Wheel hub for mounting a wheel on an axle of a work vehicle

Abstract

The invention relates to a wheel hub (30) comprising a housing (32) and a reduction system (34). The reduction system (34) comprises a planetary gearbox (48) configured to be operatively connected between an axle (36) and a wheel (26), a sleeve (50) for being slidably connected to the axle (36), and an actuation device (52) for sliding the sleeve (50). The reduction system (34) has a first operating position in which the sleeve (50) is engaged with the planetary gearbox (48) to transmit a driving force from the axle (36) with a first speed ratio, and a second operating position in which the sleeve (50) is disengaged from the planetary gearbox (48) and engaged with a closing cap (44) of the housing (32) to transmit the driving force from the axle (36) with a second speed ratio of 1:1.

Description

Technical Field

[0001] The present invention relates to a wheel hub of a work vehicle, and in particular, to a reduction system for the wheel hub. Background Art

[0002] Work vehicles, such as large trucks, typically include a chassis, a suspension system, an engine for driving, a transmission, and a drivetrain, which includes at least three axles with wheels attached. For example, a work vehicle may include a front steering axle and a pair of rear tandem axles to increase the vehicle's load-bearing and traction capabilities. To accommodate various driving conditions, the work vehicle drivetrain may include multiple clutches to drive one or more rear axles and a gearbox to provide one or more speed reductions between the engine and the wheels.

[0003] Due to the various clutches that selectively connect the drive force to the axles (and disconnect the drive force from the axles), the drive train of the work vehicle can have a variety of traction and drive configurations, such as 4×2, 6×2, 6×4, 6×6, 8×4, 8×8, or 10×8 drive configurations. For example, a work vehicle with a 6×4 drive configuration may include an undriven steerable front axle and a pair of rear tandem axles or single axles. Thus, when the work vehicle is towing a payload, such as a semi-trailer loaded with cargo, both rear axles may be driven to increase the towing capacity of the work vehicle, and when the work vehicle is on a return trip without a payload, only one of the rear axles may be driven to improve fuel economy. Additionally, in other situations, such as when towing a heavy load uphill, it may be necessary to provide drive force to all three axles of the work vehicle in a 6×6 drive configuration to increase traction.

[0004] Work vehicles can also provide one or more reduction gears between the engine and wheels to reduce wheel speed and increase engine torque. For example, a reduction gear system can be provided for each wheel hub of a corresponding axle. The reduction gear system can include a planetary gearbox operatively connected between the differential drive shaft and the wheel hub. Typically, the reduction ratio between the drive shaft and the wheel hub is fixed, such as a 2:1 reduction. However, some reduction gear systems include a selectively engageable planetary gearbox that allows for full disengagement and a variable reduction ratio.

[0005] Document WO 2016 / 110823 describes a wheel hub reduction system with a single piston and sliding sleeve for selectively engaging a planetary gearbox with the wheel hub in two indexed positions, resulting in a reduction ratio of 2:1 or 1:1 between the drive shaft and the wheel hub. In this way, the reduction in speed at the wheel can be appropriately matched to the load of the work vehicle.

[0006] WO 2018 / 107258 describes a reduction system with a dual piston system and a sliding sleeve for selectively engaging and disengaging a planetary gear box to a wheel hub. The reduction system can fully disengage the driving force from the wheel hub and provide a reduction ratio of 2:1 or 1 :1. In this way, the reduction system can accommodate a wider range of operating positions and the fully disengaged position can significantly improve the fuel economy of the work vehicle. However, the dual piston system increases the manufacturing and operating costs.

[0007] What is needed is a cost-effective wheel hub reduction system to accommodate various types of driving conditions. SUMMARY

[0008] In one embodiment according to the present application, an integrated reduction system is provided within a wheel hub of a work vehicle. The reduction system comprises a planetary gear box, a sliding sleeve and a pneumatic control device for sliding the sleeve to selectively engage the outer central gear with the planetary gear box in a reduction operating position, and wherein the closed end portion of the wheel hub is in a 1 :1 operating position.

[0009] In another exemplary embodiment according to the present application, a wheel hub is provided for mounting a vehicle wheel on an axle of a work vehicle. The wheel hub comprises a housing having a side end cap and a reduction system. The reduction system comprises a planetary gear box configured to be operably connected between the axle and the vehicle wheel, a sleeve configured to be slidably connected to the axle, and an actuating device connected to the sleeve and configured to slide the sleeve. The reduction system has a first operating position in which the sleeve is engaged with the planetary gear box to transmit the driving force from the axle at a first speed ratio, and a second operating position in which the sleeve is disengaged from the planetary gear box and engaged with the capped end portion of the housing to transmit the driving force from the axle at a second speed ratio of 1 :1.

