Patent Application
20080121070
1. Field of the Invention
This invention pertains to vehicle axles and their components and methods of manufacturing vehicle axles and components.
2. Background
Drive axle assemblies are well known structures that are in common use in most vehicles. Such axle assemblies include a number of components, which are adapted to transmit rotational power from an engine of the vehicle to the wheels thereof. Typically, an axle assembly includes a differential assembly that is rotatably supported within a non-rotating carrier. The differential is connected between an input drive shaft extending from the vehicle engine and a pair of output axle shafts extending to the vehicle wheels. The axle shafts are contained in respective non-rotating beam sections, which are secured to the carrier. Thus, rotation of the differential by the drive shaft causes corresponding rotation of the axle shafts. The carrier and the beam sections form an axle housing assembly for these drive train components of the axle assembly, inasmuch as the differential and the axle shafts are supported for rotation therein.
One of the most common types of the axle housing assemblies used in the art is banjo type axle housing. Banjo type axle housings are advantageous because the carrier and differential can be removed from the axle assembly for service without disturbing the other components thereof. The most common method for manufacturing the banjo type axle housings involves forming two opposite halves of the axle housing by stamping or forging from a pre-cut blank of sheet steel. Next, the two axle housing halves are welded along mated horizontal edges, and then the axle assembly is completed in a known manner. The above method for manufacturing the banjo type axle housings is relatively simple and efficient. However, tooling used for stamping the axle housing halves is very expensive. Moreover, when a number of axle housings of various sizes are produced, a corresponding number of different metal forming apparatuses has to be employed that requires rather large tooling expenses.
Furthermore, the banjo housings (especially larger ones) typically have square or rectangular cross-section for beaming strength, thus necessitating transitioning to round outboard end for accommodating a generally cylindrical wheelend unit. The round cross-section accommodates existing brake designs for attachment. Moreover, this design cannot easily accommodate tread width changes, or lateral repositioning of a driving head for propeller shaft relocation. Moreover, when a number of axle housings of various sizes are produced, a corresponding number of different metal forming apparatuses has to be employed that requires rather large tooling expenses.
Therefore, the drive axle housing assemblies of the prior art and methods for manufacturing thereof, including but not limited to those discussed above, are susceptible to improvements that may enhance their performance and cost. With this in mind, a need exists to develop an improved drive axle housing assembly and a method for manufacturing thereof that advances the art.
The present invention provides an improved axle housing assembly for a motor vehicle that accommodates both semi-float and full-float drive axle housing assemblies, and a method for manufacturing thereof.
The axle housing assembly in accordance with the preferred embodiments of the present invention comprises a hollow, elongated arm section extending along a center axis and a wheelend. The wheelend is fixed to an outboard end portion of the arm section. The wheelend includes an adapter plate member fixed to the outboard end of the arm section so as to extend radially outwardly therefrom, a spindle member extending axially outwardly from the adapter plate member substantially along the center axis, and a brake backer plate attached to the adapter plate. The spindle member has a substantially cylindrical bearing support surface for supporting an axle bearing.
The method for manufacturing a banjo-type axle housing assembly in accordance with the present invention comprises the following steps. First, a desired length of the axle housing is selected. Then, the axle housing is produced that has a length larger than the desired length. Subsequently, outboard end portions of the axle arm sections of the axle housing are selectively trimmed to achieve said desired length.
Therefore, the present invention allows a single wheelend to be used with the axle assemblies of various cross-sections. In case of the axle housing assemblies having generally rectangular cross-sections of the axle arm sections, the present invention allows to eliminate the transition to round. Also, the present invention facilitates installing full and semi-float wheelends to common banjo housing design. The present invention also allows accommodating existing brake mechanisms and bearing assemblies into large banjo-type drive axle housings. By integrating the bearing housing with the brake caliper mounting brake backer plate, one part can be eliminated. Thus, the present invention reduces cost, complexity and weight of the axle housing assembly. The novel method for manufacturing a banjo-type axle housing assembly of the present invention allows easily modify tread width and pinion lateral locations on the motor vehicle while using a common banjo housing design.
Other objects and advantages of the invention will become apparent from a study of the following specification when viewed in light of the accompanying drawings, wherein:
The preferred embodiments of the present invention will now be described with the reference to accompanying drawing.
For purposes of the following description, certain terminology is used in the following description for convenience only and is not limiting. The words such as “inboard”, “outboard”, “inwardly” and “outwardly” designate directions in the drawings to which reference is made. The words “smaller” and “larger” refer to relative size of elements of the apparatus of the present invention and designated portions thereof. The terminology includes the words specifically mentioned above, derivatives thereof and words of similar import. Additionally, the word “a”, as used in the claims, means “at least one”.
