Drive axle assembly

Abstract

The present disclosure relates to a drive axle assembly capable of reducing drag torque by eliminating an inner bearing seal from a wheel bearing and capable of reducing generation of friction noise at a corrugation of a shield. The drive axle assembly includes a wheel bearing assembled with a wheel housing, an outer ring having an annular shape and including an outer diameter portion fixed to an outer wheel of the wheel bearing, a shield including a large diameter portion formed at one end of the shield and assembled with an inner diameter portion of the outer ring, and a bearing seal unit provided between a small diameter portion formed at the other end of the shield and a drive shaft to restrict rotation of the shield and prevent introduction of foreign substances.

Description

Technical Field

[0001] This disclosure relates to a drive axle assembly that can reduce drag torque and thus improve vehicle fuel efficiency by eliminating inner bearing seals from wheel bearings, and can also reduce the generation of frictional noise at the corrugations of the shroud. Background Technology

[0002] The integrated drive axle (IDA) is configured such that the outer ring of the drive shaft is integrated with the wheel hub of the wheel bearing.

[0003] Because the functions of the wheel bearing and the drive shaft are integrated, the product's weight and manufacturing cost are reduced. Additionally, the distance between the wheel center and the joint center is reduced, thus increasing the drive shaft's hinge angle. Furthermore, the wheel bearing's pitch circle diameter (PCD) is increased, thereby increasing the vehicle's lateral stiffness.

[0004] However, increasing the size of the wheel bearing will increase the drag torque of the wheel bearing, resulting in a decrease in the vehicle's fuel efficiency.

[0005] As a countermeasure, the structure of the inner bearing seal used to ensure the sealing condition of the wheel bearing can be changed in order to reduce the drag torque of the wheel bearing.

[0006] However, because the inner bearing seal, which is tightly inserted between the outer and inner wheels of the wheel bearing, is exposed to the outside of the shroud, the sealing capacity of the inner bearing seal needs to be maintained at a predetermined level or higher to prevent foreign objects from entering the wheel bearing.

[0007] However, the drag torque increases proportionally to the sealing capacity of the inner bearing seal. Therefore, there are limitations on the extent to which the drag torque can be reduced.

[0008] That is, since the inner bearing seal is inserted between the inner and outer wheels, the circumferential length of the inner bearing seal is relatively long. Therefore, due to the sealing effect of the inner bearing seal, the drag torque increases.

[0009] Furthermore, because the shield rotates together with the constant velocity joint, the corrugations of the shield repeatedly fold and unfold in the circumferential direction when the vehicle makes a full turn. During this process, due to contact with moisture, dirt, de-icing agents, etc., repeatedly adhere to and separate from the corrugations of the shield, thus generating friction noise.

[0010] The information disclosed in the Background section of this disclosure is intended only to enhance the understanding of the general background of this disclosure and should not be construed as confirmation of related technologies known to those skilled in the art or as any form of advice. Summary of the Invention

[0011] Therefore, this disclosure is made in view of the above-mentioned problems, and this disclosure provides a drive axle assembly that can reduce drag torque and thus improve the fuel efficiency of the vehicle by eliminating the inner bearing seal from the wheel bearing.

[0012] This disclosure also provides a drive axle assembly that can reduce the generation of frictional noise at the corrugations of the housing.

[0013] According to this disclosure, the above and other objectives can be achieved by providing a drive axle assembly comprising: a wheel bearing assembled with a wheel housing; an outer ring having an annular shape and including an outer diameter portion of the outer wheel fixed to the wheel bearing; a shroud including a large diameter portion formed at one end of the shroud and assembled with an inner diameter portion of the outer ring; and a bearing sealing unit disposed between a small diameter portion formed at the other end of the shroud and the drive shaft to restrict rotation of the shroud and prevent the introduction of foreign matter.

[0014] The outer ring can directly face the balls disposed in the wheel bearing through the space between the outer and inner rings of the wheel bearing.

[0015] The outer ring may be equipped with an ABS sensor.

[0016] The bearing sealing unit may include: a shaft bearing disposed between the small-diameter portion of the shroud and the drive shaft to surround a portion of the drive shaft; and a shaft seal disposed between the shaft bearing and the distal end of the small-diameter portion of the shroud.

[0017] The drive axle assembly may further include a bearing housing press-fitted into the housing to contact the inner circumferential surface of the small-diameter portion of the housing and surround the shaft bearing and the shaft seal. The bearing housing may have a stepped portion formed on the inner surface of the bearing housing to form a boundary between the shaft bearing and the shaft seal.

