MXPA06006196A - Tandem axle system - Google Patents

Abstract

A tandem axle system for vehicle having an optimized inter-axle driveline is depicted and described. The system has a forward drive axle system having a forward pinion gear drivingly connected to a drive side of a forward portion of a forward ring gear. The system also has a rear drive axle system having a rear pinion gear drivingly connected to a drive side of a rear portion of a rear ring gear. An inter-axle driveline connects the forward drive axle system with the rear drive axle system.

Description

DOUBLE REAR AXLE SYSTEM FIELD OF THE INVENTION The present invention relates to a dual rear axle system for vehicles. More particularly, the present invention relates to a dual rear axle system for vehicles having an optimized inter-axle driveline between a front-drive axle system and a rear-drive axle system.

BACKGROUND PE THE INVENTION Those skilled in the art are aware that the drive is provided to a vehicle such as a class 8 truck from a front-rear drive shaft to a rear-rear traction axle of tandem axles via a driveline between axles. Typical tandem axles have high cardan joint angles of the inter axle driveline due to the raised position of the output shaft seal of the front axle and the low position of the input joint of the rear axle. The raised angles of the cardan joint of the driveline on the typical tandem axles can also be attributed to the short distance between the output joint of the front axle and the input joint of the rear axle in tandem. Those skilled in the art are aware that the raised angles of the cardan joint of the inter-axle driveline are generally undesirable since the noise and vibration of the joints increases as the angle increases. The low position of the input joint of the rear axle also undesirably decreases the ground clearance of the inter-axle driveline.

Based on the foregoing, it can be understood that a long interline axle line is desirable because such a third line will reduce the angles. Therefore, if the protruding dimension, which is the distance between the center line of the cardan shaft and the front of the input shaft of the rear axle, can be reduced, a longer wheelbase can be contained. in the system of double rear axle. Various inventions in the state of the art have tried to solve these disadvantages of the tandem axes. For example, U.S. Patent No. 1, 856,748 (hereinafter "the 748 patent") provides a transmission mechanism designed to limit excessive angles in the universal joints of the vehicle under conditions normal transmission. Figure 2 of the '748 patent depicts a propeller shaft "e" that drives a universal joint f. The seal f is connected to a first differential mechanism f1. The board f supplies power to f1 which distributes that power between the axes b1 and d. A hypoidal spiral drive sprocket with hyperbolic f 2 s provides a power to the ring gear b4 while a second hypoid sprocket of similar propulsion f3 supplies the remaining power to the ring gear c4. It should be noted that the two hypoid propulsion gears f2 and f3 are functioning on the driven side of the respective gearwheels b4 and c4, which is known to be on the undesirable weak side of the gear teeth in the '748 patent. A g-axis connects differential casings b3 and c3. To align the axis g with the drive shaft e, the axis of the front drive sprocket f2 falls down the axis of the axis b1 while the axis of the pinion f3 is below the axis of the axis d. It should be noted that the entry of the rear axle is below the center and as such does not provide a good ground clearance for the rear of the driveline between axles g. According to the '748 patent, this design aligns the axis of the pinions f2 and f3 with each other and with the axes e and g. The pinion f3 drives from the rear side of the ring gear c4 and the front pinion f 3 drives from the front side of the ring gear b4. U.S. Patent No. 1, 791, 138 (hereinafter "the '138 patent) provides a dual-axis drive having gear wheels f1 and f3 mounted on opposite sides of the drive shaft x, as best seen in Figure 6. The hypoid pinion f meshes with the ring gear f1 rearwardly of the drive shaft b3. Figure 3 of the '138 patent illustrates the front sprocket on the rear side of the front sprocket and the rear sprocket on the front side of the rear sprocket. The '138 patent also teaches that the rear sprocket is located above the center of the rear sprocket. The front sprocket is also above the center of the front sprocket. It should be noted that the front-drive hypoidal sprocket f is operated on the most powerful side desirable of the sprocket f1 but the rear-drive hypoidal sprocket f2 is operated on the undesirable weak drive side of the sprocket f3. Additionally, the placement of the differential power splitter components between axles d1, d2, d3 and the pinion of the front axle f towards the rear of the front axle results in an undesirable axle line between axles. Despite trying to solve some of the problems with tandem axes, the above representative technique discussed above can be improved.

Specifically, it would be advantageous to optimize the inter-axle driveline by minimizing the cardan joint angles and improving the ground clearance of the inter axle driveline.

BRIEF DESCRIPTION OF THE INVENTION The present invention is a dual rear axle system having a front drive axle system having a front hypoid gear set comprising a front pinion gear drive connected to a drive side of a front portion of a crown Toothed front. The system also has a rear drive axle system having a hypoid rear gear set comprising a rear pinion gear driven in a drive manner to a drive side of a rear portion of a rear sprocket. A driveline between axles connects the front drive axle system with the rear drive axle system.

