sounds over time may be normal. In other cases, addressing the perceived sounds may be desirable for customer satisfaction or other purposes.

[0004] Therefore, it is desirable to provide a vehicle transmission system that avoids the driver's perception of undesirable sounds when 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. Summary of the invention

[0005] Noise suppression systems and methods for vehicle drivetrains are provided. In various embodiments, a vehicle includes a drivetrain having a half shaft. The half shaft has a surface. A hub and bearing assembly is coupled to the half shaft. The hub and bearing assembly includes a wall that contacts the surface at an interface. The wall and / or the half shaft define a groove. A ring is compressed in the groove between the half shaft and the hub and bearing assembly.

[0006] In additional embodiments, the ring is made of a flexible elastic material.

[0007] In an additional embodiment, a gap is defined between the half shaft and the hub and bearing assembly. The gap surrounds the ring and is disposed radially outward from the ring.

[0008] In an additional embodiment, fasteners are included to secure the hub and bearing assembly to the axle shaft. The fasteners are torqued to a selected torque value that optimizes noise suppression.

[0009] In additional embodiments, the selected torque value is selected so that the wall contacts the surface and fully compresses the ring into the groove.

[0010] In additional embodiments, the fastener is torqued to a selected torque value, wherein the selected torque value is approximately 20% to 30% of a conventional torque value.

[0011] In additional embodiments, the half shaft includes a splined shaft, a ring seal interface and a splined shaft.

[0012] In additional embodiments, a surface of the half-shaft is disposed perpendicular to a centerline of the half-shaft.

[0013] In additional embodiments, a wheel hub and bearing assembly includes a hub assembly having a hub body and a bearing assembly disposed about the hub body. A wall is disposed at an inboard end of the hub body, wherein the inboard end is located inboard relative to the vehicle.

[0014] In an additional embodiment, the ring has a cross-sectional shape that tapers in the axial direction.

[0015] In many other embodiments, a method for noise suppression for a vehicle includes constructing a half shaft for a driveline of the vehicle, and providing a surface for the half shaft. A hub and bearing assembly is coupled to the half shaft. The 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 half shaft. A ring is compressed in the groove between the half shaft and the hub and bearing assembly.

[0016] In an additional embodiment, a method includes forming a ring from a flexible elastic material.

[0017] In additional embodiments, the method includes defining a gap between the axle shaft and the hub and bearing assembly such that the gap surrounds the ring and is disposed radially outward from the ring.

[0018] In additional embodiments, a method includes securing a hub and bearing assembly to an axle shaft via a fastener; and torqueing the fastener to a selected torque value that optimizes noise suppression.

[0019] In additional embodiments, the method includes selecting a torque value selected such that the wall contacts the surface and fully compresses the ring into the groove.

[0020] In additional embodiments, the method includes torquing the fastener to a selected torque value that is approximately 20% to 30% of a conventional torque value to optimize noise suppression.

[0021] In additional embodiments, a method includes forming a splined shaft on the half shaft; and sealing the interface and the splined shaft with a ring.

[0022] In additional embodiments, the method includes forming a surface of the half-shaft to be disposed perpendicular to a centerline of the half-shaft.

[0023] In an additional embodiment, a method includes having a hub assembly with a hub body and a bearing assembly disposed about the hub body in a wheel hub and bearing assembly.A wall is formed at an inboard end of the hub body, wherein the inboard end is located inboard relative to the vehicle.

[0024] In a number of additional embodiments, a noise suppression system for a vehicle is provided, the vehicle including a driveline having an axle, the axle including a surface defining an annular shape around the axle. A hub and bearing assembly is coupled to the axle. The hub and bearing assembly includes a hub body having a wall that contacts the surface at an interface. The wall and / or the surface define a groove. A fastener holds the hub and bearing assembly to the axle. By torqueing the fastener, the flexible ring is compressed in the groove between the axle and the hub and bearing assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Exemplary embodiments will be described below with reference to the following drawings, wherein like numerals represent like elements, and wherein:

[0026] Figure 1 is a schematic diagram of a vehicle according to various embodiments;

[0027] Figure 2 According to various embodiments Figure 1 A perspective view of a half shaft of a transmission system of a vehicle;

