Patent Application
20230234437
The present invention relates to vehicle differentials, and more particularly to methods and apparatus for mounting a front differential to the frame of a vehicle that has been equipped with off road components to achieve proper alignment without decreasing ground clearance.
A vehicle differential is a critical drivetrain component that transfers torque from a gearbox to the axles and subsequently to the wheels of a vehicle. Off-road vehicles are typically configured with four-wheel drive (e.g., 4×4) using a system having a front differential and a rear differential both of which are connected to a transfer case (e.g., gearbox or transmission). Consumer “light trucks” with a factory independent front suspension (IFS) are typically modified using aftermarket components such as lift kits, larger tires, and in some situations lengthening of the axles and driveline, all of which enable drivability over various terrain, thereby classifying the truck as an off-road vehicle or modified truck. Some modified trucks are specially modified for competitive rock crawling where drivers navigating over rock piles, large boulders, hills, trails, and other similar landscapes, hence the name “rock crawling.” Because the modified trucks drive over such uneven terrain, the vehicle's tires may slip causing the chassis or differential to bottom out onto the terrain below, resulting in damage to the vehicle's underside. Therefore, skid plates are frequently affixed to the vehicle's underside to protect the engine, gearbox, and drivetrain components.
A skid plate is an under vehicle component typically comprised of a durable dent-resistant material (e.g., steel or aluminum) that provides protection to sensitive or otherwise vulnerable vehicle parts and equipment from ground objects passing underneath. As such, a skid plate is typically the lowest frame-mounted item on a vehicle and determines the maximum size limitation of an object that is able to pass under the vehicle without contact. A front skid plate protects the front frame cross member and sub-frame cross members comprising the frame attachment points for the IFS assembly (e.g., lower control arms and differential assemblies in four wheel drive applications). Additionally, a front skid plate prevents dislodged debris or objects that are moved, bounced, or reflected off the ground or the vehicle itself from traveling up into critical operating components such as the engine drive belt and fan assembly, oil pan and filter, radiator, electronics, wiring and wiring harnesses, and high pressure hoses used to transport water, oil, power steering and automatic transmission fluids.
IFS allows each wheel to move vertically within the wheel fender (e.g., wheel well) such that the wheels are unconstrained from the other wheels in the drivetrain. IFS also allows the suspension components to mount to various locations on the chassis. The front differential housing (e.g., casing) connects to the chassis either with a subframe or a mounting arm therebetween, and the spindle of the pinion gear connect to the transfer case. The drivetrain of a light truck from the factory or from an original equipment manufacturer (OEM) is generally designed for comfort under common driving conditions, not off road use. In such vehicles, the differential housing is mounted to the chassis with a pair of arms, and bushings are provided between each of the arms and the chassis to dampen vibrations produced from the road. However, when a light truck is modified for rock crawling, the factory or OEM suspension and drive train may be swapped out for aftermarket components suited to the vehicle's new application. To increase the vehicle's ground clearance for rock crawling, the factory or OEM dampeners (e.g., struts), springs, control arms, wheels, and tires may be replaced with aftermarket components.
However, with an increase in clearance a new problem is introduced. The problem concerns the alignment of the drivetrain: when the described lifting components are integrated into the vehicle, the drivetrain geometry is misaligned. Drivetrain misalignment includes the drive shaft angles, axle shaft angles, which causes wear to the U-joints, seals (e.g., boots), axle strain, and bearing wear on the differential or transfer case. As a corrective measure, to cure drivetrain misalignment, spacers are placed between the differential's mounting components and the frame, typically between at the ends of the two support arms between the bushings and the chassis/frame. The spacers increase the distance of the differential from the chassis which lowers the center of gravity and aligns the front drivetrain close to or near the factory configuration, solving the misalignment problem. However, although the spacers realign the drivetrain geometry, they decrease the ground clearance at the ends of the arms, at the interface between the differential mounting arms and the frame. As a result, using spacers to realign a vehicle's drivetrain provides a contradictory solution to increasing vehicle ground clearance. Although the differential mounting arm and frame interface is at or near the apex of ground interference, in competitive rock crawling every inch of clearance counts. It is therefore desirable to provide methods and apparatus for aligning the differential and drive chain of a vehicle that has been equipped for off road use without decreasing critical ground clearance.
The present invention provides methods and apparatus for mounting a front differential to the frame of a vehicle that has been equipped with off road components to achieve proper alignment without decreasing ground clearance. In embodiments of the invention, the front differential may be attached to the frame using three different mounts: a right side (passenger side) arm, a left side (driver side) arm, and a rear mount (e.g., pinion mount). The mounting apparatus may be suitable for replacing the factory or OEM mounting components for securing front differential to a lifted vehicle with an independent front suspension and is operable to realign the vehicle drivetrain geometry to a factory configuration.
