Axle assembly with inter-axle differential unit

Abstract

The present application relates to an axle assembly having an inter-axle differential unit. An axle assembly is provided. The axle assembly includes an input shaft and an output shaft rotatable about an inter-axle differential unit axis, and an inter-axle differential unit positioned between the shafts. The assembly further includes a guide device that directs lubrication fluid to the inter-axle differential unit and houses at least a portion of the output shaft.

Description

Technical Field

[0001] This disclosure relates to an axle assembly having an interaxle differential unit. background U.S. Patent No. 9,816,603 discloses an axle assembly with an inter-axle differential unit. It is known to provide an inter-axle differential unit (IAD) to transmit torque from a first axle assembly to another axle assembly. For the IAD, lubrication is critical for its lifespan and function. Typically, axle assemblies are provided with pumping devices or other lubricant channels to guide lubricating fluid, typically splashed around the IAD cavity (nest) by the helical gear rotating with the input shaft, into the IAD cavity itself.

[0002] The present invention aims to provide one or more improvements that are superior to the prior art. Overview According to an aspect of the present invention, an axle assembly is provided. The axle assembly includes: an input shaft rotatable about an axis of an inter-axle differential unit; an output shaft rotatable about an axis of the inter-axle differential unit; an inter-axle differential unit disposed between the input shaft and the output shaft; and a guide device for guiding lubricating fluid to the inter-axle differential unit, wherein the guide device at least partially accommodates the output shaft.

[0003] The guide device directs lubricant fluid along the output shaft to lubricate the inter-axle differential unit, which helps improve the life and performance of the inter-axle differential unit. Since the output shaft is typically located in an already lubricated area of ​​the axle assembly, there is no need for an additional pump or lubrication path solely for the inter-axle differential unit, thus simplifying the axle assembly.

[0004] The axle assembly may include a differential carrier housing defining: an inter-axle differential unit chamber for supporting the inter-axle differential unit; and a differential assembly chamber for supporting a differential assembly that communicates with the input shaft for transmitting torque to at least one axle shaft of the axle assembly. An output shaft may extend between the inter-axle differential unit chamber and the differential assembly chamber. Lubricating fluid may be guided along the output shaft to the inter-axle differential unit chamber by a guide device.

[0005] The guiding device allows lubricating fluid from the sump portion of the axle housing, which is used to lubricate the differential assembly, to also be used to lubricate the inter-axle differential unit.

[0006] The guiding device may be defined at least in part by: an inter-axle differential unit compartment; and a bearing end cap for supporting the differential assembly. The bearing end cap may be located in the differential assembly compartment and fixed to the differential carrier housing.

[0007] The bearing end cap has a dual function, as it supports the differential assembly and helps guide lubricating fluid to the inter-axle differential unit.

[0008] The bearing end cap may include: a first hole arranged around a differential axis perpendicular to the axis of the inter-axle differential unit, the first hole being configured to support the differential assembly; and a second hole arranged around the axis of the inter-axle differential unit. An output shaft may pass through the second hole. Lubricating fluid may be guided along the output shaft toward the inter-axle differential unit.

[0009] The first hole can be used to locate a ring gear bearing for supporting the ring gear of the differential assembly. The bearing end cap can be configured such that when the ring gear rotates through a reservoir portion of the axle housing during use, lubricating fluid is at least partially guided through the second hole of the bearing end cap toward the inter-axle differential unit.

[0010] The bearing end cap is configured to allow the ring gear to guide fluid through a second hole without the need for a pump or other guiding device.

[0011] The inter-axle differential unit compartment may include the output shaft bearing support portion adjacent to the mouth portion.

[0012] Because the output shaft bearing support is positioned near the port, the lubricating fluid guided by the guide device is "pumped" through the output shaft bearing into the inter-axle differential unit.

[0013] The second hole in the bearing end cap extends from the first surface of the bearing end cap to the second surface of the bearing end cap. The second surface can be positioned adjacent to the opening portion of the inter-axle differential unit.

[0014] Since the second hole completely passes through a portion of the bearing end cap, lubricating fluid can flow from the differential assembly chamber to the inter-axle differential unit chamber.

[0015] The second hole can define a first cross-sectional profile. The first cross-sectional profile can increase from the first surface of the bearing end cap to the second surface of the bearing end cap.

[0016] The increased cross-sectional profile helps guide the lubricating fluid toward the inter-axle differential unit.