BRIEF DESCRIPTION OF THE DRAWINGS The foregoing, as well as other advantages of the present invention, will become apparent to those skilled in the art from the following detailed description when considered in light of the accompanying drawings, in which: Figure 1 is a view Schematic diagram of a vehicle having a front axle and tandem rear axles of the present invention. Figure 2 is a schematic side view of a front drive shaft system with the rear axle drive system of the tandem rear axles of Figure 1. Figure 3 is a side view of a front drive axle system of the present invention. Figure 4 is a schematic plan view of an embodiment of the rear drive axle system of the present invention. Figure 5 is a schematic plan view of another embodiment of the rear drive axle system of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED MODALITIES It should be understood that the invention may assume different orientations and sequences of alternative steps, except where expressly stated otherwise. It should also be understood that the specific devices and processes illustrated in the accompanying drawings, and described in the following specification, are merely exemplary embodiments of the inventive concepts defined in the appended claims. Accordingly, the dimensions, addresses or other specific physical characteristics related to the disclosed modalities should not be considered as limiting, unless expressly stated otherwise. Referring now to Figure 1, a vehicle 10 is shown having a motor 12 driven in a drive manner to a shift transmission 14. An axle 16 is coupled to the output portion of the transmission 14, such as by means of of a single universal joint fork of the cardan 18 as is known to those skilled in the art, and is coupled in a driving manner to an inlet, such as by means of a single universal joint fork of the cardan 20, also as it is known by those skilled in the art, of a front-drive axle assembly 22 of the rear double axle 24. As described in more detail below, the propulsion is transmitted from the fork 20 to a first front traction axle 26 and a second axle front drive 28 of a front drive shaft assembly 22. The first front drive shaft 26 provides propulsion to at least one wheel 30 and associated rim (not shown) and the second The front traction shaft provides propulsion to at least one wheel 32 and the associated rim (not shown), as is known to those skilled in the art. A step arrow, numbered generically with the reference number 34, extends through the front traction axle system 22 and is propelled coupled to an inter-axle driveline 36. The inter-axle driveline 36 engages the front drive axles 26., 28 with a first rear-drive shaft 38 and a second rear-drive shaft 40. More specifically, the inter-axle driveline 36 transmits propulsion from a single universal joint yoke output of the cardan 98 to an inlet, such as a single universal joint yoke of the cardan 42, as is known to those skilled in the art, for rear traction axles 38, 40. The rear traction axles 38, 40 are separated from a rear traction axle assembly 44. The first rear-drive shaft 38 provides propulsion to at least one wheel 46 and the associated rim (not shown) and the second rear-drive shaft 40 provides propulsion to at least one wheel 48 and the associated rim (not shown). ), as is known to those skilled in the art. Referring now to Figures 2 and 3, a portion of the fork 20 is shown as being connected to an input shaft 50 of the front drive shaft assembly 22. Those skilled in the art will understand that the front drive shaft assembly 22 is located within the housing of the front drive shaft assembly 52, shown only in Figure 3. The input shaft 50 is mounted to rotate with respect to I to housing 52 of the front drive shaft assembly on at least one bearing 54. As seen in the two Figures 2 and 3, a lateral helical gear 50 is secured and rotated with the input shaft 50. The helical gear l ateral 56 is engaged with a helical pinion gear 58. The helical pinion gear 58 is fixed to the pinion shaft 60 of a front sprocket gear 62. The pinion shaft 60 is mounted to rotate with respect to the housing 52 of the front drive shaft with at least one bearing 64. The front sprocket gear 62 is also held for rotation with a bearing 66. The bearing 66 can be supported by means of a bolted bearing cage 68. The front sprocket gear 62 is an art of a hypoid front gear 70 comprising also a front toothed crown 72. As shown in Figures 2 and 3, the front sprocket gear 62 is preferably engaged with a pulse side 74 of the front sprocket 72. Those skilled in the art will understand that the pulse side 74 of the front sprocket 72 comprises convex teeth 75 of toothed rim. Only a representative sample of the convex teeth 75 of the ring gear is illustrated. The engagement of the front sprocket gear 62 with the convex teeth of the ring gear 75 on the drive side 74 of the ring gear 72 is a much stronger gear than if the pinion gear 62 were engaged with the driven side of the gear 72 It is also referred to that the front fork gear 62 is engaged with a front portion 76 of the front sprocket 72 and that a rotation shaft 78 of the front sprocket gear 62 is located below a sprocket axle. rotation 80 of the ring gear 72. The front ring gear 72 is assembled to the first and second front drive axles 26, 28, with a wheel differential 82, which is partially shown in Figure 3, to provide the rotational drive to the axes 26, 28. Referring to Figures 2 and 3, the lateral helical gear 56 is illustrated as being engaged with one side 84 of an axle differential 86. The axle differential 86 is monoshaped. rotate with the input shaft 50. At least one output side gear 88 is engaged with the other side 90 of the axle differential 86. At least one bearing 92 is located between the output side gear 88 and the housing of the system of front traction shaft 52 to allow the output side gear 88 to rotate with respect to the housing 52. The output side gear 88 is connected to the output rear shaft 34. The output rear shaft 34 extends back towards the rear of the housing 52 above the rotational axis 80 of the front sprocket 