Gear reduction components

Abstract

The gear reduction assembly includes an input shaft and an output shaft extending along an axis, a ring gear arranged around the axis, a sun gear coupled to one of the shafts, a bracket extending around the shaft, and a plurality of planetary gears rotatably coupled to the bracket. The bracket can move between a direct drive position, a neutral position, and a reduction position along the axis. The planetary gears mesh with the sun gear, and the bracket is coupled to one of the shafts in each position. In the direct drive position, the bracket is fixed to the two shafts. In the neutral position, at least one of the shafts is disconnected from the bracket. In the reduction position, the planetary gears are rotatably meshed with the sun gear and the ring gear fixed to one shaft, and the bracket is fixed to the other shaft.

Description

Technical Field

[0001] A gear reduction assembly used to transfer torque between the prime mover and the wheels. Background Art

[0002] Gear reduction assemblies are used in vehicles having wheels to selectively multiply the torque transmitted to the wheels. Gear reduction assemblies are particularly suitable for applications that require traction or dragging of heavy loads, such as material handling and mining applications, agricultural applications, commercial trucks, construction, defense, forestry, ground support equipment, waste, transportation and other specialty vehicles. Gear reduction assemblies generally allow different gear ratios to be selected between the wheels and the prime mover that drives the wheels. Thus, the gear reduction assembly can transmit more torque to the wheels when desired (such as when transporting heavy loads and / or traversing off-road terrain), and reduce torque when desired (such as when unloaded and / or traversing road terrain at high speed).

[0003] Typically, a gear reduction assembly includes one or more gear combinations that are capable of applying different gear ratios between the prime mover and the wheels. The gear combinations are selectively engaged and disengaged by friction clutches. Although effective in selectively multiplying the torque delivered to the wheels, friction clutches are susceptible to wear over time and increase the weight of the gear reduction assembly. Therefore, there remains a need to provide an improved gear reduction assembly for a vehicle. Summary of the invention

[0004] The present invention provides a gear reduction assembly for transmitting torque between a prime mover and a wheel. The assembly includes an input shaft extending along an axis and configured to be rotated by a prime mover and an output shaft extending along the axis spaced apart from the input shaft and configured to rotate the wheel. The assembly also includes an annular gear (gear ring) arranged around the axis, a sun gear coupled to one of the input shaft and the output shaft, and a bracket (planet carrier) extending along the axis and around the input shaft and the output shaft. The assembly also includes a plurality of planetary gears radially spaced apart around the axis and rotatably coupled to the bracket. The bracket can move along the axis between a direct drive position, a neutral position, and a reduction position. In each of the direct drive position, the neutral position, and the reduction position, a plurality of planetary gears mesh with the sun gear, and the bracket is coupled to one of the input shaft and the output shaft.

[0005] In the direct drive position, the carrier is fixed to both the input shaft and the output shaft so that the input shaft and the output shaft rotate in unison about the axis at an equal rotational speed. In the neutral position, at least one of the input shaft and the output shaft is disconnected from the carrier so that the input shaft and the output shaft rotate independently of each other about the axis. In the reduction position, a plurality of planetary gears are rotatably engaged with a sun gear and a ring gear fixed to one of the input shaft and the output shaft, and the carrier is fixed to the other of the input shaft and the output shaft so that the input shaft and the output shaft rotate about the axis at different rotational speeds.

[0006] Thus, the gear reduction assembly provides the following advantages: a reduction in the number of components required to selectively vary the torque delivered to the wheels. In each of the direct drive position, the neutral position, and the reduction position, the continuous meshing of the planetary gears with the sun gear and the coupling of the bracket to one of the input shaft and the output shaft maintains proper alignment of the input shaft, the output shaft, and the bracket along the axis to facilitate movement of the bracket between the direct drive position, the neutral position, and the reduction position. Thus, the gear reduction assembly does not require a friction clutch to selectively engage the sun gear, the planetary gears, and the ring gear. In addition, the reduction in the number of components reduces the weight of the gear reduction assembly, facilitates a smaller packaging size of the gear reduction assembly, and thereby reduces the volume area occupied by the gear reduction assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Advantages of the present invention will be readily appreciated and better understood by referring to the following detailed description when considered in light of the accompanying drawings.

[0008] Figure 1A is a perspective view of a vehicle having an axle system.

[0009] Figure 1B is a perspective view of the axle system showing the prime mover, gearbox and gear reduction assembly.

[0010] Figure 2 is a perspective cutaway view of the gear reduction assembly showing the bracket in the direct drive position.

[0011] Figure 3 is a perspective cutaway view of the gear reduction assembly showing the bracket in a neutral position.

[0012] Figure 4 is a perspective cutaway view of the gear reduction assembly showing the bracket in the reduction position.

[0013] Figure 5 is a simplified schematic diagram of the gear reduction assembly showing the bracket in the direct drive position.

[0014] Figure 6 is a simplified schematic diagram of the gear reduction assembly showing the bracket in the neutral position.

[0015] Figure 7 is a simplified schematic diagram of the gear reduction assembly showing the bracket in the reduction position. DETAILED DESCRIPTION

[0016] Referring to the drawings, wherein like reference numerals designate like or corresponding parts throughout the several views. Figure 1A and 1B 2 is generally shown a gear reduction assembly 20 for transmitting torque between a prime mover 22 and wheels 24 of a vehicle 21. The gear reduction assembly 20 can be configured for use with an axle system 26. The axle system 26 can include a subframe 28 for mounting to a frame of the vehicle 21.