[0017] The opening portion of the inter-bridge differential unit compartment can define a second cross-sectional profile. This second cross-sectional profile can increase from a first end of the opening portion adjacent to the bearing end cap to a second end of the opening portion adjacent to the output shaft bearing support portion of the inter-bridge differential unit compartment.

[0018] Because the opening portion also has an enlarged cross-sectional profile, it defines a smooth transition from the differential assembly compartment to the inter-axle differential unit compartment.

[0019] The second cross-sectional profile can continue from the first cross-sectional profile. The first and second cross-sectional profiles can increase at a substantially linear rate, such that the guide device tapers radially outward from the first surface of the bearing end cap to the second end of the opening portion.

[0020] This defines a substantially continuous ramp that guides the lubricating fluid and can also help increase the velocity of the lubricating fluid, for example, under the influence of gravity, to facilitate the lubricating fluid through the output shaft bearing and into the inter-axle differential unit.

[0021] The inter-axle differential unit may include: an input shaft-side gear rotatable with the input shaft about an axis of the inter-axle differential unit; an output shaft-side gear rotatable with the output shaft about an axis of the inter-axle differential unit; a spider rotatable with the input shaft about an axis of the inter-axle differential unit; a planetary gear rotatably mounted on the spider and meshing with the input shaft-side gear and the output shaft-side gear; a housing at least surrounding the planetary gear and the spider, the housing having a first end and a second end; and an output shaft bearing disposed on the output shaft-side gear adjacent to the second end of the housing. The housing may have an opening at the second end of the housing configured to receive lubricating fluid passing through the output shaft bearing.

[0022] The diameter of the opening at the second end of the housing can be larger than the outer diameter of the output shaft bearing.

[0023] This housing helps ensure that the lubricating fluid (which has already been guided there by the guide device) through the output shaft bearing lubricates the inter-axle differential unit.

[0024] The housing may include a lip portion at the second end of the housing. The lip portion may extend axially in the direction of the output shaft bearing.

[0025] The lip portion of the housing helps guide the lubricating fluid leaving the output shaft bearing into the inter-axle differential unit.

[0026] The output shaft-side gear may include multiple lubricant channels for lubricating fluid.

[0027] The lubricant passage helps ensure that lubricating fluid is not blocked from entering the inter-axle differential unit from the output shaft bearing.

[0028] The lubricant channels can be distributed circumferentially around the output shaft-side gear. The lubricant channels can extend radially from the outer circumference of the output shaft-side gear.

[0029] This helps ensure that lubricating fluid can pass through the output shaft-side gear, but the lubricant channels can be distributed between the teeth of the output shaft-side gear, so the function of the lubricant channels is not negatively affected.

[0030] Within the scope of this application, it is expressly intended that the various aspects, embodiments, examples, and alternatives set forth in the foregoing paragraphs, in the claims, and / or in the following description and drawings, and in particular their respective features, may be employed individually or in any combination. All embodiments and / or features of any embodiment may be combined in any manner and / or combination unless such features are incompatible. The applicant reserves the right to amend any originally filed claim or correspondingly file any new claim, including the right to modify any originally filed claim to be subordinate to and / or include any feature of any other claim, although no right was originally claimed in that manner.

[0031] Other benefits and advantages of the invention will become apparent from the following detailed description of at least one exemplary embodiment for carrying out the invention, with reference to the accompanying drawings. Attached Figure Description

[0032] One or more embodiments of the invention will now be described by way of example only with reference to the accompanying drawings, in which: Figure 1 This is a perspective view of an axle assembly according to an embodiment of the present invention; Figure 2 yes Figure 1 A perspective view of the axle assembly viewed from the opposite direction; Figure 3 yes Figure 2 A partial sectional view; Figure 4 yes Figure 1 A perspective view of the differential carrier housing and differential assembly of the axle assembly; Figure 5 yes Figure 4 Perspective views of the differential carrier housing taken from different directions, with the details omitted; Figure 6 Is it through Figure 4 The differential carrier housing and differential assembly shown are in a cross-sectional view taken along plane 6-6; Figure 7 yes Figure 1 Differential carrier housing of axle assembly; Figure 8 It is shown Figure 1 Exploded perspective view of the inter-axle differential unit and bearing end cap components of the axle assembly; Figure 9 yes Figure 8 A perspective view of the bearing end cap; Figure 10 yes Figure 8 A perspective view of the output shaft side gear; and Figure 11 Is it through Figure 8 The cross-sectional view of the housing of the inter-bridge differential unit taken along plane 11-11. Detailed description The following describes one or more detailed embodiments of the invention. These embodiments are merely examples of the invention, which may be implemented in various and alternative forms. The drawings are not necessarily to scale; some features may be enlarged or reduced to a minimum to show details of specific components. Therefore, the specific structural and functional details included in the following description should not be construed as limiting, but merely as a representative basis for instructing those skilled in the art to use the invention in various ways.