Embodiments of the present invention provide a right side arm and a left side arm that position a differential inside the vehicle chassis. The differential position may be between a front cross members and a rear cross member of the vehicle frame. Each of the arms may have an anterior end (e.g., front) and a posterior end (e.g., rear). The anterior ends of the arms may attach to the front cross member with a plurality of threaded fasteners that thread into pre-existing locations on the front cross member. The pre-existing locations on the front cross member position the anterior ends of the arms to the underside (inferior) of the vehicle chassis and forward of the differential position. The posterior ends of the arms attach to the differential at the factory or OEM fastening locations, such as, a lateral, inferior, posterior, or a frontal location. In some embodiments, the factory or OEM differential may provide a lateral fastening location on the left side and an inferior fastening location on the right side. The front ends of the arms may secure directly to the cross member. The posterior ends of the arms may have bushings therein that interface between the arms and the differential fastening locations.
Embodiments of the present invention may have an exemplary differential that has a housing (e.g., casing) operable to enclose drivetrain components and connect a left side (driver side) axle and right side (passenger side) axle to a pinion output or input shaft. On one side (e.g. the left side) of the housing surface there may be a plurality of lateral fastening locations, and on another side (e.g., the right side) the axle connection may be separated from the differential with a front differential tube assembly. On the posterior end of the differential a pinion shaft housing may have fastening locations operable to receive a rear pinion mount. The pinion mount may connect the posterior end of the differential to a second cross member.
In embodiments of the invention, the right (passenger) side bracket may comprise a single integrated piece, having openings at one end (front) for engagement with the front cross member of the vehicle frame, and openings at the opposite end (rear) for engagement with the differential. In other embodiments, the right (passenger) side arm may comprise a chassis bracket at the anterior end, a differential bracket at the posterior end, and a connecting arm between these two brackets. In these embodiments, the chassis bracket fastens to pre-existing fastening locations on the bottom of the front cross member and the differential brackets fastens to the bottom of the differential tube assembly. The connecting arm may connect the brackets at an angle while maintaining the chassis and differential brackets parallel with each other. For example and without limitation, the connecting arm may connect to the chassis bracket at an angle ranging from 11-14 degrees to offset the top surface of the differential brackets a distance ranging from 1.15-1.5 inches from the top surface of the chassis bracket. The length of the connecting arm may vary on the OEM position of the front differential. In an exemplary embodiment, the differential bracket holes may have a diameter of 1.2 inches operable to secure a bushing assembly. In embodiments where the right side arm comprises a single piece, the arm may be formed from a sheet of material having appropriate angles to create the needed offset.
Embodiments of the present invention provide a left (driver) side arm comprising two attached brackets. In these embodiments, the left side arm comprises a first bracket having openings at the front for engagement with the front cross member of the chassis, and a second attached bracket with openings at the opposite end (rear) for engagement with the differential. However, the left side of the differential provides a plurality of mounting holes positioned on a lateral (side) surface of the differential housing, as opposed to underneath the differential. Because of this, while the first bracket is oriented in a generally horizontal plane for attachment to the cross member of the chassis, the second (differential) bracket is oriented perpendicular to the first (chassis) bracket in order to engage the openings on the side of the differential. The chassis bracket may thus attach to the bottom of the front cross member, and the differential bracket may mount laterally to a side of the differential. In most embodiments, the front ends of both the right side and left side arms are directly mounted to the cross member without a bushing or spacer, thereby increasing the clearance from the ground to the leading edge of the arms. The differential bracket location may have bushings therein to provide dampening for road vibrations and to prevent the transfer of vibration to the chassis and cabin. The geometry of the right side and left side arms may be generally derived from the mounting location of the differential and the chassis. For example and without limitation, a differential may have fastening holes positioned only on a bottom surface of the differential.
A plurality of bushings may be provided to interface between the differential and the left and right arms. Each bushing may comprise an assembly having a three piece construction where a compression sleeve is concentrically secured between two bushing halves. Each of the bushing halves may be the sleeve washer type (e.g., flange) where a washer is integrated into a sleeve. The washer portion may have an outer diameter that is larger than the outer diameter of the sleeve, but the washer and sleeve may share the same inner diameter. The sleeve portion may be concentrically positioned in the differential bracket holes and have a depth one half of the arm thickness. The sleeve halves may sandwich the differential bracket holes and the compression sleeve is concentrically placed in the inner diameter of the sleeve. The bushing halves may be constructed from common suspension materials such as rubber or urethane. A rubber bushing may be more suited for dampening road noise, vibrations and harshness and urethane bushings may have a longer life, enhances road feel, and performance.