[0017] The prime mover 22 may be mounted to the subframe 28 and configured to generate torque. As shown in the figure, the prime mover 22 is configured as an electric motor (motor) capable of generating motion that rotates the wheels 24. However, the prime mover 22 may be an internal combustion engine, a hydrogen fuel cell, or any other suitable mechanism capable of generating motion that rotates the wheels 24.

[0018] The axle system 26 may also include a gearbox 30 such as Figure 1B . The gearbox 30 is mounted to the subframe 28 and is coupled to each of the prime mover 22 and the gear reduction assembly 20. The gearbox 30 is configured to transfer and change torque from the prime mover 22 to the gear reduction assembly 20. More specifically, the gearbox 30 may have a plurality of gears that may be individually selected. Each gear may have a different gear ratio (transmission ratio). Therefore, the gearbox 30 may change the torque transferred to the gear reduction assembly 20. Such a configuration is generally referred to as a transmission in vehicle applications.

[0019] The prime mover 22 and gearbox 30 may be coupled to a single wheel 24 (or more specifically, as shown in FIG. 1 , a set of two wheels 24). Thus, if the vehicle 21 has multiple driven wheels 24 or multiple sets of driven two wheels 24, each wheel 24 or each set may have a separate and distinct prime mover, gearbox, and gear reduction assembly. For example, Figure 1A As shown in FIG, the axle system 26 includes a pair of prime movers 22, a pair of gearboxes 30, and a pair of gear reduction assemblies 20, each of which individually drives a set of dual wheels 24. However, the prime movers 22, gearboxes 30, and gear reduction assemblies 20 can be configured to drive more than one wheel 24 or more than one set of dual wheels 24.

[0020] The axle system 26 is a rear drive axle, but it is to be understood that the advantageous features of the present disclosure to be described may alternatively be applied to a front drive axle (ie, steerable), or preferably to both front drive and rear drive axles.

[0021] The axle system 26 is adapted to be fixedly mounted on the vehicle 21, and the wheels 24 are coupled thereto so that the axle system 26 supports the weight of the vehicle 21 and the cargo. In addition, the gear reduction assembly 20 is capable of multiplying the torque transmitted from the prime mover 22 to the wheels 24 for reasons to be described. Therefore, the gear reduction assembly 20 of the present disclosure may be particularly suitable for heavy material handling and mining applications. However, other suitable applications may include agricultural applications (e.g., planters, sprayers, and other farm-related vehicles), commercial trucks, construction, defense, forestry, ground support equipment, waste, transportation, and other specialty vehicles.

[0022] The gear reduction assembly 20 is mounted on the secondary frame and coupled to the prime mover 22. The assembly 20 is configured to transfer torque between the prime mover 22 and the wheels 24. Figure 2 As shown in FIG. 7 , the gear reduction assembly 20 includes an input shaft 32 extending along an axis A and configured to be rotated by the prime mover 22 , and an output shaft 34 extending along the axis A, spaced apart from the input shaft 32 , and configured to rotate the wheels 24 .

[0023] The gear reduction assembly 20 also includes an annular gear (ring gear) 36 arranged about the axis A, a sun gear 38 coupled to one of the input shaft 32 and the output shaft 34, and a carrier (planet carrier) 40 extending along the axis A and around the input shaft 32 and the output shaft 34. The gear reduction assembly 20 also includes a plurality of planetary gears 42 radially spaced about the axis A and rotatably coupled to the carrier 40.

[0024] The support 40 can be in a direct drive position along the axis A (see Figure 2 and 5 ), neutral position (see Figure 3 and 6 ) and deceleration (see Figure 4 and 7 ) positions. More specifically, the carrier 40 and the plurality of planetary gears 42 move in unison (move together) along the axis A between the direct drive position, the neutral position, and the deceleration position. In each of the direct drive position, the neutral position, and the deceleration position, the plurality of planetary gears 42 mesh with the sun gear 38, and the carrier 40 is coupled to the input shaft 32 and the output shaft 34, which maintains the input shaft 32, the output shaft 34, and the carrier 40 in proper alignment along the axis A to facilitate movement of the carrier 40 between the direct drive position, the neutral position, and the deceleration position, as will be described in more detail below.

[0025] In direct drive position (see Figure 2 and 5), the bracket 40 is fixed to both the input shaft 32 and the output shaft 34 so that the input shaft 32 and the output shaft 34 rotate in unison about the axis A at equal rotational speeds. In addition, in the neutral position (see Figure 3 and 6 ), at least one of the input shaft 32 and the output shaft 34 is disconnected from the bracket 40, so that the input shaft 32 and the output shaft 34 rotate independently of each other about the axis A. In addition, in the deceleration position (see Figure 4 and 7 ), a plurality of planetary gears 42 are rotatably meshed with a sun gear 38 fixed to one of the input shaft 32 and the output shaft 34 and with a ring gear 36, and a bracket 40 is fixed to the other of the input shaft 32 and the output shaft 34, so that the input shaft 32 and the output shaft 34 rotate around the axis A at different rotational speeds.