[0033] refer to Figure 1 An example of axle assembly 102 is shown. Axle assemblies can be installed in any suitable type of vehicle, such as trucks, buses, farm equipment, military transport or military vehicles, or cargo loading equipment for land, air or sea vessels.

[0034] Axle assembly 102 may be part of a vehicle drivetrain, which may include multiple axle assemblies that can be connected in series. For example, the axle assembly may be part of a tandem axle drivetrain configuration that may include two axle assemblies connected in series. The axle assembly operatively connected to at least one torque source (e.g., an electric motor or internal combustion engine) or located closest to the torque source may be referred to as the first axle assembly. The axle assembly receiving propulsion torque from the torque source through or by means of the first axle assembly may be referred to as the second axle assembly. Figure 1 In the image, axle assembly 102 is depicted as a first axle assembly.

[0035] In this embodiment, axle assembly 102 provides torque to its associated wheel assembly (not shown) and to a second axle assembly (not shown). In this embodiment, and as will be described in more detail below, axle assembly 102 includes an axle housing 104, a differential carrier housing 114, an input yoke 116, an input shaft 118, an inter-axle differential unit 120, a differential assembly 122, at least one half-shaft 124, an output shaft 126, an output yoke 128, or a combination thereof.

[0036] refer to Figure 1 , Figure 2 and Figure 3 The axle housing 104 can receive various components of the axle assembly 102. Additionally, the axle housing 104 facilitates the mounting of the axle assembly 102 to the vehicle. The axle housing 104 has a central portion 106 and first and second arm portions 112 extending from opposite sides of the central portion. Wheel hubs 110 are arranged at the free ends of each arm portion 112 for mounting vehicle wheels (not shown). A differential carrier housing 114 is mounted to the axle housing 104. In this embodiment, both the axle housing 104 and the differential carrier housing 114 have corresponding flanges, which are bolted together. However, it should be understood that any suitable removable or permanent fastening device can be used.

[0037] As will be described in more detail below, the differential carrier housing 114 supports the inter-axle differential unit 120 and the differential assembly 122. The differential carrier housing 114... Figure 7 The differential carrier housing 114 is shown in more detail below. It is typically a cast component made of cast iron or other suitable material. Multiple features for supporting different components of the differential assembly 122 and the inter-axle differential unit 120 are located within the differential carrier housing 114. In this embodiment, the differential carrier housing 114 defines an inter-axle differential unit chamber 130 for supporting the inter-axle differential unit 120; and a differential assembly chamber 136 for supporting the differential assembly 122.

[0038] As in Figure 4 As can be seen most clearly in this embodiment, the differential assembly 122 protrudes from the differential carrier housing 114, such that the differential assembly 122 is at least partially received within the axle housing 104. The differential assembly 122 transmits torque to the half-shaft 124 (see [link to original text]). Figure 3The differential assembly 122 is operatively connected to the half-shaft 124 and allows the half-shaft 124 to rotate at different rotational speeds in a manner known to those skilled in the art. In this embodiment, the differential assembly 122 includes a ring gear 138 that rotates about an axis AA. The ring gear 138 communicates with the input shaft 118 and transmits torque to the half-shaft 124 in a known manner. The ring gear 138 is located in the differential assembly chamber 136 and passes through a reservoir portion 108 when the ring gear 138 rotates in use. In this embodiment, the reservoir portion 108 is located in the central portion 106 of the axle housing 104. When the reservoir portion 108 contains lubricating fluid, the ring gear 138 facilitates the splashing of lubricating fluid around the differential assembly chamber 136 of the axle housing 104 and the differential carrier housing 114 to aid in the lubrication of the differential assembly 122.

[0039] like Figure 3 As shown, the half-shaft 124 transmits torque from the differential assembly 122 to the corresponding wheel hubs and wheels. The half-shaft 124 extends along and is rotatable about axis AA, which in this embodiment is the differential axis. Components of the differential assembly 122 arranged about axis AA are supported by a first bearing assembly and a second bearing assembly.

