WO2008066371A1

WO2008066371A1 - Portal unit

Info

Publication number: WO2008066371A1
Application number: PCT/MY2007/000083
Authority: WO
Inventors: Guan Chye Michael Saw
Original assignee: Auto Research And Development Sdn. Bhd.
Priority date: 2006-11-30
Filing date: 2007-11-27
Publication date: 2008-06-05
Also published as: MY141410A

Abstract

A portal unit for increasing the ground clearance of a four wheel drive light vehicle, that is trucks of less than 3 tonnage, the portal unit being universal and adapted to fit both the front and rear driven wheels, the portal a portal unit for a four wheel drive light vehicle comprising: intermeshing vertically spaced gears (9, 9A, 13, 17) supported for rotation within a housing (1) having front (2) and rear faces (2A); the rear face (2A) having an input receptor (5) through which a drive component (6, 6A) of the vehicle can extend and be coupled to a first gear (9, 9A), which meshes with an idler gear (13), which in turn meshes with a third gear (17) coupled to an output shaft (18) that extends out of the front face (2) of the casing with its axis below the axis of the input receptor (5).

Description

PORTAL UNIT

Technical Field

This invention relates to a portal unit for increasing the ground clearance of four wheel drive light vehicles, that is vehicles of less than 3 tonnage.

Background of the Invention

One of the main priorities when it comes to upgrading a vehicle for the purpose of tackling some of the roughest terrain around is to garner as much ground clearance as possible. Portal axles were first conceived to be fitted onto military trucks many years ago, and some of the older models are still in use today. The portal axles on the international market today usually come in a set that includes the axle, axle housing, and differential, in some cases a transfer case, in addition to a hub reduction via the portal drives. Even though some of these portal axles have achieved considerable popularity and commercial success, there has been a need for improvement to suit the local market, and also to cut cost.

The existing portal axles on the market today are built for high strength, but are bulky and rarely fitted onto trucks of below 3 tonnages. Even if they were to be installed, extensive modifications have to be done to the tires and the vehicle body in order to fit the portal axles. Furthermore, the gear reduction in the hub provides improved torque but reduces the drivability of the vehicle on highways. Wheel sizes have to be substantially increased just to have the vehicle keep up with traffic without straining the engine. The massive wheel changes also create other problems like the wheels not being able to clear the wheel arches without modifications to the vehicle body. There is also the question of whether the increased wheel sizes pertaining to the body of the vehicle will conform to the local highway rules.

Summary of the Invention

The main objective of the present invention is to provide a driven axle assembly with a portal "unit that could easily be modified to suit any four wheel drive light truck. The invention shall also allow for easy installation and removal for added convenience.

Furthermore, production and operation costs will be kept at a minimum because of fewer parts and the universal interchangeability of the portal unit between vehicles.

According to one aspect of the present invention there is provided a portal unit for a four wheel drive light vehicle comprising: intermeshing vertically spaced gears supported for rotation within a housing having front and rear faces; the rear face having an input receptor through which a drive component of the vehicle can extend and; the receptor being arranged such that the drive component can be coupled to a first gear, which meshes with an idler gear, which in turn meshes with a third gear coupled to an output shaft that extends out of the front face of the casing with its axis below the axis of the input receptor.

Description of Drawings and Best Mode for Carrying Out the Invention

Embodiments of this invention will now be described by way of example with reference to the accompanying drawings, in which: Figures IA, IB, 1C and ID are side elevation, end elevational and plan views of a portal unit for use with the front wheels of a vehicle;

Figures 2A and 2B are isometric views of the front portal unit;

Figures 3A, 3B, 3C and 3D are side elevation, end elevational and plan views of a portal unit for use with the rear wheels of a vehicle;

Figures 4A and 4B are isometric views of the rear portal unit;

Figure 5 is an isometric view from the underside of either the front or rear portal unit;

Figure 6 is a cross sectional view taken along the lines A-A of Figure IB of the front portal unit attached to a vehicle;

Figure 7 is a cross sectional view taken along the lines A-A of Figure 3B of the rear portal unit attached to a vehicle;

Figure 8 is a cross sectional view taken through the rotational axis of an output shaft of the portal unit;

Figures 9A and 9B are respectively cross sectional views taken along the lines M-M and C-C of Figures IA and 3λ?