72. At least one bearing 96 supports the rear output shaft 34 to rotate with respect to the housing 53. A fork 98 connects the output rear shaft 34 to the inter-axle driveline 36, as shown in Figure 2. The front drive shaft assembly 22 may also comprise a differential lock clutch between axes 100, as shown in FIG. Figure 3. The locking clutch 100 comprises an axially movable clutch gear 102 linked to the input shaft 50 with a plurality of grooves 104. The lateral helical gear 56 has a complementary clutch gear 106 for the axially movable clutch gear 102. The axially movable clutch gear 102 is connected to the shift pad 108 which moves the clutch gear 102 in and out of engagement with the clutch gear 106 on the lateral helical gear 56. The differential lock clutch between axes 100 selectively allows the front traction axle assembly 22 and the rear traction axle assembly 44 to be blocked in a simultaneously driven way. The inter-axle driveline 36 is connected to an input shaft 110 for the rear drive shaft assembly 44 with the fork 42, as seen in Figures 2 and 4. A front portion 112 of the input shaft 110 is supported. to rotate with respect to a housing 114 of the rear drive shaft assembly with a bearing 116, as seen in Figure 4. Referring to both Figures 2 and 4, a rear pinion gear 118 is connected to a rear portion 120 of the input shaft 110. Preferably, the rear end gear 1 18 is positioned concentrically about the input shaft 110 to rotate therewith. The rear sprocket gear 118 is part of a rear hypoid gear set 122 which also comprises a rear sprocket 124. The rear sprocket gear 118 is driven in a driven manner to the rear sprocket 124. In the preferred embodiment, better in Figure 2, the rear sprocket gear 118 engages a drive side 126 of a rear upper portion 128 of the ring gear 124. More specifically, a rotation shaft 130 of the rear sprocket gear 118 is located above of an axis of rotation 132 of the rear sprocket 124. Those skilled in the art will understand that the drive side 126 of the rear sprocket 124 comprises convex toothed ring teeth 129. Only a representative sample of the convex toothed crown teeth 129. The engagement of the rear toothed crown 124 with the convex crown teeth of inlet 1 28 inlet drive 126 of the rear sprocket 124 is much stronger than if the pinion gear 118 were engaged with the driven side of the gear 118. As seen in Figure 4, the rear sprocket gear 118 and the input shaft 118 are assembled to rotate with respect to the housing of the rear drive shaft assembly 114 with a bearing 134. The rear sprocket 124 is connected to a rear wheel differential 136 as shown in Figure 4. The rear wheel differential 136 provides the drive to the first and second rear-drive axles 38, 40, as is known to those skilled in the art. The rear wheel differential 136 is preferably offset to one side of the input shaft 110 to allow the input shaft to clear the rear wheel differential 136 and connect to the rear sprocket gear 118. Figure 5 illustrates an alternative embodiment of the present invention wherein the rear sprocket gear 118 and the input shaft 110 are supported to rotate with respect to the housing of the rear drive shaft assembly 114 with two bearings 134. Similar reference numbers have been used in Figure 5 for identical or indirect components represented in Figure 4 and described above. Regardless of the number of bearings used to hold the rear sprocket gear 118, and / or the input shaft 110, it is preferred that the rear output shaft 34 of the front drive shaft assembly 22, the inter-axle driveline 36 and the input shaft 110 of the rear drive shaft assembly 44 virtually share a rotational axis 138 common, substantially straight. In the preferred embodiment, an angle 140 between the rear output shaft 34, the inter-axle driveline 36 and the input shaft 110 is between zero degrees and ± three degrees. In a more preferred embodiment, the angle 140 is zero degrees. Rear traction shaft assemblies 44 shown in Figures 4 or 5 also advantageously have a reduced projecting dimension 142, 142 'as compared to other known designs. Note that Figure 5 may have a salient dimension 142 'slightly different than the dimension shown in Figure 4. Those skilled in the art know that the protruding dimension is typically defined as the distance between a front portion 144 of the input shaft 110 centerline 146 of cardan shaft 38 or 40. Based on the capacity requirements for the rear traction axle assembly 44, the protruding dimensions will vary between sets. For example, the greater capacity of the set, the greater outstanding dimension. It is distinguished that for a rear drive shaft assembly of the state of the art of a particular capability, a rear drive shaft assembly 44 of the present invention design having the same capacity will have a smaller protruding dimension. For example, the protruding dimension for a rear drive shaft assembly of the prior art could be between about 85% to 95% of the diameter 148, 148 'of the ring gear. The projecting dimension 142, 142 'for a rear drive shaft assembly 44 of the present invention, however, is between about 70% to 80% of the diameter 148, 148' of the ring gear. Preferably, the protruding dimension 142, 142 'for a rear drive shaft assembly 44 of the present invention, is approximately 72% to 75% of the diameter 148, 148 'of the gear ring. The inter-axle driveline 38 is thus optimized to reduce or eliminate I at a vertical distance between the fork 98 shared by the pitch axle 34 of the front-drive axle assembly 22 and the inter-axle driveline 36, and the fork 42 shared by the input shaft 110 of the rear-drive shaft assembly 44 and the inter-axle driveline 36. Additionally, the fork 42 shared by the input shaft 110 of the rear-drive shaft assembly 44 and the inter-axle driveline 36 it is higher than that of the prior art thus advantageously providing a high ground clearance. 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 must be distinguished that the invention can be practiced other than as it was illustrated and described in a specific way without departing from its spirit or scope.