[0018] The shield may have a housing support portion extending radially inward from the distal end of the small-diameter portion of the shield. The bearing housing may have a sealing support portion extending radially inward from the end of the bearing housing facing the housing support portion. The sealing support portion may be supported by the inner surface of the housing support portion.

[0019] The bearing housing may have a labyrinth-forming portion that extends in a stepped manner toward the housing support portion along the inner circumferential surface of the sealing support portion. The shield may have a foreign object blocking portion that extends radially in a stepped manner along the inner circumferential surface of the housing support portion to cover the labyrinth-forming portion.

[0020] The drive axle assembly may further include a reinforcing ring connected to the outer diameter portion of the outer ring. The reinforcing ring may be inserted into the wheel bearing such that the outer peripheral surface of the reinforcing ring contacts the inner peripheral surface of the outer wheel of the wheel bearing.

[0021] The reinforcing ring and the outer wheel of the wheel bearing corresponding to the reinforcing ring can be connected to each other in a groove-protrusion connection manner.

[0022] The drive axle assembly may further include an O-ring inserted between the reinforcing ring and the outer wheel of the wheel bearing corresponding to the reinforcing ring.

[0023] The outer wheel can be partially inserted into the outer ring, such that the outer peripheral surface of the outer wheel contacts the inner peripheral surface of the outer ring.

[0024] The outer wheel may have a stepped insertion portion that extends in a stepped manner from the end of the outer peripheral surface of the outer wheel to have a reduced outer diameter. The stepped insertion portion may be press-fitted into the outer ring such that the outer peripheral surface of the stepped insertion portion contacts the inner peripheral surface of the outer ring.

[0025] The outer wheel may have a stepped insertion portion extending in a stepped manner from the end of the outer peripheral surface of the outer wheel to have a reduced outer diameter, and the outer ring may have a stepped insertion groove formed in the outer diameter portion of the outer ring to correspond to the stepped insertion portion. The stepped insertion portion may be press-fitted into the stepped insertion groove.

[0026] The large-diameter portion of the shield can surround the inner-diameter portion of the outer ring, such that a gap smaller than a predetermined value is formed between the large-diameter portion of the shield and the wheel housing. The outer ring may have a protruding portion formed on the inner surface of the outer ring facing the wheel bearing, such that a gap smaller than a predetermined value is formed between the protruding portion and the inner surface of the wheel bearing.

[0027] The ratio of the axial length of the bearing housing excluding the labyrinth-forming portion to the length from the inner surface of the bearing housing facing the shaft seal to the distal end of the shaft bearing can be expressed as follows:

[0028] 1.1≤b / C≤1.4

[0029] Wherein, "b" represents the axial length of the bearing housing excluding the labyrinth-forming portion, and "C" represents the length from the inner surface of the bearing housing facing the shaft seal to the distal end of the shaft bearing.

[0030] The ratio of the outer diameter of the portion of the drive shaft and the bearing sealing unit assembled together to the outer diameter of the spline portion at the distal end of the drive shaft can be expressed as follows:

[0031] 1.03≤d2 / d1≤1.16

[0032] Wherein, "d2" represents the outer diameter of the portion of the drive shaft and the bearing sealing unit assembled together, and "d1" represents the outer diameter of the spline portion at the distal end of the drive shaft.

[0033] The ratio of the inner diameter of the distal end of the small-diameter portion of the shield to the outer diameter of the portion of the drive shaft and the bearing sealing unit assembled together can be expressed as follows:

[0034] 0.9≤D² / d²≤1

[0035] Wherein, "D2" represents the inner diameter of the distal end of the small-diameter portion of the shield, and "d2" represents the outer diameter of the portion of the drive shaft assembled with the bearing sealing unit.

[0036] The ratio of the length from the center of the groove formed in the wheel housing to the center of the shaft bearing to the outer diameter of the portion of the wheel housing and the inner wheel of the wheel bearing assembled together can be expressed as follows:

[0037] 0.56≤L / D1≤0.73

[0038] Wherein, "L" represents the length from the center of the groove formed in the wheel housing to the center of the shaft bearing, and "D1" represents the outer diameter of the portion of the wheel housing and the inner wheel of the wheel bearing assembled together. Attached Figure Description

[0039] The above and other objects, features and advantages of this disclosure will become clearer from the following detailed description taken in conjunction with the accompanying drawings, in which:

[0040] Figure 1 This is a cross-sectional view showing the drive axle assembly according to this disclosure;

[0041] Figure 2 yes Figure 1 An enlarged view of part A in the image;

[0042] Figure 3 This is a cross-sectional view of the bearing housing according to this disclosure;

[0043] Figure 4 and Figure 5 This is a view showing the structure of the outer ring of the outer wheel connected to the inner circumferential surface of the wheel bearing according to the present disclosure;

