WO2016209878A1

WO2016209878A1 - Air skirt for truck axle

Info

Publication number: WO2016209878A1
Application number: PCT/US2016/038640
Authority: WO
Inventors: Harry W. TROST; Steven G. Slesinski
Original assignee: Dana Heavy Vehicle Systems Group, Llc
Priority date: 2015-06-22
Filing date: 2016-06-22
Publication date: 2016-12-29

Abstract

The present invention relates to air skirting for axles of tractor trailers. Specific embodiments relate to air skirting for tandem axles of tractor trailers. The air skirt is attached to the axle assembly and helps reduce drag during operation of the vehicle caused by turbulence of air moving over exposed components of the axle assembly. The air skirt may also contain vents to aid regulation of temperature surrounding the axle assembly.

Description

TITLE

AIR SKIRT FOR TRUCK AXLE

RELATED APPLICATIONS

This application is claiming the benefit, under 35 U.S.C. § 119(e), of the provisional application filed on June 22, 2015, under 35 U.S.C. § 111(b), which was granted Serial No. 62/183,044, and is hereby incorporated by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates to air skirting for axles of tractor trailers. Specific embodiments relate to air skirting for drive axles of tractor trailers.

BACKGROUND OF THE INVENTION

Fuel efficiency is a huge concern for the transportation industry.

Passenger cars use underbody air skirting to reduce the coefficient of drag and increase fuel economy. Commercial truck fleets are increasingly interested in increasing the efficiency of their fleets. In the truck market, companies like SmartTruck sell their UT6 Plus TM trailer axle skirting system to increase the fuel efficiency 0.6%. The cost of the system is $3375, so the system saves 1% fuel economy for every $3 8 invested into the system. In contrast, the Eaton Cummins SmartAdvantage TM system advertises fuel savings of 3-6%. The upcharge in the market for an Ultrashift ® transmission alone is anywhere from $6500 to $9800. This system provides^ 1% fuel economy increase for every $1100-3300 invested into the system. In this simple comparison the undertray air skirting is a vastly more effective use of invested capital. By creating air skirting underneath the axles of a tractor trailer, it's expected that fuel economy gains can be achieved and because such a system has favorable economics, it's likely to be successful in the market. As the fleets allocate their capital investment in new trucks, they will allocate it towards features that produce the greatest fuel economy gains for the lowest cost and based on market data, air skirting is cost effective. This invention proposes an arrangement where the air skirting is attached to at least one axle of a tractor trailer. The operation of the invention is very simple. As the tractor is traversing down a road, air is moving under the tractor. Adding air skirting to at least one axle will smooth the air flow and prevent it from flowing over rough uneven surfaces like the head assembly carrier casting, axle housing, brake chambers, suspension components, and frame rails. Smoothing the air flow and reducing drag will improve efficiency. As the axle articulates over roads, bumps, and uneven terrain, the air skirting will move with the axle. This eliminates any interference concerns between the axles and the air skirting which are present when the air skirting is attached to the frame.

Covering the axle assembly with an air skirt can also serve as a protective element. The components of the axle assembly will be exposed to less corrosive material, thereby lengthening the life span of the sale assembly.

In addition, the embodiments of the invention as described herein include features, such as louvres or vents, that help regulate the temperature of the axle. Temperature of the axle is important for several reasons. For example, too much heat results in increase wear and breakdown of axle components. In contrast, increased heat surrounding the axle can decrease the viscosity of the oil lubricating the axle, thereby making the oil less viscous, increasing axle efficiency, and decreasing fuel consumption. Therefore, controlling the temperature is an important consideration in addition to those surrounding efficiency.

The embodiments described herein allow for increased fuel efficiency for the vehicle and temperature regulation of the axle.

SUMMARY OFTHE INVENTION

The present invention is directed toward an axle assembly where the axle assembly has an axle with a first and second half; and an air skirt. The air skirt has a first and second attachment end, wherein the first attachment end is attached to the first half of the axle and the second attachment end is attached to the second half of the axle, and wherein a portion of the air skirt between the first and second attachment has a contour that follows a contour of the axle. BRIEF DESCRIPTION OF THE DRAWINGS The above, as well as other advantages of the present invention, will become readily apparent to those skilled in the art from the following detailed description when considered in the light of the accompanying drawings in which:

Figs. 1A and 1B show a conventional tractor trailer combination.

Fig. 2 shows a side view of a tandem axle in accordance with an embodiment of the invention.

Fig. 3 shows a front view of an axle assembly in accordance with an embodiment of the invention.

Fig. 4 shows a bottom view of a front and rear axle air skirt in a second embodiment of the invention.

Fig. 5 shows a top-down perspective view of the air skirt of Fig. 4.

Fig. 6 shows a side view of -the air skirt of Fig. 4.

Fig. 7 shows a front bottom-up perspective view of the air skirt of Fig. 4 attached to a tractor in accordance with one embodiment of the invention.