Claims (19)

1. A dual rear axle system, characterized in that it comprises: a front drive shaft assembly having a front hypoid gear set comprising a front pinion gear driven in a driven manner to a pulse side of a front portion of a front gear; a rear drive axle assembly having a hypoid rear gear set comprising a rear pinion gear connected in a driven manner to a driving side of a rear portion of a rear sprocket; and an inter-axle driveline that connects the front drive axle assembly with the rear drive axle assembly.

2. The system according to claim 1, further characterized in that the rear pinion gear is located above an axis of rotation of the rear gear.

3. The system according to claim 1, further characterized in that the front pinion gear is located below a rotation axis of the front gear. The system according to claim 1, further characterized in that the rear sprocket gear is mounted to rotate within the rear drive shaft assembly on a bearing. The system according to claim 1, further characterized in that the rear pinion gear is mounted to rotate within the rear traction axle assembly on two bearings. The system according to claim 1, further characterized in that the front drive axle assembly has a differential between axles and a rear output shaft connected in a driven manner to the axle differential, and the rear axle assembly has an input shaft connected in a driven manner to a wheel hub, wherein the rear output shaft, the inter-axle driveline and the rear input shaft substantially share a common rotation axis. The system according to claim 6, further characterized in that the angle between the pitch axis, the inter-axis driveline and the rear entry axis is approximately zero degrees. The system according to claim 6, further characterized in that the rear pinion gear is mounted concentrically to the rear input shaft of the rear drive shaft assembly. The system according to claim 1, further characterized in that the protruding dimension of the rear drive shaft assembly is between about 70% to 80% of the diameter of the ring gear. The system according to claim 1, further characterized in that the protruding dimension of the rear drive shaft assembly is between about 72% to 75% of the diameter of the ring gear. The system according to claim 6, further characterized in that the line between the axes is substantially above an axis of rotation of the front gear and an axis of rotation of the gear ring. 12. The system according to claim 6, further characterized in that the rear pinion gear is driven in a rotary manner and is at least partially supported by the rear axle, the rear axle is separated from the rear pinion gear. 13. A dual rear axle system, characterized in that it comprises: a front axle drive assembly including a differential between axles, a rear output shaft connected in a driven manner to the axle differential and a front hypoid gear set comprising a gear front pinion connected in a pulsed manner to a pulse side of a front portion of a front gear; a rear drive shaft assembly including a rear input shaft and a rear hypoid gear set comprising a rear pinion gear connected in a driven manner to a drive side of a rear portion of a rear gear; and an inter-axle drive line connected in a driven manner to the rear output shaft and the input shaft, wherein the inter-axle driveline, the rear output shaft and the rear input shaft substantially share a common rotation axis, and the Rear pinion gear is mounted concentrically on the rear input shaft to rotate with it. The system according to claim 13, further characterized in that the rear pinion gear is located above an axis of rotation of the rear sprocket. 15. The system according to claim 14, further characterized in that the front pinion gear is positioned below an axis of rotation of the front gear. 16. The system according to claim 13, further characterized in that the angle between the pitch axis, the inter-axis drive line and the rear input shaft is approximately zero degrees. 17.. The system according to claim 13, further characterized in that the protruding dimension of the rear drive shaft assembly is between about 72% to 75% of the diameter of the ring gear. 18. The system according to claim 13, further characterized in that the rear pinion gear is driven in a rotary manner and is at least partially supported by the rear axle, the rear input shaft being separated from the rear pinion gear. 19. The system according to claim 13, further characterized in that the front sprocket gear is engaged with the convex teeth of the ring gear in the front sprocket, and the rear sprocket gear is engaged with the convex teeth. of the ring gear on the rear gear ring.