[0044] Figure 6 and Figure 7 This is a view showing the structure of an O-ring inserted between the outer wheel and the outer ring of a wheel bearing according to the present disclosure;

[0045] Figure 8 and Figure 9 This is a view showing the structure of the outer ring of the outer wheel connected to the outer peripheral surface of the wheel bearing according to the present disclosure;

[0046] Figure 10 yes Figure 1 An enlarged view of part B in the image; and

[0047] Figure 11A This is a view used to illustrate the numerical relationships between the main components of the drive axle assembly according to this disclosure, and Figure 11B It is used for explanation Figure 11A An enlarged view of the right side of the drive axle assembly shown. Detailed Implementation

[0048] Various exemplary embodiments will now be described more fully with reference to the accompanying drawings, in which only a few exemplary embodiments are shown. The specific structural and functional details disclosed herein are representative only for the purpose of describing exemplary embodiments. However, this disclosure may be implemented in many alternative forms and should not be construed as limited to the exemplary embodiments set forth herein.

[0049] Therefore, while various modifications and alternative forms are possible with respect to the exemplary embodiments of this disclosure, these embodiments are illustrated by way of example in the accompanying drawings and will be described in detail herein. However, it should be understood that this disclosure is not intended to be limited to the specific exemplary embodiments disclosed. Rather, the exemplary embodiments will cover all modifications, equivalents, and substitutions falling within the scope of this disclosure.

[0050] It should be understood that although the terms “first,” “second,” etc., may be used herein to describe various elements, these elements should not be limited by these terms. These terms are used only to distinguish one element from another. For example, without departing from the scope of exemplary embodiments of this disclosure, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element.

[0051] It should be understood that when an element is referred to as "connected" or "linked" to another element, it can be directly connected or linked to the other element, or there may be intermediate elements. Conversely, when an element is referred to as "directly connected" or "directly linked" to another element, there are no intermediate elements. Other terms used to describe the relationship between elements should be interpreted in a similar manner (e.g., "between" to "directly between," "adjacent" to "directly adjacent," etc.).

[0052] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments of this disclosure. As used herein, the singular forms “a,” “an,” and “the” are also intended to include the plural forms unless the context clearly indicates otherwise. It will also be understood that the terms “comprising,” “including,” “containing,” and / or “containing” as used herein specify the presence of the stated feature, integer, step, operation, element, component, or combination thereof, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

[0053] Unless otherwise defined, all terms used herein, including technical or scientific terms, shall have the same meaning as those commonly understood by one of ordinary skill in the art. Terms (e.g., those defined in common dictionaries) shall be interpreted as having the same meaning as the terms in the context of the relevant art and shall not be interpreted as having an ideal or overly formal meaning unless expressly defined in the specification.

[0054] In the following, exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0055] Figure 1 This is a cross-sectional view showing the drive axle assembly according to this disclosure.

[0056] Referring to the accompanying drawings, the drive axle assembly of this disclosure is an integrated drive axle (IDA), wherein the outer wheel 210 of the wheel bearing 200 is fixed to the steering knuckle or bracket, wherein the balls (or rollers) 230 and the cage are assembled and integrated with each other between the outer wheel 210 and the inner wheel 220 of the wheel bearing 200, and wherein the wheel bearing 200 is mounted on the outer peripheral surface of the wheel housing 100.

[0057] A track forming process is performed on the distal portion of the wheel housing 100, causing the distal portion of the wheel housing 100 to bend radially outward, and the wheel bearing 200 is preloaded, so that the inner wheel 220 is fixed to the wheel housing 100.

[0058] The drive shaft 500 is connected to the interior of the wheel housing 100 via a constant velocity joint. Therefore, the driving force of the powertrain is transmitted to the constant velocity joint through the drive shaft 500, and the constant velocity joint moves and hinges according to the behavior of the vehicle, thereby rotating the wheel housing 100.

[0059] The protective cover assembly, including the cover 400, is disposed between the outer wheel 210 of the wheel bearing 200 and the drive shaft 500, and is assembled with the outer wheel 210 and the drive shaft 500 in a state of restricted rotation.

[0060] See Figure 1 and Figure 2 The present disclosure includes: a wheel bearing 200 assembled with a wheel housing 100; an outer ring 300 having an annular shape and including an outer diameter portion 300a of an outer wheel 210 fixed to the wheel bearing 200; a shroud 400 including a large diameter portion 400a formed at one end of the shroud 400 and assembled with an inner diameter portion 300b of the outer ring 300; and a bearing sealing unit disposed between a small diameter portion 400b formed at the other end of the shroud 400 and a drive shaft 500 to restrict rotation of the shroud 400 and prevent the introduction of foreign matter.

