阅读说明：本技术 用于车辆的驱动轮的轮轴组件 (Axle assembly for a drive wheel of a vehicle ) 是由 柳成树 裵奭镐 金羲日 崔元准 于 2020-11-30 设计创作，主要内容包括：本公开提供一种用于车辆的驱动轮的轮轴组件,在行驶时使车轮侧万向节和轴与保护罩分开旋转,以从根本上防止保护罩的摩擦噪声的产生。该轮轴组件包括：轴,通过从动力系统接收驱动力而旋转；轮轴壳,被设置成穿过连接到转向设备的转向节的中心；车轮轴承,安装在转向节和轮轴壳之间；万向节轴承,安装在轴的外部；以及保护罩单元,保护罩单元的第一端联接到万向节轴承的外环,保护罩单元的第二端联接到车轮轴承的外环,以在轴的外部形成用于填充润滑剂的空间。(The present disclosure provides an axle assembly for a driving wheel of a vehicle, which rotates a wheel-side universal joint and a shaft separately from a protective cover while driving, to fundamentally prevent generation of frictional noise of the protective cover. The axle assembly includes: a shaft that rotates by receiving a driving force from a power system; a wheel axle housing disposed to pass through a center of a knuckle connected to a steering apparatus; a wheel bearing installed between the knuckle and the wheel axle housing; a universal joint bearing installed outside the shaft; and a boot unit, a first end of which is coupled to the outer ring of the universal joint bearing, and a second end of which is coupled to the outer ring of the wheel bearing to form a space for filling with lubricant outside the shaft.)

1. An axle assembly for a drive wheel of a vehicle, comprising:

a shaft that rotates by receiving a driving force from a power system;

a wheel axle housing provided to pass through a center of a knuckle connected to a steering apparatus and coupled to the shaft through a universal joint to rotate integrally with the shaft;

a wheel bearing mounted between the knuckle and the axle housing;

a universal joint bearing installed outside the shaft and spaced apart from the universal joint by a predetermined distance; and

a boot unit having a first end coupled to the outer ring of the universal joint bearing and a second end coupled to the outer ring of the wheel bearing to form a space for filling with lubricant outside the shaft.

2. The axle assembly of claim 1,

the wheel bearing includes:

a wheel bearing outer race coupled to the knuckle;

a wheel bearing inner ring mounted on an outer circumferential portion of the axle housing; and

a plurality of wheel bearing balls rotatably disposed between the wheel bearing outer ring and the wheel bearing inner ring.

3. The axle assembly of claim 2,

a boot unit fixing portion is integrally formed with the wheel bearing outer ring, and a second end of the boot unit is coupled to the boot unit fixing portion.

4. The axle assembly of claim 2,

the universal joint bearing includes:

a gimbal bearing outer ring coupled to a first end of the boot unit;

a gimbal bearing inner ring coupled to an exterior of the shaft; and

a plurality of gimbal bearing balls rotatably disposed between the gimbal bearing outer ring and the gimbal bearing inner ring.

5. The axle assembly of claim 4,

the universal joint includes:

a gimbal inner ring coupled to the shaft to rotate integrally with the shaft; and

a joint outer ring that is formed integrally with the wheel axle housing and rotates integrally with the joint inner ring by a plurality of joint balls that are provided between the joint outer ring and the joint inner ring.

6. The axle assembly of claim 5,

the joint bearing inner ring is coupled to an outside of a joint inner ring extension that is integrally formed with the joint inner ring and provided on an outer circumferential surface of the shaft.

7. The axle assembly of claim 1,

a boot seal is installed between an outer circumferential surface of the axle housing and an inner circumferential surface of the boot unit, and the boot seal is disposed at a position between the wheel bearing and the joint bearing to prevent the lubricant from flowing to a space between the boot seal and the wheel bearing.

8. The axle assembly of claim 4,

the protective cover unit includes:

a first boot member having a first end sealingly coupled to an exterior of the outer ring of the universal joint bearing; and

a second boot member having a first end sealingly coupled to the second end of the first boot member and a second end sealingly coupled to an exterior of the wheel bearing outer ring.

9. The axle assembly of claim 2,

a lock nut is coupled to an outer circumferential portion of the axle housing, and the wheel bearing inner ring is pressed against the engagement protrusion of the axle housing by the lock nut when the wheel bearing inner ring is coupled to the outer circumferential portion of the axle housing.