[0010] A possible advantage of one embodiment of a work vehicle is that the reduction system can accommodate various driving conditions of the work vehicle to selectively increase or decrease the wheel torque and traction.

[0011] Another possible advantage of one embodiment of a work vehicle is that the reduction system can significantly improve the fuel economy of the work vehicle. BRIEF DESCRIPTION OF DRAWINGS

[0012] The accompanying drawings illustrate certain embodiments of the application for purposes of explanation only. It should be understood, however, that the application is not limited to the precise arrangements, sizes, and instrumentalities shown in the attached drawings. Like reference numerals in different drawings identify the same features. In the drawings:

[0013] Figure 1illustrates a side view of one embodiment of a work vehicle including a rear tandem axle assembly according to one embodiment of the present invention;

[0014] Figure 2 illustrates a cross-sectional view of a wheel hub having a housing and a reduction system according to one embodiment of the present invention, wherein the reduction system is in a 2:1 speed ratio reduction operating position; and

[0015] Figure 3 Pictured Figure 2 A cross-sectional view of a wheel hub, wherein the reduction system is in a 1:1 speed ratio operating position;

[0016] Figure 4 illustrates a cross-sectional view of a wheel hub having a housing and an inclined reduction system according to one embodiment of the present invention, wherein the reduction system is in a 2:1 speed ratio reduction operating position; and

[0017] Figure 5 Pictured Figure 4 A cross-sectional view of a wheel hub, wherein the reduction system is in a 1:1 speed ratio operating position;

[0018] Figure 6 illustrates a cross-sectional view of another embodiment of a wheel hub having a housing and an inclined reduction system according to an embodiment of the present invention, wherein the reduction system is in a 1.7:1 speed ratio reduction operating position; and

[0019] Figure 7 Pictured Figure 6 Cross-sectional view of the wheel hub with the reduction gear system in 1:1 speed ratio operating position. DETAILED DESCRIPTION

[0020] The terms "front," "rear," "left," and "right" as used in connection with a vehicle and / or its components are generally defined with reference to the vehicle's forward direction of travel and are not to be construed as limiting. The terms "longitudinal" and "lateral" are defined with reference to the vehicle's forward and rearward directions and are not to be construed as limiting.

[0021] Referring now to the drawings, and more particularly to the Figure 1, shows a work vehicle 10, which generally includes a chassis 12, a cab 14 for an operator, a main engine 16, such as a diesel engine 16, a front axle 18, a rear axle assembly 20 having at least two axles 22, 24, wheels 26 attached to axles 18, 22, 24, and a drive system including a transmission with a gearbox and a main drive shaft 28 for transmitting driving force, i.e., driving torque, from the engine 16 to the rear axle assembly 20 to provide primary traction for the work vehicle 10. The front wheels 26 of the front axle 18 are generally configured to be steered to provide directional control for the work vehicle 10. The engine 16, via the drive system, can drive the wheels 26 of any axle 18, 22, 24. The work vehicle 10 can have any desired drive configuration, such as a 4×2, 6×6, 6×4, 6×2, 8×8, 8×4, or 10×6 drive configuration. Work vehicle 10 may be in the form of any desired vehicle 10, such as a heavy / large truck or bus. For example, work vehicle 10 may be a commercial truck weighing up to 45 tons, having a 4x2 or 6x2 drive configuration.

[0022] Now common reference Figure 2 and Figure 3 , a wheel hub 30 for use with the work vehicle 10 is shown. The wheel hub 30 may generally include a housing 32 and a reduction system 34 disposed within the housing 32. The reduction system 34 has a first reduction operating position to provide a reduction in speed ratio, such as a 2:1 reduction ( ) between a drive axle 36—for example, a drive shaft 36 extending from a rear differential of a corresponding axle 22—and the wheels 26. Figure 2 The reduction system 34 also has a second non-reduction operating position for transmitting the driving force from the axle 36 to the wheels 26 at a 1:1 speed ratio ( Figure 3 ). Thus, deceleration system 34 can selectively select an appropriate speed ratio or disengagement position to appropriately adapt to the operating conditions of work vehicle 10, such as fully loaded, partially loaded, or unloaded. For example, when work vehicle 10 is fully loaded, deceleration system 34 can provide a 2:1 speed reduction ratio in the deceleration position of deceleration system 34 to increase torque and force on wheels 26, or alternatively, when work vehicle 10 is unloaded, deceleration system 34 can provide a 1:1 speed ratio in the non-deceleration position of deceleration system 34 to significantly improve the fuel economy of work vehicle 10. As can be appreciated, one or more of front axle 18 and / or rear axles 22, 24 can include wheel hub 30.