[0040] As in Figure 4 As can be seen most clearly in this embodiment, the first bearing assembly is located at the first end of the differential assembly 122 and includes a first bearing portion 140 integrally formed with the differential carrier housing 114. The first bearing portion 140 positions the first differential bearing 156 and includes a first pin 142 that protrudes from the first bearing portion 140 and is received in a corresponding receiving recess (not shown) on the axle housing 104.

[0041] As in Figure 4 and Figure 5 Most clearly visible, the second bearing assembly is located at the second end of the differential assembly 122 and includes a second bearing portion in the form of a bearing end cap 144. The bearing end cap 144 is secured to the differential carrier housing 114 and positions the second differential bearing, referred to in this embodiment as a ring gear bearing 158. The bearing end cap 144 includes a second pin 154 that protrudes from the bearing end cap 144 and is received in a corresponding receiving recess (not shown) on the axle housing 104. The bearing end cap 144... Figure 9 As shown in the figure, and will be described in more detail below.

[0042] refer to Figure 5 and Figure 6The output shaft 126 extends along and is rotatable about axis BB, which in this embodiment is the axis of the inter-axle differential unit. The inter-axle differential unit axis BB is perpendicular to the differential axis AA. The output shaft 126 is supported by one or more bearings that may be disposed on the axle housing 104. The output shaft 126 is coupled to the inter-axle differential unit 120. The output yoke 128 facilitates the coupling of the axle assembly 102 to another axle assembly. The output yoke 128 is securely coupled to the output shaft 126 in any suitable manner (e.g., by fasteners with mating splines and nuts). The output yoke 128 can be operatively connected to the second axle assembly in any suitable manner (e.g., via a driveshaft).

[0043] The input yoke 116 facilitates the connection of the axle assembly 102 to a torque source. It is conceivable that the input yoke 116 could be omitted, for example, when a torque source similar to an electric motor is integrated with the axle assembly 102. If the input yoke 116 is provided, it is operatively connected to the input shaft 118. The input shaft 118 extends along and is rotatable about the inter-axle differential unit axis BB. The input shaft 118 is rotatably supported by one or more bearings that can be mounted on the differential carrier housing 114. The input shaft 118 is operatively connected to the output shaft 126 via the inter-axle differential unit 120. The input shaft 118 is also operatively connected to the differential assembly 122 in a known manner, which will not be described in detail.

[0044] The inter-axle differential unit 120 adapts to or compensates for rotational speed differences between different drive axle assemblies, such as the speed difference between axle assembly 102 and a second axle assembly connected in series with axle assembly 102. In this embodiment, the inter-axle differential unit 120 operatively connects the input shaft 118 and the output shaft 126, allowing the input shaft 118 and the output shaft 126 to rotate relative to each other at different speeds under various operating conditions. In this embodiment, the inter-axle differential unit 120 is located in the inter-axle differential unit chamber 130 of the differential carrier housing 114.

[0045] Reference Figure 6 In this embodiment, the inter-bridge differential unit 120 includes a first side gear 160, a second side gear 162, a cross shaft 168, at least one planetary gear 170, and a housing 172.

[0046] In this embodiment, the first side gear 160 is an input shaft side gear. The first side gear 160 is rotatable about the inter-axle differential unit axis BB and is selectively coupled to the input shaft 118. The first side gear 160 includes first side gear teeth arranged about the inter-axle differential unit axis BB, which mesh or engage with the teeth of at least one planetary gear 170. The first side gear teeth are disposed within the housing 172.

[0047] exist Figure 8 and Figure 10 The second side gear 162 can be seen in more detail below. In this embodiment, the second side gear 162 is an output shaft side gear. The second side gear 162 is rotatable together with the output shaft 126 about the inter-axle differential unit axis BB. An output shaft bearing 166 is disposed on the second side gear 162. In this embodiment, the second side gear 162 extends along the inter-axle differential unit axis BB and has a central bore that receives or surrounds the end of the output shaft 126 and the end of the input shaft 118. In this embodiment, the central bore includes a spline or spline portion spaced apart from the input shaft 118 and engaging with a corresponding spline of the output shaft 126. In this way, the second side gear 162 is prevented from rotating relative to the output shaft 126 about the inter-axle differential unit axis BB.

