LUBRICATION ARRANGEMENT FOR A DRIVE AXLE OF A TRANSPORT VEHICLE

Abstract

Drive axle assembly (70) comprising: a housing (72); an input shaft (100) extending into the housing (72) and arranged about an axis of rotation (68); a first spur gear (110) disposed about the input shaft (100) and the rotational axis (68), the first spur gear (110) configured to deliver power to a first wheel differential (82), the first wheel differential (82) having a ring gear (150); a second spur gear (112) disposed about a pinion shaft (140), the pinion shaft (140) configured to deliver power to the first wheel differential (82) via a pinion gear (146), the second spur gear (112) being drivingly coupled to the first spur gear (110); a front bearing (116) disposed forward of and adjacent to the first spur gear (110), the front bearing (116) being disposed around the input shaft (100) and rotatably supporting the input shaft (100) within the housing (72); and a rear bearing (117) disposed rearward of and adjacent to the first spur gear (110), the rear bearing (117) being disposed about the input shaft (100) and rotatably supporting the input shaft (100) within the housing (72), the first and second spur gears (110, 112) pumping a lubricant (78) from the housing (72) to a lubricant passage (160) and delivering the lubricant (78) to a radial face (180) of at least one of the front and rear bearings (116, 117); wherein the lubricant passage (160) has a plurality of passages (162) for supplying the lubricant (78) to the front bearing (116); wherein the plurality of passages (162) includes a first passage (166) arranged tangentially to an outer surface (170) of the first spur gear (110); wherein the lubricant (78) pumped from the outer surface (170) of the first spur gear (110) enters the first passage (166) and flows from the first passage (166) to the radial face (180) of the front bearing (116); and wherein the plurality of passages (162) are formed inwardly from an outer surface (164) of a cover member (90).

Description

Technical field

[0001] The present invention relates to a center axle assembly for an articulated transport vehicle and, more particularly, to a lubrication assembly for a support bearing of a drive shaft for the center axle assembly. background

[0002] Transport trucks, both on-road and off-road, have three axles: a front axle, a center axle, and a rear axle. Output from a power source is delivered to all three axles via driveshafts. A gearbox is directionally engaged to supply power to the axle assemblies. The front axle assembly can be operatively engaged / disengaged through the use of a pre-gearbox to allow the truck to operate in a four-wheel drive mode. Each axle assembly has a differential gear set that includes a pinion gear meshing with a ring gear. The pinions of the front and rear axle assemblies are generally driven directly via driveshafts through splined connections via a yoke and flange, respectively. The center axle, on the other hand, has a through shaft that drives a series of gears to drive the pinion gear and ultimately the differential gear.

[0003] The through shaft is supported at each end by a pair of bearings. One pair of bearings supports the front end of the through shaft, and an additional pair of bearings supports the rear end of the through shaft.

[0004] There is a need to provide lubrication for components of the center axle assembly, and in particular the support bearings for the through shaft. Conventional methods for lubricating the bearings involve splashing the pinion and bevel gear during operation of the haul truck. However, due to the location of each bearing, splashing lubrication from pinion and bevel gear rotation cannot reach all of the bearings at the front end of the center axle assembly. One known method for lubricating components of the center axle assembly is shown in U.S. Patent No. 7,258,641 B2, issued to Green et al. on August 21, 2007, and assigned to Dana Corporation. In U.S. Patent No. 7,258,641 B2, lubricant splashed from the ring gear is collected and then distributed within the housing for the assembly by a bearing that rotatably supports the output gear.The bearing delivers lubricant to the differential gears, where seals and / or tight tolerances retain the lubricant and allow it to flow to the surfaces of the input shaft and the helical gear mounted around the input shaft. The output gear mounted around the output shaft may also have a passage to allow lubricant to flow through the gear to the bearing surfaces of the output shaft and the output gear. Not all centerline assemblies have the differential gears, and tight tolerances are expensive to manufacture.

