WO2015065877A1

WO2015065877A1 - Propshaft assembly with damper

Info

Publication number: WO2015065877A1
Application number: PCT/US2014/062340
Authority: WO
Inventors: Michael Voight; Jeffrey P. Nyquist; Zhaohui Sun; Jason Ley; William Braun
Original assignee: Michael Voight; Nyquist Jeffrey P; Zhaohui Sun; Jason Ley; William Braun
Priority date: 2013-10-30
Filing date: 2014-10-27
Publication date: 2015-05-07

Abstract

A propshaft assembly that includes a tubular member, first and second end connections coupled to opposite ends of the tubular member, and a damper received in the tubular member and positioned between the first and second end connections. The damper includes a core, a first damping member and a second damping member. The core is a hollow structure. The first damping member is fixedly coupled to the core. The first damping member includes a contact element that extends radially from and helically about the core. The contact element is formed of an elastic, rubbery material and is engaged to the interior circumferential surface. The second damping member is formed of closed-cell foam and fixedly coupled to the core. The second damping member extends helically about the core and engages the interior cylindrical surface.

Description

PROPSHAFT ASSEMBLY WITH DAMPER

FIELD

[0001] The present disclosure relates to a propshaft assembly with a damper.

BACKGROUND

[0002] This section provides background information related to the present disclosure which is not necessarily prior art.

[0003] The consumers of modern automotive vehicles are increasingly influenced in their purchasing decisions and in their opinions of the quality of a vehicle by their satisfaction with the vehicle's sound quality. In this regard, consumers increasingly expect the interior of the vehicle to be quiet and free of noise from the power train and drive line. Consequently, vehicle manufacturers and their suppliers are under constant pressure to reduce noise to meet the increasingly stringent expectations of consumers.

[0004] Drive line components and their integration into a vehicle typically play a significant role in sound quality of a vehicle as they can provide the forcing function that excites specific driveline, suspension and body resonances to produce noise. Since this noise can be tonal in nature, it is usually readily detected by the occupants of a vehicle regardless of other noise levels. Common driveline excitation sources can include driveline imbalance and/or runout, fluctuations in engine torque, engine idle shake, and motion variation in the meshing gear teeth of the hypoid gear set (i.e., the pinion gear and the ring gear of a differential assembly).

[0005] Propshafts are typically employed to transmit rotary power in a drive line. Modern automotive propshafts are commonly formed of relatively thin-walled steel or aluminum tubing and as such, can be receptive to various driveline excitation sources. The various excitation sources can typically cause the propshaft to vibrate in a bending (lateral) mode, a torsion mode and a shell mode. Bending mode vibration is a phenomenon wherein energy is transmitted longitudinally along the shaft and causes the shaft to bend at one or more locations. Torsion mode vibration is a phenomenon wherein energy is transmitted tangentially through the shaft and causes the shaft to twist. Shell mode vibration is a phenomenon wherein a standing wave is transmitted circumferentially about the shaft and causes the cross-section of the shaft to deflect or bend along one or more axes.

[0006] Several techniques have been employed to attenuate vibrations in propshafts including the use of weights and liners. U.S. Patent No. 2,001 ,166 to Swennes, for example, discloses the use of a pair of discrete plugs or weights to attenuate vibrations. The weights of the Ί 66 patent are frictionally engaged to the propshaft at experimentally-derived locations and as such, it appears that the weights are employed as a resistive means to attenuate bending mode vibration. As used herein, resistive attenuation of vibration refers to a vibration attenuation means that deforms as vibration energy is transmitted through it (i.e., the vibration attenuation means) so that the vibration attenuation means absorbs (and thereby attenuates) the vibration energy. While this technique can be effective, the additional mass of the weights can require changes in the propshaft mounting hardware and/or propshaft geometry (e.g., wall thickness) and/or can change the critical speed of the propshaft. Moreover, as the plugs tend to be relatively short, they typically would not effectively attenuate shell mode vibration or torsion mode vibration.

[0007] U.S. Patent No. 2,751 ,765 to Rowland et al., U.S. Patent No. 4,014,184 to Stark and U.S. Patent Nos. 4,909,361 and 5,976,021 to Stark et al. disclose hollow liners for a propshaft. The 765 and Ί 84 patents appear to disclose hollow multi-ply paperboard or cardboard liners that are press-fit to the propshaft; the liners are relatively long and appear to extend substantially coextensively with the hollow shaft. The '361 and Ό21 patents appear to disclose liners having a hollow cardboard core and a helical retaining strip that extends a relatively short distance (e.g., 0.03 inch) from the outside diameter of the core. The retaining strip has high frictional properties to frictionally engage the propshaft. Accordingly, the liners of the 765, Ί 84, '361 and Ό21 patents appear to disclose a resistive means for attenuating shell mode vibration.

