The disclosure generally relates to constant velocity joints and more particularly, to high angle, high-speed constant velocity joints and protective high angle joint boots.
Articulating joints are common components in all types of automotive vehicles. Articulating joints are typically used where transmission of rotary motion is desired or required. In other words, articulating joints operate to transmit torque between two rotational members. The rotational members are typically interconnected by a cage or yoke that allow operation at relative angles and are typically sealed by a boot cover assembly. The joints typically connect shafts to drive units, which characteristically have an output shaft or an input shaft for receiving the joint. The drive unit may be an axle, transfer case, transmission, power take-off unit, or other torque transmitting device, all of which are common components in automotive vehicles.
Common types of articulating joints include but are not limited to, double cardan joint, a plunging tripod constant velocity (CV) joint, a fixed tripod CV joint, a plunging ball CV joint, and a fixed ball CV joint. These joints can be used in a variety of different configurations, including four wheel drive vehicles, all wheel drive vehicles, front wheel drive vehicles or rear wheel drive vehicles. Single or double cardan joints are typically used where high driveline operating angles over 8° are encountered. Double cardan joints are typically used to remove vibration and joint bind found in high angle drivelines using a single universal joint. A double cardan joint configuration uses two universal joints joined back to back, which cancels any velocity error that may be introduced by a single joint and functions similarly to a constant velocity joint. However, the cardan joint is heavy and adds greater weight to the driveline.
Constant velocity joints are commonly classified by their operating characteristics. One important operating characteristic relates to the relative angular velocities of the two shafts connected thereby. In a constant velocity joint, the instantaneous angular velocities of the two shafts are always equal, regardless of the relative angular orientation between the two shafts. In a non-constant velocity joint the instantaneous angular velocities of the two shafts vary with the angular orientation (although the average angular velocities for a complete rotation are equal). Another important operating characteristic of the constant velocity joint is the ability of the joint to provide similar articulation between the two shafts, as does the cardan joint, while eliminating driveline vibrations and weight savings.
Unlike cardan joints, all of these constant velocity joints are generally grease lubricated for life and sealed by a sealing boot when used on drive members. Thus, the constant velocity joints are sealed in order to retain grease inside the joint while keeping contaminants and foreign matter, such as dirt and water, out of the joint. The sealing protection of the constant velocity joint is necessary, because contamination of the inner chamber may cause internal damage and destruction of the joint, which increases heat and wear on the boot, inevitably leading to premature boot and grease failures and failure of the overall joint. The problem of higher temperatures in high speed constant velocity joint is also greatly enhanced at the higher angles. Thus, the increased temperatures because of the higher angles, along with increased stresses on the boot caused by higher angles, may result in premature failures of the prior art constant velocity joints.
In a typical prior art constant velocity joint, a bulky and heavy outer race is used, having a spherical inner surface and a plurality of grooves on a surface therein. The joints also include an inner race, having a spherical outer surface with guide grooves formed therein. The prior art constant velocity joints use six torque transmitting balls, which are arranged between the guide grooves and the outer and inner race surfaces of the constant velocity joint by a cage retainer. The balls allow a predetermined displacement angle to occur through the joint thus, transmitting a constant velocity through the shafts of the automotive drive train system. The standard fixed high angle and high-speed constant velocity joints have limitations to operational articulation clearance between the shaft and the boot, as well as similar assembly angle limitations, while the double cardan joints are bulky, require greater maintenance due to the lack of a sealing boot, and are typically inefficient as compared to a true constant velocity joint. However, the use of a constant velocity joint requires a resilient and robust sealing system that can handle the high angle up and down excursions in conjunction with the rotational speeds required for propshafts, which are typically in the range of 3500 RPMs to 8000 RPMs. These limitations result in premature failure of the joints due to lack of a sealing boot and damage to the sealing boot from contact between the joint and boot during full suspension jounce articulation.
Therefore, there is a need in the art for a joint that is lighter, efficient and more robust than a typical cardan joint or a standard constant velocity joint. There is also a need in the art for a constant velocity joint sealing system that is capable of having greater articulation during installation, while providing greater operating articulation and resistivity to boot and joint damage during full suspension jounce articulation.