[0005] DE 10 2012 207 134 A1 discloses a lubrication device for a spur gear axle. Furthermore, US 5 161 644 A discloses a system for lubricating a front bearing support member of an input shaft of a vehicle tandem axle assembly, wherein liquid lubricant is delivered to the front bearing support member while the vehicle is climbing an incline. Furthermore, CN 102 312 995 A discloses an interaxial differential lubrication structure of a continuous drive axle and a vehicle with the lubrication structure. Furthermore, US 2008 / 0257 629 A1 discloses a method for controlling the rotational speed of at least one rotating member in the drive train of a vehicle.

[0006] The present disclosure is directed to overcoming one or more of the deficiencies set forth above. Summary of the invention

[0007] The object of the present invention is achieved by drive axle assemblies and by a transport vehicle according to the independent claims. The subclaims relate to preferred embodiments of the invention.

[0008] According to one aspect of the present disclosure, a drive axle assembly includes a housing and an input shaft extending into the housing and disposed about a rotational axis. A first spur gear is disposed about the input shaft and the rotational axis, the first spur gear configured to provide power to a first wheel differential and including a ring gear. A second spur gear is disposed about a pinion shaft. The pinion shaft is configured to provide power to the first wheel differential via a pinion gear. The second spur gear is drivingly coupled to the first spur gear. A forward bearing is positioned forward of and adjacent to the first spur gear, the bearing being disposed about the input shaft and rotatably supporting the input shaft within the housing.A rear bearing is positioned rearward of and adjacent to the first spur gear, the bearing being disposed around the input shaft and rotatably supporting the input shaft within the housing. The first and second spur gears pump lubricant from the housing to a lubricant passage and deliver the lubricant to a radial face of at least one of the front and rear bearings.

[0009] According to another aspect of the present disclosure, a drive axle assembly includes a housing and an input shaft extending into the housing and disposed about a rotational axis. A through shaft is connected to the input shaft at a first end and supported by a pair of bearings at a second end. A first spur gear is disposed about the input shaft and the rotational axis, the first spur gear configured to provide power to a first wheel differential, the first wheel differential including a ring gear. A second spur gear is disposed about a pinion shaft, the pinion shaft configured to provide power to the first wheel differential via a pinion gear, and the second spur gear is drivingly coupled to the first spur gear. A bearing is positioned adjacent to the first spur gear and disposed about the input shaft and rotatably supports the input shaft within the housing.The first and second spur gears pump lubricant from the housing into the lubricant passage and to at least one of the front and rear bearings supporting the input shaft.

[0010] According to yet another aspect of the present disclosure, a transport vehicle includes a frame assembly having at least a front portion and a rear portion, a pivot joint connecting the front and rear portions and configured to permit pivotal movement about the pivot by the front and rear portions. Front, center, and rear axles support the frame assembly and include a plurality of ground-engaging devices attached to the axles. An operator compartment is also supported on the frame assembly. A bed is configured to support a load and is also connected to the frame assembly. A motor that generates torque is carried by the frame assembly. A transmission is coupled to the motor for receiving the torque, the transmission having an output clutch for delivering the torque to the front, center, and rear axles. The center axle includes a drive axle assembly. Short description of the drawings Fig. 1 is a side view of an articulated truck of the present description; Fig. 2 is a pictorial representation of a drive train of an articulated truck used in Fig. 1 is shown; Fig. 3 is a cutaway view of a center axis arrangement of the Fig. 2 shown drive train; and Fig. Figure 4 is a partially cutaway view of a portion of the centerline assembly taken along the section lines shown in Fig. 2 are shown. Detailed description

[0011] Now with reference to the Fig. 1 and Fig. 2, a transport vehicle 10 is shown, for example, as an articulated truck for carrying loads over a variety of work cycles. The transport vehicle 10 includes an operator station or cab 12, a body 14, and a main frame 16. The main frame 16 includes a front portion 20, a rear portion 22, and an articulation 24 for steering the transport vehicle 10. The articulation 24 connects the front and rear portions 20, 22 and allows pivoting movement about the articulation 24 of the front and rear portions 20, 22 through an axle 26 so that the transport vehicle 10 can be steered via hydraulic cylinders (not shown). The front portion 20 of the frame 16 is supported by a front axle 30 ( Fig. 2), and the rear portion 22 of the main frame 16 is supported by a center axle 32 and a rear axle 34. A plurality of ground-engaging devices 38 are supported on the front axle 30, the center axle 32, and the rear axle 34.