10. The axle assembly of claim 2,

a molding portion having a curved shape and protruding outward in a radial direction of the axle housing is formed at one end of the axle housing, and when the wheel bearing inner ring is coupled to an outer circumferential portion of the axle housing, the wheel bearing inner ring is pressed against the engagement protrusion of the axle housing by the molding portion.

Technical Field

The present disclosure relates to an axle assembly for a driving wheel of a vehicle, and more particularly, to an axle assembly for a driving wheel that can reduce noise caused by folding of a protection cover of a driving shaft.

Background

Typically, a drive shaft is used to transmit drive force between a powertrain and wheels of a vehicle.

The drive shaft typically comprises two constant velocity joints and one shaft connecting the two constant velocity joints to absorb changes in angle and distance due to the behavior of the suspension system. A boot filled with grease for lubricating parts in a constant velocity joint is mounted on the constant velocity joint.

Fig. 1 (prior art) is a perspective view illustrating a conventional axle assembly for driving wheels using a drive shaft, and fig. 2 (prior art) is a view illustrating a state in which an angle is formed between a joint outer ring of the drive shaft and a shaft of the drive shaft when steering while driving.

As shown in fig. 1, the conventional axle assembly includes: a knuckle 10 connected to a steering apparatus of a vehicle; a hub 30 coupled to the inside of the knuckle 10 by a hub bearing 20; a wheel disc 40 fixed to an outer circumferential surface of the hub 30 by bolts 34; a driving shaft 50 passing through the center of the hub 30 and splined to the inner circumferential surface of the hub 30; and a hub nut 32 configured to fix the drive shaft 50 to the hub 30.

The drive shaft 50 is configured to transmit the driving force of the power system to the drive wheels. In particular, the drive shaft 50 is an assembly that includes a wheel-side universal joint 52, a powertrain-side universal joint 54, a shaft 56, and a boot 58.

Here, the shaft 56 connects the wheel-side universal joint 52 and the powertrain-side universal joint 54. Further, the protective cover 58 is formed as a bellows structure that is deformable under a traveling condition where a large angle is formed between the outer ring 52a of the wheel-side joint 52 and the shaft 56, one end of the protective cover 58 is fixed to the outer ring 52a of the wheel-side joint 52, and the other end of the protective cover 58 is fixed to the shaft 56.

The wheel-side joint 52 is an assembly including an outer ring 52a, an inner ring 52b, balls 52c, and a cage.

The outer ring 52a is connected to the inner ring 52b through the balls 52c, thus receiving rotational force from the inner ring 52b, and the inner ring 52b is coupled to the shaft 56, thus rotating integrally with the shaft 56, thus receiving driving force (rotational force) from the power system. Further, the outer ring 52a has a shaft-type hub coupling portion 52 a' passing through the center of the hub 30 and splined to the inner circumferential surface of the hub 30.

Therefore, when steering while traveling, the wheel hub 30 and the outer ring 52a of the wheel side joint 52 move integrally in correspondence to the movement of the knuckle 10, and therefore, an angle is formed between the outer ring 52a of the wheel side joint 52 and the shaft 56 under the condition that the outer ring 52a of the wheel side joint 52 and the shaft 56 rotate. Here, the boot 58 rotates integrally with the outer ring 52a of the wheel-side joint 52 and the shaft 56.

When an angle is generated between the outer ring 52a of the wheel-side joint 52 and the shaft 56, peaks (between valleys) of the boot 58 are brought into contact with each other due to the characteristics of the bellows structure of the boot 58, and the lubricant on the surface of the boot 58 causes smooth sliding between the peaks of the boot 58, so that generation of noise caused by friction between the peaks of the boot 58 can be prevented.

However, when the lubricant on the surface of the boot 58 is removed or the lubricant does not work due to foreign matter (e.g., mud, moisture, a deicing agent, etc.) during driving, the boot 58 is stuck, and therefore stick-slip noise is generated due to relative movement on the contact surface between peaks of the boot 58.

That is, if the lubricant on the surface of the boot 58 is removed or the lubricant does not function, frictional noise due to folding of the boot 58 may occur when turning during running.