In some embodiments, the right side arm and left side arm may be manufactured from plates having slots and tabs to positioned and align the chassis brackets and differential brackets at pre-determined angles depending on the expected misalignment of the vehicle drivetrain. For example, the right-side arm may comprise a chassis plate and a differential plate offset by an elongated arm. The chassis plate may have a slot on the rear end, and the differential plate may have a slot on the front end. The elongated arm may have tabs on the front and rear that align with the slots of the chassis plate and differential plate that position the elongated arm perpendicular to the two plates. The elongated arm may have different lengths depending on the necessary offset. The seam of the slot and tabs may be welded together in manufacturing, thereby forming a rigid right side arm. The left side arm may have a chassis plate with a slot for receiving a tab of a differential plate. The differential plate may be perpendicularly attached to the chassis plate. The left and right side arms may have openings with bushings to dampen the transfer of vibrations to the vehicle chassis. Each of the plates of the arms may be formed from weldable metals such as steel, aluminum, titanium, or other alloys, and should have a thickness of at least ⅜ of an inch. In some embodiments, the left and right arms may be provided in a single integrated piece; in other embodiments, the left and right arms may comprise multiple brackets and/or arms that may be welded together.
Attaching embodiments of the right and left side arms of the present invention may result in offsetting the position of the front differential by dropping and moving the differential forward from the location of the differential using OEM or factory arms. In some embodiments, and without limitation the offset drop may range from about ⅜ inch to about 1½ inches, and the forward positioning may be between about ⅛ inch and about ¾ inch. This change in position is needed when a vehicle has been equipped with off road components in order to realign the differential.
Embodiments of the present invention may also provide a rear pinion mount that attaches to the bottom of a differential's pinion shaft housing and to the top of a rear cross member of the chassis. The pinion mount may be secured to the rear cross member with a nut and bolt, and may be secured to the differential with openings that align with openings on the pinion shaft housing operable to receive a fastener that is threaded into the pinion mount. The pinion mount of the differential may also be provided with a bushing in the center for dampening the transfer of vibrations to the vehicle chassis.
In some aspects, the methods and apparatus of the present invention may further comprise a skid plate attached to the front cross member and the chassis front end and operable to shield the engine and drivetrain. It is to be appreciated that due to the nature of the front skid plate being mounted under the IFS and front differential sub frame assembly, that it must be fitted beneath the differential brackets. This ultimately limits the distance between the front skid plate and the ground. In embodiments of the present invention, the thickness of each forward differential arm connection at the sub frame is greatly reduced thereby allowing a new ultra-low profile front skid plate to be used. Therefore, when used in conjunction with embodiments of the present invention, a new ultra-low profile front skid plate is able to achieve ground clearance greatly exceeding OEM or existing aftermarket front skid plate designs that pass under traditional forward differential arm designs.
In some embodiments of the present invention, a novel differential pinion mount is provided (as shown in
In some aspects, embodiments of the invention provide methods and apparatus for mounting a front differential to the pre-existing fastening locations of a lifted vehicle chassis that has been equipped with off road components, where the vehicle has an independent front suspension system. In these aspects, the apparatus may comprise a first side arm having a frame bracket and a differential bracket that may be separated by an elongated arm where the frame bracket mounts to the bottom of a front cross member of the vehicle chassis, and the differential bracket has a plurality of mounting holes with bushings therein for mounting the differential bracket to the factory mounting location of the differential; a second side arm comprising a frame bracket at one end with holes for mounting the arm to the factory bolt locations on a front cross member of the vehicle chassis, and a differential bracket at the opposite end having a plurality of mounting holes with bushings therein for engaging with the factory mounting holes of the differential; at least one rear pinion mount operable to secure the differential to a rear cross member at pre-existing fastening location(s); and a plurality of bolts for fastening the first side arm and second side arm to the front cross member and to the differential, and for fastening the rear pinion mount to the rear cross member and to the differential; where the first arm, second arm, and rear pinion mount replace the factory components, and position the differential in a forward and lower position such that the drivetrain components of a lifted vehicle are realigned to the factory position while providing the vehicle with increased forward clearance.