[0012] Power is supplied to the front axle 30, the center axle 32 and the rear axle 34 by a motor 40 ( Fig. 2), a gearbox 42 ( Fig. 2) and a pre-transmission gear 44 for receiving the torque and transmitting the torque to a plurality of drive shafts 50, 52, 54, 56 ( Fig. 2). The plurality of ground-engaging devices 38 (each one) are attached to each end of the front, center, and rear axles 30, 32, 34 and are preferably used to travel along a terrain surface 60.

[0013] Power from the engine 40 is transmitted via a direct connection to the transmission 42. The transmission 42 includes a plurality of gears (not shown) that can be engaged in various combinations to achieve desired gear ratios for powering the haulage vehicle 10 at various speeds and output torques. Additionally, the gears control the direction of rotation of the output of the transmission 42 to enable forward and reverse movement of the haulage vehicle 10. The output from the transmission 42 is delivered through the drive shaft 50 to the transmission 44. The transmission 44 splits the rotational input into two directions and provides an output to the drive shafts 52 and 54. The output to the drive shaft 52 can be selectively activated to enable the haulage vehicle 10 to operate in a four-wheel drive mode.The drive shaft 54 is connected to the input of the center axle 32 and the drive shaft 56 is connected to the rear axle 34.

[0014] Fig. 3 illustrates a sectional view of a drive axle assembly 70 of the central axle 32 taken vertically along an axis of rotation 68. As previously mentioned, the central axle 32 receives input from the drive shaft 54 and is connected to the rear axle 34 by the drive shaft 56. The central axle 32 is provided to drive two of the plurality of ground engaging devices 38 carried on each side of the central axle 32 on half shafts (not shown) extending from the central axle 32. The central axle 32 is particularly adapted for use in a transport vehicle 10. It should be understood, however, that the present invention is not limited to use in a transport vehicle 10 and may be used in a wide variety of vehicles having tandem axles. The drive axle assembly 70 may include a housing 72, a drive flange, oran input yoke 74, an output flange or output yoke 76, a pinion shaft assembly 80 and a wheel differential 82.

[0015] The housing 72 provides structural support for the other components of the drive axle assembly 70. The housing 72 also protects the other components of the drive axle assembly 70 from foreign objects and the environment, and contains a level or reservoir of lubricant 78. The housing 72 may be constructed of conventional metal and / or metal alloys, such as steel, and may include a plurality of cover members 90, 92, 94, and 96 sized relative to components of the drive axle assembly 70 and coupled together using conventional fasteners 98.

[0016] An input shaft 100 transmits power from the drive shaft 54 to the drive axle assembly 70. The shaft 100 may be constructed of conventional metals and / or metal alloys. The shaft 100 is driven by the drive shaft 54 through the input yoke 74. The input yoke 74 may be splined to the forward end of the input shaft 100 and may be secured thereto by a fastener 104 and washer disposed within a threaded opening 106 extending into the forward end of the shaft 100. A cover 107 is disposed around the input yoke 74. The input yoke 74 is received in an opening in the cover member 107. The input yoke 74 is sealed for rotation about the rotational axis 68 within an opening in the cover 107 by a seal 108 disposed within the opening.