[0061] In one example, an outer ring 300 made of plastic material is fixed to the large diameter portion 400a of the cover 400 and connected to the outer wheel 210 of the wheel bearing 200.

[0062] The bearing sealing unit is disposed between and assembled with the small-diameter portion 400b of the shroud 400 and the drive shaft 500 to surround a portion of the drive shaft 500, thereby allowing the drive shaft 500 to rotate relative to the shroud 400 and restricting the rotation of the shroud 400.

[0063] As described above, since the area between the outer wheel 210 and the inner wheel 220 of the wheel bearing 200 is covered by the outer ring 300, foreign objects are prevented from being introduced into the wheel bearing 200. Therefore, the conventional inner bearing seal is eliminated, which allows for a reduction in drag torque, thereby improving the vehicle's fuel efficiency.

[0064] Furthermore, since the shield 400 is prevented from rotating even when the constant velocity joint rotates, the corrugations of the shield 400 will not repeatedly fold and unfold in the circumferential direction when the vehicle is making full turns or driving in any of the other driving modes. Therefore, friction noise caused by repeated contact and separation between the corrugations of the shield can be prevented when the vehicle is in motion.

[0065] like Figure 2 As shown, the outer ring 300 can directly face the balls 230 disposed in the wheel bearing 200 through the space between the outer wheel 210 and the inner wheel 220 of the wheel bearing 200.

[0066] That is, the outer ring 300 is connected to the outer wheel 210 of the wheel bearing 200, and thus blocks the space between the outer wheel 210 and the inner wheel 220 of the wheel bearing 200, thereby preventing foreign objects from entering the wheel bearing 200.

[0067] As described above, the conventional inner bearing seal is eliminated from the wheel bearing, and the outer ring 300 is arranged to face the balls 230 disposed in the wheel bearing 200. Therefore, it is possible to prevent the drag torque from increasing due to the inner bearing seal.

[0068] In addition, an ABS sensor 320 is provided on the outer ring 300.

[0069] In one example, the ABS sensor 320 is mounted in the outer ring 300 adjacent to the wheel bearing 200 to detect wheel speed.

[0070] Still refer to Figure 2 The bearing sealing unit includes a shaft bearing 600 and a shaft seal 700.

[0071] In detail, the bearing sealing unit includes: a shaft bearing 600 surrounding a portion of a drive shaft 500 and disposed between a small-diameter portion 400b of a shroud 400 and the drive shaft 500 for assembly therewith; and a shaft seal 700 disposed between the shaft bearing 600 and the distal end of the small-diameter portion 400b of the shroud 400 for assembly therewith.

[0072] The shaft bearing 600 can be, for example, a ball bearing or a needle bearing. The inner wheel of the shaft bearing 600 is supported by the drive shaft 500, and the outer wheel of the shaft bearing 600 is supported by the small-diameter portion 400b of the protective cover 400.

[0073] Because the shaft seal 700 is installed inside the distal end of the small-diameter portion 400b of the shroud 400 to surround a portion of the drive shaft 500, foreign matter is prevented from being introduced into the shaft bearing 600 and the shroud 400.

[0074] Although the shaft seal 700 affects the drag torque, due to its positional characteristics on the drive shaft 500, the shaft seal 700 has a very short circumferential length compared to a conventional internal bearing seal mounted on the wheel bearing 200. Therefore, the drag torque is reduced compared to the case where an internal bearing seal is used, thereby improving the vehicle's fuel efficiency.

[0075] Figure 3 This is a cross-sectional view of the bearing housing 800 according to this disclosure.

[0076] Referring to the accompanying drawings, the bearing housing 800 can be press-fitted into the housing 400 to contact the inner circumferential surface of the small diameter portion 400b of the housing 400 and surround the shaft bearing 600 and the shaft seal 700, and the bearing housing 800 can have a stepped portion 820 formed on the inner surface of the bearing housing 800 to form the boundary between the shaft bearing 600 and the shaft seal 700.

[0077] In one example, the shaft bearing 600 is disposed on the inner surface of the bearing housing 800 adjacent to the large diameter portion 400a of the shroud 400 relative to the stepped portion 820, and the shaft seal 700 is disposed on the inner surface of the bearing housing 800 adjacent to the small diameter portion 400b of the shroud 400 relative to the stepped portion 820.

[0078] That is, due to the stepped portion 820 formed in the middle of the inner surface of the bearing housing 800, the shaft bearing 600 and the shaft seal 700 can be securely and stably installed in the bearing housing 800.