[0028] Figure 3 According to various embodiments Figure 1 A partial exploded perspective view of a right front area of ​​a vehicle;

[0029] Figure 4 According to various embodiments Figure 1 A partial cross-sectional schematic diagram of the vehicle's half-axle to wheel bearing and hub assembly interface area;

[0030] Figure 5 According to various embodiments Figure 1 A partial cross-sectional schematic diagram of a noise suppression system area of ​​a transmission system of a vehicle; and

[0031] Figure 6 According to various embodiments Figure 1 A partial cross-sectional perspective view of an elastic element of a noise suppression system of a vehicle's driveline. DETAILED DESCRIPTION

[0032] 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.

[0033] refer to Figure 1 , shows an example of a vehicle 20 having a noise suppression system 22 in its transmission system 24. Figure 1 As depicted in FIG. 1 , the vehicle 20 generally includes a structure including a body 26 that is supported by a suspension assembly (eg, Figure 3 20) is supported on wheel assemblies 28. Body 26 can be of various types that define physical shapes for the desired purpose. Body 26 substantially surrounds the components of vehicle 20, and wheel assemblies 28 are each rotatably coupled near respective corners of body 26. In various embodiments, vehicle 20 can be a front-wheel drive vehicle, a rear-wheel drive vehicle, or an all-wheel drive vehicle as shown, with any number of wheels in each case. In additional embodiments, other drive arrangements are contemplated.

[0034] Propulsion of the vehicle 20 (such as on the road 32) is provided by a propulsion system 34 that includes a powerplant 36. The powerplant 36 may be any of a variety of types, such as electric, internal combustion, hybrid, or other. The torque generated by the powerplant 36 is transferred to the wheel assemblies 28 through the driveline 24. The driveline 24 includes a plurality of torque transfer elements that may be coupled to any number of the wheel assemblies 28. In this embodiment, the powerplant 36 is coupled to the front wheel assemblies 28 through a pair of half shafts 40 and 42 of the driveline 24.

[0035] The vehicle 20 is propelled by transferring torque from the powerplant 36 through the driveline 24, and using force generated as a result of traction due to friction between the wheel assemblies 28 and the road 32. In an embodiment, the wheel assemblies 28 may also be operable 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.

[0036] Additional references Figure 2 And continue to refer to Figure 1 , one half shaft 40 is shown separately. It should be understood that the other half shaft 42 is similar or identical to the half shaft 40. The half shaft 40 includes an inner end 44 configured to be directly or indirectly coupled to the power device 36 and an outer end 46 configured to be directly or indirectly coupled to the wheel assembly 28. For example, as a coupling mechanism, the inner end 44 includes a collar 48 and the outer end 46 includes a spline shaft 50. In other embodiments, different types of coupling mechanisms may be used.

[0037] The half shaft 40 is configured to allow the outboard end 46 to pivot at various angles relative to the inboard end 44 when rotated, such as to accommodate suspension travel and steering angles. Adjacent to the inboard end 44, or closer to the inboard end 44 than the inboard end 44, the half shaft 40 includes a joint assembly 52, such as a tripod joint, covered by a sleeve 54. Adjacent to or relatively closer to the outboard end 46, the half shaft 40 includes a joint assembly 56, such as a constant velocity joint, covered by a sleeve 58. The half shaft 40 includes a shaft 60 interconnecting the joint assemblies 52, 56. As a result, torque can be transmitted between the inboard end 44 and the outboard end 46, and suspension and steering travel can be accommodated.

[0038] refer to Figure 3 , a view of the area around the outboard end 46 of the half-shaft 40 shows selected aspects of the right front corner of the vehicle 20. The half-shaft 40 extends through the steerable suspension assembly 62 with its spline shaft 50 exposed. Shown removed from the spline shaft 50 is a hub and bearing assembly 64. The hub and bearing assembly 64 includes a bearing assembly 66 and a connected hub assembly 68. The hub and bearing assembly 64 includes a flange 70 for connecting with the suspension assembly 62 and presents a rotatable spline opening 72 for receiving the spline shaft 50. The hub assembly 68 includes a stud 74 for connecting with the wheel assembly 28. The hub and bearing assembly 64 is configured so that the hub assembly 68 can be rotated by the engaged half-shaft 40 with the flange 70 rotatably fixed to the suspension assembly 62.

