FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
As amended by the Patents (Amendment) Act, 2005
&
The Patents Rules, 2003 As amended by the Patents (Amendment) Rules, 2006
PROVISIONAL SPECIFICATION
(See section 10 and rule 13)
TITLE OF THE INVENTION
A sealing device for bearings in motor vehicle wheel hubs
APPLICANTS
Mahindra & Mahindra Ltd., Gateway Building, Apollo Bunder, Mumbai 400001. Maharashtra.
India.
INVENTOR
Ingle Mangesh, Plot No 59, Vijay Houshing Society, Behind Khandelwal School, Gorakshan
Road, Akola - 444004, Maharashtra, an Indian national
PREAMBLE TO THE DESCRIPTION
The following specification describes the invention

FIELD OF THE INVENTION
[0001] The present invention relates generally to wheel hubs suitable for use in motor
vehicles and more particularly, to a sealing device for bearings of such wheel hubs.
DESCRIPTION OF THE BACKGROUND ART
[0002] Wheel hubs are quite well known for their usage on most of front and rear
drive axles of motor vehicles. Such wheel hubs are mechanically coupled with relatively stationary spindles of the drive axles via a plurality of bearings. Typically, bearings are present between the wheel hub and the spindle to allow smooth rotary motion to the wheel hub relative to the spindle along a spindle axis. It is also quite well known that such wheel hub bearings provide very good operating performance, however, are quite expensive in nature. Simultaneously, it also becomes imperative that an arrangement needs to be put in place that protects the bearings during operating condition of the motor vehicle.
[0003] Due to the fact that the motor vehicles move on land, the wheel hubs are
subjected to outside environment. The environment may include operating the motor vehicles on roads, hilly terrains, fields, etc. While operating in such environment the chances-of external polluting agents, for example water, dirt, dust, mud, and the like elements getting infiltrated within the wheel hub is very high. Even though there is/are dust covers present on the spindle and arranged with the wheel hub to prevent infiltration of polluting agents, however, under general operating condition, it is observed that infiltration still occurs. Practically, this infiltration is a result of an important design consideration during manufacturing of the wheel hub and the dust cover and also their respective mechanical arrangement with each other on the spindle of the drive axle. When the wheel hub is assembled on the spindle a small clearance is present between the wheel hub and the dust cover. This clearance opens into outside environment and results in

providing a guideway for the polluting agents to reach in proximity to the areas where bearings are seated.
[0004] The polluting agents present within the wheel hub and proximal to the
bearings' seating area may contact the bearings and cause harm to the efficient functioning of the bearings and in the worst scenario leading to failure of the bearings. This would eventually be extremely detrimental to smooth rotary movement of the wheel hub on the spindle. The very nature of infiltration would be better understood by considering an example of a tractor puddling the paddy fields. During puddling, most portion of the wheel hub is submerged under muddy water and therefore the polluting agents very easily infiltrate the wheel hub. In order to avoid the problem of the polluting agents causing harm to the bearings, seals are generally used to protect the bearings. During operation of the motor vehicle, the seal prevents the polluting agent from contacting the bearings.
[0005] The seal is generally disposed within the wheel hub and fixedly attached to an
inner surface thereof. Further, bearings are also disposed within the wheel hub on its inner surface and positioned at a distance from the seal. On assembling the wheel hub on the spindle, the bearings support the wheel hub on the spindle surface with both the bearings and the seal separated by a predetermined space. Furthermore, the seal is formed from a combination of a flexible material (e.g. elastomeric materials) and a non-flexible material (e.g. steel or the like materials). A portion of the non-flexible material is press fitted on the inner surface of the wheel hub whereas a portion of the flexible material is rested on the spindle in known manner.
[0006] However, the construction of such seals and the manner in which they are
engaged between the wheel hub and the spindle offers limitations to the efficient functioning and working of the seals while the wheel hub is in operation. One of the limitations is wear and tear