[0048] In this embodiment, the second side gear 162 includes a plurality of lubricant channels 164. The lubricant channels 164 are distributed circumferentially around the second side gear 162. In this embodiment, each lubricant channel 164 extends radially from the outer circumference of the second side gear 162 and helps ensure that lubricating fluid can pass through the second side gear 162. The lubricant channels 164 are distributed between the teeth of the second side gear 162, so that the function of the lubricant channels 164 is not negatively affected. Each lubricant channel 164 has a substantially U-shaped profile to help ensure smooth flow through the second side gear 162. In other embodiments, the lubricant channels 164 may be between every other pair or fewer teeth of the second side gear 162. However, it should be understood that the more lubricant channels 164 the better, as there will be less restriction on the flow into the inter-axle differential unit 120.

[0049] The cross shaft 168 is rotatable together with the input shaft 118 about the inter-axle differential unit axis BB. In this embodiment, the cross shaft 168 includes a central bore comprising a spline or spline portion that engages with a corresponding spline of the input shaft 118 to help prevent rotation of the cross shaft 168 relative to the input shaft 118 about the inter-axle differential unit axis BB. The cross shaft 168 and the housing 172 are rotatable relative to each other. In this embodiment, the cross shaft 168 is partially or completely received within the housing 172 and is rotatable relative to the housing 172 about the inter-axle differential unit axis BB. The cross shaft 168 also includes one or more pins extending away from the central bore of the cross shaft 168.

[0050] One or more planetary gears 170 are rotatable relative to the cross shaft 168. In this embodiment, the planetary gears 170 are rotatably disposed on each pin of the cross shaft 168. Each planetary gear 170 defines a cavity that receives the corresponding pin in a manner that allows the planetary gear 170 to rotate about the pin. The planetary gear 170 includes teeth that mesh or engage with the teeth of the first side gear 162 and the second side gear 162.

[0051] The housing 172 receives components of the inter-axle differential unit 120. The housing 172 surrounds at least a portion of the first side gear 160, the second side gear 162, the cross shaft 168, the planetary gear 170, or a combination thereof.

[0052] exist Figure 8 and Figure 11 The housing 172 can be seen in more detail. In this embodiment, the housing 172 is a single, integral, one-piece component. The housing 172 has a first housing end 174, a second housing end 176, a first housing opening 178, a second housing opening 180, and a housing cavity 182.

[0053] In this embodiment, the first end 174 of the housing faces the first side gear 160 or from... Figure 6 The view shown faces to the right. The first end 174 of the housing extends around the axis BB of the inter-axle differential unit and surrounds the first opening 178 of the housing.

[0054] The second end 176 of the housing is located at the end of the housing 172 opposite to the first end 174 of the housing. In this way, the second end 176 of the housing is away from the first side gear 160. The second end 176 of the housing extends around the axis BB of the inter-axle differential unit and surrounds the second opening 180 of the housing.

[0055] refer to Figure 6 The first opening 178 of the housing receives and surrounds at least a portion of the first side gear 160. The second opening 180 of the housing receives and surrounds at least a portion of the second side gear 162.

[0056] The housing cavity 182 is at least partially defined by a partially spherical surface 186. The partially spherical surface 186 extends between the second end 176 and the first end 174 of the housing. The partially spherical surface 186 faces the inter-axle differential unit axis BB and surrounds the cross shaft 168 and at least a portion of the planetary gears 170. In this embodiment, the partially spherical surface 186 extends continuously around the inter-axle differential unit axis BB and is positioned at a substantially constant radial distance from a center point located along the inter-axle differential unit axis BB. In this embodiment, the partially spherical surface 186 resembles a portion of a sphere and extends around a spherical segment that may be a portion of the sphere disposed between two substantially parallel planes that may be substantially perpendicular to the inter-axle differential unit axis BB. The term "substantially perpendicular" is used herein to specify features or axes that are the same as or very close to perpendicular, and includes features within ±2° of each other.

[0057] In this embodiment, the housing 172 is fixedly connected to the first side gear 160 in any suitable manner. In this way, the first side gear 160 cannot rotate relative to the housing 172.

[0058] The housing 172 also includes a lip portion 184 at a second end 176 of the housing. In this embodiment, the lip portion 184 surrounds the second opening 180 of the housing. When the inter-axle differential unit 120 is located in the inter-axle differential unit chamber 130, the lip portion 184 extends axially in the direction of the output shaft bearing 166. As will be described in more detail below, the lip portion 184 of the housing 172 facilitates the guidance of lubricating fluid leaving the output shaft bearing 166 into the inter-axle differential unit 120.