The above information disclosed in this background section is only for enhancement of understanding of the background of the disclosure and therefore may contain information that does not form the prior art that is already known to a person of ordinary skill in the art.

Disclosure of Invention

The present disclosure provides an axle assembly for a driving wheel of a vehicle, which rotates a wheel-side universal joint and a shaft separately from a protective cover while driving, to fundamentally prevent generation of frictional noise of the protective cover.

In one aspect, the present disclosure provides an axle assembly for a drive wheel of a vehicle, the axle assembly comprising: a shaft that rotates by receiving a driving force from a power system; a wheel axle housing provided to pass through a center of a knuckle connected to a steering apparatus and coupled to a shaft through a universal joint to rotate integrally with the shaft; a wheel bearing installed between the knuckle and the wheel axle housing; a universal joint bearing installed outside the shaft and spaced apart from the universal joint by a predetermined distance; and a boot unit, a first end of which is coupled to the outer ring of the universal joint bearing, and a second end of which is coupled to the outer ring of the wheel bearing to form a space for filling with lubricant outside the shaft.

In a preferred embodiment, the wheel bearing may comprise: a wheel bearing outer race coupled to the knuckle; a wheel bearing inner ring installed on an outer circumferential portion of the axle housing; and a plurality of wheel bearing balls rotatably disposed between the wheel bearing outer ring and the wheel bearing inner ring.

In another preferred embodiment, the boot unit fixing portion may be integrally formed with the wheel bearing outer ring, and the second end of the boot unit may be coupled to the boot unit fixing portion.

In another preferred embodiment, the universal joint bearing may include: a universal joint bearing outer ring coupled to a first end of the boot unit; a gimbal bearing inner ring coupled to an exterior of the shaft; and a plurality of gimbal bearing balls rotatably disposed between the gimbal bearing outer ring and the gimbal bearing inner ring.

In another preferred embodiment, the universal joint may comprise: a gimbal inner ring coupled to the shaft to rotate integrally with the shaft; and a joint outer ring that is formed integrally with the wheel axle housing and rotates integrally with the joint inner ring through a plurality of joint balls provided between the joint outer ring and the joint inner ring.

In another preferred embodiment, the joint bearing inner ring may be coupled to an outer portion of the joint inner ring extension integrally formed with the joint inner ring and disposed on an outer circumferential surface of the shaft.

In a further preferred embodiment, a boot seal may be installed between an outer circumferential surface of the wheel shaft housing and an inner circumferential surface of the boot unit, and the boot seal may be disposed at a position between the wheel bearing and the joint bearing to prevent lubricant from flowing to a space between the boot seal and the wheel bearing.

In another further preferred embodiment, the protective cover unit may include: a first boot member having a first end sealingly coupled to an exterior of the outer race of the universal joint bearing; and a second boot member having a first end sealingly coupled to the second end of the first boot member and a second end sealingly coupled to an exterior of the wheel bearing outer race.

In another further preferred embodiment, a lock nut may be coupled to an outer circumferential portion of the axle housing, and the wheel bearing inner ring may be pressed against the engagement protrusion of the axle housing by the lock nut to support the wheel bearing inner ring when the wheel bearing inner ring is coupled to the outer circumferential surface of the axle housing.

In another further preferred embodiment, a molding having a curved shape and protruding outward in a radial direction of the axle housing may be formed at one end of the axle housing, and when the wheel bearing inner ring is coupled to the outer circumferential portion of the axle housing, the wheel bearing inner ring may be pressed against the engagement protrusion of the axle housing by the molding to support the wheel bearing inner ring.

Other aspects and preferred embodiments of the disclosure are described below.

Drawings

The above and other features of the present disclosure will now be described in detail with reference to a few exemplary embodiments thereof, which are given below by way of illustration only, and thus do not limit the present disclosure, as shown in the accompanying drawings, wherein:

FIG. 1 (Prior Art) is a view showing a conventional axle assembly for a drive wheel using a drive shaft;

fig. 2 (prior art) is a view showing a state where an angle is formed between a joint outer ring of a drive shaft and a shaft of the drive shaft when steering while traveling;

FIG. 3 is a perspective view of an axle assembly for a drive wheel according to one embodiment of the present disclosure;

FIGS. 4 and 5 are cross-sectional views illustrating some elements of an axle assembly according to one embodiment of the present disclosure;

fig. 6 is a view showing a structure for fixing a wheel bearing according to another embodiment of the present disclosure;

fig. 7 is a view illustrating a structure for preventing a lock nut from loosening according to one embodiment of the present disclosure; and

fig. 8 is a view illustrating a state in which the axle housing rotates independently of the protection cover unit when the shaft of the axle assembly according to one embodiment of the present disclosure rotates.