Figure 10 is a front elevational view of the portal un.11 housing;

Figure 11 is an internal view of the output side of the housing cover;

Figure 12 is an illustration of a modified main drive shaft for the front portal unit; Figure 13 is an illustration of a modified main drive shaft for the rear portal unit;

Figure 14 is an illustration of a shaft for an idler gear;

Figure 15 is a view of the main output shaft and drive pinion gear;

Figure 16 is a cross sectional view showing details of a front knuckle; Figure 17 is a cross sectional view of the housing of the front portal unit;

Figure 18 is a cross sectional view of the housing of the rear portal unit; and Figure 19 is a cross sectional view of a front cover of the housing.

Note all the Figures referred to above illustrate the right portions of the front and rear portal units. The left portions are mirrored representations of the right portions. The drawings represent both front and rear portal units unless otherwise stated.

As shown in Figure 1, the front portal unit comprises a main body or housing 1 having a front face 2 and a rear face 2A. The rear face 2A adjacent the upper end has an input receptor 5 and the front face has at the lower end a forwardly projecting output shaft housing 23. The input receptor 5 and output shaft 18 are vertically spaced.

Figure 6 also shows the front portal unit, including the main body of housing 1 and the front housing cover 2. The existing knuckle 3 of the vehicle has a shortened shaft housing 4 that fits into the portal unit input receptor 5. The shortened shaft housing 4 houses the modified main drive shaft 6 (individual view FIG. 12) . The main drive shaft 6 will be modified so that the external spline specifications 7 will match the internal spline specifications 8 on the input gear 9. The input gear 9 and the modified main drive shaft 6 are held together with two external circlips 10 on each side of the input gear 9. The modified main drive shaft 6 is supported by a deep groove ball bearing 11 on one side, which is held in place by an internal circlip 12. The other side is supported by the existing components from the vehicle. FIG. 7 shows the rear portal unit and highlighting the components that are different from the front portal unit (FIG. 6) . This includes the input receptor 5A, the modified main drive shaft 6A, input gear 9A, taper roller bearing 37, deep groove ball bearing 37A and oil seal 38. As the input gear 9 and 9A (of the front and rear portal unit, respectively) rotates, it meshes with the idler gear 13 below it. The idler gear 13 is a one piece gear and shaft combination mentioned above as a centre idler/pinion shaft 14 (individual view FIG. 14) , which is supported on both ends by two pairs of deep groove ball bearings 15. The deep groove ball bearings 15 are separated by a spacer 16.

The rotating idler gear 13 will mesh with the output gear 17, which is also a one piece gear 17 and shaft 18 combination with drive pinion gear in situ (individual view FIG. 15) . The output shaft 18, with drive pinion gear, is supported by a single row taper roller bearing 19 on each side. An external circlip 20 is used to keep the single row taper roller bearing 19 in place. An oil seal 21 is fitted onto the output portion of the housing cover 2 to prevent any lubricants from spilling out from the portal housing. A spacer 22 is placed right after the oil seal 21. Replacement disc brakes will be placed on the new shaft housing 23 extruding from the housing cover 2. The spline 24 on the end of the main output 18 with drive pinion gear 17 connects to a new four wheel drive automatic locking free running hub for the front and a full time locking system on the rear, which in turn drives the wheel of the vehicle.

All the said gears and bearings are lubricated by splash lubrication from an oil bath (not shown) . A certain amount of oil is filled into the cavity of the portal housing via a filler plug and washer 25 (shown in FIG. 2 and 4A and 4B) . The oil bath ensures the rotating components of the portal unit, such as the gears and bearings, run smoothly and efficiently. The lubrication is also to provide for a reduced operating temperature, thus minimizing wear and tear, and also material fatigue on the rotating components. A drain plug and washer 26 (shown in FIG. 5) is located on the bottom of the portal housing to ease oil drainage .

A bracket 27 (shown in FIG. 6, 8, 2 and 4A and 4B) is provided as part of the housing so that bolts can be used to fasten the portal housing onto the existing knuckle 3. The size and location of the bracket 27 may vary depending on the knuckle dimensions on the particular vehicle. A hole must be threaded on each side of the knuckle so that the bra-cket 27 can be bolted onto the sides of the existing knuckle 3.