Fig. 8 shows a bottom up view of the air skirt of Fig. 4 attached to a tractor in accordance with one embodiment of the invention.

Fig. 9 shows a rear bottom-up perspective of the air skirt of Fig. 4 attached to a tractor in accordance with one embodiment of the invention.

Fig. 10 shows a front top-down perspective view of the air skirt of Fig. 4 attached to the tractor in accordance with one embodiment of the invention.

Fig. 1 shows a side view of the air skirt of Fig. 4 attached to the tractor trailer in accordance with one embodiment of the invention.

Fig. 12 shows a front bottom-up perspective view of an axle assembly with an air skirt in accordance with an alternative embodiment of the invention.

Fig. 13 shows a front top-down perspective view of an axie assembly in accordance with an alternative embodiment of the invention.

DETAILED DESCRIPTION

Fig. 1 A shows a side view of a conventional tractor trailer combination including a tractor unit 1 , a trailer (detachable) 2, an engine compartment 3, a cabin 4, a sleeper (not present in all trucks) 5, an air dam (not present in all trucks) 6, fuel tanks 7, a fifth wheel coupling 8, an enclosed cargo space 9, landing gear 10, for when the trailer is detached, tandem trailer axles 11 , tandem drive axles 12 and front drive axle 14.

Fig. 1B shows the underneath of the tractor trailer combination of Fig. 1A.

The air skirt 108 can be attached to one or both of drive axles 14 or tandem axle 12 one or both trailer axles 11. The specific shape of the air skirt 108 can be the same for the front axle and rear axle or tandem axles 1 or 12, or it can be different. For example, Fig. 2 shows a schematic of a side view of the front 100 and rear axle assemblies 101 of a tandem drive axle 102, with the front of the tractor trailer to the left. The front axle shaft 103 and rear axle shaft 104 are shown, as well as the front differential carrier 105 and rear differential carrier 106. The air skirting 108 is shown in side profile as the dark black line. Note that the profile of the air skirting 108 contains a front axle portion 109 and a rear axle portion 110. The front axle portion 109 has a curved portion 111 and a flat portion 112. The transition 111a between the curved portion 111 and the flat portion 112 can occur at any point along front axle portion 109. The flat portion 112 can extend rearward past the differential carrier 105. Likewise, the rear axle portion 110 can extend forward past the differential carrier 106.

Fig. 3 shows a frontal view of either a front or rear differential carrier

105,106 with (cutaway) axle shafts 103,104 extending therefrom. In this embodiment, the air skirting 108 follows the contour of the axle assembly 100,101 to create a convex portion 113 under the differential carrier 105, 106.

Fig. 4 shows a bottom view of an -air skirt 200 that has a front axle portion 202 and a rear axle portion 204. The front axle portion 202 has an upward trending portion 206. A transition zone 208 extends between the front main body 210 of the front axle portion 202 and the upward trending portion 206. The rear axle portion 204 of the air skirt 200 has a rear main body 212 and a front upward tilt section 214 and a rear upward tilt section 216. In addition, the air skirt 200 may have ribs 218. The ribs 218 are shown as grooves that project upward in this perspective (see. Fig. 6 below for

clarification), but the ribs 218 could be projections that project downward and still be considered within the scope of the invention. Likewise, although not illustrated in the air skirt 200, the ribs 218 could have holes or slots or some other aperture to allow for air flow.

The upward trending portion 206 may also have a cut out area 220, as shown in Fig. 12) to fit around other complements of the tractor unit 1.

Fig. 5 shows the air skirt of Fig. 4 from a top-down perspective.

The side profile of the air skirting 200 is shown in Fig. 6. The front of the tractor 1 would be to the left.

Fig. 7 shows a front bottom-up perspective view of the air skirt 200 of Fig. 4 attached to the tractor 1. In addition to the air skirt 200, Fig. 7 shows the tractor chassis 300 and the driveshaft 302 and tires 304.

Fig. 8 shows a bottom up view of the air skirt 200 of Fig. 4 attached to the tractor 1.

Fig. 9 shows a rear bottom-up perspective view of the air skirt 200 of Fig. 4 attached to the tractor 1.

Fig. 10 shows a front top-down perspective view of the air skirt 200 of

Fig. 4 attached to the tractor 1.

Fig. 11 shows a side view of the air skirt 200 of Fig. 4 attached to the tractor 1.

