FORM 2
THE PATENT ACT, 1970,
(39 OF 1970)
&
THE PATENTS RULE, 2003
COMPLETE SPECIFICATION
(SEE SECTION 10; RULE 13)
"AN IMPROVED CLUTCH RELEASE BEARING"
DELUX BEARINGS LIMITED, A COMPANY REGISTERED UNDER THE PROVISION OF INDIAN COMPANIES ACT, 1956 HAVING ADDRESS AT GATE NO. 183, VILLAGE-SANASWADI, TAL-SHIRUR, DISTRICT-PUNE-412 208, MAHARASHTRA, INDIA.
THE FOLLOWING SPECIFICATION DESCRIBES THE NATURE OF THE INVENTION AND MANNER IN WHICH IT IS TO BE PERFORMED

FIELD OF THE INVENTION:-
Present invention relates to an improved clutch release bearing. More particularly clutch release bearing made of polyamide material hub effecting in reduction of weight and maintenance free performance features.
BACKGROUND AND PRIOR ART:-
The existing design of CRB comprises Thrust, Ball or Angular Contact Bearing. The Bearing is sealed in a sheet metal cover and a carrier sleeve made up of Cast Iron is press fitted in the cover. Thus, there are three separate components i.e. Cover, bearing and Hub in a CRB.
The Cast Iron Hub is machined to provide contact planes for the Clutch
fork.
As the Hub slides back and forth on the hollow shaft, it is subjected to
friction and wear.
The Hub bore requires intermittent greasing which is done manually
through grease nipples provided on the Hub. Normally the greasing is
carried out at the time of servicing the vehicle as the location of the CRB
is not easily assessable for the user of the vehicle.
while clutching, the CRB copies in contect with the dutch Fingers and the inner race of the CRB starts rotating along with the clutch fingers. The rotating fingers of the clutch plate act as a fan and sucks in dust particles and worn out particles of mating parts.
A common remedy is to provide dust shields at the open end of the CRB. Still the shield cannot provide 100% dust-protection for the CRB.

DISADVANTAGES OF PRIOR TECHNOLOGY:-
1. The Hub, which slides on a hollow shaft at the front of the
transmission housing is made of Cast Iron
Hub weight is more
Heavy Hub creates imbalanced load on the bearing
Wear of the Hub is more
Castings are prone to blow holes
Hub manufacturing cost is more
2. Hub & sheet metal cover are two separate parts. Hub is press
fitted in the bore of the cover face.
Relative motion between the cover face bore and Hub cause slippages and entire CRB is subjected to rotation while clutching
3. The Hub bore requires intermittent greasing which is normally
done by servicing personnel. There is always a chance of dry
sliding of the Hub in the absence of grease.
Non-lubricated operation of the Hub creates friction and causes excessive wear of the Hub. This causes eccentric loading of the CRB leading to premature failure.
4. The resting planes of the Hub are machined faces which are in
contact with clutch fork. Clutch pedal motion is transferred from
the clutch fork to the Hub planes and delivered by the inner race
of CRB.
As cast hardness being less, the Hub planes get worn out causing efficiency loss in clutching operation.

5. The engagement of CRB is achieved with the help of mechanical linkages between clutch pedal and the CRB.
The CRB is subjected to shock loading due to the mechanical linkages. These shocks result into induced wear of CRB components. The induced wear causes premature failure of CRB.
OBJECT OF THE INVENTION:-
Object of the present invention aims at developing clutch release bearing made of polyamide hub effecting reduction in weight by 60%.
Yet another object of invention aims to make polyamide Hub & sheet metal cover are two separate parts make one piece by co-moulding together.
Yet another object of invention aims to self lubricating the hub by grease whenever needed.
Yet another object invention aims to make fork resting plate made of hardened steel strip plane surfaces withstand friction of the clutch fork.
Yet another object of invention aims to absorb the shocks means to avoid vibrations due to the mechanical linkages up-to the bearing contact face thereby increase life of the clutch release bearing.
STATEMENT OF INVENTION:-
Accordingly the invention provides a clutch release bearing for auto mobile vehicle comprises a hub made of polyamide with at one end a cup shaped cover and a pair of fork plate below the said cover diametrically opposite co- molded; a circular damping pad sand witched