It should be understood that the drawings are not necessarily to scale, showing a somewhat simplified representation of various preferred features illustrative of the basic principles of the disclosure. The specific design features of the present disclosure, including, for example, specific dimensions, orientations, locations, and shapes, disclosed herein will be determined in part by the particular intended application and use environment.

In the drawings, like or equivalent elements of the present disclosure are referred to by reference numerals throughout the several views of the drawings.

Detailed Description

It is understood that the term "vehicle" or "vehicular" or other similar terms as used herein generally includes motor vehicles, e.g., passenger vehicles including Sport Utility Vehicles (SUVs), buses, trucks, various commercial vehicles, watercraft including various boats and ships, aircraft, and the like, and includes hybrid vehicles, electric vehicles, plug-in hybrid vehicles, hydrogen-powered vehicles, and other alternative fuel (e.g., resource-derived fuels other than petroleum) vehicles. As referred to herein, a hybrid vehicle is a vehicle having two or more power sources, such as a gasoline and electric hybrid vehicle.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items. Throughout this specification, unless explicitly stated to the contrary, the word "comprise", and variations such as "comprises" or "comprising", will be understood to imply the inclusion of stated elements but not the exclusion of any other elements. In addition, the terms "unit", "device", "means", and "module" described in this specification mean a unit for processing at least one function or operation, and may be implemented by hardware components or software components, and a combination thereof.

Further, the control logic of the present disclosure may be embodied as a non-transitory computer readable medium on a computer readable medium containing executable program instructions executed by a processor, controller, or the like. Examples of computer readable media include, but are not limited to, ROM, RAM, Compact Disc (CD) -ROM, magnetic tape, floppy disk, flash drive, smart card, and optical data storage. The computer readable medium CAN also be distributed in a networked computer system so that the computer readable medium is stored and executed in a distributed fashion, for example, by a telematics server or a Controller Area Network (CAN).

Reference will now be made in detail to the various embodiments of the disclosure, examples of which are illustrated in the accompanying drawings and described below. While the disclosure will be described in conjunction with exemplary embodiments, it will be understood that the description is not intended to limit the disclosure to exemplary embodiments. On the contrary, the present disclosure is intended to cover not only exemplary embodiments, but also various alternatives, modifications, equivalents, and other embodiments that may be included within the spirit and scope of the present disclosure as defined by the appended claims.

Fig. 3 is a perspective view of an axle assembly for a drive wheel according to one embodiment of the present disclosure, and fig. 4 and 5 are cross-sectional views illustrating some elements of the axle assembly according to one embodiment of the present disclosure.

As shown in fig. 3 to 5, the axle assembly according to the present disclosure includes an axle 110, an axle housing 120, a wheel bearing 150, a universal joint bearing 160, and a protective cover unit 170.

The shaft 110 serves to receive a driving force from a powertrain (not shown) of the vehicle and transmit the driving force to driving wheels, and the shaft 110 receives the driving force generated by the powertrain through a powertrain-side universal joint 140 coupled to a first end of the shaft 110 in an axial direction of the shaft 110 and transmits the driving force of the powertrain to the driving wheels through a wheel-side universal joint 130 coupled to a second end of the shaft 110.

The shaft 110, the wheel-side universal joint 130, and the power system-side universal joint 140 may serve as a universal drive shaft. Here, the wheel-side joint 130 may be a constant velocity joint. Specifically, the wheel-side universal joint 130 connects the axle housing 120 and the shaft 110 so that the axle housing 120 and the shaft 110 can be integrally rotated.

The wheel axle housing 120 is provided to pass through the center of a knuckle 200 connected to a steering apparatus (not shown) of the vehicle, and is coupled to the shaft 110 through a wheel-side universal joint 130 to rotate integrally with the shaft 110.