[0008] In view of the foregoing, there remains a need in the art for an improved propshaft assembly that is more effectively damped to control shell mode vibration. SUMMARY

[0009] This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features.

[0010] In one form, the present teachings provide a propshaft assembly that includes a tubular member, first and second end connections coupled to opposite ends of the tubular member, and a damper received in the tubular member and positioned between the first and second end connections. The damper includes a core, a first damping member and a second damping member. The core is a hollow structure. The first damping member is fixedly coupled to the core. The first damping member includes a contact element that extends radially from and helically about the core. The contact element is formed of an elastic, rubbery material and is engaged to the interior circumferential surface. The second damping member is formed of closed-cell foam and fixedly coupled to the core. The second damping member extends helically about the core and engages the interior cylindrical surface.

[0011] In a further form, the present teachings provide a method for assembling a propshaft assembly. The method includes: providing a tubular member having a wall member that defines an interior circumferential surface; providing a damper having a core and at least one damping member that is coupled to the core, the at least one damping member extending helically about the core in a predetermined helical direction; and inserting the damper into the interior circumferential surface while simultaneously rotating the damper in the predetermined helical direction relative to the tubular member.

[0012] In yet another form, the present teachings provide a propshaft assembly that includes a tubular member, first and second end connections coupled to opposite ends of the tubular member, and a damper received in the tubular member and positioned between the first and second end connections. The tubular member has a wall member that defines an interior circumferential surface. The damper includes a core and a plurality of damping members. The core is a hollow structure. Each of the damping members is fixedly coupled to the core and includes a contact element that extends radially from and helically about the core. The contact elements are formed of an elastic, rubbery material and are engaged to the interior circumferential surface. The damping members are spaced circumferentially apart from one another by an equal amount.

[0013] Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.

DRAWINGS

[0014] The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.

[0015] Figure 1 is a schematic illustration of an exemplary vehicle constructed in accordance with the teachings of the present disclosure;

[0016] Figure 2 is a top partially cut-away view of a portion of the vehicle of Figure 1 illustrating the rear axle and the propshaft assembly in greater detail;

[0017] Figure 3 is a sectional view of a portion of the rear axle and the propshaft assembly;

[0018] Figure 4 is a top, partially cut away view of the propshaft assembly;

[0019] Figure 5 is a view similar to that of Figure 4 but illustrating a propshaft assembly that employs a tubular member having two necked-down areas;

[0020] Figure 6 is a section view taken along the line 6-6 of Figure 4;

[0021] Figure 7 is a top, partially cut away view of another propshaft assembly constructed in accordance with the teachings of the present disclosure; and

[0022] Figure 8 is an end view of a portion of the propshaft assembly of Figure 7 taken in the direction of arrow 8 in Figure 7 and illustrating an end of a damper.

[0023] Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings. DETAILED DESCRIPTION

[0024] With reference to Figure 1 of the drawings, an exemplary vehicle constructed in accordance with the teachings of the present disclosure is generally indicated by reference numeral 10. The vehicle 10 can include an engine 14 and a drive line 16. The drive line 16 can include a transmission 18, a propshaft assembly 20, a rear axle 22 and a plurality of wheels 24. The engine 14 can produce rotary power that can be transmitted to the transmission 18 in a conventional and well known manner. The transmission 18 can be conventionally configured and can include a transmission output shaft 18a and a gear reduction unit (not specifically shown). As is well known in the art, the gear reduction unit can change the speed and torque of the rotary power provided by the engine such that a rotary output of the transmission 18 (which can be transmitted through the transmission output shaft 18a) can have a relatively lower speed and higher torque than that which was input to the transmission 18. The propshaft assembly 20 can be coupled for rotation with the transmission output member 18a to permit drive torque to be transmitted from the transmission 18 to the rear axle 22 where can be selectively apportioned in a predetermined manner to the left and right rear wheels 24a and 24b, respectively.

[0025] It will be appreciated that while the vehicle in the particular example provided employs a drive line with a rear-wheel drive arrangement, the teachings of the present disclosure have broader applicability. In this regard, a shaft assembly constructed in accordance with the teachings of the present disclosure may interconnect a first drive line component with a second drive line component to transmit torque therebetween. In the context of an automotive vehicle, the drive line components could be a transmission, a transfer case, a viscous coupling, an axle assembly, or a differential, for example.