In some of these aspects, the first side arm frame bracket and second side arm frame bracket may be mounted to the front crossmember on the same plane and are parallel with respect to each other. The differential mounts on the opposite end of the first side arm may be attached to factory mounting locations on the bottom of the differential; and the differential mounts at the opposite end of the second side arm may be attached to factory mounting locations on the side of the differential. Because of the positions of the factory mounting locations on the differential, it is to be appreciated that the differential bracket of the first side arm is generally parallel with the frame bracket of the first side arm, but the differential bracket of the second side arm is generally perpendicular to the frame bracket of the second side arm. In these aspects, an elongated arm may separate the frame bracket and differential bracket of the first side arm such that these brackets are offset from each other and are on different planes that are parallel.
In some of these aspects, the rear pinion mount may be operable to secure the differential on a pinion shaft housing that extends longitudinally out of the posterior face of the differential and to a rear cross member. The rear pinion mount may have a bushing therein for engaging between the differential and the rear crossmember. The bushings may be operable to dampen vibrations transferred from the drivetrain to the vehicle chassis. The right side arm differential bracket's factory mounting location may mount to an inferior position on a tube assembly that extends out laterally from the differential. The frame bracket of the first and second side arms may not have a bushing so as to increase the clearance under the cross member at the frame bracket mounting location.
As noted elsewhere herein, installing the left and right arms of embodiments of the present invention changes the position of the differential. In some embodiments, the forward position of the differential may range from about ⅜ inch to about 1½ inches from the factory position; and the differential may be at a lower position in a range of about ⅜ inch to about 2 inches from the factory position. In these embodiments, the elongated arm member of the first arm may attach to the frame bracket and differential bracket at an angle ranging from about 10 degrees to about 17.5 degrees, and may offset the brackets for a distance ranging from about ½ inch to about 2 inches. It is to be appreciated that these angles and offsets may be larger or smaller, and the amount of change in the forward and offset positions of the differential may be larger or smaller, depending on such factors as, without limitation, the size of the vehicle, the particular off road equipment that is installed, the size of the vehicle tires, and other factors.
In some embodiments, the bushings may comprise an assembly that includes two symmetrical sleeve bushings and a compression sleeve. The forward clearance may be measured from the base of the fasteners to the ground. The first side arm may be formed by cold working the material into the arm shape. The second side arm frame bracket may be formed such that the differential bracket center point is offset from the frame bracket. The second side arm frame bracket may be weldably attached to the differential bracket. The first side arm may be positioned on the passenger side of the differential, and the second side arm may be positioned on the driver side.
In other aspects, embodiments of the present invention provide methods and apparatus for mounting a front differential to the pre-existing fastening locations of a vehicle chassis that has been lifted as a result of the installation of off road equipment. In these aspect, the vehicle has an independent front suspension system, a front cross member and a rear cross member. A first side arm may be provided comprising a frame plate and a differential plate separated by an elongated arm, where the frame plate attaches to pre-existing fastening locations on the underside of a front cross member, and the differential plate has a plurality of mounting holes with bushings therein for aligning with pre-existing fastening location on said front differential. A second side arm may be provided comprising a frame plate operable to attach to a pre-existing fastening location on the bottom of a front cross member and a differential plate having a plurality of mounting holes with bushings therein for aligning laterally with the factory mounting holes of said differential. At least one rear pinion mount may be provided that may be operable to secure the differential to pre-existing fastening locations on a rear cross member. A plurality of bolts may be used for fastening the first side arm and second side arm to the front cross member and to the differential, and for fastening the rear pinion mount to the rear cross member and to the differential. The first and second side arms, and rear pinion mount replace the factory components and are operable to position the differential in a forward and lower position such that drive train components of a lifted vehicle are realigned to the factory position providing the vehicle with increased forward clearance.
In some aspects, a bushing assembly may be provided that includes two symmetrical sleeve bushings for securing concentrically in the mounting holes and having a flange operable to rest on the exterior surface of the differential plates. The bushings may include a compression sleeve nested inside the sleeve bushing and operable to align a bolt and dampen vibration. In these aspects, the first side arm is a passenger side arm and the second side arm is a driver side arm. The first side arm frame plate and differential plate may have slots operable to secure an elongated arm between each of the plates. The elongated arm may have a frame plate tab and differential plate tab on opposite ends, where the frame plate tab interfaces with a bottom surface of the frame plate and the differential plate tab interfaces with a top surface of the differential plate. The first side arm frame plate and differential plate may interface with the elongated arm at an angle that may range from between about 10 degrees and 17.5 degrees, although greater or lesser angles may be used to achieve proper alignment in vehicles of different sizes, with different wheels, with different off road equipment, etc.