Referring now to the drawings, illustrative embodiments are shown in detail. Although the drawings represent some embodiments, the drawings are not necessarily to scale and certain features may be exaggerated, removed, or partially sectioned to better illustrate and explain the present invention. Further, the embodiments set forth herein are exemplary and are not intended to be exhaustive or otherwise limit or restrict the claims to the precise forms and configurations shown in the drawings and disclosed in the following detailed description.
Referring to the drawings and
A typical driveline for a vehicle includes a plurality of constant velocity joints 10 with at least one constant velocity joint being a high angle constant velocity joint 60. However, it should be noted that the constant velocity joint disclosed herein can be used in rear wheel drive only vehicles, front wheel drive only vehicles, all wheel drive vehicles and four wheel drive vehicles. Generally, a driveline includes an engine that is connected to a transmission and a power take-off unit or transfer case interconnected to at least one differential. A front differential may have a right hand side shaft and a left hand side shaft, each of which are connected to a wheel and deliver power to the wheels. On both ends of the right hand front side shaft and left hand front side shaft are constant velocity joints. A propeller shaft connects the front differential and the rear differential to the transfer case or power take-off unit. The rear differential may include a right hand rear side shaft and a left hand rear side shaft, each of which ends with a wheel on an end thereof. Generally, a constant velocity joint is located on both ends of the side shaft that connect to the wheel and the rear differential. The propeller shaft generally may be a multi-piece propeller shaft that includes a plurality of joints, specifically high speed constant velocity joints. Typically, at least one of the joints on the propeller shaft may be a high angle high speed constant velocity joint (HACVJ) 60. The HACVJ 60 transmits power to the wheels through the drive shaft even if the wheels or the shaft have changing angles due to steering, raising or lowering of the suspension of the vehicle, etc. The HACVJ 60 allows for transmission of constant velocities at a variety of angles, which are found in everyday driving of automotive vehicles on both the half shafts and prop shafts of these vehicles. The high angle movement feature enables the shaft to articulate at greater operating angles above 10° and full suspension jounce articulation angle above 15° without damaging the constant velocity joint assembly during various suspension angle changes in the drive line.
Positioned within the circumferentially shaped cavity 64 is an inner race 80. The inner race 80 includes an outer surface 82 and an inner surface 84. The inner race outer surface 82 includes a plurality of indentations or tracks 86 that correspond to a plurality of indentations or tracks 88 positioned in the inner surface 66 of the outer race 62. When inner race 80 is positioned with outer race 62, the tracks 86, 88 create channels for receiving a plurality of torque transmitting balls 96 that are retained within a cage 94. The tracks 86, 88 may be counter tracks where a first channel set may open towards the aperture 71 and a second channel set may open away from the aperture 71. The first set of channels may be spaced an equidistance with every other channel being a first channel or front track with the other channel being the second channel or rear track. A rotation of the outer race 62 will rotate the inner race 80 at the same or constant speed thus allowing for constant velocity to flow through the joint 60 in a straight line or through an angle up to a predetermined fixed angle (See
Additionally, the tracks 86, 88 may include the first front track and the second rear track. The front track may extend a length range of approximately 18.5 mm to approximately 22.5 mm and have a front track wrap angle ratio range of approximately 16° to approximately 19.5° with a front track length and front wrap angle ratio increase of approximately 19.8% over previous designs. The rear track may extend a length range of approximately 30 mm to approximately 34 mm and have an approximate rear track wrap angle ratio range of approximately 30° to approximately 34° with a rear track length ratio increase of 6.8% over previous designs and a rear wrap angle ratio increase of approximately 6.5% over previous designs. The wrap angle may be the angle range in which the torque transmitting ball 96 is surrounded by the associated channel. The front and rear track lengths and the front and rear track wrap angle ratios provide a path allowing the torque transmitting balls 96 to rotate and extend or rotatively travel in opposite directions while providing proper strength and support through the wrap angle ratios described above. This rotational travel allows the HACVJ 60 inner race 80 to articulate and move relative to the outer race 62 as the torque transmitting balls 96 roll within the tracks 86, 88. This rolling motion is a function of clearance provided by the relationship of the tracks 86, 88, which aids in keeping the balls from sliding and eliminates any added friction when the balls do not roll. The track length and the track wrap angle ratios provide the basis for allowing the HACVJ 60 to articulate at such high angles without placing the joint in bind or allowing the balls to extend outside the circumferentially shaped cavity 64, which would result in HACVJ 60 failure.