[0026] With reference to Figure 2, the rear axle 22 can include a differential assembly 30, a left axle shaft assembly 32 and a right axle shaft assembly 34. The differential assembly 30 can include a housing 40, a differential unit 42 and an input shaft assembly 44. The housing 40 can support the differential unit 42 for rotation about a first axis 46 and can further support the input shaft assembly 44 for rotation about a second axis 48 that is perpendicular to the first axis 46.

[0027] With additional reference to Figure 3, the housing 40 can be formed in a suitable casting process and thereafter machined as required. The housing 40 can includes a wall member 50 that can define a central cavity 52 that can have a left axle aperture 54, a right axle aperture 56, and an input shaft aperture 58. The differential unit 42 can be disposed within the central cavity 52 of the housing 40 and can include a case 70, a ring gear 72, which can be fixed for rotation with the case 70, and a gearset 74 that can be disposed within the case 70. The gearset 74 can include first and second side gears 82 and 86 and a plurality of differential pinions 88, which can be rotatably supported on pinion shafts 90 that can be mounted to the case 70. The case 70 can include a pair of trunnions 92 and 96 and a gear cavity 98. A pair of bearing assemblies 102 and 106 can support the trunnions 92 and 96, respectively, for rotation about the first axis 46. The left and right axle assemblies 32 and 34 can extend through the left and right axle apertures 54 and 56, respectively, where they can be coupled for rotation about the first axis 46 with the first and second side gears 82 and 86, respectively. The case 70 can be operable for supporting the plurality of differential pinions 88 for rotation within the gear cavity 98 about one or more axes that can be perpendicular to the first axis 46. The first and second side gears 82 and 86 each include a plurality of teeth 1 08 which meshingly engage teeth 1 10 that are formed on the differential pinions 88.

[0028] The input shaft assembly 44 can extend through the input shaft aperture 58 where it can be supported in the housing 40 for rotation about the second axis 48. The input shaft assembly 44 can include an input shaft 120, a pinion gear 122 having a plurality of pinion teeth 124 that meshingly engage the teeth 126 that are formed on the ring gear 72, and a pair of bearing assemblies 128 and 130 that can cooperate with the housing 40 to rotatably support the input shaft 120. The input shaft assembly 44 can be coupled for rotation with the propshaft assembly 20 and can be operable for transmitting drive torque to the differential unit 42. More specifically, drive torque received the input shaft 120 can be transmitted by the pinion teeth 124 to the teeth 126 of the ring gear 72 such that drive torque is distributed through the differential pinions 88 to the first and second side gears 82 and 86.

[0029] The left and right axle shaft assemblies 32 and 34 can include an axle tube 150 that can be fixed to the associated axle aperture 54 and 56, respectively, and an axle half-shaft 152 that can be supported for rotation in the axle tube 150 about the first axis 46. Each of the axle half-shafts 152 can include an externally splined portion 154 that can meshingly engage a mating internally splined portion (not specifically shown) that can be formed into the first and second side gears 82 and 86, respectively.

[0030] With reference to Figure 4, the propshaft assembly 20 can include a tubular member 200, a first end connection 202a, a second end connection 202b, and a damper 204. The tubular member and the first and second end connections 202a and 202b can be conventional in their construction and need not be described in significant detail herein. Briefly, the tubular member 200 can be formed of an appropriate structural material, such as steel or aluminum, and can include an annular wall member 224. The annular wall member 224 can have an interior circumferential surface 228 and can define a hollow cavity 230. Depending on the particular requirements of the vehicle 10 (Fig. 1 ), the wall member 224 may be sized in a uniform manner over its entire length, as is shown in Figure 4, or may be necked down or stepped in diameter in one or more areas along its length, as is shown in Figure 5. The first and second end connections 202a and 202b can be configured to couple the propshaft assembly 20 to other rotary components of the vehicle 10 (Fig. 1 ) in a desired manner to transmit rotary power therebetween. For example, the first end connection 202a and/or the second end connection 202b could comprise a universal joint (e.g., Cardan or constant velocity joint) or components thereof. Optionally, one or both of the first and second end connections 202a and 202b can be vented to permit air to flow into or out of the hollow cavity 230. In the particular example provided, a vent 232 is installed to each of the first and second end connections 202a and 202b. In the particular example provided, the vents 232 comprise holes formed in the first and second end connections 202a and 202b, but it will be appreciated that the vent(s) 232 can be constructed in any desired manner. [0031] With reference to Figures 4 and 6, the damper 204 can comprise a base or core 250, a first damping member 252 and a second damping member 254. The core 250 can be formed of an appropriate structural material, such as a lightweight fibrous material. For example, the core 250 can be formed of two or more plies of paperboard or cardboard, wherein the plies can overlie one another in a desired manner. In the example provided, the core 250 is formed of paperboard and the plies are helically wrapped.