[0023] The housing 32 of the hub 30 is connected to the housing 38 of the drive shaft 36 by means of bearings 40. The housing 32 includes a cylindrical portion 42 and a side end cap 44 connected to the cylindrical portion 42. The inner surface of the side end cap 44 may include teeth 46. It should be understood that the housing 32 can have any desired shape and can be composed of any desired material.

[0024] The reduction system 34 may generally include a planetary gearbox 48, a sliding sleeve 50, and an actuating device 52 for sliding the sleeve 50 between a reduction operating position and a non-reduction operating position to respectively engage the planetary gearbox 48 and the end cover 44. The reduction system 34 may also include a tensioning element 54 for tilting the sleeve 50 to engage the planetary gearbox 48.

[0025] A planetary gearbox 48 is operatively connected between the axle 36 and the wheels 26. The planetary gearbox 48 may be located within the housing 32. The planetary gearbox 48 generally includes a fixed gear 56, a movable gear 58, at least two intermediate gears 60, 62 positioned between the central fixed gear 56 and the movable gear 58, and a planetary carrier 64 for carrying the gears 60, 62. The inner fixed gear 56 may be securely attached to the housing 38 of the drive shaft 36. The outer movable gear 58, such as the central gear 58, may be movably mounted within the housing 32 of the hub 30 via bearings and / or designated planetary liner. The intermediate gears 60, 62 are in the form of satellite gears or planetary gears 60, 62, operatively connected between the fixed gear 56 and the movable central gear 58 and rotatable relative to the fixed gear 56 and the movable central gear 58. In this embodiment, the planetary gearbox 48 includes four planetary gears 60, 62. Gears 56, 58, 60, 62 may be bevel gears; however, gears 56, 58, 60, 62 may have any desired configuration. Planetary carrier 64 has a receiving aperture that at least partially receives sleeve 50. Planetary carrier 64 may take the form of any desired key, fork, or gear carrier. As used herein, the term planetary gearbox 48 broadly refers to the central planetary arrangement that transmits force from drive shaft 36 to wheels 26. It should be understood that planetary gearbox 48 may be configured in a variety of ways to have any desired number and size of gears.

[0026] Sleeve 50 is selectively connectable to planetary gearbox 48 and end cap 44 of housing 32 to provide two different speed ratios, 2:1 and 1:1, respectively, between drive shaft 36 and wheels 26. Sleeve 50 has a first inner bore 66 and a second outer bore 68, which is coaxial with and oppositely oriented from first inner bore 66. Sleeve 50 also has at least one set of teeth 70 circumferentially arranged around the outer periphery of sleeve 50. The teeth 70 of sleeve 50 selectively engage with corresponding teeth on central gear 58 of planetary gearbox 48 in a speed reduction operating position and engage with teeth 46 of end cap 44 of housing 32 in a non-speed reduction operating position. As will be appreciated, sleeve 50 may include one, two, or more sets of teeth 70 that engage with planetary gearbox 48 and housing 32, respectively. Sleeve 50 is not operatively engaged with carrier 64 by means of designated grooves or teeth to transmit drive force therethrough, and therefore, sleeve 50 can rotate and slide independently relative to carrier 64. Thus, when driving force is transmitted through the planetary gearbox 48 in the reduction position, driving force is transmitted from the axle 36 through the sleeve 50, the outer central gear 58 fully coupled to the sleeve 50, the planetary gears 60, 62 and the inner fixed gear 56, and finally leaves the housing 32 of the hub 30 by means of the bearing 40. In addition, in the non-reduction operating position, driving force is fully transferred from the planetary gearbox 34, and the sleeve 50 is fully connected to the housing 32 by means of the end cover 44.

[0027] The first hole 66 is directed toward and opens toward the drive shaft cover 36, and the second hole 68 is directed toward and opens toward the inner surface of the end cover 44. The first hole 66 is associated with the actuator 52 and receives the cover of the drive shaft 36. It should be understood that the hole 66 may have internal grooves or teeth to engage with corresponding engagement members on the axle 36. The second hole 68 receives at least a portion of the tensioning element 54. The holes 66, 68 may have multiple internal cross-sections with different diameters. The holes 66, 68 may be generally symmetrical mirror images of the sleeve, or the holes 66, 68 may differ from each other in diameter, depth, and cross-sectional shape.