[0026] The neutral position of the bracket 40 may be disposed between the direct drive position and the deceleration position of the bracket 40. In addition, the direct drive position and the deceleration position may define opposite ends of the travel of the bracket 40. Referring to the drawings, the direct drive position of the bracket 40 is the leftmost position of the bracket 40 (see Figure 2 and 5 ), the deceleration position is the rightmost position of the bracket 40 (see Figure 4 and 7 ), and the neutral position places the bracket 40 between the direct drive position and the deceleration position (see Figure 3 and 6 ). However, the relative position (i.e., left / right) of the bracket 40 is with respect to the orientation of the drawings and may vary depending on the view of the gear reduction assembly 20. In addition, although the neutral position of the bracket 40 is shown as being arranged between the direct drive position and the reduction position of the bracket 40, in other embodiments not explicitly shown herein, the positions of the direct drive position, the neutral position, and the reduction position may be arranged in a different order. In addition, the direct drive position and the reduction position may not define the relative travel ends of the bracket 40. In addition, the bracket 40 may include one or more additional positions between or outside the direct drive position, the neutral position, and the reduction position.

[0027] like Figure 2 As shown in FIG. 4 , the gear reduction assembly 20 may further include a housing 44 defining an interior 46 along the axis A, and the input shaft 32, the output shaft 34, the sun gear 38, the plurality of planetary gears 42, and the carrier 40 are disposed within the housing 44. Thus, the housing 44 may provide protection for the components of the gear reduction assembly 20 disposed therein by reducing the intrusion of contaminants (such as dust and water) that may degrade the components.

[0028] The input shaft 32 and the output shaft 34 may be fixed longitudinally along the axis A, and the bracket 40 is configured to move along the input shaft 32 and the output shaft 34 while moving between the direct drive position, the neutral position, and the deceleration position. Figure 2 As shown in Figure 4, the gear reduction assembly 20 may include an input bearing 48 coupled to the housing 44 and supporting the input shaft 32. Although not shown in the drawings, the gear reduction assembly may also include an output bearing coupled to the housing 44 and supporting the output shaft 34. The input bearing 48 and the output bearing position the input shaft 32 and the output shaft 34 within the housing 44, respectively, and facilitate rotation of the input shaft 32 and the output shaft 34 about the axis A. In addition, the bearings reduce movement of the shafts 32, 34 transverse to the axis A. The input bearing 48 and the output bearing may also be defined as thrust bearings that reduce movement of the input shaft 32 and the output shaft 34 along the axis A under axial loads. An example of an axial load applied to the gear reduction assembly 20 is a centripetal force applied to the wheel 24 along the axis A during cornering of the vehicle 21.

[0029] The housing 44 may be a structural member configured to carry lateral loads between the frame and the wheels 24. In this configuration, the housing 44 is commonly referred to in the art as a bridge tube. Additionally, the structural rigidity of the housing 44, along with the bearings, may reduce lateral loads applied to the rotating components of the gear reduction assembly 20 (i.e., the input and output shafts 32, 34, the carrier 40, the sun gear 38, the planetary gears 42, etc.) that may inhibit such rotation. Additionally, reducing lateral loads on the rotating components reduces deflection of the components that may result in axial misalignment, which introduces inefficiencies and excessive wear to the assembly 20.

[0030] like Figure 2 As shown in Figure 4, the ring gear 36 can be fixed to the housing 44 within the interior 46. In addition, as shown in the figure, the ring gear 36 can be integrally formed with the housing 44, so that the ring gear 36 and the housing 44 include a single common material. However, the ring gear 36 and the housing 44 can be separate components that are fixed to each other in any suitable manner (e.g., fasteners, welding, etc.). In addition, the ring gear 36 and the housing 44 can be spaced apart from each other, and an intermediate component can be arranged between them to fix the ring gear 36 to the housing 44.

[0031] like Figure 2As shown in FIG. 4 , each of the input shaft 32, the output shaft 34, and the bracket 40 may include splines 52, 54, 56 extending longitudinally along the axis A, and the splines 56 of the bracket 40 are configured to engage with and slide along the splines 52, 54 of the input shaft 32 and the output shaft 34 as the bracket 40 moves longitudinally along the axis A between the direct drive position, the neutral position, and the deceleration position. Therefore, the splines 56 of the bracket 40 and the splines 52 of the input shaft 32 have a corresponding relative configuration, which rotationally locks the bracket 40 with the input shaft 32, while the extension of the splines 52, 56 along the axis A allows the bracket 40 to slide along the axis A and maintains the rotational lock between the bracket 40 and the input shaft 32. Similarly, the splines 56 of the bracket 40 and the splines 54 of the output shaft 34 have a corresponding relative configuration, which rotationally locks the bracket 40 with the output shaft 34, while the extension of the splines 54, 56 along the axis A allows the bracket 40 to slide along the axis A and maintains the rotational lock between the bracket 40 and the output shaft 34.