The main mounting points 28 (shown in FIG. 6 and 9) on the portal unit shall be located around the portal unit input receptor 5. The mounting points 28 allow the portal unit to be bolted onto the existing knuckle 3. The size and location of the mounting points 28 may vary depending on the particular vehicle. Holes have to be threaded on the knuckle plate to allow the portal unit to be bolted onto the existing knuckle 3, via the mounting points 28.

The housing cover 2 is fastened onto the main body 1 of the housing by means of mounting points 29 (eleven of them in total) all around the housing cover 2. These mounting points 29 are unthreaded but holes must be threaded on the portion of the main body 1 directly adjacent to the mounting points 29, to allow for the housing cover 2 to be bolted onto the main body 1. The bearing housing 30 (shown in FIG. 11) extrudes from the housing cover 2 and intrudes into the main body 1. The shaded areas (shown in FIG. 11) represents the carved out area 31 of the housing cover 2 that aims to lighten the weight of the portal unit and promote cost saving. The disc brake rotor that is positioned on the new shaft housing 23 has its brake caliper mounting 32 on the side of the housing cover 2. The old brake caliper mounting located on the existing knuckle 3 will not be used because the portal unit with the disc brake conversion will already have created an extension of the horizontal and vertical distance between the disc brake rotors and the mounting previously located on the existing knuckle 3.

For purpose of clarity, FIG. 16, 17, 18, and 19 has been included, showing the disassembled cross sectional views of FIG. 6 and also FIG. 7. Because of the tight spaces around the deep grove ball bearings 15 of the center idler/pinion shaft 14, brought by the fact that there are two bearings on each side instead of the usual one, an oil channel 33 is drilled through the bearing housing 35, which supports the deep groove ball bearings 15 of the main body 1, to reduce the chances of oil starvation on the bearings. An oil channel 34 is also drilled through the bearing housing 30, which supports the deep groove ball bearings 15 of the housing cover 2.

For the added convenience of removing the housing cover 2 in the case of service and maintenance, extractor holes 36 are threaded all the way through the housing cover 2. These extractor holes 36 permit bolts of the same size as the threads, to be bolted onto the housing cover 2, and be used as a leverage to dismantle the housing cover 2 from its main body 1. The bolts for the extractor holes 36 are tightened until the tip of the bolts come in contact with the main body 1. At this point, going through a sequence, the bolts are tightened one by one by a certain amount. The bolts are tightened further going through the same sequence. The cycle is repeated until the bolts that are attached to the housing cover 2, manage to push the main body 1 away from the housing cover 2, freeing the housing cover 2 from its main body 1. These holes are situated along the same plane but in different positions to the mounting points 29 mentioned earlier, used to bolt the housing cover 2 onto the main body 1.

The basic idea is to leave the original axle housing and differential alone. That means other than the axle shafts and the front knuckle that require a few minor modifications to suit the design, everything else from the axle housing to the differential will be left untouched. Though a disc brake conversion job is required if the original unit on the vehicle does not match the configuration on the portal unit.

The portal unit is bolted onto the axle housing for the rear axle, and onto the knuckle for the front axle. Minor modifications are to be done on the mounting points on the input side of the portal housing before installation to suit different vehicles. Each vehicle will have two pairs of portal units; one pair for the front and another for the rear. The output portion of the portal unit will then be connected to the wheel end drive assemblies.

The portal housing for the front and rear axles are similar in design, given that it consists of three gears with the same size arranged in a vertical manner. The center point of the gears are all in-line with each other. The similar sized gears will provide for a 1:1 ratio that is required to maintain the vehicle at reasonable operating speeds on the highway. That means that after installation of the portal unit, the power output to the wheels at a given engine speed will be the same as before installation. The uppermost positioned gear will be connected to the modified existing axle shaft from the vehicle. The said shaft will be modified at the spline end according to pre-planned specifications. This will be the input shaft for the portal unit. The gear below it is a one piece gear and shaft combination and comes together with the portal unit. The bottommost gear is also a one piece gear and shaft combination and has a splined end that connects to a special hub that will be included with the portal unit .