[0059] As previously described, the inter-axle differential unit 120 is located in the inter-axle differential unit chamber 130. A guide device is provided for guiding lubricating fluid from the differential assembly chamber 136 to the inter-axle differential unit 120. The guide device is defined at least in part by the inter-axle differential unit chamber 130 and the bearing end cap 144.

[0060] Bearing end cover 144 Figure 9 The bearing end cap 144 is shown in more detail below. It includes a first bore 146 and a second bore 152. The bearing end cap 144 has a dual function, supporting the differential assembly 122 and facilitating the direct flow of lubricating fluid to the inter-axle differential unit 120.

[0061] The first hole 146 is arranged around and around the differential axis AA, and is configured to support the differential assembly 122. Specifically, the first hole 146 positions the ring gear bearing 158 for supporting the ring gear 138 of the differential assembly 122.

[0062] The second hole 152 is arranged around and around the axis BB of the inter-axle differential unit. Therefore, the second hole 152 is arranged perpendicular to the first hole 146. The output shaft 126 passes through the second hole 152. The second hole 152 of the bearing end cover 144 extends from the first surface 148 of the bearing end cover 144 to the second surface 150 of the bearing end cover 144.

[0063] The second hole 152 defines a first cross-sectional profile. The first cross-sectional profile increases from a first surface 148 of the bearing end cap 144 to a second surface 150 of the bearing end cap 144. This can... Figure 6 As can be seen most clearly, dimension X represents the diameter of the second bore 152. The increased cross-sectional profile facilitates the guidance of lubricating fluid toward the inter-axle differential unit 120. The bearing end cap 144 is configured such that when the ring gear 138 rotates in use through the reservoir portion 108 of the axle housing 104, lubricating fluid is at least partially guided through the second bore 152 of the bearing end cap 144 toward the inter-axle differential unit 120. The bearing end cap 144 is configured such that the ring gear 138 guides fluid through the second bore 152 without requiring a pump or other guiding device. Lubricating fluid is guided along the output shaft 126 toward the inter-axle differential unit 120.

[0064] The second side 150 of the bearing end cover 144 is positioned adjacent to the opening portion of the inter-axle differential unit chamber. Since the second hole 152 completely passes through a portion of the bearing end cover 144, lubricating fluid can flow from the differential assembly chamber 136 to the inter-axle differential unit chamber 130.

[0065] As in Figure 6 The most clearly visible part is the inter-bridge differential unit chamber 130, which includes an opening portion 132 and an output shaft bearing support portion 134.

[0066] The opening portion 132 of the inter-axle differential unit chamber 130 defines a second cross-sectional profile. The second cross-sectional profile increases from the first end of the opening portion 132 to the second end of the opening portion 132. This can... Figure 6 The most clearly visible part is where dimension Y represents the diameter of the opening portion 132.

[0067] The output shaft bearing support portion 134 is adjacent to the opening portion 132. The output shaft bearing support portion 134 extends around the axis BB of the inter-axle differential unit and defines a seat for the output shaft bearing 166. The diameter of the output shaft bearing support portion 134 is substantially equal to the outer diameter of the output shaft bearing 166. In this embodiment, the output shaft bearing 166 is a tapered roller bearing, thus it can accept radial and axial loads during use. The output shaft bearing 166 has an inner race and an outer race, and a plurality of roller elements located between the inner and outer races. The outer diameter of the outer race of the output shaft bearing 166 is substantially equal to the diameter of the output shaft bearing support portion 134, thus the outer race of the output shaft bearing 166 is rotatably fixed to the output shaft bearing support portion 134. The inner diameter of the inner race of the output shaft bearing 166 is substantially equal to the diameter of the second side gear 162, and the inner race of the output shaft bearing 166 is rotatably fixed to the second side gear 162. In this embodiment, the second side gear 162 has a shoulder portion to axially position the output shaft bearing 166 in place. As an example, in this embodiment, the selected output shaft bearing 166 has an outer diameter of 95 mm, but the size can be varied to accommodate the size of the axle assembly 102, which varies depending on the power to be distributed and other factors.