[0032] like Figure 2 As shown in FIG. 4 , the bracket 40 may extend along the axis A between a first end 58 and a second end 60. The bracket 40 may define a bore 62 extending completely through the bracket 40 along the axis A, and the input shaft 32 enters the bore 62 at the first end 58 and the output shaft 34 enters the bore 62 at the second end 60. The splines 56 of the bracket 40 may extend inwardly toward the axis A in the bore 62. The splines 52, 54 of the input shaft 32 and the output shaft 34 may extend outwardly away from the axis A to engage with the splines 56 of the bracket 40. However, the opposite may be true (i.e., the input shaft 32 and the output shaft 34 may define a bore and have the splines 52, 54 extending inwardly toward the axis A, while the bracket 40 may have the splines 56 extending outwardly away from the axis A from the outer surface of the bracket 40). Additionally, the input shaft 32 and the output shaft 34 may have opposite configurations (e.g., the input shaft 32 may have inwardly extending splines 52 to engage a portion of the splines 46 of the outwardly extending bracket 40, and the output shaft 34 may have outwardly extending splines 54 to engage a portion of the splines 56 of the inwardly extending bracket 40).

[0033] like Figure 2 -4, the sun gear 38 may be fixed to the input shaft 32. Therefore, the planetary gears 42 surround and mesh with the sun gear 38 on the input shaft 32, and the ring gear 36 is positioned around the sun gear 38 on the input shaft 32. However, the situation may be reversed. More specifically, the carrier 40 may be inverted so that the planetary gears 42 surround and mesh with the sun gear 38 fixed to the output shaft 34, and the ring gear 36 is positioned around the sun gear 38 on the output shaft 34.

[0034] The sun gear 38 may define splines 52, 54 of one of the input shaft 32 and the output shaft 34. More specifically, in the embodiment shown in the figures, the sun gear 38 defines the splines 52 of the input shaft 32. Thus, the splines 52 of the input shaft 32 and the sun gear 38 may be referred to interchangeably below, with the sun gear 38 being able to mesh with the splines 56 of the carrier 40 and the splines 52 of the input shaft 32 being able to mesh with the planet gears 42.

[0035] like Figure 2 As shown in FIG. 4 , the sun gear 38 and the input shaft 32 may be an integral component including a single material. In other words, the sun gear 38 may be formed on the input shaft 32. However, the sun gear 38 and the input shaft 32 may be separate components that are fixed to each other in any suitable manner (e.g., fasteners, welding, etc.).

[0036] The bracket 40 may include a wall 64 extending transverse to the axis A and bisecting the splines 56 to define an input portion 66 of the splines 56 configured to engage the splines 52 of the input shaft 32 and an output portion 68 of the splines 56 configured to engage the splines 54 of the output shaft 34. The wall 64 may engage at least one of the input shaft 32 and the output shaft 34 to define an end stop to prevent the bracket 40 from further moving beyond one of the direct drive position, the neutral position, and the deceleration position. More specifically, the splines 56 of each of the input portion 66 and the output portion 68 may extend inwardly toward the axis A, and one of the input portion 66 and the output portion 68 extends further toward the axis A than the other, with the wall 64 transitioning between the input portion 66 and the output portion 68. In the embodiment shown in the figures, the splines 56 of the input portion 66 extend further toward the axis A than the output portion 68.

[0037] like Figure 2 4, the input shaft 32 and the output shaft 34 are sized to accommodate the input portion 66 and the output portion 68 of the splines 56 of the bracket 40. More specifically, the input shaft 32 and the output shaft 34 are sized such that the splines 52 of the input shaft 32 are disposed between and engage the input portions 66 of the splines 56 of the bracket 40, and the splines 54 of the output shaft 34 are disposed between and engage the output portions 68 of the splines 56 of the bracket 40.

[0038] In the embodiment shown in the figures, the splines 56 of the input portion 66 extend further toward the axis A than the splines 56 of the output portion 68 . Thus, the splines 54 of the output shaft 34 extend further away from the axis A than the splines 52 of the input shaft 32 .

[0039] Wall 64 may be substantially orthogonal to axis A. Figure 4As shown in FIG. 1 , the wall 64 can engage the output shaft 34. Thus, the wall 64 defines an end stop that prevents the bracket 40 from further moving beyond the deceleration position (ie, as shown in FIG. 1 ). Figure 4 , the wall 64 inhibits further rightward movement beyond the deceleration position). Thus, the deceleration position of the bracket 40 may define an endpoint (terminal end) of the movement of the bracket 40, and the wall 64 prevents the bracket 40 from moving beyond the deceleration position. The end stop that prevents the bracket 40 from further moving beyond the deceleration position ensures proper alignment and engagement of the planetary gears 42 with both the sun gear 38 and the ring gear 36. Although the wall 64 defines an end stop for engaging with the output shaft 34, thereby preventing the bracket 40 from moving beyond the deceleration position, the wall 64 may define an end stop for engaging with the input shaft 32 or any other suitable component to prevent the bracket 40 from moving to or beyond any position, including those explicitly described and not explicitly described herein.

[0040] When the bracket 40 is in the neutral position and the deceleration position, the splines 56 of the bracket 40 can be longitudinally spaced apart and disconnected from the splines 52, 54 of one of the input shaft 32 and the output shaft 34 along the axis A. More specifically, when the bracket 40 is in the neutral position and the deceleration position, the splines 56 of the bracket 40 can be longitudinally spaced apart and disconnected from the splines 52 of the input shaft 32 along the axis A, as shown in FIG. Figure 3 and 4 Because the splines 56 of the carrier 40 are spaced apart and disconnected from the splines 52 of the input shaft 32, the input and output shafts 32, 34 do not rotate in unison, thereby facilitating independent rotation of the input and output shafts 32, 34 (neutral position) and rotation at different rotational speeds (reduction position).