[0017] The input shaft 100 includes a first spur gear 110 that transmits torque to a second spur gear 112 and to the pinion shaft assembly 80. The first and second spur gears 110, 112 may be, for example, helical gears or any other conventional gears known in the art and may be made of conventional metals and / or metal alloys. The spur gear 110 is disposed about the input shaft 100 and rotatable therewith.

[0018] The input shaft 100 is rotatable by supporting front and rear bearings 116, 117 located on either side of the first spur gear 110. One side of the rear bearing 117 can contact a shoulder 118 located in the cover 92, and the other side abuts against the rear portion of the first spur gear 110. The front bearing 116 abuts against the front side of the first spur gear 110. A cover 120, held in place by fasteners, contacts the front bearing 116, providing preload and securing the front and rear bearings 116, 117, the first spur gear 110, and the input shaft 100, preventing axial movement thereof. The cover 120 also forms a radial cavity 121 forward of the front bearing 116.

[0019] The input shaft 100 may be splined to a through shaft 122. The through shaft 122 is provided to transmit a portion of the power provided by the input shaft 100 and the through shaft 122 to the drive assembly of the rear axle 34 (in Fig. 2) through the input shaft 56. The shaft 122 is conventional in the art and is arranged coaxially relative to the input shaft 100 along the axis 68 and has a boss 124 at its forward end on which the input shaft 100 is journaled. The shaft 122 extends through openings in housing members 92 and 94, respectively, and is journaled therein by a pair of bearings disposed in a bearing seat 128 housed in an opening of the housing member 96.

[0020] The pinion shaft assembly 80 transmits power from the first spur gear 110 to the wheel differential 82. The pinion shaft assembly 80 may include a second spur gear 112 driven helically to transmit torque to a pinion shaft 140. The gear 112 may be drivingly coupled to the shaft 140 by axially extending splines (not shown) on the shaft 140. The shaft 140 may be rotatably supported by bearings 142, 144 within the bearing seats in the cover members 90 and 92. The pinion shaft 140 has a pinion gear 146 at the rear end.

[0021] The wheel differential 82 is provided to enable the ground-engaging members 38 carried on each side of the center axle assembly 32 to rotate at different speeds. The assembly 82 includes a ring gear 150 and a conventional bevel gear set 152 disposed within a differential carrier 154. The ring gear 150 transmits torque from the pinion gear 146 to the gear set 152 and is known in the art. The ring gear 150 may be made of conventional metal and / or metal alloys and may comprise a hypoid gear. The gear 150 is fixed to the carrier 154 or may be integral therewith. The gear set 152 is provided to deliver torque from the ring gear 150 to the axle half-shafts (not shown) that support the ground-engaging members in a conventional manner.

[0022] Now with reference to Fig. 4 is a cutaway portion of the drive axle assembly 70 taken along a portion of section line 4-4 in Fig. 2 and some of the components in Fig. 3, which shows the housing 72. A lubricant passage 160 is formed in the cover member 90 of the housing 72. In particular, the lubricant passage 160 is formed by a plurality of passages 162 extending from an exterior surface 164 of the cover member 90. A first passage 166 may be formed in the cover member 90 in an upwardly directed manner so as to extend on an interior 168 of the housing 72 tangential to an exterior surface 170 of the first spur gear 110. A second passage 172 is formed on a mounting surface 174 of the cover member 90 in an inclined manner, with the first passage 166 being intersected perpendicularly. A generally vertical passage 176 is formed on the outer surface 164 at a predetermined depth and intersects the second passage 172.Finally, a generally horizontal passage 178 is formed from the outer surface 164 of housing 72 and exits the interior 168 of the cover member 90. The generally horizontal passage 178 forms a lubrication outlet 182 adjacent a radial face 180 of the front bearing 116. The plurality of passages are each shown blocked from the outer surface 164 in a conventional manner, such as by threaded or press-fit plugs (not shown), so that contaminants are not permitted to enter the interior 168 of the housing 72. However, it should be understood that cast holes would function as well.While the specific description of the drive axle assembly 70 has focused on the center axle 32, it should be understood that a front or rear axle 30, 34 driving the pinion assembly 80 via first and second spur gears 110, 112 and not having a through shaft 112 may be implemented in a similar manner. Industrial applicability