[0039] refer to Figure 4 , schematically illustrating the interface area between the half shaft 40 and the hub and bearing assembly 64. The hub assembly 68 includes a flange 76 for coupling with the wheel assembly 28 (the studs 74 are omitted in this view). The hub assembly 68 includes a hub body 78 integral with the flange 76, which is tubular and extends through the bearing assembly 66. The shaft 50 of the half shaft 40 defines an axis 81 substantially along its centerline. The axial direction is along or parallel to the axis 81. The hub body 78 defines a spline opening 72 that receives the spline shaft 50 of the half shaft 40 along the axis 81.

[0040] The bearing assembly 66 is shown schematically and generally includes an outer race and a rotatable inner race, the outer race being configured such as by Figure 3The flange 70 is coupled to the suspension system 62, and the inner race supports the hub assembly 68 and the half shaft 40. An example bearing assembly is disclosed in the commonly assigned U.S. Patent No. 8,297,631B2, which is specifically incorporated herein by reference. The inner (inboard) end 80 of the hub body 78 is formed on the bearing assembly 66, such as by rolling, so as to form a wall 82 that protrudes radially outward from the hub body 78 and is annular in shape. The formation of the wall 82 fixes the bearing assembly 66 and the hub assembly 68 together in the hub and bearing assembly 64. The hub and bearing assembly 64 is fixed to the half shaft 40 by one or more fasteners, such as a nut 84 that is screwed onto a threaded section 86 that protrudes from the spline shaft 50 at the outboard end 46 of the half shaft 40. When torqued, the nut 84 forces the wall 82 against the surface 88 of the half shaft 40. In the current embodiment, the surface 88 faces laterally outward relative to the vehicle 20 and extends radially outward along the wall 82. In the current embodiment, the surface 88 is disposed in a plane perpendicular to the centerline of the half shaft 40 and defines an annular shape around the half shaft 40 toward the outboard end 46. In various embodiments, the surface 88 may serve as and may be referred to as an interface surface or contact surface with the hub and bearing assembly 64, or with the hub assembly 68, or with the bearing assembly 66.

[0041] There are various interfaces with the half shaft 40. For example, one interface 77 is the spline connection between the spline 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 half shaft 40 at the surface 88. There may be various other interfaces.

[0042] Regarding interfaces, the interface between the nut 84 and other components is generally not a concern for noise generation because the nut 84 is typically secured in place on the threaded portion 86 by a pin, such as a cotter pin (not shown), by a clip (not shown), or by other means.

[0043] As part of the current disclosure, it has been discovered that the interface between the wall 82 and the half shaft 40 at the surface 88 is a source of sounds that may be considered noise or may develop into noise over time. Due to intermittent and variable torque transmission, which may be described as fatigue cycling, including in both propulsion mode and regenerative braking mode, the surface 88 and / or the wall 82 may wear over time or may experience changing clamping loads. In addition, the wall 82 and / or the surface 88 at the interface may experience corrosion. As a result, a sound that may be described as a rattling sound may be generated.

[0044] Also as part of the present disclosure, it has been discovered that the interface between the hub body 78 and the spline shaft 50 of the half shaft 40 is a source of sound that may be considered noise or may develop into noise over time. The interface is also subject to intermittent and variable torque transfer, including in both propulsion mode and regenerative braking mode, which may be described as fatigue cycling. Oxidation / corrosion may occur on the spline surfaces in the interface, oxides may wear away, and new corrosion may occur in a repetitive manner. As a result, results such as micromotion may occur, which may cause the generated sound to change and may be classified as noise.

[0045] In general, the noise suppression system 22 can include various aspects, including a resilient element in the form of a ring 90 and including a nut 84, as further described below. In an embodiment, the ring 90 can be referred to as a noise suppression ring or a resilient element or a flexible element. In an embodiment, the ring 90 surrounds the half shaft 40 and / or its centerline. In an embodiment, the ring 90 can be annular in shape or can have another shape, such as a non-circular shape, a wavy shape, or an irregular shape. In an embodiment, the ring 90 can have a circular cross-sectional shape or another cross-sectional shape.