Specifically, the axle housing 120 includes: a joint outer ring 132 serving as an outer ring of the wheel-side joint 130; and a hub 122, the disk 190 being coupled to the hub 122 by bolts.

In particular, the axle housing 120 has a structure in which the gimbal outer ring 132 and the hub 122 are integrated. Thus, the axle housing 120 can serve as both a universal hub and a gimbal outer ring 132.

Hub 122 is the part to which wheel disc 190 and a wheel (not shown) are mounted. The disc 190 is coupled to the hub 122, and thus may be disposed at an outer circumferential portion of the axle housing 120 and integrally rotate with the axle housing 120.

The axle housing 120 is coupled to the knuckle 200 by a wheel bearing 150.

The wheel bearing 150 is installed between the knuckle 200 and the axle housing 120, and serves to support the axle housing 120 passing through the center of the knuckle 200 such that the axle housing 120 can rotate independently of the knuckle 200.

In particular, the wheel bearing 150 may include a wheel bearing outer ring 152, a wheel bearing inner ring 154, and a plurality of wheel bearing balls 156.

The wheel bearing outer ring 152 is coupled to one side of the knuckle 200 using bolts, and here, a portion of the wheel bearing outer ring 152 may be press-fitted into the knuckle 200. In particular, the wheel bearing outer ring 152 may have a knuckle coupling portion 152b coupled to the knuckle 200, and the knuckle coupling portion 152b may protrude from the outside of the wheel bearing outer ring 152 in the radial direction of the wheel bearing outer ring 152.

A wheel bearing inner ring 154 is mounted on an outer circumferential portion of the axle housing 120, and wheel bearing balls 156 are rotatably disposed between the wheel bearing outer ring 152 and the wheel bearing inner ring 154. Thus, the wheel bearing outer ring 152 may rotatably support the wheel bearing inner ring 154 via the wheel bearing balls 156 arranged in the circumferential direction of the wheel bearing 150.

Here, the wheel bearing balls 156 may be arranged in two rows in the axial direction of the wheel bearing 150, the wheel bearing balls 156 in one row (referred to as first wheel bearing balls 156) may be disposed between the wheel bearing outer ring 152 and the wheel bearing inner ring 154, and the wheel bearing balls 156 in the other row (referred to as second wheel bearing balls 156) may be disposed between the wheel bearing outer ring 152 and the outer circumferential surface of the wheel axle housing 120.

The wheel bearing 150 may include a one-side portion of the wheel axle housing 120 serving as a bearing inner ring, and in this case, the wheel bearing 150 shares the one-side portion of the wheel axle housing 120 with the wheel axle housing 120.

When the wheel bearing 150 is coupled to the knuckle 200, the wheel bearing 150 rotatably supports the axle housing 120.

Further, the wheel bearing inner ring 154 may be supported in a pre-compressed state by a lock nut 180 coupled to an outer circumferential surface of the axle housing 120.

The lock nut 180 is fixedly coupled to the outer circumferential surface of the axle housing 120 by a thread formed on the inner circumferential surface of the lock nut 180. When the lock nut 180 is tightened onto the outer circumferential surface of the axle housing 120, the lock nut 180 adjacent to the wheel bearing inner ring 154 applies a preload to the wheel bearing inner ring 154, and thus, the wheel bearing inner ring 154 is fixed so as not to be disengaged from the outer circumferential surface of the axle housing 120.

Here, the wheel bearing inner ring 154 is located between the engagement protrusion 124 of the axle housing 120 and the lock nut 180, one side of the wheel bearing inner ring 154 is supported by the lock nut 180, and the other side of the wheel bearing inner ring 154 is supported by the engagement protrusion 124. That is, when the wheel bearing inner ring 154 is coupled to the outer circumferential portion of the axle housing 120, the wheel bearing inner ring 154 is pressed against the engagement protrusion 124 by the lock nut 180, thereby being supported.

The engaging protrusion 124 is formed at one side portion of the wheel axle housing 120 (a portion of the wheel axle housing 120 serves as an inner ring of the wheel bearing 150), and the wheel bearing inner ring 154 and the engaging protrusion 124 mounted on the outer circumferential surface of the wheel axle housing 120 have the same height in the radial direction of the wheel axle housing 120.