between pair of plain circular spacers placed in the space between said hub and cover; Angular contact ball bearing, having balls held in cage between outer diameter of inner ring and inner diameter of outer ring, mounted over the said damping pad such that the said outer ring of said angular contact ball bearing mounted loose fit in the said cover for self centering arrangement; the said inner ring, freely rotates over the said balls of bearing, having a flange towards other end of said hub with clearance between the said flange and hub edge; one or more annular grooves made on the inner diameter of the said inner ring; a pair of grease pocket with shield cover provided at the said one end of said hub, diagonally opposite adjacent to the said fork plate; and the sealing paste applied to the gap between the said inner diameter of the said inner ring and outer diameter of the said hub.
BRIEF DESCRIPTION OF DRAWINGS:-
Invention is described with reference to the figures of accompanying
drawings wherein;
Figure 1 shows the sectional view figure 2 along section xx-xx of the
clutch release bearing figure to according to invention;
Figure 1A shows the sectional view of moulded hub with cover and fork
plate;
Figure 2 shows the perspective of clutch release bearing according to
invention;
Figure 3a shows the damping pad support to the ball bearing shown in
the figure 1;
Figure 3 B shows the cut portion hub with cover molded;
Figure 3 C shows part portion of hub provided with grease cup;
Figure 3 D shows part portion of hub provided with thermal indicator;
Figure 4 A shows part portion sectional view of hub provided with ball
bearing with outer ring and inner ring with flange;
Figure 4 B shows part portion sectional view of hub provided with
sealing paste between outer diameter of hub and inner diameter of inner
ring;

Figure 4 C shows part portion sectional view of hub provided with rubber seal to both side of bearing;
Figure 4 D shows part portion sectional view of hub provided with sheet metal cover for protecting from dust.
BRIEF DESCRIPTION:-
The Clutch Release Bearing (CRB) is the heart of clutch operation. When the clutch pedal is depressed, the CRB moves toward the flywheel, pushes in the pressure plate's release fingers and moves the pressure plate fingers or levers against pressure plate spring force. This action moves the pressure plate away from the clutch disc, thus interrupting power flow.
Conventionally, the CRB is mounted on an iron casting called a hub and slides on a hollow shaft at the front of the transmission housing. The clutch fork and connecting linkage convert the movement of the clutch pedal to the back and forth movement of the CRB. To disengage the clutch, the CRB is moved toward the flywheel by the clutch fork. As the CRB contacts the pressure plate's release fingers, it begins to rotate with the pressure plate assembly. The CRB continues to move forward and pressure on the release levers or fingers causes the force of the pressure plate's spring to move away from the clutch disc. To engage the clutch, the clutch pedal is released and the CRB moves away from the pressure plate. This action allows the pressure plate's springs to force against the clutch disc, engaging the clutch to the flywheel. Once the clutch is fully engaged, the CRB is normally stationary and does not rotate with the pressure plate.
Now, referring to figures 1,1 A, and 2, a constructional feature of clutch release bearing according to invention is explained. A clutch release bearing for auto mobile vehicle comprises a hub 1 made of polyamide of and the material is PA 6.6 + 50 % glass fiber. The said hub 1 provided with at one end a cup shaped cover 5 and a pair of fork plate/pad 6

below the said cover 5 diametrically opposite co- molded. A circular damping pad 10 sand witched between pair of plain circular spacers 11 placed in the space between said hub 1 and cover 5. A angular contact ball bearing, having balls held in cage 7 between outer diameter of inner ring 2 and inner diameter of outer ring 3, mounted over the said damping pad 10 such that the said outer ring 3 of said angular contact ball bearing mounted loose fit in the said cover 5. The said inner ring 2 freely rotates over the said balls 4 of bearing, having a flange towards other end of said hub 1 with a clearance between the said flange and hub edge. One or more annular grooves made on the inner diameter of the said inner ring 2. Pair of grease pocket 14 with shield cover 13 provided at the said one end of said hubl, diagonally opposite adjacent to the said fork plate 6. The sealing paste 12 applied to the gap between the said inner diameter of the said inner ring 2 and outer diameter of the said hub 1. The bearing is provided with rubber seals 8 at both sides to protect from dust. A Belleville spring placed at gap between the said cover bend edge and over the face of the said outer ring.
Positioning of the fork resting plate is ensured during molding. Hardened plane surfaces withstand friction of the clutch fork. Efficiency o operation is improved.
INVENTION ACHIEVEMENTS:-
1) Bearing Life improvement: 150 to 165% against old design.
2) Bearing Weight reduction: 55 to 60% against 2.2 Kg to 1.25 Kg.
3) Cost Reduction: < 30 against old Design.
4) Life in Cycles: Million Cycles against 0.60 Million Cycles of Old Design.
Life in Kms achieved: 300000 as against Km 100000 of Old
design. (Theoretical) Km against 170000 Km