[0041] exist Figure 2 In the embodiment shown in FIG. 1 , in the direct drive position, the splines 56 of the carrier 40 engage the splines 52 of the input shaft 32. The carrier 40 moves from the direct drive position to the neutral position and the deceleration position (ie, as shown in FIG. 1 ). Figure 2 -4, from left to right) causes the carrier 40 to move away from the input shaft 32 (which remains stationary along the axis A) and disconnects the carrier 40 from the input shaft 32. In addition, the output portion 68 of the splines 56 of the carrier 40 is configured to remain engaged with the splines 54 of the output shaft 34 in each of the direct drive position, the neutral position and the deceleration position, which will be described in more detail below.

[0042] like Figure 2As shown in FIG. 4 , the bracket 40 may have a flange 70 at the first end 58 extending outwardly away from the axis A. Each planet gear 42 may be rotatably coupled to the flange 70. The planet gears 42 may be configured as spur gears having radially extending teeth. However, the planet gears 42 may have any suitable configuration for meshing with each of the sun gear 38 and the ring gear 36.

[0043] In the deceleration position, the planet gears 42 may be disposed between the ring gear 36 and the sun gear 38 and radially spaced about the sun gear 38, such as Figure 4 . Thus, in the deceleration position, a plurality of planetary gears 42 may be rotatably meshed with the ring gear 36 and the input shaft 32 through the sun gear 38. The rotation of the input shaft 32 and the sun gear 38 about the axis A at a first rotational speed causes the planetary gears 42 meshed with both the sun gear 38 and the ring gear 36 to rotate independently and move along the sun gear 38 and the ring gear 36. Thus, the planetary gears 42 move about the axis A at a second rotational speed different from the first rotational speed. Because the planetary gears 42 are rotatably coupled to the bracket 40, the movement of the planetary gears 42 about the axis A causes the bracket 40 to also rotate about the axis at the second rotational speed. Since the output portion 68 of the spline 56 of the bracket 40 is engaged with the spline 54 of the output shaft 34 in the deceleration position, the output shaft 34 also rotates at the second rotational speed. Therefore, the rotation of the input shaft 32 at the first rotational speed in the deceleration position causes the rotation of the output shaft 34 at the second rotational speed in the deceleration position. In the reduction position, the plurality of planetary gears 42 can be rotatably meshed with the ring gear 36 and the sun gear 38 to provide a gear ratio of at least 3:1. Thus, the gear reduction assembly 20 in the reduction position can provide a mechanical advantage to the wheels 24 attached to the output shaft 34 to increase the torque transmitted to the wheels 24. Figure 2 The planetary gear 42 shown in FIG. 4 has a gear ratio of 3:1, but the planetary gear 42 may have any suitable gear ratio to provide a mechanical advantage to the wheels 24 .

[0044] like Figure 2As shown in FIG. 4 , the planetary gears 42 may be arranged on a plane P orthogonal to the axis A, and the planetary gears 42 are spaced apart from the splines 56 of the carrier 40 to define a gap 72 having a distance X along the axis A. The ring gear 36 may have a length L along the axis A that is less than or equal to the distance X of the gap 72 between the planetary gears 42 and the splines 56 of the carrier 40, wherein the ring gear 36 is arranged within the gap 72 when the carrier 40 is in the neutral position. As shown, in the neutral position, the planetary gears 42 are arranged to the left of the ring gear 36. In addition, the size of the input portion 66 of the splines 56 of the carrier 40 along the axis A is such that movement of the carrier 40 to the neutral position causes the carrier 40 to be disconnected from the input shaft 32. Therefore, in the neutral position, the input shaft 32 in the carrier 40 rotates inconsistently. In addition, since the planetary gears 42 are not meshed with the ring gear 36 in the neutral position, the planetary gears 42 simply rotate independently on the sun gear 38 without causing rotation of the carrier 40 about the axis A. In other words, in the neutral position, the planet gears 42 are freewheeling on the sun gear 38. Therefore, in the neutral position, the input shaft 32 and the output shaft 34 may rotate at different rotational speeds. In the embodiment shown in the figures, the arrangement of the neutral position between the direct drive position and the reduction position prevents simultaneous direct engagement between the input shaft 32 and the output shaft 34, and gear reduction between the input shaft 32 and the output shaft 34 through the sun gear 38, the planet gears 42 and the ring gear 36, which would damage the gear reduction assembly 20.

[0045] like Figure 2 As shown in FIG. 4 , each planet gear 42 may have an outer surface 74 facing away from the carrier 40 and spaced a first distance D1 from the wall 64 along the axis A. The sun gear 38 may extend along the axis A by a second distance D2 at least equal to the first distance D1 to facilitate coupling of the sun gear 38 with the carrier 40 and at least one of the plurality of planet gears 42. Thus, movement of the carrier 40 along the axis A may occur between the direct drive position, the neutral position, and the reduction position without requiring the input shaft 32 to disengage from both the carrier 40 and the planet gears 42. Disengagement of the input shaft 32 from both the carrier 40 and the planet gears 42 may result in rotational misalignment between the sun gear 38 and the planet gears 42 / carrier 40, which may result in engagement therebetween as movement of the carrier 40 attempts to reengage the input shaft 32. Similarly, the output portion 68 of the splines 56 of the carrier 40 may extend along the axis A by a third distance D3 at least equal to the first distance D1 to maintain meshing between the carrier 40 and the output shaft 34 in each of the direct drive position, the neutral position, and the reduction position.