[0023] Now with reference to the Fig. 3 and Fig. 4, the lubrication system for the center axle drive axle assembly 70 is described in more detail. During operation of the transport vehicle 10, rotational input power is supplied to the drive axle assembly 70 via the drive shaft 54. When the wheel differential 82 is rotated, lubricant is sprayed and lubricates the bearings 126, 142, 144 and the rear bearing 117 and other associated components of the drive axle assembly 70. Additionally, the lubricant 78 is pumped by the second spur gear 112 to the first spur gear 110. The lubricant 78 pumped by the first and second spur gears 110, 112 is supplied to the radial face 180 of the front bearing 116 through the lubricant passage 160 through the plurality of passages 162, along the directional arrows shown in Fig.4. In particular, lubricant 78 is ejected from the first spur gear 110 in a tangential manner into the first passage 166. From the first passage 166, lubricant 78 flows downwardly, via pumping action from the first and second spur gears 110, 112 and gravity, into the second passage 172. The lubricant 78 completes its journey by flowing through the generally vertical and horizontal passages 176, 178 into the interior 168 of the housing 72 into the radial cavity 121 between the front surface 180 of the front bearing 116 and the cover 120.

[0024] It should be noted that with the design of the drive axle assembly 70, more or less lubrication can be delivered to the front bearing 116 by determining various aspects, such as dimensions and ratios. By controlling the dimensions of the plurality of passages 162, the viscosity of the lubricant 78, and the clearances between the first spur gear 110 and the cover member 90, the amount of lubricant 78 delivered to the front and rear bearings 116, 117 can be controlled. In this manner, the drive axle assembly 70 provides improved lubrication to components located above the level of lubricant 78 in the housing 72 and farthest from any splash lubrication provided by the rotation of the differential gear 82.