[0079] In one example, the shaft bearing 600 and the shaft seal 700 can be press-fitted into the bearing housing 800, and the bearing housing 800 can be integrated with the shield 400.

[0080] In addition, refer to Figure 2 and Figure 3 The shroud 400 includes a housing support portion 410 that extends radially inward from the distal end of the small-diameter portion 400b of the shroud 400, and the bearing housing 800 includes a sealing support portion 810 that extends radially inward from the end of the bearing housing 800 facing the housing support portion 410. The sealing support portion 810 is supported by the inner surface of the housing support portion 410.

[0081] In other words, the sealing support portion 810 is in close contact with the inner surface of the housing support portion 410, thereby preventing external foreign objects from entering the housing 400 through the gap between the small diameter portion 400b of the housing 400 and the bearing housing 800.

[0082] In addition, the bearing housing 800 includes a labyrinth-forming portion 812 that extends in a stepped manner toward the housing support portion 410 along the inner peripheral surface of the sealing support portion 810, and the shield 400 includes a foreign object blocking portion 412 that extends radially inward in a stepped manner along the inner peripheral surface of the housing support portion 410 to cover the labyrinth-forming portion 812.

[0083] In one example, the foreign object blocking portion 412 extends radially inward toward the drive shaft 500 and covers the labyrinth-forming portion 812 in the axial direction.

[0084] Therefore, even if a foreign object is introduced into the space between the foreign object blocking portion 412 and the drive shaft 500, the foreign object is prevented from entering the area between the housing support portion 410 and the sealing support portion 810 because the labyrinth forming portion 812 is in close contact with the inner surface of the foreign object blocking portion 412.

[0085] Therefore, it prevents external foreign objects from entering the shield 400 through the gap between the small-diameter portion 400b of the shield 400 and the bearing housing 800. In addition, the shaft seal 700 reliably prevents foreign objects from being introduced into the shield 400.

[0086] In addition, this disclosure also includes a reinforcing ring 310, which is connected to the outer diameter portion 300a of the outer ring 300.

[0087] The reinforcing ring 310 can be inserted into the wheel bearing 200, so that the outer peripheral surface of the reinforcing ring 310 contacts the inner peripheral surface of the outer wheel 210 of the wheel bearing 200.

[0088] In one example, the reinforcing ring 310 may be made of steel and may be integrally formed with the outer ring 300. The protective cover 400 may be integrally manufactured with the bearing housing 800 and the outer ring 300, and the ABS sensor 320 may be integrally formed with the outer ring 300.

[0089] Figure 4 and Figure 5 This is a view showing the structure of the outer ring 300 connected to the inner circumferential surface of the outer wheel 210 of the wheel bearing 200 according to the present disclosure. The reinforcing ring 310 and the outer wheel 210 of the wheel bearing 200 corresponding to the reinforcing ring 310 can be connected to each other in a groove-protrusion connection manner.

[0090] In one example, see Figure 4 The reinforcing ring 310 has an assembly groove 312 formed in the outer peripheral surface of the reinforcing ring 310 in the circumferential direction, and the outer wheel 210 of the wheel bearing 200 has an assembly protrusion 212 formed in the inner peripheral surface of the outer wheel 210 in the circumferential direction to correspond to the assembly groove 312. The assembly protrusion 212 is fitted into the assembly groove 312.

[0091] In another example, see Figure 5 The reinforcing ring 310 has an assembly protrusion 314 formed in the circumferential direction on the outer peripheral surface of the reinforcing ring 310, and the outer wheel 210 of the wheel bearing 200 has an assembly groove 214 formed in the circumferential direction on the inner peripheral surface of the outer wheel 210 so as to correspond to the assembly protrusion 314. The assembly protrusion 314 is fitted into the assembly groove 214.

[0092] Therefore, the reinforcing ring 310 is firmly assembled with the outer wheel 210 of the wheel bearing 200, thereby preventing the guard 400 from separating from the outer wheel 210 of the wheel bearing 200.

[0093] Furthermore, the distal end of the inner circumferential surface of the outer wheel 210 of the wheel bearing 200 is formed at an angle, so that the assembly protrusion 314 formed on the reinforcing ring 310 can be easily assembled into the assembly groove 214 formed in the outer wheel 210.

[0094] Figure 6 and Figure 7 This is a view showing the structure of an O-ring O inserted between the outer wheel 210 and the outer ring 300 of a wheel bearing 200 according to the present disclosure. The O-ring O can be inserted between a reinforcing ring 310 and the outer wheel 210 of the wheel bearing 200 corresponding to the reinforcing ring 310.

[0095] In one example, refer to Figure 6 The reinforcing ring 310 may have an annular groove 316 formed in the outer peripheral surface of the reinforcing ring 310 in the circumferential direction, and the O-ring O may be fitted into the annular groove 316.