[0046] In the direct drive position, the input shaft 32 may be secured to the bracket 40 via the sun gear 38. Figure 2 and 5, the planetary gears 42 and the carrier 40 are arranged in their farthest position on the left. The input portion 66 of the splines 56 of the carrier 40 meshes with the sun gear 38 / splines 52 of the input shaft 32, thereby fixing the input shaft 32 to the carrier 40. The planetary gears 42 mesh with the sun gear 38, but cannot rotate along the sun gear 38 because the input shaft 32 and the carrier 40 cannot rotate independently of each other. As described above, the output portion 68 of the splines 56 of the carrier 40 meshes with the splines 54 of the output shaft 34, thereby fixing the output shaft 34 to the carrier 40. Therefore, in the direct drive position, the input shaft 32, the carrier 40, and the output shaft 34 rotate in unison.

[0047] like Figure 2 As shown in FIG. 4 , the input shaft 32 may include a second wall 76 that extends transversely to the axis A and may engage the planetary gear 42 to define an end stop that prevents the carrier 40 from further moving beyond one of the direct drive position, the neutral position, and the deceleration position. The second wall 76 may be at the end of the spline 52 of the input shaft 32, and the second wall 76 transitions to a smooth outer surface of the input shaft 32.

[0048] The second wall 76 may be substantially orthogonal to the axis A. Figure 2 As shown in , in the direct drive position, the second wall 76 can engage with the planet gear 42 (i.e., the planet gear 42 meshing with the spline 52 of the input shaft 32 can move along the axis A until the planet gear 42 abuts the second wall 76 located at the end of the spline 52). Thus, the second wall 76 defines an end stop that prevents the bracket 40 from moving further out of the direct drive position (i.e., as Figure 2 , the second wall 76 inhibits further leftward movement out of the direct drive position). Thus, the direct drive position of the bracket 40 may define an endpoint (terminal end) of movement of the bracket 40, and the second wall 76 prevents the bracket 40 from moving out of the direct drive position. The end stop that prevents the bracket 40 from further moving out of the direct drive position ensures that the splines 52 of the input shaft 32 properly engage the input portion 66 of the splines 56 of the bracket 40 to transfer torque to the wheels 24. Although the second wall 76 defines an end stop for engaging with the planetary gears 42 to prevent the bracket 40 from moving out of the direct drive position, the second wall 76 may define an end stop for engaging with the bracket 40 or any other suitable component to prevent the bracket 40 from moving to or out of any position, including those explicitly described and not explicitly described herein.

[0049] For illustrative purposes only, the operation of moving the bracket 40 from the direct drive position to the deceleration position to increase the torque transmitted to the wheels 24 according to the embodiment shown in the figures will be described below.

[0050] When the bracket 40 is in the direct drive position (see Figure 2 and 5 ), the input portion 66 of the splines 56 of the carrier 40 engages the splines 52 of the input shaft 32, and the output portion 68 of the splines 56 of the carrier 40 engages the splines 54 of the output shaft 34. The planetary gears 42 mesh with the sun gear 38 / splines 52 of the input shaft 32, but are spaced apart from the ring gear 36 and thus remain stationary about the input shaft 32. Rotation of the input shaft 32 (driven by the prime mover 22) causes the carrier 40 and the output shaft 34 to rotate in unison with the input shaft 32. Rotation of the output shaft 34 causes rotation of the wheels 24.

[0051] To move the bracket 40 to the deceleration position, the bracket 40 is moved away from the input shaft 32 along the axis A. The bracket 40 is first moved to the neutral position (see Figure 3 and 6 ). In the neutral position, the output shaft 34 remains coupled to the carrier 40 and rotates in unison with the carrier 40. However, the input portion 66 of the splines 56 of the carrier 40 is displaced from and spaced apart from the splines 52 of the input shaft 32. Thus, the carrier 40 is disconnected from the input shaft 32. The carrier 40 and the output shaft 34 can rotate independently of the input shaft 32. The planet gears 42 remain engaged with the sun gear 38 / splines 52 of the input shaft 32 and remain spaced apart from the ring gear 36. Therefore, any rotation of the carrier 40 of the input shaft 32 causes the planet gears 42 to freewheel about the input shaft 32. In the neutral position, torque cannot be transferred between the input shaft 32 and the output shaft 34.

[0052] The support 40 continues to move along the axis A away from the input shaft 32 from the neutral position to the deceleration position. Figure 4 and 7 ), the output shaft 34 remains coupled to the carrier 40 and rotates in unison with the carrier 40. The input portion 66 of the splines 56 of the carrier 40 remains spaced apart from the splines 52 of the input shaft 32. The planet gears 42 remain meshed with the sun gear 38 / splines 52 of the input shaft 32 and are now meshed with the ring gear 36. The rotation of the input shaft 32 and the sun gear 38 about the axis A at the first rotational speed causes the planet gears 42 meshed with both the sun gear 38 and the ring gear 36 to each independently rotate and move along the sun gear 38 and the ring gear 36. Therefore, the planet gears 42 move about the axis A at a second rotational speed that is different from the first rotational speed. The movement of the planet gears 42 about the axis A causes the carrier 40 and the output shaft 34 to also rotate about the axis A at the second rotational speed. Therefore, the rotation of the input shaft 32 at the first rotational speed in the deceleration position causes the rotation of the output shaft 34 at the second rotational speed in the deceleration position.