[0032] The first damping member 252 can be configured to dampen shell mode vibration transmitted through the tubular member 200. Shell mode vibration, also known as breathing mode vibration, is a phenomenon wherein a standing wave is transmitted circumferentially about the tubular member 200 and causes the cross-section of the shaft to deflect (e.g., expand or contract) and/or bend along one or more axes.

[0033] The first damping member 252 can comprise a length of an elastic, rubbery material, such as ethylene propylene diene monomer (EPDM) rubber or silicone rubber, having friction properties much greater than those of the inside circumferential surface of the tubular member 200. The first damping member 252 can be fixedly coupled to the core 250 and can extend radially outwardly therefrom where it can terminate at one or more contact elements 260, such protuberances, fingers, projections, that are configured to contact the inside circumferential surface 228 of the tubular member 200. In the particular example provided, the first damping member 252 is generally T-shaped, having a base 262, which is fixedly coupled to the core 250, and a single contact element 260 that is shaped as a finger that extends perpendicularly from the base 262. The first damping member 252 can be secured to the core 250 in any desired manner. For example, the first damping member 252 can be bonded to the core 250 with a suitable adhesive material such that the first damping member 252 extends helically about the core 250. The base 262 in the example provided is bonded to an intermediate ply 270 of paperboard (i.e., a ply that is disposed radially inwardly of the outermost ply 272 and radially outwardly of the innermost ply 274) and the plys of paperboard that are disposed radially outwardly of the intermediate ply 270 are wrapped such that the sides of the material that forms the ply are abutted against the first damping member 252. In the example shown, the edges 280 of a first one of the plys 282 that is disposed radially outwardly of the intermediate ply 270 are abutted against the lateral sides 284 of the base 262, while the edges 286 of the outermost ply 272 are abutted against the lateral sides 288 of the contact element 260 such that the outermost ply 272 overlies the base 262 on its radially outward side. The helical pitch of the first damping member 252can be selected to provide a desired level of damping.

[0034] The second damping member 254 can also be configured to dampen shell mode vibration transmitted through the tubular member 200. In the particular example provided, the second damping member 254 is a strip of damping material that is wound helically about the core 250 and bonded to the core 250 via an appropriate adhesive. The damping material can be a foam, such as a closed cell foam that can be formed of a suitable material. Examples of suitable materials include polyethylene; polyurethane; sponge rubber; PVC and vinyl nitrile blends; PP and nylon foam blends; and melamine, polyimide and silicone. The damping material can have an appropriate density, such as between 1 .0 pounds per cubic foot to 2.5 pounds per cubic foot, preferably between 1 .2 pounds per cubic foot to about 1 .8 pounds per cubic foot, and more preferably between 1 .20 pounds per cubic foot to 1 .60 pounds per cubic foot.

[0035] The width of the strip that forms the second damping member 254 can be sized to correspond to the pitch of the first damping member 252. In the example provided, the width of the strip that forms the second damping member 254 is somewhat less than the pitch of the first damping member 252 such that the sides - of the strip of material are spaced apart from the contact element 260 of the first damping member 252 by a desired to form a gap 290 of a desired size between the contact element 260 and each of the lateral sides 288. Accordingly, a single strip can be employed to fill the desired space between the helical wraps of the first damping member 252. It will be appreciated, however, that multiple strips can be employed to form the second damping member 254.

[0036] The height of the second damping member 254 can be sized in a manner so that the strip of material is compressed between the core 250 and the inside circumferential surface 228 of the tubular member 200 to a desired degree. For example, the height of the strip of material can be sized so that the outer diameter of the damper 204 (taken across the second damping member 254) is about 5% to about 20% larger than the diameter of the inside circumferential surface 228 of the tubular member 200, and more preferably about 10% larger than the diameter of the inside circumferential surface 228 of the tubular member 200.

[0037] The damper 204 can be tuned for a particular vehicle configuration in part by altering one or more characteristics of the components of the damper 204, including the length of the core 250, the damping characteristics of the first damping member 252, the extent to which the first damping member 252 extends over the length of the core 250, the damping characteristics of the second damping member 254 and the extent to which the second damping member 254 extends over the length of the core 250.

[0038] For example, the first damping member 252 can extend over substantially all of the length of the core 250, and/or the first and second damping members 252 and 254 can extend over an equal extent of the length of the core 250. In the particular example provided, the first and second damping members 252 and 254 can extend over an equal extent of the length of the core 250 and the extent of the core 250 that the second damping member 254 extends over is coincident with the extent of the core 250 that the first damping member 252 extends over

[0039] The damper 204 can be installed to the tubular member 200 in any desired manner. For example, the damper 204 can be pushed into the tubular member 200 with a ram (not shown). Optionally, the damper 204 can be rotated in the direction of the helix of the first damping member 252 as the damper 204 is pushed into the tubular member 200.