[0046] refer to Figure 5 , showing the interface area between the wall 82 and the half shaft 40 at the surface 88. A groove 92 is formed in at least one of the surface 88 and / or the wall 82. In this embodiment, a groove 92 is formed in the half shaft 40 at the surface 88. The groove 92 contains a ring 90. An adhesive may be used to hold the ring 90 in the groove 92. The groove 92 and the ring 90 are positioned closer to the outer diameter of the wall 82 than to its inner diameter to maximize the area of ​​the interface defined by the ring 90, thereby optimizing the prevention of noise transmission.

[0047] Ring 90 is annular in shape and is sized to be compressed between wall 82 and surface 88 when nut 84 is torqued. Elastic element / ring 90 is made of compressible and / or deformable or otherwise flexible material, and the material is selected to have enough toughness and temperature compatibility for the application environment. For example, ring 90 has physical strength and the ability to keep its characteristics after long-term exposure to heat, lubricants and forces. For example, a material that can withstand 80 degrees Celsius and deflect to 130 degrees Celsius can be selected. An example is a rubbery material, such as a hydrogenated nitrile rubber material, but other materials can also be considered.

[0048] 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 establishes metal-to-metal contact between the wall 82 and the surface 88 of the half shaft 40. Radially outward from the ring 90, a gap 93 may be provided between the wall 82 and the half shaft 40 at the surface 88. The gap 93 provides space between the wall 82 and the surface 88 in the area radially outward of the ring 90 that does not provide the benefit of the ring 90. In some embodiments, a washer (not shown) may be added between the wall 82 and the surface 88 / ring 90.

[0049] In various embodiments, to optimize the aforementioned features, the ring 90 may have a Figure 6 The configuration shown in . The ring 90 has a body 100 of a generally annular shape. In this embodiment, the ring 90, specifically the body 100, has a cross-sectional shape in which the thickness in the axial direction is greater than the thickness in the radial direction. In this embodiment, the ring 90 has a protrusion 101 protruding radially outward from the outer diameter of the body 100 and a protrusion 102 protruding radially inward from the inner diameter of the body 100. The protrusions 101 are spaced apart from each other and are arranged around the outer diameter of the body 100. The protrusions 102 are spaced apart from each other and are arranged around the inner diameter of the body 100. The cross-sectional size of the body 100 gradually decreases in both directions from its center 103 to the outer side 104 and to the inner side 105 in the axial direction. The inner side 105 is configured for insertion into the groove 92, and the protrusions 101, 102 engage the side of the groove 92, which acts as a clamp to keep the ring 90 in place in the groove 92 during processing. During assembly, the ring 90 is inserted into the groove 92, with the outer side 104 protruding outwardly from the groove 92 beyond the surface 88. After the hub and bearing assembly 64 is positioned, and as the nut 84 is torqued, force is applied to the outer side 104 through the hub and bearing assembly 64, with the wall 82 compressing the ring 90 into the groove 92. This forces the inner side 105 against the half shaft 40 within the groove 92, thereby ensuring secure contact on both sides. The cross-section of the ring 90 can be deformed under compression so that the material of the elastomeric ring 90 fills the groove 92 and provides a tight contact at the interface, including within the machining / tolerance variations of the interface components.

[0050] The inclusion of ring 90 provides many benefits. The presence of ring 90 changes the acoustic properties of the interface element, such as by changing the natural frequency. In an embodiment, ring 90 can provide damping of vibrations. In addition, adding ring 90 changes the way energy is radiated, thereby providing attenuation, especially in the higher frequency range where sound may not be expected. In addition to changing the vibration before it occurs, ring 90 can also block sound from emitting / radiating from the interface, thereby acting as a barrier. In addition, ring 90 seals the interface from external elements, preventing liquids and other corrosive elements from entering the interface between wall 82 and half shaft 40, and preventing entry into the interface between hub body 78 and spline shaft 50, thereby avoiding the generation of noise.