[0068] The output shaft bearing 166 is selected such that the inner diameter of the outer race of the output shaft bearing 166 and the outer diameter of the inner race of the output shaft bearing 166 form an angle, substantially corresponding to the slope of the opening portion 132 of the differential carrier housing 114, thereby defining a continuous path to the inter-axle differential unit chamber 130. The rolling elements of the output shaft bearing 166 correspond to the angled surfaces of the inner and outer races. In this embodiment, the rolling elements are substantially cylindrical, and the cross-sectional area decreases from the minimum inner diameter of the outer race of the output shaft bearing 166 to the maximum inner diameter of the outer race of the output shaft bearing 166. In other words, see... Figure 6 The cross-sectional area of ​​the rolling elements decreases from left to right. This helps to increase the pumping effect of the output shaft bearing 166 on the fluid passing through the inlet portion 132 of the differential carrier housing 114.

[0069] In this embodiment, the diameter of the output shaft bearing support portion 134 is less than or equal to the diameter of the housing second opening 180 and / or the lip portion 184 of the housing 172. Because the output shaft bearing support portion 134 is positioned adjacent to the opening portion 132, lubricating fluid guided by the guide device is "pumped" through the output shaft bearing 166 into the housing 172 of the inter-axle differential unit 120. The relative dimensions of the output shaft bearing 166, the output shaft bearing support portion 134, and / or the housing second opening 180 help ensure that lubricating fluid is guided into the housing 172. The lip portion 184 also facilitates the guidance of lubricating fluid into the housing 172.

[0070] The bearing end cap 144 is arranged adjacent to the opening portion 132 of the inter-axle differential unit chamber 130. When the bearing end cap 144 is arranged adjacent to the opening portion 132, lubricating fluid guided through the second hole 152 of the end cap is guided into the opening portion 132 of the inter-axle differential unit chamber 130. The first end of the opening portion 132 is adjacent to the bearing end cap 144, and the second end of the opening portion 132 is adjacent to the output shaft bearing support portion 134 of the inter-axle differential unit chamber 130. As the second cross-sectional profile increases from the first end to the second end, a smooth transition is defined from the differential assembly chamber 136 to the inter-axle differential unit chamber 130.

[0071] In this embodiment, the second cross-sectional profile of the opening portion 132 continues from the first cross-sectional profile of the second hole 152. The first and second cross-sectional profiles increase at a substantially linear rate, causing the guide device to taper radially outward from the first face 148 of the bearing end cap 144 to the second end of the opening portion 132. This defines a substantially continuous ramp that guides the lubricating fluid and can also help increase the velocity of the lubricating fluid, for example, under gravity, to facilitate the passage of the lubricating fluid through the output shaft bearing 166 and into the inter-axle differential unit 120.

[0072] The output shaft 126 typically has a diameter between 40 mm and 60 mm. In this embodiment, the output shaft 126 has a diameter of 55 mm, and the minimum clearance between it and the second hole 152 of the bearing end cap 144 is approximately 3 mm. It should be understood that the dimensions can be appropriately varied according to the requirements of the axle assembly 102.

[0073] As described above, the axle assembly 102 allows lubricating fluid to be guided from the reservoir portion 108 of the axle housing 104 along the output shaft 126 to the inter-axle differential unit chamber 130 via a guide device. Furthermore, since the output shaft 126 passes directly through the bearing end cap 144, the width of the differential carrier housing 114 can be reduced, thereby reducing the package space and weight.

[0074] While exemplary embodiments have been described above, these embodiments are not intended to describe all possible forms of the invention. Rather, the terminology used herein is descriptive rather than restrictive, and it should be understood that various changes may be made without departing from the spirit and scope of the invention. Additionally, features of various implementations of the embodiments may be combined to form other embodiments of the invention.

[0075] When the word "or" appears, it should be interpreted as meaning "and / or". This makes it possible for the items mentioned to be mutually exclusive and to be used in any appropriate combination.

[0076] The invention has been described above with reference to one or more specific embodiments. However, this description is not exhaustive, and the invention is not limited to the described embodiments. Various changes and modifications can be made without departing from the scope of the invention as defined in the claims. For example, (insert any alternatives not yet mentioned here).

Claims

1. An axle assembly, comprising: An input shaft that is rotatable about the axis of the inter-bridge differential unit; An output shaft that is rotatable about the axis of the inter-bridge differential unit; An inter-bridge differential unit is disposed between the input shaft and the output shaft; and A guiding device for directing lubricating fluid to the inter-axle differential unit. The guiding device at least partially accommodates the output shaft.