of the flexible portions of the seal. The wheel hub rotates against the steady spindle and therefore, the flexible portion of the seal that is in continuous contact with the spindle rub hard against the spindle. After prolonged relative motion between the seal and the spindle, the flexible portions wear out. This wearing creates small passages for the polluting agents to creep into the gap present between the seal and the bearings, which would have otherwise restricted behind the seal if the seal has not worn out. This is a major problem with most of the seals and needs to be addressed urgently. Another limitation is that there is no provision for additional security so as to prevent polluting agents from entering space between the seal and the bearing. Additionally, portions of the wheel hub adjacent to the clearance have a steep configuration. The steep configuration assists the polluting agents to move towards the clearance and eventually within the wheel hub.
[0007] Thus, there is a need to have a seal/sealing device compatibly finable with the
wheel hub that addresses at least some of the above mentioned limitations.
[0008] Accordingly, an object of the present invention is to prevent entering of
foreign particles in proximal areas of bearings with a wheel hub.
[0009] Another object of the present invention is to provide an additional layer of
prevention that restricts penetration of the foreign particles into the proximal areas of the bearings.
[0010] Yet another object of the present invention is to reduce clearance space
between a dust cover and a sealing device within the wheel hub.

A BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The above-mentioned and other features and advantages of the various
embodiments of the invention, and the manner of attaining them, will become more apparent will be better understood by reference to the accompanying drawings, wherein:
|0012] FIG. 1 is a sectional view of a wheel hub assembled on a front axle of a
motor vehicle according to an embodiment of the present invention;
[0013] FIG. 2 is a cut-sectional view of a sealing device that is arranged on the front
axle of FIG. 1; and
{0014] FIG. 3 is an enlarged sectional view a portion of the front axle of FIG. 1 and
having the sealing device of FIG. 2 assembled therein.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0015] In the following description, for the purpose of explaining various
embodiments of the present invention, reference is given to a front axle of a tractor (not shown). However, the working principle and the features of the present invention are also applicable to the front and rear axles of all forms of motor vehicles and construed to be within the scope of the present invention. Reference will now be given to FIG. 1 that shows a sectional view of one side of a front axle 100 of the tractor having a rotatable wheel hub 102 assembled thereon according to an embodiment of the present invention. The front axle 100 is shown to include a spindle 104 that remains stationary with respect to the wheel hub 102. Further, the spindle 104 has a stepped configuration that allows the wheel hub 102 and several other components of the wheel hub 102 assembly tightly fitted thereon.

[0016] The rotatable wheel hub 102 comprises of a solid casted body defined by an
inner surface 106 and an outer surface 108. an inner end 110 and an outer end 112, and a central bore 114 extending throughout the length of the wheel hub 102. The inner end 110 of the wheel hub 102 has a sleeve portion 116 formed therein. Preferably, the wheel hub 102 is cylindrical in shape however, the wheel hub 102 may also have other shapes that are compatible with the design of the spindle's stepped configuration and also that provides tight fitting on the spindle 104. The outer surface 108 of the wheel hub 102 has a portion 118 for mounting a wheel rim (not shown) thereon.
(0017] As shown in FIG. 1, the inner surface 106 of the wheel hub 102 preferably has
a first bearing 120 and a second bearing 122 tightly seated thereon. Both the first and the second the bearings 120. 122 are positioned at a predetermined distance from each other on the inner surface 106 of the wheel hub 102. The space 124 between the first and the second bearings 120, 122 generally contains some amount of any of lubricant, for example grease, therein. The first bearing 120 is seated proximal to the inner end 110 of the wheel hub 102 whereas the second bearing 122 is seated proximal to the outer end 112 of (he wheel hub 102. Each of the bearings 120, 122 is formed by a bearing cone 126, a plurality of integral rollers 128, and a bearing cup 130. Further, the bearings 120, 122 are also subjected to sufficient lubrication so that the bearings 120. 122 function smoothly while rotating. Thus, the bearing cones 126, the bearing rollers 128, and the bearing cones 130 become very critical components of the bearing. Further, any malfunctioning of the bearings 120, 122 due to deposit of foreign particles (not shown) therein would severely impact performance of the bearings 120. 122. As a result, relative motion between the wheel hub 102 and the spindle 104 would also be severely affected. Therefore. the bearings 120, 122 needs to be adequately protected.