[0028] The actuating device 52 is operatively connected to the sleeve 50. The actuating device 52 includes a fluid line 74 and an internal fluid chamber 76 ( Figure 3). Since the first bore 66 of the sleeve 50 is connected to the fluid line in the receiving (separate) bore and the axle cover 34 to form a seal with the help of corresponding seals 78, the interior space of the first bore 66 defines a fluid chamber 76. In this way, the sleeve 50 slides in and out by emptying and filling the fluid chamber 76. In essence, the fluid chamber 76 defined by the first bore 66 acts as a fluid piston to drive the sleeve 50. In operation, in the 2:1 reduction operating position, the fluid chamber 76 is emptied of fluid, so that the force of the tensioning element 54 engages the sleeve 50 with the planetary gearbox 48 ( Figure 2 ), and in the 1:1 non-reduction operating position, the fluid chamber 76 is filled with fluid so that the force of the fluid in the fluid chamber 76 exceeds the force of the tensioning element 54 and causes the sleeve 50 to engage with the teeth 46 of the end cap 44 ( Figure 3 ). The fluid line 74 extends through the end cap 44, centrally through the tensioning element 54 and the second hole 68, and into the receiving orifice of the sleeve 50, thereby filling or emptying the fluid chamber 76. The fluid line 74 can be in the form of a designated hose or a series of conduits, such as a groove in the hub 30. As should be understood, the seal 78 can be in the form of any desired seal, such as a rubber O-ring seal, etc. The actuator 52 is illustrated as a pneumatic control device, however, the actuator 52 can use any desired fluid. It should be understood that the actuator 52 can also include an air pump, a compressor, various valves and / or an accumulator. The actuator 52 can also be operably connected to a control system in the cab of the work vehicle 10 so that an operator can enter user commands into the control system to switch between desired speed ratios.

[0029] The tensioning element 54 is at least partially received within the second bore 68 of the sleeve 50. The tensioning element 54 is thus connected between the end cap 44 and the sleeve 50 and acts on the end cap 44 and the sleeve 50. The tensioning element 54 is configured to tilt the sleeve 50 into engagement with the planetary gearbox 48 in the 2:1 reduction operating position. The tensioning element 54 is located outside the fluid chamber 76. The tensioning member 54 can take the form of any desired tensioning member 54, such as a coil spring 54.

[0030] Now refer to Figures 4 to 7, these figures show two alternative embodiments of a reduction gear system 34 having a planetary gearbox 48 having fixed and moving central gears 80, 82, 90, 92 of different sizes and tilted planetary gears 84, 86, 94, 96 having tilted planetary carriers 88, 98 to provide an alternative reduction ratio to the 2:1 reduction ratio of the horizontally arranged planetary gears 60, 62 discussed above. Thus, by changing the position and / or size of the gears within the planetary gearbox 48 without altering or changing the housing 32 of the hub 30, the reduction ratio can be effectively changed. Figure 4 As shown in FIG, central gears 80, 82 and inclined gears, such as inclined planetary gears 84, 86, provide a reduction ratio of 2.7:1. Figure 6 As shown in FIG, central gears 90, 92 and inclined gears, such as inclined planetary gears 94, 96, provide a reduction ratio of 1.7:1. It should be understood that the planetary gearbox 48 can achieve any desired reduction ratio. As can be appreciated, even with the use of helical gears, the reduction system 34 can still provide a 1:1 reduction ratio when the sleeve 50 is engaged with the end cap 44 of the housing 32. Like components have been identified with like reference numerals throughout the various views.

[0031] These and other advantages of the present invention will be apparent to those skilled in the art from the foregoing descriptive description. Therefore, it will be appreciated by those skilled in the art that changes or modifications may be made to the above-described embodiments without departing from the broad inventive concept of the present invention. It should be understood that the present invention is not limited to the specific embodiments described herein, but is intended to include all changes and modifications that come within the scope and spirit of the present invention.