As illustrated, the inner surface 84 may define a generally cylindrical through aperture 90 for receiving a shaft 92. However, depending on the application, the inner race 80 may also be formed with an integral shaft 92. The shaft 92 connects the HACVJ 60 to at least one of the propeller shafts 40, 42, the differentials 32, 44, or the power take-off unit 26. The outer race 62 and inner race 80 are generally made of a steel material; however it should be noted that any other type of metal material, hard ceramic, plastic, polymer or composite material, etc. may also be used for the outer 62 and inner 80 races. The material is required to be able to withstand the high speeds, temperatures and contact pressures of the HACVJ 60. As illustrated, the outer race 62 generally extends into a mounting flange 70. Additionally, the circumferentially shaped cavity 64 may also include the sealing cap 72, which may be used to minimize the amount of open space available within the cavity 64. The minimized space may help to reduce the volume of lubricant required for the HACVJ 60.
Depending on the application, the outer race 62 may include a variety of mounting options for securing the HACVJ 60 to the propeller shaft 40, 42 or other torque transmitting member. The mounting options may include mechanical securing elements, such as, but not limited to, welding, bolting, splines, plug-on, plug-in, tube mounted, companion flange, fusing, chemically bonding, polymers or other known mount techniques that are integrated into the HACVJ 60. Accordingly, the shape of the end of the outer race 62 may be dependent on the type of mechanical securement that is required. As illustrated, the HACVJ 60 includes the mounting flange 70 for affixing the HACVJ 60 to one of the components of the driveline 20. To facilitate the mechanical securement when using the flange includes the use of a plurality of mounting orifices 76 that may be located around and extend through an outer periphery of the mounting flange 70 for receiving bolts (not shown). The mounting orifices 76 may be arranged equidistant from one another and may be organized depending on the application and driveline 20 component that the flange 70 is mounted.
On the outer surface 68 of the HACVJ 60, at least one circumferential channel 74 may be located. The channel 74 may provide a surface for engaging a first member 122 of a sealing member 120, as discussed in greater detail below. As illustrated, HACVJ 60 includes two channels 74 that extend circumferentially around the outer surface 68 for engaging the first member 122. Additionally, the channel 74 may extend around the entire outer periphery of the outer surface 68 and allows for the placement of a sealing o-ring (not shown) for sealing the lubricant within the sealing member 120 to create a fluid barrier.
As discussed above, the sealing member 120 may be affixed to the HACVJ 60 at the channel 74. The sealing member 120 includes the first member 122 and a second substantially flexible member 142 secured to the first member 122. The first member 122 may be at least one of flexible or rigid depending on the application. As illustrated, the first member 122 is formed of a generally rigid material, such as, but not limited to steel, aluminum, polymer, composite or composite metal matrix materials. The flexible member 142 is a generally pliable material for allowing expansion and contraction of the flexible member. The first member 122 may be formed as a continuous stepped ring, depending on the application.
Specifically, in one exemplary arrangement, the first member 122 has an inner surface 134 and an outer surface 136. The inner surface 134 may directly contact the HACVJ 60 while the outer 136 surface may be directly in contact with the environment. The first member 122 may be constructed having a contacting surface that may follow the outer contour of outer surface 68 of the HACVJ 60. However, the shape of the first member 122 is dependent upon the joint with which the sealing member 120 is used. The first member 122 may be contoured with a slightly smaller diameter as compared to the outer surface 68 for a press fit. Additionally, a lip (not shown) may be contoured about the first member 122 for engaging the channel 74 such that the first member 122 may be removably attached directly to the HACVJ 60. As illustrated in
As illustrated in one exemplary arrangement, the first member 122 extends to a generally inwardly angled section 128 and terminates at a generally outwardly flared section 130 where the first member 122 connects to the flexible member 142. The first member 122 may be physically and/or chemically bonded to the flexible member 142 using any brown process for adhering a rubber, a composite, or other known flexible materials to a rigid, semi-rigid or flexible object. Generally, the flexible member 142 may be molded directly to the first member 122 during production of the flexible member 142. However, it some applications the first member 122 and the flexible member 142 may be made of a continuous piece.