Referring to
The axle housing 12 of the present invention, illustrated in detail in
As further illustrated in
Referring again to
As illustrated in detail in
As illustrated in detail in
The bearing cup 46 has a substantially cylindrical bearing support surface 47 for supporting the antifriction bearing assembly 30. The bearing support surface 47 is oriented substantially coaxially to the center axis 21. The wheelend spindle member 28 is securely attached to the adapter 26 by means of threaded studs 50 and complementary nuts 52 so that the threaded studs 50 extend through corresponding holes 37 and 49 in the adapter plate member 34 of the wheelend adapter 26 and the backer plate 48 of the spindle member 28, respectively. It will be appreciated that the spindle member 28 may be secured to the adapter plate member 34 by any other appropriate means known in the art, such as welding, adhesive bonding, etc. More specifically, the wheelend spindle member 28 is attached to the adapter 26 so that an inboard face 66 of the brake backer plate 48 of the spindle member 28 engages the outboard face 40 of the wheelend adapter 26. Moreover, as further illustrated in
Furthermore, the brake backer plate 48 of the spindle member 28 is provided to support a wheel brake mechanism, such as a brake caliper 70. More specifically, the brake caliper 68 is non-rotatably coupled to the brake backer plate 48 by means of threaded fasteners 69 extending through corresponding threaded holes 53 in a brake flange 51 integrally formed with the backer plate 48 of the spindle member 28. It will be appreciated that the brake caliper 70 may be secured to the brake backer plate 48 of the spindle member 28 by any other appropriate means known in the art, such as welding, adhesive bonding, etc. As further shown in
Preferably, the anti-friction bearing assembly 30 is in the form of a double row tapered roller bearing and includes an outer race 60, an inner race 61, and bearing rollers 62 located between the outer race 60 and the inner race 61. In an assembled condition, as illustrated in
The method of assembling the drive axle 10 according to the first exemplary embodiment of the present invention is performed in the following manner.
First, as illustrated in
Next, the axle shaft 20 is inserted into the central opening 35 in the adapter plate member 34 of the wheelend adapter 26 so that the inboard face 66 of the brake backer plate 48 of the spindle member 28 engages the outboard face 40 of the adapter plate member 34 of the wheelend adapter 26. Subsequently, the spindle member 28 is non-rotatably secured to the wheelend adapter 26 by firmly coupling the backer plate 48 of the spindle member 28 to the adapter plate member 34 of the wheelend adapter 26 with the threaded fasteners 50, 52. Subsequently, the brake caliper 70 is coupled to the brake backer plate 48 of the spindle member 28 with the threaded fasteners 69.
The novel wheelend unit including a wheelend adapter of the present invention allows easily modify a tread width on the motor vehicle by manufacturing the axle housing wider than typically required, then trimming axle arm sections of the axle housing assembly to desired length. In other words, the present invention facilitates multiple tread widths and pinion lateral locations while using a common banjo housing design.
Thus, the present invention is also directed to a method for manufacturing a range of banjo-type axle housings of selective tread width (i.e. a length of the axle housing) and pinion lateral locations (i.e. a location of a pinion drive gear relative to geometric center of the axle housing in a transverse direction along the center axis 21) by manufacturing axle housings with unequal length of the arm sections thereof. The method for manufacturing the banjo-type drive axle housing assembly 11 in accordance with the present invention is performed in the following manner.
First step is the operation of forming substantially identical upper and lower channel-shaped half members 16U and 16L of the axle housing 12, as illustrated in
As illustrated in
Next step is to select a desired length LD of the axle housing 12 (which is equal or smaller than the original length LM) for a particular motor vehicle corresponding to a required thread width of the particular motor vehicle. Alternatively, desired lengths LDL and LDR of the left and right axle arm sections 18L and 18R, respectively, of the axle housing 12 may be selected such that correspond to a required thread width of the particular motor vehicle and a required lateral location of a pinion drive gear (not shown). In other words, the desired lengths LDL and LDR of the axle arm sections 18L and 18R of the axle housing 12 could be equal or different so that:
LDL≧LDR (as shown in FIG. 4) or LDL≦LDR.
It will be appreciated that a sum of the lengths LDL and LDR is equal or smaller than the original length LM, i.e.
L
DL
+L
DR
≦L
M.
Then, if necessary, appropriate portions of the axle arm sections 18L and 18R of the axle housing 12 are selectively trimmed (or cut) by any appropriate means known in the art along a phantom lines 15L and 15R, respectively, as illustrated in
Alternatively, the appropriate portions of axle arm sections of the upper and lower housing half members 16U and 16L could be trimmed separately, before assembling the axle housing 12 by welding upper and lower housing half members 16U and 16L along mating horizontal edges.