[0051] In addition to including the ring 90 in the noise suppression system 22, as part of the method for the noise suppression system 22, the torque on the nut 84 can be customized to reduce / avoid noise. Without using the current disclosure, the torque used to tighten the hub and bearing assembly 64 and the half shaft 40 together is set to a level (conventional torque value) that is maximized for retention purposes and below an upper threshold value. The upper threshold value is the torque value that compresses the bearing assembly 66 to the deformation / damage point. Therefore, the torque is generally maximized as much as possible. In multiple embodiments of the present disclosure, the torque (selected torque value) is selected to be higher than but approximately the lower threshold value. The lower threshold value is the torque value at which the ring 90 is compressed into the groove 92 and the wall 82 contacts the surface 88, which has been found to provide optimized and safe noise suppression. It has been found that higher torque levels may reduce noise suppression characteristics. In this case, the torque is set to a selected torque value of about 20%-30% of the standard torque value. Non-limiting specific examples include a conventional torque value of 250Nm and a selected torque value of 50Nm. In this way, the torque is reduced than expected and the noise suppression characteristics are optimized.

[0052] By using the ring 90, the torque on the nut 84 can be reduced to a selected torque value, which has been found to help eliminate the undesirable sound. In an embodiment, the torque is selected at a level 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 can be performed to determine the optimal torque on the fastener / nut 84 to avoid generating undesirable sounds.

[0053] Therefore, a noise suppression system and method are provided that addresses potential transmission system 24 sounds. Undesirable sounds can be reduced or eliminated, and the benefits persist over long periods of time during repeated fatigue cycles. Although at least one exemplary embodiment has been presented in the foregoing detailed description, it should be understood that there are a large number of variations. It should also be understood that the exemplary embodiment or multiple exemplary embodiments are merely examples and are not intended to limit the scope, applicability, or configuration of the present disclosure in any way. On the contrary, the foregoing detailed description will provide those skilled in the art with a convenient roadmap for implementing the exemplary embodiment or multiple exemplary embodiments. It should be understood that various changes may be made to the function and arrangement of the elements without departing from the scope of the present disclosure as set forth in the appended claims and their legal equivalents.

Claims

1. A noise suppression system for a vehicle, comprising: an axle shaft configured for use in a driveline of the vehicle, the axle shaft having a surface; a hub and bearing assembly configured to couple with the axle shaft, the hub and bearing assembly comprising a wall contacting the surface at an interface, wherein at least one of the wall and the axle shaft defines a groove; as well as A ring is configured to be compressed in the groove between the axle shaft and the hub and bearing assembly.

2. The noise suppression system according to claim 1, wherein: The ring comprises a flexible elastic material.

3. The noise suppression system according to claim 1, wherein: A gap is defined between the half shaft and the hub and bearing assembly, the gap surrounding the ring and disposed radially outwardly from the ring.

4. The noise suppression system of claim 1, comprising a fastener configured to secure the hub and bearing assembly to the axle shaft, wherein: The fastener is torqued to a torque value selected to optimize noise suppression.

5. The noise suppression system according to claim 4, wherein: The selected torque value is selected so that the wall contacts the surface and fully compresses the ring into the groove.

6. The noise suppression system according to claim 4, wherein: The fastener is torqued to a selected torque value, wherein the selected torque value is approximately 20% to 30% of a conventional torque value.

7. The noise suppression system of claim 1, comprising a splined shaft on the half shaft, wherein: The ring is configured to seal the interface and the splined shaft.

8. The noise suppression system of claim 1, wherein: The surface of the semi-shaft is arranged perpendicular to the center line of the semi-shaft.

9. A method for noise suppression in a vehicle, comprising: constructing an axle shaft configured for use in a driveline of the vehicle and providing a surface for the axle shaft; coupling a hub and bearing assembly to the axle shaft, the hub and bearing assembly including a wall contacting the surface at an interface; forming a groove in at least one of the wall and the half shaft; as well as A ring is compressed in the groove between the axle shaft and the hub and bearing assembly.

10. The method of claim 9 including defining a gap between the axle shaft and the hub and bearing assembly such that the gap surrounds the ring and is disposed radially outward from the ring.

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