[0096] See another example. Figure 7 The outer wheel 210 of the wheel bearing 200 may have an annular groove 216 formed in the inner circumferential surface of the outer wheel 210 in the circumferential direction, and the O-ring O may be fitted into the annular groove 216.

[0097] O-rings are used not only to prevent foreign objects from entering the wheel bearing 200, but also to prevent grease from leaking from the wheel bearing 200.

[0098] Figure 8 and Figure 9 This is a view showing the structure of the outer ring 300 connected to the outer peripheral surface of the outer wheel 210 of the wheel bearing 200 according to the present disclosure. A portion of the outer wheel 210 can be inserted into the outer ring 300 such that the outer peripheral surface of the outer wheel 210 contacts the inner peripheral surface of the outer ring 300.

[0099] In one example, see Figure 8 The outer wheel 210 may have a stepped insertion portion 218, which extends in a stepped manner from the end of the outer peripheral surface of the outer wheel 210 to have a reduced outer diameter. The stepped insertion portion 218 may be press-fitted into the outer ring 300 such that the outer peripheral surface of the stepped insertion portion 218 contacts the inner peripheral surface of the outer ring 300.

[0100] That is, the stepped insertion portion 218 can be formed in a stepped shape on the outer peripheral surface of the outer wheel 210 of the wheel bearing 200. The stepped insertion portion 218 can be press-fitted into the outer ring 300 such that the distal end of the stepped insertion portion 218 in the axial direction is in close contact with the inner surface of the outer ring 300, thereby ensuring a seal between the outer wheel 210 and the outer ring 300 and preventing the cover 400 from separating.

[0101] In one example, with the reinforcing ring 310 fixed to the inner circumferential surface of the outer ring 300, the reinforcing ring 310 can be in close contact with the outer circumferential surface of the stepped insertion portion 218.

[0102] In another example, refer to Figure 9 The outer wheel 210 may have a stepped insertion portion 218, which extends in a stepped manner from the end of the outer peripheral surface of the outer wheel 210 to have a reduced outer diameter, and the outer ring 300 may have a stepped insertion groove 308, which is formed in the outer diameter portion 300a of the outer ring 300 to correspond to the stepped insertion portion 218. The stepped insertion portion 218 may be press-fitted into the stepped insertion groove 308.

[0103] That is, the stepped insertion portion 218 can be formed in a stepped shape on the outer peripheral surface of the outer wheel 210 of the wheel bearing 200. The stepped insertion portion 218 can be press-fitted into the stepped insertion groove 308 formed in the outer ring 300, such that the stepped insertion portion 218 is surrounded by the outer ring 300, and the distal end of the stepped insertion portion 218 in the axial direction is in close contact with the end of the inner surface of the stepped insertion groove 308, thereby ensuring a seal between the outer wheel 210 and the outer ring 300 and preventing the cover 400 from separating.

[0104] Figure 10 yes Figure 1 A magnified view of part B in the image.

[0105] Referring to the accompanying drawings, the large-diameter portion 400a of the guard 400 surrounds the inner-diameter portion 300b of the outer ring 300, thereby creating a gap g1 with a size smaller than a predetermined value between the large-diameter portion 400a of the guard 400 and the wheel housing 100. The outer ring 300 may have a protrusion 302 formed on the inner surface of the outer ring 300 facing the wheel bearing 200, thereby creating a gap g2 with a size smaller than a predetermined value between the protrusion 302 and the inner surface of the wheel bearing 200.

[0106] In one example, a small gap may be formed between the inner wheel 220 of the wheel bearing 200 and the inner surface of the outer ring 300 facing the inner wheel 220, and a small gap may be formed between the distal end of the wheel housing 100 that has undergone the track forming process and the large diameter portion 400a of the shield 400 facing the distal end of the wheel housing 100.

[0107] Due to the formation of these two small gaps, a labyrinth structure is formed in the cover 400, thereby preventing the grease used for the constant velocity universal joint in the wheel housing 100 from mixing with the grease used for the bearing in the wheel bearing 200.

[0108] Figure 11A This is a view used to illustrate the numerical relationships between the main components of the drive axle assembly according to this disclosure, and Figure 11B It is used for explanation Figure 11A An enlarged view of the right side of the drive axle assembly.

[0109] See Figure 11B The ratio of the axial length b of the bearing housing 800 excluding the labyrinth-forming portion 812 to the length C from the inner surface of the bearing housing 800 facing the shaft seal 700 to the far end of the shaft bearing 600 can be expressed by the following expression (1).