[0053] The present invention also provides a method of operating the gear reduction assembly 20 for transmitting torque between the prime mover 22 and the wheels 24. Figure 2 As shown in FIG. 4 , the assembly 20 includes an input shaft 32 extending along an axis A. The input shaft 32 is configured to be rotated by the prime mover 22. The output shaft 34 extends along the axis A spaced apart from the input shaft 32 and is configured to rotate the wheel 24. The ring gear 36 is arranged around the axis A. The sun gear 38 is coupled to one of the input shaft 32 and the output shaft 34. The carrier 40 extends along the axis A and around the input shaft 32 and the output shaft 34. A plurality of planetary gears 42 are radially spaced apart around the axis A and are rotatably coupled to the carrier 40. The carrier 40 is movable along the axis A between a direct drive position, a neutral position, and a reduction position. In each of the direct drive position, the neutral position, and the reduction position, the plurality of planetary gears 42 mesh with the sun gear 38, and the carrier 40 is coupled to one of the input shaft 32 and the output shaft 34.

[0054] The method includes the steps of arranging the bracket 40 in a direct drive position, wherein the bracket 40 is fixed to both the input shaft 32 and the output shaft 34 so that the input shaft 32 and the output shaft 34 rotate in unison about the axis A at equal rotational speeds, such as Figure 2 and 5 The method further includes the following steps: when at least one of the input shaft 32 and the output shaft 34 is disconnected from the bracket 40 so that the input shaft 32 and the output shaft 34 rotate independently about the axis A, the bracket 40 is moved along the axis A to a neutral position, as shown in Figure 3 and 6 The method further includes the following steps: when the plurality of planetary gears 42 are rotatably meshed with the sun gear 38 and the ring gear 36 fixed to one of the input shaft 32 and the output shaft 34 and the bracket 40 is fixed to the other of the input shaft 32 and the output shaft 34 so that the input shaft 32 and the output shaft 34 rotate around the axis A at different rotation speeds, the bracket 40 is moved along the axis A to a deceleration position, as shown in FIG. Figure 4 and 7 as shown in .

[0055] As described above, the neutral position of the bracket 40 can be arranged between the direct drive position and the deceleration position of the bracket 40. Therefore, the method may further include the following steps: moving the bracket 40 from the direct drive position (see Figure 2 and 5 ) to the neutral position (see Figure 3 and 6 ) and from the neutral position to the deceleration position (see Figure 4 and 7 ).

[0056] The present invention has been schematically described, it is to be understood that the terms used are intended to be descriptive rather than limiting. As will be apparent to those skilled in the art, many modifications and variations may be made to the present invention in light of the above teachings. Thus, it is to be understood that within the scope of the appended claims, the present invention may be practiced in a manner other than the specific description, in which the reference numerals are for convenience only and not for limitation.

Claims

1. A gear reduction assembly for transmitting torque between a prime mover and wheels; the assembly comprising: an input shaft extending along an axis and configured to be rotated by the prime mover; an output shaft extending along the axis spaced apart from the input shaft and configured to rotate the wheel; a ring gear disposed about the axis; a sun gear coupled to one of the input shaft and the output shaft; a bracket extending along the axis and around the input shaft and the output shaft; as well as a plurality of planetary gears radially spaced about the axis and rotatably coupled to the carrier, wherein the carrier is movable along the axis between a direct drive position, a neutral position, and a reduction position, and in each of the direct drive position, the plurality of planetary gears mesh with the sun gear, and the carrier is coupled to one of the input shaft and the output shaft; wherein, in the direct drive position, the bracket is fixed to both the input shaft and the output shaft so that the input shaft and the output shaft rotate in unison about the axis at equal rotational speeds; wherein, in the neutral position, at least one of the input shaft and the output shaft is disconnected from the bracket so that the input shaft and the output shaft rotate independently of each other about the axis; and Wherein, in the deceleration position, the plurality of planetary gears are rotatably meshed with the sun gear and the ring gear fixed to one of the input shaft and the output shaft, and the bracket is fixed to the other of the input shaft and the output shaft so that the input shaft and the output shaft rotate around the axis at different rotational speeds.

2. The gear reduction assembly according to claim 1, characterized in that: Each of the input shaft, the output shaft and the bracket includes a spline extending longitudinally along the axis, and the splines of the bracket are configured to engage with and slide along the splines of the input shaft and the output shaft as the bracket moves longitudinally along the axis between the direct drive position, the neutral position and the deceleration position.

3. The gear reduction assembly according to claim 2, characterized in that: When the carrier is in the neutral position and the deceleration position, the splines of the carrier are longitudinally spaced apart and disconnected from the splines of one of the input shaft and the output shaft along the axis.

4. The gear reduction assembly according to claim 3, characterized in that: When the carrier is in the neutral position and the deceleration position, the splines of the carrier are longitudinally spaced apart and disconnected from the splines of the input shaft along the axis.

