Patent Application
20240399791
Portal axle assemblies are used to lift a vehicle's differential and axle housing, leading to increased overall ride-height, tire-size, and vehicle ground clearance. Additionally, intra-portal drive ratio reduction helps maintain torque performance when employing larger tires without having to re-gear upstream components of the vehicle's drivetrain.
Having first appeared on military and agricultural vehicles in the 20th century, portal axles provide a way to increase vehicle and axle-differential housing and axle-arm ground clearance (Especially on but not limited to solid-axle vehicles). Using portals to lift a vehicle's driveline significantly improves a vehicle's ability to drive over severe terrain without parts of the drivetrain and axles getting stuck or damaged. Conversely, some trains use an inverted portal design to lower the train's center of gravity, relative to the axle's traditional station.
In military, agricultural and offroad-enthusiast markets, higher ground clearance allows portal users to also employ larger-diameter tires without any further vehicle modification which in-turn, results in (1) further increases to vehicle ground clearance due to the increase in tire diameter and (2) improvements to tire approach angle (also due to tire diameter increase) when encountering rocks, ledges, or other such obstacles.
Early portal equipped vehicles first utilized a 2-gear portal system that required a reversed driveshaft rotational input because input and output gears/shafts will cause counter-rotation relative to each other in a direct-drive configuration. On later applications, this problem was solved by employing one and later two idler gears between the input and output drive gears to cancel the counter-rotation inherent to two-gear portals as well as increasing the quantity of gear-tooth engagement in 4-gear configuration. Additionally, an intra-portal gear ratio reduction was introduced by utilizing a differentially larger output gear size vs. the input gear. This feature provides the ability to retain torque performance when utilizing larger tires
Multi-gear, hydraulic, and even electric portal designs have been patented (U.S. Pat. No. 8,844,669; U.S. Pat. Pend. No. 20220332185A1; U.S. Pat. Nos. 8,118,133; 8,484,611; 8,985,264; 9,625,021; 7,185,688; U.S. Pat. No. 20210245599; U.S. Pat. No. 11,072,237 B2; U.S. Pat. No. 10,479,156 B2; EP. Pat. No. 2,581,240 B1; EP. Pat No. 1,510,365 B1; DE. Pat No. 10 2004 003 645 A1), with two, three and four-gear designs commonly used in the offroad enthusiast community. The current invention for which patent protection is being applied for utilizes a simplified gearless design employing an inverted/silent chain and sprockets instead of gears. This gearless direct-drive system represents a major design departure from all other previously patented gear-driven portal axle designs.
The appealing benefits of portal axles has long been recognized by the consumer offroad community, but repurposing legacy portals from other vehicles is cumbersome for offroad enthusiasts as it requires modifying a vehicle's stock axle/steering linkages to accept a repurposed portal's unique attachment profile and then further modification to the portal's housing to be compatible with modern unit-bearing hubs that drive a vehicle's wheel. The current generation of “consumer aftermarket” portal axle offerings often employ a modular portal gearbox that incorporates OEM compatible axle/steering linkage attachment and also provides standard attachment compatibility for typical unit bearing hub assemblies in order to attach a typical wheel to the assembly.
Modern off-road enthusiasts often modify their vehicles' suspensions to increase ride-height and allow for larger tires, further increasing differential clearance. The use of portal axles is increasingly thought of as being a superior way to gain significantly more differential clearance relative to suspension modification alone, when compared with similar amounts of overall vehicle lift. Given that modern portal axle manufacturers provide for standard axle attachment and unit-bearing integration on a vehicle-specific basis, portal axles are increasingly recognized as being the preferred method of gaining vehicle and tire clearance in the consumer offroad aftermarket industry.
The Gearless chain- and sprocket direct-drive Portal Axle assembly utilizes a chain and two sprockets to provide dislocated (usually lower) input-output power at the vehicle's wheel. Input power is delivered from an axle shaft to the drive sprocket, which transfers power via chain or belt to the driven output sprocket and then to an integrated unit-bearing, hub, or other wheel-attachment device. The relocated drive output provides the ability to both increase a vehicle's driveline ground-clearance and provide the option to employ larger tires due to increased clearance of a tire's diameter relative to a vehicle's bodywork, thus allowing the potential for even further increases to ground-clearance.
The chain and sprocket approach is a major design departure from common multi-gear portal axle offerings. One prominent feature of this “gearless” approach is superior drive tooth-engagement, due to the benefit of significant chain-wrap around the sprockets, engaging many teeth at once. This may provide additional strength for some heavy-duty applications.
The gearless portal may utilize an inverted, “silent”, or other type of matched chain or belt and sprocket protocol, depending on vehicle and use-case. The function of the gearless design may provide advantages in terms of noise and vibration reduction when compared with spur-gears associated with earlier multi-gear designs.
Due to a comparatively large number of sprocket teeth, the gearless portal provides for a wide range of drive ratio optionality providing compensatory operational value in scenarios such as maintaining torque-performance when utilizing oversized tires.
The bifurcated design of the gearless portal's housing provides for ease of adaptation to a variety of methods for portal-vehicle attachment, both on the input and output side of function. The input (proximal) side of the gearless portal can be made to attach to a vehicle's axle housing, steering linkage, suspension componentry or other location(s), including solid-axle, independent suspension, and other OEM applications, providing adaptability for utilization on both existing and future vehicle offerings and use-cases. Similarly, the output (distal) part of the gearless portal housing can be customized to mate to a variety of present and future OEM and aftermarket wheel-mounting devices, including hubs, unit-bearings and other modalities.
Another aspect of the gearless portal design is the provision for the ability to utilize full-floating axles on both the input and output modalities or not, depending on application requirements. This feature allows the vehicle's weight to be transferred through the portal axle's housing to the associated attachment members rather than through the axle shafts, themselves, depending on application and configuration.
The gearless portal axle's assembly additionally provides for adaptation for use of a variety of brake caliper brackets via integral brake mounting surfaces that are designed to be customizable, based on vehicle and intended use case.
The Gearless Portal Axle Assembly represents a novel approach to portal axle design that is substantially differentiated from all previously patented multi-gear portal axle iterations in that it utilizes a simplified, gear-free drive mechanism. Designed to be a modular system with the core architecture consisting of two sprockets and a matching laminate chain of any type, the bifurcated proximal and distal housing components are meant to be readily adapted, from a design and manufacture standpoint, for precision fitment to a wide range of current and future vehicle adaptation. Prerequisite to this detailed description of embodiments, the following Table of Components is provided for reference to the included drawings and the following information:
Various embodiments herein provide a mechanism to lift a vehicle from the ends of the axles and/or steering and suspension componentry. In some embodiments the portal mounts to an existing rotating axle steering component 27. In other embodiments the portal mounts to a fixed solid axle component 30. In yet other embodiments, the gearless portal is attached to OEM or aftermarket suspension components such as ball-joints, steering and or suspension linkage components, depending on the vehicle and application.
In the example shown on
The bearings shown on
At the proximal side of the sprocket 1 there is an end cap 4. The end cap is held in place with a retaining ring 5. The end cap has a groove that houses a seal 2 to keep the oil from leaking outside of the gearless chain drive chamber.
In the example shown in
in the example shown in
The proximal housing 8 and the distal housing 13 are fixed together with housing attachment bolts 17. The open area around the chain drive inside the proximal and distal housings is the gearless chain drive chamber. Between the housing surfaces is a seal 18 that keeps oil inside the gearless chain drive chamber while keeping contaminants out.