[0040] With reference to Figures 7 and 8, another damper constructed in accordance with the teachings of the present disclosure is generally indicated by reference numeral 204'. The damper 204' can include a core 250' and two or more damping members 252'. The core 250' can be formed of an appropriate structural material, such as a lightweight fibrous material. For example, the core 250' can be formed of two or more plies of paperboard or cardboard, wherein the plies can overlie one another in a desired manner. In the example provided, the core 250' is formed of paperboard and the plies are helically wrapped.

Claims

[0041] The damping members 252' can be constructed in a manner that is generally similar to the construction of the first damping member 252 (Fig. 6). The damping members 252' can also be secured to the core 250' in a manner that is generally similar to the manner in which the first damping member 252 (Fig. 6) is secured to the core 250 (Fig. 6). The damping members 252' can have the same pitch, but can be offset from one another about the core 250' by an angle (in degrees) equal to 360/n where (n) is the quantity of the damping members 252' (i.e., the damping members 252' can be spaced evenly apart in a circumferential direction). In the example provided, the quantity (n) is equal to (2) so that the damping members 252' are circumferentially spaced apart from one another by 180 degrees. Construction in this manner provides additional flexibility in tuning the damper 204' to a particular propshaft assembly and aids in maintaining the core 250' in a position that is centered in the tubular member 200. [0042] The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure. CLAIMS What is claimed is:

1 . A propshaft assembly comprising:

a tubular member having a wall member that defines an interior circumferential surface;

first and second end connections coupled to opposite ends of the tubular member; and

a damper received in the tubular member and positioned between the first and second end connections, the damper comprising a core, a first damping member and a second damping member, the core being a hollow structure, the first damping member being fixedly coupled to the core, the first damping member comprising a contact element that extends radially from and helically about the core, the contact element being formed of an elastic, rubbery material and being engaged to the interior circumferential surface, the second damping member being formed of closed-cell foam and fixedly coupled to the core, the second damping member extending helically about the core and engaging the interior cylindrical surface.

2. The propshaft assembly of Claim 1 , wherein the first damping member extends over substantially all of the length of the core.

3. The propshaft assembly of Claim 1 , wherein the first and second damping members extend over an equal extent of the length of the core.

4. The propshaft assembly of Claim 3, wherein the extent of the core that the second damping member extends over is coincident with the extent of the core that the first damping member extends over. 5. The propshaft assembly of Claim 1 , wherein the closed-cell foam has a density of between 1 .0 pounds per cubic foot and 2.

5 pounds per cubic foot.

6. The propshaft assembly of Claim 5, wherein the density is between 1 .2 pounds per cubic foot and 1 .8 pounds per cubic foot.

7. The propshaft assembly of Claim 6, wherein the density is between 1 .20 pounds per cubic foot and 1 .60 pounds per cubic foot.

8. The propshaft assembly of Claim 1 , wherein the core is formed of a fibrous material.

9. The propshaft assembly of Claim 8, wherein the fibrous material is a cardboard or a paperboard.

10. The propshaft assembly of Claim 1 , wherein a gap is disposed between contact element and a side of the second damper member.

1 1 . The propshaft assembly of Claim 1 , wherein a diameter of the damper taken about an outside surface of the second damping member is 5% to 20% larger than a diameter of the inside circumferential surface prior to the insertion of the damper into the tubular member.

12. The propshaft assembly of Claim 1 1 , wherein the diameter of the damper taken about the outside surface of the second damping member is about 10% larger than the diameter of the inside circumferential surface prior to the insertion of the damper into the tubular member.

13. A method for assembling a propshaft assembly comprising:

providing a tubular member having a wall member that defines an interior circumferential surface;

providing a damper having a core and at least one damping member that is coupled to the core, the at least one damping member extending helically about the core in a predetermined helical direction ; and inserting the damper into the interior circumferential surface while simultaneously rotating the damper in the predetermined helical direction relative to the tubular member.

14. A propshaft assembly comprising:

a damper received in the tubular member and positioned between the first and second end connections, the damper comprising a core and a plurality of damping members, the core being a hollow structure, each of the damping members being fixedly coupled to the core and comprising a contact element that extends radially from and helically about the core, the contact elements being formed of an elastic, rubbery material and being engaged to the interior circumferential surface, wherein the damping members are spaced circumferentially apart from one another by an equal amount.