2. The axle assembly of claim 1, comprising a differential carrier housing, the differential carrier housing defining: An inter-axle differential unit compartment, the inter-axle differential unit compartment being used to support the inter-axle differential unit; and A differential assembly compartment for supporting a differential assembly that communicates with the input shaft for transmitting torque to at least one half-shaft of the axle assembly. in, The output shaft extends between the inter-axle differential unit chamber and the differential assembly chamber, and the lubricating fluid is guided along the output shaft to the inter-axle differential unit chamber by the guide device.

3. The axle assembly according to claim 2, wherein, The guiding device is defined in at least part by the following: The inter-bridge differential unit compartment; and A bearing end cap for supporting the differential assembly, the bearing end cap being located in the differential assembly chamber and fixed to the differential carrier housing.

4. The axle assembly according to claim 3, wherein, The bearing end cap includes: A first hole, arranged around a differential axis perpendicular to the axis of the inter-axle differential unit, is configured to support the differential assembly; and A second hole is arranged around the axis of the inter-bridge differential unit, wherein the output shaft passes through the second hole, and lubricating fluid is guided along the output shaft toward the inter-bridge differential unit.

5. The axle assembly according to claim 4, wherein, The first hole positions a ring gear bearing for supporting the ring gear of the differential assembly, and the bearing end cap is configured such that when the ring gear rotates through a reservoir portion of the axle housing during use, lubricating fluid is at least partially guided through the second hole of the bearing end cap toward the inter-axle differential unit.

6. The axle assembly according to claim 4 or 5, wherein, The inter-bridge differential unit compartment includes an opening portion, wherein the bearing end cap is arranged adjacent to the opening portion of the inter-bridge differential unit compartment.

7. The axle assembly according to claim 6, wherein, The inter-bridge differential unit compartment includes an output shaft bearing support portion adjacent to the port portion.

8. The axle assembly according to claim 7, wherein, The second hole of the bearing end cap extends from the first surface of the bearing end cap to the second surface of the bearing end cap, wherein the second surface is located adjacent to the opening portion of the inter-bridge differential unit.

9. The axle assembly according to claim 8, wherein, The second hole defines a first cross-sectional profile that increases from the first surface of the bearing end cap to the second surface of the bearing end cap.

10. The axle assembly according to claim 9, wherein, The opening portion of the inter-bridge differential unit compartment defines a second cross-sectional profile that increases from a first end of the opening portion adjacent to the bearing end cap to a second end of the opening portion adjacent to the output shaft bearing support portion of the inter-bridge differential unit compartment.

11. The axle assembly according to claim 10, wherein, The second cross-sectional profile extends from the first cross-sectional profile, and the first and second cross-sectional profiles increase at a substantially linear rate, such that the guide device tapers radially outward from the first face of the bearing end cap to the second end of the mouth portion.

12. The axle assembly according to any one of claims 1 to 11, wherein, The inter-bridge differential unit includes: An input shaft-side gear, which is capable of rotating together with the input shaft around the axis of the inter-bridge differential unit; An output shaft-side gear, which is capable of rotating together with the output shaft around the axis of the inter-bridge differential unit; A cross shaft, which is capable of rotating together with the input shaft around the axis of the inter-bridge differential unit; Planetary gears, rotatably mounted on the cross shaft, and meshing with the input shaft-side gear and the output shaft-side gear; A housing, the housing at least surrounding the planetary gear and the cross shaft, the housing having a first end and a second end; and An output shaft bearing, wherein the output shaft bearing is disposed on the output shaft side gear adjacent to the second end of the housing. The housing has an opening at a second end of the housing, the opening being configured to receive lubricating fluid passing through the output shaft bearing, optionally wherein the diameter of the opening at the second end of the housing is larger than the outer diameter of the output shaft bearing.

13. The axle assembly according to claim 12, wherein, The housing includes a lip portion at the second end of the housing, the lip portion extending axially in the direction of the output shaft bearing.

14. The axle assembly according to claim 12 or 13, wherein, The output shaft-side gear includes multiple lubricant channels for lubricating fluid.

15. The axle assembly according to claim 14, wherein, The lubricant channels are distributed circumferentially around the output shaft-side gear, and optionally, the lubricant channels extend radially from the outer circumference of the output shaft-side gear.

Images