Claims

1. A wheel hub (30) for mounting a wheel (26) on an axle (36) of a work vehicle (10), the wheel hub (30) comprising: - a housing (32), said housing (32) comprising an end cap (44); as well as A deceleration system (34), the deceleration system (34) comprising: - a planetary gearbox (48) configured to be operatively connected between the axle (36) and the housing (32); - a sleeve (50) configured to be connected to the axle (36) in a sliding manner; and - an actuating device (52) configured to slide the sleeve (50), The reduction system (34) has a first operating position in which the sleeve (50) is engaged with the planetary gearbox (48) to transmit the driving force from the axle (36) at a first speed ratio and a second operating position in which the sleeve (50) is disengaged from the planetary gearbox (48) and engaged with the end cover (44) of the housing (32) to transmit the driving force from the axle (36) at a second speed ratio of 1:

1. wherein the sleeve (50) comprises a first hole (66) associated with the actuating device (52) and a second hole (68) coaxial with the first hole (66), wherein the first hole (66) is configured to receive an end of an axle (36) so that the sleeve (50) operably engages and slides relative to the axle (36), and the second hole (68) is oriented opposite the first hole (66) and extends toward an inner surface of the end cap (44) of the housing (32), The actuating device (52) includes a fluid line (74) and an internal fluid chamber (76), wherein the fluid chamber (76) is located within the housing (32) and is fluidically connected to the fluid line (74). Characterized in that the first hole (66) of the sleeve (50) is connected to the fluid line (74), and a seal (78) is arranged between the fluid line (74) and another hole in the sleeve (50), and the fluid chamber (76) is defined by the first hole (66) and the end of the axle (36) so that filling or emptying the fluid chamber (76) causes the sleeve (50) to slide.

2. The wheel hub (30) according to claim 1, characterized in that The reduction system (34) further includes a tensioning element (54) at least partially received in the second hole (68) and connected between the end cover (44) and the sleeve (50), and the tensioning element (54) is configured to tension the sleeve (50) in a direction in which the sleeve (50) can engage with the planetary gearbox (48).

3. The wheel hub (30) according to claim 2, characterized in that The tensioning element (54) is a coil spring (54).

4. The wheel hub (30) according to claim 2 or claim 3, characterized in that The sleeve (50) further includes a receiving orifice for receiving the fluid line (74), the receiving orifice being fluidically connected to the first hole (66) such that the fluid chamber (76) is fluidically connected to the fluid line (74); in the first operating position, the fluid chamber (76) is emptied of fluid such that the force of the tensioning element (54) causes the sleeve (50) to engage with the planetary gearbox (48); and in the second operating position, the fluid chamber (76) is filled with fluid such that the force of the fluid within the fluid chamber (76) overcomes the force of the tensioning element (54) and causes the sleeve (50) to engage with the end cap (44).

5. The wheel hub (30) according to claim 4, characterized in that The fluid line (74) extends through the end cap (44) of the housing (32), centrally through the tensioning element (54) and the second hole (68), and into the aperture receiving the sleeve (50), thereby filling or emptying the fluid chamber (76).

6. The wheel hub (30) according to any one of claims 1, 2, 3 and 5, characterized in that: The sleeve (50) includes at least one set of teeth (70) circumferentially arranged around an outer periphery of the sleeve (50) for selectively engaging with the planetary gearbox (48) in the first operating position and engaging with the end cover (44) of the housing (32) in the second operating position.

7. The wheel hub (30) according to any one of claims 1, 2, 3 and 5, characterized in that: The planetary gearbox (48) includes gears (56, 80, 90), a moving gear (58, 82, 92), at least two planetary gears (60, 62, 84, 86, 94, 96), and a carrier (64, 88, 98) for carrying the at least two planetary gears (60, 62, 84, 86, 94, 96), and the carrier (64, 88, 98) includes a receiving aperture to at least partially receive the sleeve (50).

8. The wheel hub (30) according to claim 7, characterized in that The sleeve (50) is not operatively engaged with the carrier (64, 88, 98) by means of designated grooves or teeth for transmitting driving force through the grooves or teeth, so that the sleeve (50) can rotate and slide independently relative to the carrier (64, 88, 98), and in the first operating position the sleeve (50) is fully engaged with the moving gear (58, 82, 92) to transmit driving force through the planetary gearbox (48).

9. The wheel hub (30) according to any one of claims 1, 2, 3, 5 and 8, characterized in that: The first speed ratio of the first operating position is 2:1, 2.7:1 or 1.7:

1.

10. The wheel hub (30) according to claim 9, characterized in that The planetary gearbox (48) includes planetary gears (60, 62), and the first speed ratio is 2:1, with the rotation axis of each planetary gear (60, 62) being arranged perpendicular to the rotation axis of the axle (36).

11. The wheel hub (30) according to claim 9, characterized in that The planetary gearbox (48) includes planetary gears (84, 86, 94, 96), and the first speed ratio is 2.7:1 or 1.7:1, and the rotation axis of each planetary gear (84, 86, 94, 96) is arranged obliquely relative to the rotation axis of the axle (36).

Images