[0110] 1.1≤b / C≤1.4 (1)

[0111] Here, "b" represents the axial length of the bearing housing excluding the labyrinth-forming portion, and "C" represents the length from the inner surface of the bearing housing facing the shaft seal to the distal end of the shaft bearing.

[0112] Based on the above numerical relationships, the shaft bearing 600 and the shaft seal 700 are stably assembled in the bearing housing 800, which improves the ease of assembly of the bearing sealing unit and ensures its sealing capability.

[0113] See still Figure 11A The ratio of the outer diameter d2 of the part of the drive shaft 500 and the bearing sealing unit assembled together to the outer diameter d1 of the spline part at the far end of the drive shaft 500 can be expressed by the following expression (2).

[0114] 1.03≤d2 / d1≤1.16 (2)

[0115] Here, "d2" represents the outer diameter of the part of the drive shaft and the bearing seal unit assembled together, and "d1" represents the outer diameter of the splined part at the far end of the drive shaft.

[0116] Based on the above numerical relationships, the ease of assembly of the components can be improved, and the vibration of the rotating body, including the drive shaft 500, can be reduced.

[0117] See also Figure 11A and Figure 11B The ratio of the inner diameter D2 of the distal end of the small diameter portion 400b of the shield 400 to the outer diameter d2 of the portion of the drive shaft 500 and the bearing seal unit assembled together can be expressed by the following expression (3).

[0118] 0.9≤D² / d²≤1 (3)

[0119] Here, "D2" represents the inner diameter of the far end of the small-diameter portion of the shield, and "d2" represents the outer diameter of the portion of the drive shaft and bearing seal unit assembled together.

[0120] Based on the above numerical relationship, the foreign object blocking part 412 is formed in the maze forming part 812, thereby realizing the maze structure and preventing foreign objects from being introduced into it.

[0121] See also Figure 11A The ratio of the length L from the center of the groove formed in the wheel housing 100 to the center of the shaft bearing 600 to the outer diameter D1 of the part of the wheel housing 100 and the inner wheel 220 of the wheel bearing 200 assembled together can be expressed by the following expression (4).

[0122] 0.56≤L / D1≤0.73 (4)

[0123] Here, "L" represents the length from the center of the groove formed in the wheel housing to the center of the shaft bearing, and "D1" represents the outer diameter of the portion of the wheel housing and the inner wheel of the wheel bearing assembled together.

[0124] As is apparent from the above description, according to this disclosure, a conventional inner bearing seal that eliminates the gap between the outer wheel 210 and the inner wheel 220 of the sealed wheel bearing 200, and an outer ring 300 that is configured to cover the outer wheel 210, not only prevents the introduction of foreign objects but also reduces the drag torque generated by the seal, thereby improving the fuel efficiency of the vehicle.

[0125] Furthermore, because the shield 400 is prevented from rotating, the corrugations of the shield 400 will not repeatedly fold and unfold in the circumferential direction when the vehicle is making a full turn or driving in any of the other driving modes. Therefore, frictional noise caused by repeated contact and separation between the corrugations of the shield can be prevented during vehicle operation.

[0126] Although specific embodiments of this disclosure have been disclosed for illustrative purposes, those skilled in the art will understand that various modifications, additions, and substitutions are possible without departing from the scope and spirit of this disclosure as disclosed in the appended claims.

Claims

1. A drive axle assembly, the drive axle assembly comprising: A wheel bearing, wherein the wheel bearing and the wheel housing are assembled together; An outer ring having an annular shape and including an outer diameter portion of an outer wheel fixed to the wheel bearing; A protective cover, the protective cover including a large-diameter portion formed at one end of the protective cover and assembled with the inner diameter portion of the outer ring; as well as A bearing sealing unit is disposed between a small-diameter portion formed at the other end of the shield and the drive shaft to restrict the rotation of the shield and prevent the introduction of foreign objects. The outer ring directly faces the balls disposed in the wheel bearing through the space between the outer and inner rings of the wheel bearing.

2. The drive axle assembly according to claim 1, wherein, The outer ring is equipped with an anti-lock braking system sensor.

3. The drive axle assembly according to claim 1, wherein, The bearing sealing unit includes: A shaft bearing, disposed between the small-diameter portion of the shroud and the drive shaft, so as to surround a portion of the drive shaft; and A shaft seal is disposed between the shaft bearing and the distal end of the small-diameter portion of the shroud.

4. The drive axle assembly according to claim 3, further comprising: A bearing housing, which is press-fitted into the housing to contact the inner circumferential surface of the small-diameter portion of the housing and surround the shaft bearing and the shaft seal. The bearing housing has a stepped portion formed on the inner surface of the bearing housing to form the boundary between the shaft bearing and the shaft seal.