The air skirting 108 or 200 can be made from any suitable material such as plastic, epoxy, aluminum, other metals, or the like, or any combination. The material can be formed with at least one vent 250. The vent 250 can be of any shape, size, and can be placed in any location in air skirt 108 or 200. The vent 250 may be in the form of an opening as shown in Fig. 12, or may be louvered (not shown), or covered in a mesh or other breathable material (not shown). The purpose of the vent 250 is to help maintain the temperature around the axle assembly in a desired range by both or either containing heat generated by axle during operation or allowing air to cool the axle assembly. The vent 250 can be formed or cut or machined into the air skirt 108 or 200. The vent 250 can be unitary with the air skirt 108 or 200 or comprise a separate piece that is attached to the air skirt 108 or 200 via conventional means. As mentioned above in the description for Fig. 4, the ribs 218 could have holes or slots or some other aperture to allow for air flow. In order to prevent the accumulation of debris (for example, snow) in the air skirt 108 or 200, an axle assembly 12 may have a frame cover 260. The frame cover 260, as shown in Fig. 13, may cover the axle 103/104 associated with the air skirt 108 or 200. The frame cover 260 could extend to cover both axles of a tandem axle 12 of tractor 1 or tandem axle 14 of trailer 2 or the front drive axle 14 as needed. The frame cover 260 as shown in Fig. 13 is a unitary piece, but could be non-unitary. The frame cover 260 can be attached to the chassis 300 using any conventional fastening means. The frame cover 260 can be made from any suitable material such as plastic, epoxy, aluminum, other metals, or the like, or any combination.

In addition, the air skirt 108 or 200 is shown in Figs. 2-13 as being attached to the tandem axle 12 of tractor 1. However, it is an embodiment of 1he invention to have an air skirt 108 or 200 attached to the front drive axle 14 of the tractor 1. Likewise, these air skirt 108 or 200 may be attached to the tandem axle 11 of the trailer 2. It is possible and within the scope of this invention that any of these alternative embodiments would use either both portions of the air skirt 108 or 200, or a single portion (front axle portion 202 or rear axle portion 204).

In most embodiments, the air skirt 108 or 200 is not a unitary piece. However, it is conceivable that the air skirt 108 or 200 may be composed of a single unitary piece. In addition, the front axle portion 109 or 202 and rear axle portion 110 or 204 may be attached to one another, either rigidly (with straps or screws or the like, as non-limiting examples) or flexibly (with hinges, as a non- limiting example).

Regarding attachment of the air skirt 108 or 200 to the tractor 1 or trailer

2, any suitable method of attachment is hereby included in the scope of this invention. One non-limiting example of such methods may be bolting to the axle housing or differential carriers. Another non-limiting example may be to have hasps, such as a U-bolt, that wrap around the axle shafts 103 or 104 and are bolted to the air skirt 08 or 200. A similar method could be used to attach the air skirt 108 or 200 to the chassis 300 itself. The embodiments described herein each have features that are interchangeable between embodiments. As one, non-limiting example, the air skirt 108 shown in Fig. 3 can be formed with ribs 218. Likewise, air skirt 200 can be made with a convex portion 113 that follows the differential 105, 106.

In accordance with the provisions of the patent statutes, the present invention has been described in what is considered to represent its preferred embodiments. However, it should be noted that the invention can be practiced otherwise than as specifically illustrated and described without departing from its spirit or scope.

Claims

WHAT IS CLAIMED IS:

1. An air skirt for an axle, wherein the air skirt comprises a front axle portion and a rear axle portion, and wherein the front axle portion has an upwardly curved portion.

2. The air skirt of claim 1 , wherein the air skirt comprises a rear axle portion.

3. The air skirt of claim 1 comprising ribs.

4. The air skirt of claim 1 wherein the front axle portion comprises the upwardly curved portion and a main body portion and a transition between the main body portion and the upwardly curved portion.

5. The air skirt of claim 2 wherein the rear axle portion comprises a front upward tilt section and a rear upward tilt section.

6. The air skirt of claim 1 wherein the front axle portion comprises at least one vent.

7. An axle assembly comprising the air skirt of claim 1.

8. An axle assembly comprising:

an axle with a first and second half; and

an air skirt, wherein said air skirt has a first and second attachment end wherein the first attachment end is attached to the first half of the axle and the second attachment end is attached to the second half of the axle, and wherein a portion of the air skirt between the first and second attachment has a contour that follows a contour of a differential case.

9. The axle assembly of claim 8, wherein the air skirt comprises ribs.

10. The axle assembly of claim 8, wherein the air skirt comprises a front axle portion with an upwardly curved portion, a main body portion and a transition between the main body portion and the upwardly curved portion.

11. The axle assembly of claim 8, wherein the air skirt comprises a rear axle portion with a front upward tilt section and a rear upward tilt section.

12. An axle assembly comprising:

an air skirt for a tandem axle, wherein the air skirt comprises a front axle portion and a rear axle portion, wherein the front axle portion has an upwardly curved portion and wherein the air skirt is attached to one of (i) the tandem axle or (ii) a chassis; and

a frame cover, situated above the air skirt, attached to the chassis.

13. The axle assembly of claim 12, wherein the air skirt comprises ribs.

14. The axle assembly of claim 12, wherein the air skirt comprises a front axle portion with an upwardly curved portion, a main body portion and a transition between the main body portion and the upwardly curved portion.

15. The axle assembly of claim 12, wherein the air skirt comprises a rear axle portion with a front upward tilt section and a rear upward tilt section.