For the front of the vehicle, the shaft housing extending from the existing knuckle of a vehicle is where the disc brake sits on. After removal of disc brakes, the said shaft housing must be chopped off, and the input receptor for the portal unit must be modified to match the shape of the above mentioned shaft housing. This shaft housing will then sit snugly inside the input receptor of the portal unit. The knuckle end plate and the area around the input receptor of the portal unit have to be drilled where applicable so that the portal unit can be bolted onto the said knuckle end plate. The new location where the disc brake sits will be the new shaft housing on the portal unit output side. That means the disc brake will no longer be sitting on the same axis as the drive shaft but along the wheel centerline, which are two gear distances below, because of the portal unit. The portal unit comes with a front and rear disc brake conversion kit, and new hubs. The disc brake conversion kit includes a disc rotor, caliper, and wheel studs designed to fit a 16 inch rim with a 6 bolt pattern. The wheels will of course have to be changed if it does not match this specification. The new disc brakes will be located at the position as mentioned above. The original hubs are removed and replaced by new four wheel drive automatic locking free running hubs .

For the rear of the vehicle, the axle housing will not be modified for the purpose of this portal unit conversion. Thus, the shaft will be redesigned to required specifications. The input receptor for the portal unit must be modified to fit the axle housing spigot. Holes are drilled around the input receptor of the portal unit to match the holes found on the axle housing flange. This permits the portal unit to be bolted onto the axle housing flange. The original brakes for the vehicle are removed. The rear disc brakes go through the same conversion procedure as the front disc brakes. Because the axle shaft flange (not the same as axle housing flange) is removed, as mentioned above, the wheel studs that drive the wheel are also removed as well. Thus a hub with the same configuration as the front hub, except that it will be a full time locking system, will be installed on the rear to drive the wheel . The hub connects to the output shaft from the portal unit.

The design for both the front and rear portal unit is basically the same except for the input receptor, the input shaft, and also in terms of the different bearings used to support the input shaft. Everything else after that is the same (e.g. idler shaft and gear, and output shaft and gear, with their associated bearings and components . The hubs are the same except for the different locking systems.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. A portal unit for a four wheel drive light vehicle comprising: intermeshing vertically spaced gears (9, 9A, 13, 17) supported for rotation, within a housing (1) having front (2) and rear faces (2A) ; the rear face (2A) having an input receptor (5) through which a drive component (6, 6A) of the vehicle can extend and be coupled to a first gear (9, 9A) / which meshes with an idler gear (13) , which in turn meshes with a third gear (17) coupled to an output shaft (18) that extends out of the front face (2) of the casing with its axis below the axis of the input receptor (5) .

2. The portal unit according to claim 1, wherein the output shaft (18) has a splined end (24) and extends through a shaft housing (23) that projects forwardly of the front face (2) .

3. The portal unit according to claim 1, wherein the drive component is a splined drive shaft (6, 6A) on which the first gear (9, 9A) is coaxially mounted.

4. The portal unit according to any one of the preceding claims when configured for use with the front wheels of the vehicle, wherein the splined drive shaft (6) is supported by ball bearings (11) housed adjacent the front face (2) of the housing (1) and the first gear (9) is mounted on a splined surface (7) of the splined drive shaft (6) .

5. The portal unit according to any one of claims 1 to 3 when adapted for use with the rear wheels of the vehicle, wherein the splined drive shaft (6A) is supported by a ball bearing (37A) positioned adjacent the front face (2) of the housing (1) and a tapered roller bearing (37) positioned adjacent the rear face (2A) , the first gear (9A) being driven by the splined surface (7) of the drive shaft (6A) .

6. The portal unit according to claim 1, wherein the idler gear (13) is supported on an idler shaft (14) supported at either end by roller bearings (15) .

7. The portal unit according to claim 6, including oil channels to provide oil access to the bearings.

8. The portal unit according to claim 1, wherein the housing (1) has a filler plug (25) so that the housing (1) can contain oil that lubricates the gears (9, 13, 17) and bearings (11, 37, 37A, 15).

9. The portal unit according to claim 1, wherein the rotational axes of the gears (9, 13, 17) are arranged in a vertically spaced parallel array.

10. The portal unit according to claim 1, wherein the gears (9, 13, 17) are selected to define a one to one ratio between the drive component and the output shaft (18) .

11. The portal unit according to claim 1, wherein the front face (2) of the housing (1) is adapted to support a brake calliper.

12. The portal unit according to claim 1, wherein the housing (1) has projecting location points (28) to facilitate attachment to the vehicle.

13. The portal unit according to claim 1, wherein the front face (2) is secured to the housing through a peripheral array of bolts extending through mounting points (29) .