Claims

[1] Drive axle assembly (70) comprising: a housing (72); an input shaft (100) extending into the housing (72) and arranged about an axis of rotation (68); a first spur gear (110) disposed about the input shaft (100) and the rotational axis (68), the first spur gear (110) configured to deliver power to a first wheel differential (82), the first wheel differential (82) having a ring gear (150); a second spur gear (112) disposed about a pinion shaft (140), the pinion shaft (140) configured to deliver power to the first wheel differential (82) via a pinion gear (146), the second spur gear (112) being drivingly coupled to the first spur gear (110); a front bearing (116) disposed forward of and adjacent to the first spur gear (110), the front bearing (116) being disposed around the input shaft (100) and rotatably supporting the input shaft (100) within the housing (72); and a rear bearing (117) disposed rearward of and adjacent to the first spur gear (110), the rear bearing (117) being disposed about the input shaft (100) and rotatably supporting the input shaft (100) within the housing (72), the first and second spur gears (110, 112) pumping a lubricant (78) from the housing (72) to a lubricant passage (160) and delivering the lubricant (78) to a radial face (180) of at least one of the front and rear bearings (116, 117); wherein the lubricant passage (160) has a plurality of passages (162) for supplying the lubricant (78) to the front bearing (116); wherein the plurality of passages (162) includes a first passage (166) arranged tangentially to an outer surface (170) of the first spur gear (110); wherein the lubricant (78) pumped from the outer surface (170) of the first spur gear (110) enters the first passage (166) and flows from the first passage (166) to the radial face (180) of the front bearing (116); and wherein the plurality of passages (162) are formed inwardly from an outer surface (164) of a cover member (90). [2] The drive axle assembly (70) of claim 1, wherein the plurality of passages (162) are closed from the outer surface (164) of the cover member (90). [3] The drive axle assembly (70) of claim 2, further comprising: a cover (120) that positions the front bearing (116) against the first spur gear (110). [4] Drive axle assembly (70) according to claim 3, wherein the cover (120) forms a radial cavity (121) in an interior (168) of the housing (72) between the cover (120) and the radial end face (180) of the front bearing (116). [5] A drive axle assembly (70) comprising: a housing (72); an input shaft (100) extending into the housing (72) and arranged about an axis of rotation (68); a through shaft (122) connected to the input shaft (100) at a first end and supported by a pair of bearings (126) at a second end; a first spur gear (110) disposed about the input shaft (100) and the rotational axis (68) and integral with the input shaft (100), the first spur gear (110) configured to deliver power to a first wheel differential (82), the first wheel differential (82) having a ring gear (150); a second spur gear (112) disposed about a pinion shaft (140), the pinion shaft (140) configured to deliver power to the first wheel differential (82) via a pinion gear (146), the second spur gear (112) being drivingly coupled to the first spur gear (110); a front bearing (116) disposed forward of and adjacent to the first spur gear (110), the front bearing (116) being disposed around the input shaft (100) and rotatably supporting the input shaft (100) within the housing (72); and a rear bearing (117) disposed rearward of and adjacent to the first spur gear (110), the rear bearing (117) being disposed around the input shaft (100) and rotatably supporting the input shaft (100) within the housing (72), wherein the first and second spur gears (110, 112) pump a lubricant (78) from the housing (72) to a lubricant passage (160) and deliver it to at least one of the front and rear bearings (116, 117) supporting the input shaft (100). [6] The drive axle assembly (70) of claim 5, wherein the lubricant passage (160) includes a plurality of passages (162) for supplying the lubricant (78) to the front bearing (116) disposed forward of and adjacent to the first spur gear (110). [7] The drive axle assembly (70) of claim 6, wherein the plurality of passages (162) includes a first passage (166) disposed tangentially to an outer surface (170) of the first spur gear (110). [8] The drive axle assembly (70) of claim 7, wherein the lubricant (78) pumped from the outer surface (170) of the first spur gear (110) enters the first passage (166) and flows from the first passage (166) to the radial face (180) of the front bearing (116). [9] The drive axle assembly (70) of claim 8, wherein the plurality of passages (162) are formed inwardly from an outer surface (164) of a cover member (90). [10] The drive axle assembly (70) of claim 9, wherein the plurality of passages (162) are closed from the outer surface (164) of the cover member (90). [11] The drive axle assembly (70) of claim 10, further comprising: a cover (120) that positions the front bearing (116) against the first spur gear (110). [12] The drive axle assembly (70) of claim 11, wherein the cover (120) forms a radial cavity (121) in an interior (168) of the housing (72) between the cover (120) and the radial face (180) of the front bearing (116). [13] Transport vehicle (10) comprising: a frame assembly (16) having at least one front part (20) and a rear part (22); a joint connection (24) which connects the at least one front and rear part (20, 22) and is designed to allow pivoting movement about the hinge connection (24) by the front and rear parts (20, 22); a front axle (30), a central axle (32) and a rear axle (34), which support the frame assembly (16); a plurality of ground engaging devices (38) mounted on the axles (30, 32, 34); an operator compartment carried on the frame assembly (16); a trough (14) designed to carry a load and to be connected to the frame assembly (16); a motor (40) for generating torque carried by the frame assembly (16); a transmission (42) coupled to the engine (40) for receiving the torque, the transmission (42) having an output connection provided to transmit torque to the front, middle and rear axle (30, 32, 34); and wherein the central axle (32) comprises the drive axle assembly (70) according to claim 12. [14] Transport vehicle (10) according to claim 13, wherein the front axle (30) carries the front part (20) of the frame assembly (16) and the middle and rear axles (32, 34) carry the rear part (22) of the frame assembly (16). [15] Transport vehicle (10) according to claim 14, which has a primary transmission (44) arranged between the transmission (42) and the front axle (30) and between the transmission (42) and the central and rear axles (32, 34).

Images