Referring to another embodiment shown in fig. 6, the wheel bearing inner ring 154 may be supported in a pressurized state by the molding portion 132b of the wheel axle housing 120 instead of the locking nut 180, and thus the wheel bearing inner ring 154 may be fixed to the outer circumferential surface of the wheel axle housing 120.

The molding part 132b may be formed at one end of the wheel axle housing 120 through an orbital molding process.

In particular, the molding portion 132b may be formed at one end of the gimbal outer ring 132 of the axle housing 120 through an orbital molding process, and formed in a curved shape and protruding outward in a radial direction from one end of the gimbal outer ring 132.

Here, the molding portion 132b is bent so as to tightly wrap one end of the wheel bearing inner ring 154 coupled to the outer circumferential surface of the axle housing 120, and presses the wheel bearing inner ring 154 against the engagement protrusion 124 so as to support the wheel bearing inner ring 154.

The molding portion 132b contacts one side end portion of the wheel bearing inner ring 154, thus pressing the wheel bearing inner ring 154 against the engaging protrusion 124, so that the wheel bearing inner ring 154 can be prevented from being disengaged from the axle housing 120 in the same manner as the lock nut 180.

Further, in fig. 4 and 5, reference numeral 157 denotes a retainer 157 of the wheel bearing 150, and reference numeral 158 denotes a bearing seal 158 of the wheel bearing 150. A retainer 157 may be disposed between the wheel bearing inner ring 154 and the wheel bearing outer ring 152 and serves to limit the position of the wheel bearing balls 156. The bearing seal 158 serves to seal lubricant injected into the space between the wheel bearing outer ring 152 and the wheel bearing inner ring 154 to lubricate the wheel bearing balls 156.

Referring to fig. 7, the check ring 182 may be coupled to the lock nut 180 by a bolt member 184. In this case, at least one engaging protrusion 182a is formed on the inside of the lock ring 182 in the radial direction of the lock ring 182, and the engaging protrusion 182a is inserted into the groove 126 formed in the outer circumferential surface of the hub shell 120. Specifically, the engagement projection 182a is inserted into the groove 126 formed in the outer circumferential surface of the joint outer ring 132 of the axle housing 120.

When the lock nut 180 is coupled to the outer circumferential surface of the axle housing 120, the lock nut 180 is prevented from rotating by inserting the engagement protrusion 182a into the groove 126. Accordingly, the anti-loosening ring 182 may prevent the lock nut 180 from being loosened at the outer circumferential surface of the axle housing 120.

Further, the wheel-side joint 130 includes a joint inner ring 134, a joint outer ring 132, and a plurality of joint balls 136 arranged in the circumferential direction of the wheel-side joint 130.

A joint inner ring 134 is spline-coupled to one end of the shaft 110 to rotate integrally with the shaft 110, and a joint outer ring 132 is coupled to the joint inner ring 134 through a joint ball 136 to rotate axially integrally with the joint inner ring 134.

Specifically, the joint outer ring 132 is integrally molded with the hub 122 of the axle housing 120, and is rotated integrally with the shaft 110 by receiving the rotational force of the shaft 110 through the joint balls 136.

The joint balls 136 are disposed between the joint outer ring 132 and the joint inner ring 134, and transmit the rotational force of the joint inner ring 134 to the joint outer ring 132. For this, an outer ring groove 132a is formed in the joint outer ring 132, a joint ball 136 is mounted in the outer ring groove 132a so as to rotate integrally with the joint outer ring 132, an inner ring groove 134a is formed in the joint inner ring 134, and the joint ball 136 is mounted in the inner ring groove 134a so as to rotate integrally with the joint inner ring 134.

Specifically, an outer ring groove 132a is formed in the inner circumferential surface of the joint outer ring 132 and extends in the axial direction, and an inner ring groove 134a is formed in the outer circumferential surface of the joint inner ring 134 and extends in the axial direction. Therefore, even when the shaft 110 is bent with respect to the axle housing 120 and thus an angle is formed between the shaft 110 and the axle housing 120, the joint ball 136 may connect the joint outer ring 132 and the joint inner ring 134 so that the joint outer ring 132 and the joint inner ring 134 rotate integrally.