[0018] According to another embodiment of the present invention and also shown in
FIG. 1, one of the stepped portions 132 of the spindle 104 has a sealing device 134 received thereon and positively fitted on to the spindle 104, The sealing device 134 is positioned adjacent to a dust cover 136 that is tightly fitted on another stepped portion 138 of the spindle 104. Preferably, the sealing device 134 is press fitted on the spindle 104 however, it would be appreciated by a skilled person that other known methods are also considered to be within the scope of the present invention. The wheel hub 102 having the first and the second bearings 120, 122 are received on the spindle 104 of the front axle 100 in a manner as shown in FIG. 1. It will be understood that the central bore 114 of the wheel hub 102 is received on the spindle 104 via the inner end 110 and the First and the second bearings 120, 122 supports the wheel hub 102 on the spindle 104 when the wheel hub 102 is fully received on the spindle 104.
[0019] Once assembled, the inner end 110 of the wheel hub 102 is positioned
adjacent to the sealing device 134 and the dust cover 136 whereas, the outer end 112 of the wheel hub 102 is positioned adjacent to an outer end of the spindle 104. Further, the inner end 110 of the wheel hub 102 is designed in such a manner that the inner end 1 10 matches to both the dust cover 136 and the sealing device 134. As seen from FIG. 1, the wheel hub 102 has a clearance 140 formed between the dust cover 136 and a back side of the sealing device 134 and which opens up to the outside environment. The outer end 112 of the wheel hub 102 is then closed by attaching grease filled wheel cap 142 to the wheel hub 102 with the help of fastening members 144 such as bolts, washer etc.
[0020] FIG. 2 illustrates a cut-sectional view of a sealing device 134 that is positively
fitted on the wheel hub 102, according to one embodiment of the present invention. The sealing device !34 is made up of a flexible material 146 supported over a rigid material 148. In one

embodiment of the present invention, the flexible material 146 is made up of elastomeric material (like nitrile, viton etc.) whereas the rigid material 148 is made up of steel. Alternatively, other materials well known in the art could also be used for flexible and rigid materials 146, 148, respectively, and considered to be within the scope of the present invention. As seen from FIG. 2. the rigid material 148 of the sealing device 134 further includes an elongated structure 150 that is bent at least four positions to form at least four corresponding flanges namely, a first flange 152, a second flange 154, a third flange 156 and a fourth flange 158. The second flange 154 is bent inwardly from one of the ends of the first flange 152 and whereas the third flange 156 bents from one of the ends of the second flange 154. The fourth flange 158 that is generally of an L-shape is bent from one of the ends of the third flange 156,
[0021 As seen from FIG. 2, the first flange 152 and the second flange !54 lightly
hold a first flexible material 159 thereon whereas the third and the fourth flanges 156, 158 tightly hold a second flexible material 160. Both free ends 162 of the rigid material 148 are embedded within the first and the second flexible materials 159, 160 thereby allowing the first flexible material 159 and the second flexible material 160 to act as free ends 164 of the sealing device 134. Preferably, the first and the second flexible materials 159, 160 are moulded and bonded on their respective flanges thereon however other methods known in the art could also be used and construed to be within the scope of the present invention. The first flexible material 159 has at least one lip 166 formed therein and the second flexible material 160 has at least three lips 168 formed therein. The primary purpose of the plurality of lips is to seal the first bearing 120 from getting exposed to the foreign particles that may cause malfunctioning. In some embodiments of the present invention, each of the lips 166, 168 are provided with a biasing member 170 that tightly holds the lips, 166, 168 and eventually the sealing device 134 within the wheel hub 102.