5. The drive axle assembly according to claim 4, wherein, The shield has a housing support portion that extends radially inward from the distal end of the small-diameter portion of the shield. The bearing housing includes a sealing support portion that extends radially inward from the end of the bearing housing facing the housing support portion. The sealing support portion is supported by the inner surface of the housing support portion.

6. The drive axle assembly according to claim 5, wherein, The bearing housing has a labyrinth-forming portion that extends in a stepped manner towards the housing support portion along the inner circumferential surface of the sealing support portion, and The shield has a foreign object blocking portion that extends radially inward in a stepped manner along the inner circumferential surface of the housing support portion to cover the labyrinth-forming portion.

7. The drive axle assembly according to claim 1, further comprising: A reinforcing ring, the reinforcing ring being connected to the outer diameter portion of the outer ring, The reinforcing ring is inserted into the wheel bearing such that the outer peripheral surface of the reinforcing ring contacts the inner peripheral surface of the outer wheel of the wheel bearing.

8. The drive axle assembly according to claim 7, wherein, The reinforcing ring and the outer wheel of the wheel bearing corresponding to the reinforcing ring are connected to each other by a groove-protrusion connection.

9. The drive axle assembly of claim 7, further comprising an O-ring inserted between the reinforcing ring and the outer wheel of the wheel bearing corresponding to the reinforcing ring.

10. The drive axle assembly of claim 1, wherein, The outer wheel is partially inserted into the outer ring such that the outer peripheral surface of the outer wheel contacts the inner peripheral surface of the outer ring.

11. The drive axle assembly of claim 10, wherein, The outer wheel has a stepped insertion portion that extends in a stepped manner from the end of the outer peripheral surface of the outer wheel to have a reduced outer diameter. The stepped insertion portion is press-fitted into the outer ring, such that the outer peripheral surface of the stepped insertion portion contacts the inner peripheral surface of the outer ring.

12. The drive axle assembly of claim 10, wherein, The outer wheel has a stepped insertion portion that extends in a stepped manner from the end of the outer peripheral surface of the outer wheel to have a reduced outer diameter. The outer ring has a stepped insertion groove formed in the outer diameter portion of the outer ring to correspond to the stepped insertion portion. The stepped insertion portion is press-fitted into the stepped insertion groove.

13. The drive axle assembly according to claim 1, wherein, The large-diameter portion of the protective cover surrounds the inner-diameter portion of the outer ring, such that a gap smaller than a predetermined value is formed between the large-diameter portion of the protective cover and the wheel housing. The outer ring has a protruding portion formed on the inner surface of the outer ring facing the wheel bearing, such that a gap smaller than a predetermined value is formed between the protruding portion and the inner surface of the wheel bearing.

14. The drive axle assembly of claim 6, wherein, The ratio of the axial length of the bearing housing excluding the labyrinth-forming portion to the length from the inner surface of the bearing housing facing the shaft seal to the distal end of the shaft bearing is expressed as follows: 1.1≤b / C≤1.4 Wherein, "b" represents the axial length of the bearing housing excluding the labyrinth-forming portion, and "C" represents the length from the inner surface of the bearing housing facing the shaft seal to the distal end of the shaft bearing.

15. The drive axle assembly according to claim 1, wherein, The ratio of the outer diameter of the portion of the drive shaft and the bearing sealing unit assembled together to the outer diameter of the spline portion at the distal end of the drive shaft is expressed as follows: 1.03≤d2 / d1≤1.16 Wherein, "d2" represents the outer diameter of the portion of the drive shaft and the bearing sealing unit assembled together, and "d1" represents the outer diameter of the spline portion at the distal end of the drive shaft.

16. The drive axle assembly of claim 1, wherein, The ratio of the inner diameter of the distal end of the small-diameter portion of the shield to the outer diameter of the portion of the drive shaft and the bearing sealing unit assembled together is expressed as follows: 0.9≤D² / d²≤1 Wherein, "D2" represents the inner diameter of the distal end of the small-diameter portion of the shield, and "d2" represents the outer diameter of the portion of the drive shaft and the bearing sealing unit assembled together.

17. The drive axle assembly of claim 3, wherein, The ratio of the length from the center of the groove formed in the wheel housing to the center of the shaft bearing to the outer diameter of the portion of the wheel housing and the inner wheel of the wheel bearing assembled together is expressed as follows: 0.56≤L / D1≤0.73 Wherein, "L" represents the length from the center of the groove formed in the wheel housing to the center of the shaft bearing, and "D1" represents the outer diameter of the portion of the wheel housing and the inner wheel of the wheel bearing assembled together.

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