Subsequently, the wheelend units 14 are fixed (attached) to the corresponding outboard end portions 22 of the axle housing 12. More specifically, the adapter plate member 34 of the wheelend adapter 26 is fixed to the outboard end portion 22 of the arm section 18 of the axle housing 12 substantially coaxially to the center axis 21 by welding along mating edges, as indicated at 44, so that the inboard face 36 of the adapter plate member 34 engages the end face 24 of the axle housing 12.
Subsequently, the spindle member 28 is non-rotatably secured to the wheelend adapter 26 by firmly coupling the backer plate 48 of the spindle member 28 to the adapter plate member 34 of the wheelend adapter 26 with the threaded fasteners 50, 52 so that the inboard face 66 of the brake backer plate 48 of the spindle member 28 engages the outboard face 40 of the adapter plate member 34 of the wheelend adapter 26.
The drive axle 110 according to the second exemplary embodiment of the present invention is in the form of a full-float axle and comprises a banjo-type axle housing assembly 12 including a pair of opposite full-float wheelend units 114 mounted at the opposite ends of the axle housing assembly 12 (shown in
The wheelend component 125, shown in detail in
As further illustrated in detail in
The wheelend adapter 126 is secured to the outboard end portion 22 of the arm section 18 of the axle housing assembly 12 so as to extend radially outwardly therefrom. Preferably, the adapter plate member 134 of the wheelend adapter 126 is fixed to the outboard end portion 22 of the arm section 18 substantially coaxially to the center axis 121 so that the adapter plate member 134 is disposed substantially perpendicularly to the center axis 121. Further preferably, the adapter plate member 134 is fixed to the outboard end portion 22 of the arm section 18 by welding, as indicated at 44 in
Preferably, the axle bearings 130 and 131 are in the form of tapered roller bearings. Each of the axle bearings 130 and 131 includes an inner race mounted to the outer peripheral surface of the wheelend adapter 126, an outer race mounted to an inner peripheral surface of the wheel hub 150, and tapered rollers located between the outer race and the inner race.
The full-float wheelend unit 114 further includes a brake backer plate 148 attached to the adapter plate member 134 of the wheelend adapter 126. The brake backer plate 148 is securely attached to the adapter plate member 134 of the wheelend adapter 126 by means of threaded studs 50 and complementary nuts 52 so that the threaded studs 50 extend through corresponding holes 137 and 149 in the adapter plate member 134 and the backer plate 148, respectively. It will be appreciated that the brake backer plate 148 may be secured to the adapter plate member 134 of the wheelend adapter 126 by any other appropriate means known in the art, such as welding, adhesive bonding, etc. The brake backer plate 148 is provided to support a wheel brake mechanism, such as a brake caliper 70. More specifically, the brake caliper 70 is non-rotatably coupled to the brake backer plate 148 by means of threaded fasteners 69 extending through corresponding threaded holes in the backer plate 148. It will be appreciated that the brake caliper 70 may be secured to the brake backer plate 148 by any other appropriate means known in the art, such as welding, adhesive bonding, etc.
Therefore, the present invention provides a novel wheelend unit including a wheelend adapter allowing a single wheelend unit to be used with the axle assemblies of various cross-sections. The present invention allows to eliminate the transition to round in the axle housing assemblies having generally rectangular cross-sections of the axle arm sections. Also, the present invention facilitates installing full and semi-float wheelend units to a common banjo housing design. More specifically, with various flange designs at each end of the banjo housing, both semi-float and full-float wheel end concepts can be accommodated. Furthermore, the present invention allows accommodating existing brake mechanisms and bearing assemblies into large banjo-type drive axle housings. By integrating the bearing housing with the brake caliper mounting brake backer plate, one part can be eliminated. Thus, the present invention reduces cost, complexity and weight of the axle housing assembly.
The present invention also provides a novel method for manufacturing a banjo-type drive axle housing assembly that allows easily modify tread width and pinion lateral locations on the motor vehicle by manufacturing the housing wider than typically required, then selectively trimming axle arm sections of the axle housing assembly to desired length. In other words, the present invention facilitates multiple tread widths and pinion lateral locations while using a common banjo housing design.
The foregoing description of the preferred embodiments of the present invention has been presented for the purpose of illustration in accordance with the provisions of the Patent Statutes. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. The embodiments disclosed hereinabove were chosen in order to best illustrate the principles of the present invention and its practical application to thereby enable those of ordinary skill in the art to best utilize the invention in various embodiments and with various modifications as suited to the particular use contemplated, as long as the principles described herein are followed. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains. Thus, changes can be made in the above-described invention without departing from the intent and scope thereof. It is also intended that the scope of the present invention be defined by the claims appended thereto.