The first side arm frame plate may attach to pre-existing fastening location with a through hole operable to receive a bolt for securing the plate to the front cross member. The second side arm frame plate may include a slot operable to align with a slot and tab on a differential plate such that the differential plate is perpendicular to the frame plate. The differential plate tab may interface with the frame plate on the bottom surface of the frame plate. The second side arm frame plate may attach to pre-existing fastening locations with a plurality of through holes operable to receive a plurality of bolts for securing the plate to the front cross member. There may be multiple holes (frequently two of them) for mounting the first side arm differential plate, and multiple holes (frequently three of them) for mounting the second side arm differential plate. In some embodiments, and without limitation, the differential forward position may range from about ¼ inch to about 1¼ inches, and the differential lower position may range from about ½ inch to about 2 inches. It is to be appreciated that the amount of change in the forward and offset positions of the differential may be larger or smaller, depending on such factors as, without limitation, the size of the vehicle, the particular off road equipment that is installed, the size of the vehicle tires, and other factors.
In embodiments of the invention, the pinion mount may be positioned between the rear pinion shaft housing of the differential and the top of the rear crossmember. Embodiments of the invention may further comprise a skid plate extending from the rear cross member to the front end of the vehicle, and may be operable to protect and cover the first arm, second arm, pinion mount, engine, and front differential. Embodiments of the invention may further provide for the removal of any centrally located jacking point on the front cross member.
Further aspects and embodiments will be apparent to those having skill in the art from the description and disclosure provided herein.
It is an object of the present invention to provide methods and apparatus for realigning a differential of a vehicle that has been equipped with off road components without using spacers in order to increase ground clearance below the vehicle.
It is another object of the present invention to provide methods and apparatus for realigning a differential of a vehicle that has been equipped with off road components using two differential arms that lower the differential and increase ground clearance under a front cross member.
It is a further object of the present invention to provide methods and apparatus for realigning a differential of a vehicle that has been equipped with off road components that allows an ultra-low profile skid plate to cover and protect the engine, differential, and mounting component.
It is a further object of the present invention to provide methods and apparatus for realigning a differential of a vehicle that has been equipped with off road components that includes a novel pinion mount that works with a skid plate to disperse forces acting on the vehicle frame to reduce stresses thereon and avoid damage.
It is a further object of the present invention to provide a differential mounting system operable to realign the front drivetrain of a lifted vehicle.
The above-described objects, advantages and features of the invention, together with the organization and manner of operation thereof, will become apparent from the following detailed description when taken in conjunction with the accompanying drawings, wherein like elements have like numerals throughout the several drawings described herein. Further benefits and other advantages of the present invention will become readily apparent from the detailed description of the preferred embodiments.
Reference will now be made in detail to certain embodiments of the invention, examples of which are illustrated in the accompanying drawings. While the invention will be described in reference to these embodiments, it will be understood that they are not intended to limit the invention. To the contrary, the invention is intended to cover alternatives, modifications, and equivalents that are included within the spirit and scope of the invention. In the following disclosure, specific details are given to provide a thorough understanding of the invention. However, it will be apparent to one skilled in the art that the present invention may be practiced without all of the specific details provided.
Referring to the drawings wherein like reference characters designate like or corresponding parts throughout the several views, and referring particularly to
Referring to the embodiment shown in
Exemplary embodiments of a left side (driver side) support arm 110 are illustrated in
In other embodiments, the right side (passenger side) support arm may be manufactured from flat plates as shown in
An exemplary vehicle differential 300 including a housing 302 (e.g., casing) that encloses drivetrain components is illustrated in
Referring to the embodiment illustrated in
These exemplary bushings 150 may have a three-piece construction where a compression sleeve 152 aligns a first sleeve bushing 151a and a second sleeve bushing 151b. The first and second sleeve bushings 151a, 151b may be symmetrically positioned about the mid line of the compression sleeve 152 and may have identical geometries. The geometry may be flange like where the diameter Di is sized to fit snuggly in the arm mounting holes and outer diameter Do is sized to sandwich the arm where the arm may fit has a thickness T. The length of the compression sleeve 152 may be the combined length of the first and second sleeve bushings 151a, 151b.
Referring to
In alternative embodiments, a stronger pinion mount and skid plate are provided. As shown in
Referring to
It is to be understood that variations, modifications, and permutations of embodiments of the present invention, and uses thereof, may be made without departing from the scope of the invention. It is also to be understood that the present invention is not limited by the specific embodiments, descriptions, or illustrations or combinations of either components or steps disclosed herein. The embodiments were chosen and described in order to best explain the principles of the invention and its practical application, to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. Although reference has been made to the accompanying figures, it is to be appreciated that these figures are exemplary and are not meant to limit the scope of the invention. It is intended that the scope of the invention be defined by the claims appended hereto and their equivalents.