The flexible member 142 may be an internal rolling diaphragm (IRD) member, which may be shaped in the form of a concave arc. However, other types of flexible members 242, 342, illustrated in
As discussed above, the first member 122 and the flexible member 142 may be of varied configurations depending on the joint that is being mated with the sealing member 120.
The first member 222, as illustrated in
As illustrated in
The first member 222 extends generally longitudinally to second section 228 and terminates at an outwardly flared section 230 where the first member 222 connects with the flexible member 242 and forms the coupling region 248. The first member 222 may be coupled with the flexible member 242 by physically and/or chemically bonding the members 222, 242 together using any known process for adhering a rubber, a composite, or other known bonding processes. The members 222, 242 may also be coupled together using any known mechanical fastener. In one exemplary arrangement, the flexible member 242 is molded directly to the first member 222 during production of the flexible member 242. Merely by way of example, if the molding process is used to couple the two separate members 222, 242, together, the first member 222 is generally produced first, and a polymer, activating element, composite, activating catalyst or adhesive (not shown) is applied to the coupling region 248 of first member 222 and placed into a mold then the flexible member 242 is molded around and fused to the first member 222 at the coupling region 248. The molding process may be generally referred to as an overmolding process where at least one previously molded part is inserted into a mold and a new layer of plastic is formed around the existing part. The process generally utilizes high heat and pressure to activate a chemical reaction between the polymer, activating element and composite activating catalyst or adhesive fuse together the first flexible member and the substantially flexible member to create an exemplary arrangement of a sealing member 220.
Like the previously discussed flexible member 142, flexible member 242 may be an internal rolling diaphragm (IRD) member, which may be shaped in the form of a concave arc. The flexible member 242 includes a first end 244, a downwardly extending transition portion 246 extending to an arced concave portion 250, and a second transition portion 252 ultimately terminating at a second end 254. The first end 244 may be bonded directly to the first member 222 at a coupling region 248, as previously discussed, while the second end 254 may be secured to the shaft 92. Generally, the first end 244 and concave portion 250 may be of a uniform thickness, while the second transition portion 252 and second end 254 may be of varied thickness. However, as illustrated, the varied thickness at the second transition portion 252 and at the second end 254 provides a substantially rigid area 256 that is used to create a sealing portion 258. The rigid area 256 of sealing portion 258 is used to seal and secure the flexible member 242 to the shaft 92.
Turning to
The first member 322, as illustrated in
As illustrated in
As illustrated, flexible member 342 is generally “S” shaped and includes a first end 344, an upwardly extending first transition portion 346 extending to an arced convex portion 350, a downwardly extending second transition portion 352 extending to an arced concave portion 354, and an upwardly extending third transition portion 356 that ultimately terminates at a second end 358 adjacent the shaft 92. The first end 344 may be bonded directly to the rigid member 322 at a coupling region 348, as previously discussed, while the second end 358 may be secured to the shaft 92. Generally, the first end 344, first transition portion 346, arced convex portion 350, second transition portion 352 and arced concave portion 354 may be of a uniform thickness, while the third transition portion 356 and second end 358 may be of varied thickness. However, as illustrated, the varied thickness at the third transition portion 356 and at the second end 358 provides a substantially rigid area 360 that is used to create a sealing portion 362. The rigid area 360 sealing portion 362 is used to seal and secure the flexible member 342 to the shaft 92. The exemplary sealing members 220 and 320 illustrated in
Turning to
Additionally, in
The preceding description has been presented only to illustrate and describe exemplary embodiments of the methods and systems of the present invention. It is not intended to be exhaustive or to limit the invention to any precise form disclosed. It will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the claims. The invention may be practiced otherwise than is specifically explained and illustrated without departing from its spirit or scope. The scope of the invention is limited solely by the following claims.
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/US11/52887 | 9/23/2011 | WO | 00 | 3/7/2014 |