Further, a cage 138 disposed outside the joint inner ring 134 prevents the joint balls 136 from being disengaged from the outer ring groove 132a and the inner ring groove 134 a. Here, the cage 138 is provided not to interfere with the operation of the joint ball 136 for transmitting the rotational force.

A cardan bearing 160 is mounted on the outside of the shaft 110.

The gimbal bearing 160 is installed outside the shaft 110 and spaced apart from the wheel-side gimbal 130 coupled to one end of the shaft 110 by a predetermined distance, and includes a gimbal bearing outer ring 162, a gimbal bearing inner ring 164, and a plurality of gimbal bearing balls 166 arranged in a circumferential direction of the gimbal bearing 160.

The joint bearing inner ring 164 is coupled to the outside of the shaft 110 at a position spaced apart from the wheel-side universal joint 130 by a predetermined distance so as to rotate integrally with the shaft 110. In particular, the gimbal bearing inner ring 164 may be coupled to the outside of the gimbal inner ring extension 134b so as to rotate integrally with the gimbal inner ring extension 134 b.

The joint inner ring extension 134b integrally extends from one end of the joint inner ring 134, and is formed to contact the outer circumferential surface of the shaft 110 at one end of the joint inner ring 134.

The joint bearing inner ring 164 may be forcibly inserted into the outer portion of the joint inner ring extension 134b, thereby preventing leakage of lubricant filled in the space between the joint bearing inner ring 164 and the wheel-side joint 130.

Although the joint bearing inner ring 164 may be mounted on the outer circumferential surface of the shaft 110 in a sealing manner so as to prevent leakage of lubricant, the joint bearing inner ring 164 may be mounted outside the joint inner ring extension 134b in order to facilitate separation of the shaft 110 from the joint bearing inner ring 164.

The joint bearing inner ring 164 is rotatably supported by the joint bearing outer ring 162 by joint bearing balls 166 rotatably disposed between the joint bearing outer ring 162 and the joint bearing inner ring 164. Here, the universal joint bearing outer ring 162 is coupled to the knuckle 200 by the wheel bearing outer ring 152 and the boot unit 170.

The gimbal bearing outer ring 162 is not coupled to the wheel axle housing 120 or the wheel bearing inner ring 154, but rather is coupled to the knuckle 200 and therefore does not rotate with the shaft 110 as the shaft 110 rotates.

In particular, the universal joint bearing outer ring 162 may be coupled to the first end 171a of the boot unit 170 and secured to the knuckle 200. Here, the gimbal bearing outer ring 162 may be coupled to the first end 171a of the boot unit 170 in a sealing manner by a ring 174.

The ring 174 is an annular member formed of an elastic material, and may be elastically mounted at the first end 171a of the protection cover unit 170 disposed on the outside of the joint bearing outer ring 162. Here, the ring 174 surrounds the outside of the first end 171a of the boot unit 170 and presses the joint bearing outer ring 162 side.

The second end 172b of the shield case unit 170 is disposed at a position opposite to the first end 171a in the axial direction of the shaft 110. The second end 172b is coupled to the wheel bearing outer race 152 in a sealed manner.

Therefore, the protective cover unit 170 is formed to surround a space for filling the lubricant outside the shaft 110.

The protective cover unit 170 may include a first protective cover member 171 and a second protective cover member 172 coupled to each other. Here, the first and second shield members 171 and 172 may be formed by molding using an elastic material.

The first boot member 171 may be formed in the shape of a U-shaped plate, one end (i.e., a first end) of the first boot member 171 may be coupled to the universal joint bearing outer ring 162, and the other end (i.e., a second end) of the first boot member 171 may be coupled to the caulking coupling portion 172a of the second boot member 172. Here, a first end of the first protective cover member 171 is a first end 171a of the protective cover unit 170, and a second end of the first protective cover member 171 is a caulking coupling portion 171 b.

The second boot member 172 may be formed in a tube shape, one end (i.e., a first end) of the second boot member 172 may be coupled to the caulking coupling portion 171b of the first boot member 171, and the other end (i.e., a second end) of the second boot member 172 may be coupled to the boot unit fixing portion 152a of the wheel bearing outer ring 152. Here, the second end of the second boot member 172 is the second end 172b of the boot unit 170, and the first end of the second boot member 172 is the caulking coupling portion 172 a.