5. The gear reduction assembly according to claim 2, characterized in that: The planetary gears are arranged on a plane orthogonal to the axis, and the planetary gears are spaced apart from the splines of the carrier to define a gap having a distance along the axis.

6. The gear reduction assembly according to claim 5, characterized in that: The length of the ring gear along the axis is less than or equal to the distance of the gap between the splines of the planet gears and the carrier, wherein the ring gear is disposed within the gap when the carrier is in the neutral position.

7. The gear reduction assembly according to claim 2, characterized in that: The bracket includes a wall extending transverse to the axis and bisecting the bracket's splines to define an input portion of the bracket's splines and an output portion of the bracket's splines, the input portion of the splines being configured to engage with the splines of the input shaft, the output portion of the splines being configured to engage with the splines of the output shaft, and the wall being engageable with at least one of the input shaft and the output shaft to define an end stop to prevent further movement of the bracket beyond one of the direct drive position, the neutral position, and the deceleration position.

8. The gear reduction assembly according to claim 7, characterized in that: Each of the planet gears has an outer surface facing away from the bracket and spaced a first distance from the wall along the axis, and the sun gear extends a second distance along the axis at least equal to the first distance to allow the sun gear to be coupled to the bracket and at least one of the plurality of planet gears.

9. The gear reduction assembly according to claim 7, characterized in that: The splines of each of the input portion and the output portion extend inwardly toward the axis, one of the input portion and the output portion extends further toward the axis than the other, and the wall transitions between the input portion and the output portion.

10. The gear reduction assembly according to claim 7, characterized in that: The deceleration position of the bracket defines an end point of movement of the bracket, and the wall prevents the bracket from moving beyond the deceleration position.

11. The gear reduction assembly according to claim 2, characterized in that: The sun gear defines a spline with one of the input shaft and the output shaft.

12. The gear reduction assembly according to claim 1, characterized in that: The sun gear and the input shaft are an integral component comprising a single material.

13. The gear reduction assembly according to claim 1, characterized in that The neutral position of the carrier is disposed between the direct drive position and the deceleration position of the carrier.

14. The gear reduction assembly according to claim 1, characterized in that The input shaft and the output shaft are longitudinally fixed along the axis, and the carrier is configured to move along the input shaft and the output shaft while moving between the direct drive position, the neutral position, and the reduction position.

15. The gear reduction assembly according to claim 1, characterized in that The invention also includes a housing defining an interior along the axis, wherein the input shaft, the output shaft, the sun gear, the plurality of planetary gears and the carrier are arranged in the housing, and the ring gear is fixed to the housing in the interior.

16. The gear reduction assembly according to claim 1, characterized in that In the direct drive position, the sun gear is fixed to the input shaft, and the input shaft is fixed to the carrier through the sun gear, and in the reduction position, the plurality of planetary gears are rotatably meshed with the ring gear and the input shaft through the sun gear.

17. The gear reduction assembly according to claim 1, characterized in that: The plurality of planet gears rotatably meshing with the ring gear and the sun gear in the reduction position have a gear ratio of at least 3:

1.

18. An axle system for transmitting torque to wheels of a vehicle, the axle system comprising: a subframe, the subframe being adapted to be mounted on a frame of the vehicle; a prime mover mounted on the sub-frame and configured to generate torque; as well as The gear reduction assembly of claim 1, mounted to the secondary frame and coupled to the prime mover, the assembly being configured to transfer torque between the prime mover and the wheels.

19. The axle system according to claim 18, characterized in that Also included is a gearbox mounted to the sub-frame and coupled to each of the prime mover and the gear reduction assembly, the gearbox being configured to transfer and change torque from the prime mover to the gear reduction assembly.

20. A method of operating a gear reduction assembly for transmitting torque between a prime mover and wheels, the assembly comprising: an input shaft extending along an axis and configured to be rotated by the prime mover; an output shaft extending along the axis spaced apart from the input shaft and configured to rotate the wheels; a ring gear disposed about the axis; a sun gear coupled to one of the input shaft and the output shaft; a carrier extending along the axis and around the input shaft and the output shaft; and a plurality of planetary gears radially spaced about the axis and rotatably coupled to the carrier, and the carrier is movable along the axis between a direct drive position, a neutral position, and a reduction position, and in each of the direct drive position, the neutral position, and the reduction position, the plurality of planetary gears mesh with the sun gear, the carrier being coupled to one of the input shaft and the output shaft, the method comprising the following steps: placing the carrier in the direct drive position, the carrier being fixed to both the input shaft and the output shaft so that the input shaft and the output shaft rotate in unison about the axis at equal rotational speeds; moving the carrier along the axis to the neutral position, disconnecting at least one of the input shaft and the output shaft from the carrier, thereby allowing the input shaft and the output shaft to rotate independently of each other about the axis; and The bracket is moved along the axis to the deceleration position, the plurality of planetary gears are rotatably meshed with the sun gear and the ring gear fixed to one of the input shaft and the output shaft, and the bracket is fixed to the other of the input shaft and the output shaft, so that the input shaft and the output shaft rotate around the axis at different rotational speeds.

21. The method according to claim 20, characterized in that The neutral position of the bracket is arranged between the direct drive position and the deceleration position of the bracket, and the method further comprises the steps of moving the bracket in a single direction along the axis from the direct drive position to the neutral position and from the neutral position to the deceleration position.

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