As seen in FIG, 2, some of the lips 166, 168 are shown to have a corresponding biasing member 170 in the form of spring 170. As shown in FIG. 3, the spring 170 of the first flexible member !59 allows the lip 166 to be tightly disposed against the inner surface 106 of the wheel hub 102.. Similarly, spring 170 provide on one of the lips 168 of the second flexible material 160 tightly disposes the lip 168 against the spindle 104.
[0022] FIG. 3 shows an enlarged sectional view a portion of the front axle 100. The
fourth flange 158 is rigidly attached, preferably press fitted, on to the stepped portion 132 of the spindle 104. Further, the dust cover 136 is also fixedly attached to one of the stepped portions and positioned behind the sealing device 134. So, both the dust cover 136 and the sealing device 134 remain stationary against a rotating wheel hub 102. During assembly of the wheel hub 102 on the spindle 104, the first and the second bearings 120, 122 support the wheel hub 102 on the spindle 104. The lips of the first flexible material 159 is inserted into the sleeve portion 116 of the wheel hub 102 and provided with sufficient interference so as to allow the first flexible material 159 and the second flexible material 160 to be securely rested therein. Whereas, the second flexible material 160 is given proper interference so as to positively contacts a surface of the inner end 110 of the wheel hub 102. Preferably, the plurality of lips 168 of the second flexible member 160 slidably contacts the inner end 110. In some embodiments of the present invention, between the first flexible member and the second flexible member, a cavity 172 is formed that is subjected to application of grease 174 that acts as a repellent to the foreign particles. Alternatively, in another embodiment, the cavity 172 may be filled with grease 174 that may be applied via a grease nipple (not shown). Accordingly, provisions in the wheel hub 102 structure are given so as to add the grease 174 from the grease nipple.

[0023] As seen in FIG. 3, the clearance 140 between the dust cover 136 and the
sealing device 134 opens up to an outside environment and runs down towards a back surface of the third flange 156 of the sealing device 134. While the tractor is operating along with the rotating wheel hub 102, say in a puddling operation, the foreign particles occupy the space defined by the clearance 140. It will be understood by a skilled person that due to the fact that the sealing device 134 is press-fitted on the spindle 104, there is least chance that the foreign particles would try to enter the wheel hub !02 through this path. Thus, this press-fitting of the sealing device on the spindle provides additional restriction to the foreign particles from entering the proximal areas of the first bearing 120. As the wheel hub 102 rotates, even though the sealing device 134 remains stationary, lips 166 of the first flexible member and some of the lips 168 of the second flexible member are subjected to relative motion with respect to the inner surface 106 of the wheel hub 102.
|0024] After prolonged operation of the tractor, it is quite obvious that the lips may
be subjected to wear and tear. If such a situation happens, the only entry path that could be generated for the foreign particles to move towards the first bearing 120 is through the first flexible member in the sleeve portion 116 of the wheel hub 102. However, the embodiments of the present invention ensure that that the foreign particles anyhow do not reach to the proximal areas of the bearings due to following reasons. First, the gap between the first flange 1 52 and the inner surface 106 of the wheel hub 102 within the sleeve portion 116 is so small that not all foreign particles will creep in. Second, assuming that the foreign particles enters inside and the lips of first flexible member have worn out, the foreign particles would still not be able to find their way towards the bearings because of the grease 174 present between the first and the

second flexible members. Thus, the grease 174 acts as an additional layer of security against the foreign particles.
[0025] In another embodiment of the present invention and as shown in FIGS. 1 and
3, the outer surface 108 of the wheel hub 102 adjacent to the inner end 110 is casted in such a manner that a portion of the wheel hub 102 adjacent to the inner end 110 is arcuately depressed 176 radially inside. This depression ensures that the outer surface 108 does not facilitate the foreign particles to move towards the clearance' opening 178. This is in sharp contrast with the prior art structures of the wheel hub 102. Various other shapes of depressions that hinder movement of the foreign particles would be construed to be within the scope of the present invention.
[0026] It will be apparent to those skilled in the art that various modifications and
variations can be made to the present invention without departing from the spirit and scope of the invention. Thus it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.