The protective cover unit fixing portion 152a integrally extends from the shaft-side end of the wheel bearing outer ring 152.

A second end 172b of the second boot member 172 is closely coupled to the outside of the boot unit fixing portion 152a without a gap by a caulking process, and a first end of the second boot member 172, i.e., a caulking coupling portion 172a is coupled to a second end of the first boot member 171, i.e., a caulking coupling portion 171 b. The caulking coupling portion 172a is surrounded by the caulking process and closely coupled to the caulking coupling portion 171b without a gap.

The boot unit 170 of the above configuration has a structure obtained by removing peaks and valleys from a conventional boot.

Further, in order to restrict the flow of the lubricant in the space (i.e., the lubricant-filled space) surrounded by the boot unit 170 between the wheel bearing 150 and the joint bearing 160, a boot seal 176 is installed between the outer circumferential surface of the axle housing 120 and the inner circumferential surface of the boot unit 170.

Specifically, a boot seal 176 is mounted in a sealing manner between the inner circumferential surface of the second boot member 172 and the outer circumferential surface of the joint outer ring 132.

Here, the boot seal 176 is provided at a position between the wheel bearing 150 and the universal joint bearing 160, thereby restricting the flow of lubricant to the inside of the space between the boot seal 176 and the universal joint bearing 160. That is, the boot seal 176 provided at a position between the wheel bearing 150 and the joint bearing 160 can prevent lubricant from flowing to a space between the boot seal 176 and the wheel bearing 150.

The space surrounded by the protective cover unit 170 is filled with lubricant so as to lubricate the wheel-side universal joint 130 when the shaft 110 rotates. When the lubricant flows toward the wheel bearing 150 due to centrifugal force and moves in the radial direction to the space outside the joint outer ring 132 (i.e., the space between the boot seal 176 and the wheel bearing 150), the lubricating performance is degraded, and therefore, in consideration of such degradation of the lubricating performance, it is necessary to fill the space surrounded by the boot unit 170 with a large amount of unnecessary lubricant.

Thus, the boot seal 176 may be used to restrict the flow of lubricant to the space between the boot seal 176 and the gimbal bearing 160.

Further, in fig. 4 and 5, reference numeral 168 denotes a seal 168 of the gimbal bearing 160.

Seals 168 may be used to seal lubricant injected into the space between the outer gimbal bearing ring 162 and the inner gimbal bearing ring 164 to lubricate the gimbal bearing balls 166.

In the wheel axle assembly according to the present disclosure having the above configuration, as shown in fig. 8, the rotating unit and the stationary unit are connected through the wheel bearing 150 and the universal joint bearing 160, and thus the rotating unit can rotate independently of the stationary unit.

Here, the rotating unit includes the shaft 110, the axle housing 120, and elements coupled to the axle housing 120 so as to rotate integrally with the axle housing 120, and the fixing unit includes elements that do not receive the rotational force of the rotating unit through the wheel bearing 150 and the universal joint bearing 160. Specifically, the fixing unit includes a boot unit 170, a knuckle 200, and the like.

Since the shield cover unit 170 does not rotate integrally with the rotation unit, that is, the shield cover unit 170 does not rotate but maintains a state of being fixed to the knuckle 200 when the rotation unit rotates, frictional noise generated in the conventional shield cover may be eliminated, and thus durability of the shield cover unit 170 may be greatly improved and it is not necessary to apply a separate coating agent for preventing frictional noise to the surface of the shield cover unit 170.

Further, even in the case where the shaft 110 is bent with reference to the axial direction of the hub shell 120 and thus an angle is formed between the shaft 110 and the axial direction of the hub shell 120, the shield case unit 170 is only deformed, i.e., bent, but does not rotate integrally with the shaft 110 according to such an angle of the shaft 110 with respect to the axial direction of the hub shell 120.

As apparent from the above description, in the wheel axle assembly for a driving wheel of a vehicle according to the present disclosure, the shield case unit does not rotate integrally with the shaft, and thus it is possible to eliminate frictional noise generated in the conventional shield case when steering during driving, thereby greatly improving durability of the shield case unit.

The present disclosure has been described in detail with reference to the preferred embodiments thereof. However, it would be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the disclosure, the scope of which is defined in the claims and their equivalents.