IMPROVEMENTS MADE IN THE PRESENT INVENTION:-
1. The Hub material is changed from Cast Iron to Polyamide with Glass Fiber (weight reduction & less friction with mating parts).
2. The Hub is molded with sheet metal fork resting plate forming a single unit.
3. Two grease pockets provided for storirig Thermal grease which is released at elevated temperature and supplied to the Hub bore in actual working condition when temperature reaches to its melting point.
4. A damping pad is provided at the bottom of the bearing to absorb shocks due to engagement of clutch plate with release bearing assembly.
5. A sealing paste is applied at the Hub diameter to arrest dust particles from entering the bearing Close tolerance for hub inner diameter not possible due to polyamide glass filed material. Whole bearing / clutch assembly affects when polyamide hub get failed due to crack. When close tolerance is required and to avoid failure due to cracks to hub a Sheet metal sleeve fitted with polyamide hub by using wave spring & circlip for locking arrangement of cover & hub. 4 Pegs are provided in moulded hub to restrict the slippage of cover.
6. Fork resting plate is made of hardened steel strip an molded with the Hub
ADVANTAGES OF THE PRESENT INVENTION:-
1. The Hub material is changed from Cast Iron to Polyamide with Glass Fiber

Hub weight is reduced by 60% making the CRB lighter in weight. The Hub weight is balanced to ensure symmetric load on the CRB
Molding process ensures uniformity of Hub structure
Hub manufacturing cost is very less
2. The Hub is molded with sheet metal cover forming a single unit There is no relative motion between the cover & the Hub. 100% motion transfer is achieved while declutching
3. Two grease pockets provided for storing Thermal grease which is released at elevated temperature and supplied to the Hub bore ( Figure 3C)
Application of thermal grease makes the CRB absolutely service free during operation. As the CRB temperature rises to the defined value, the thermal grease is released from the grease pockets to the Hub bore. Thus the Hub bore is adequately lubricated during the operation.
4. Fork resting plate is made of hardened steel strip an molded with
the Hub
Positioning of the fork resting plate is ensured during molding. Hardened plane surfaces withstand friction of the clutch fork. Efficiency of operation is improved.
5. A damping pad is provided at the bottom of the bearing (figure
3a)
Damping pad absorbs the impact load of declutching and vibrations due to stiffness difference in clutch fingers and enhances the bearing life.

6. A sealing paste is applied at the Hub diameter to arrest dust
particles from entering into the bearing (figure 4B)
Sealing paste is provided in between the gap of Hub outer diameter and CRB inner ring. The sealing paste accumulates and retains any dust particles which are forced by hot air which is created by rotating pressure plate.
7. Hub bore is coated with thermal lubricant to reduce friction
The thermal lubricant endures the elevated temperature, dust particles and uneven duration of loading unloading cycles. Effective lubrication reduces wear of the Hub bore thereby imparting prolonged life to the CRB.
8. Hub is provided with a Life indicator wax/heat plug provided to
indicate abnormal temperature of the CRB (figure 3 D)
The unique Life indicator is a feature which indicates the CRB has undergone abnormal working condition as the temperature has crossed the predetermined values. The CRB is to be replaced at this moment to avoid any malfunctioning of the clutch.

WE CLAIM:-
1. A clutch release bearing for auto mobile vehicle comprises a hub made of polyamide with at one end a cup shaped cover and a pair of fork plate below the said cover diametrically opposite co-molded; a circular damping pad sand witched between pair of plain circular spacers placed in the space between said hub and cover; a angular contact ball bearing, having balls held in cage between outer diameter of inner ring and inner diameter of outer ring, mounted over the said damping pad such that the said outer ring of said ball bearing mounted loose fit in the said cover; the said inner ring, freely rotates over the said balls of bearing, having a flange towards other end of said hub with clearance between the said flange and hub edge; one or more annular grooves made on the inner diameter of the said inner ring; a pair of grease pocket with shield cover provided at the said one end of said hub, diagonally opposite adjacent to the said fork plate; and the sealing paste applied to the gap between the said inner diameter of the said inner ring and outer diameter of the said hub.
2. A clutch release bearing as claimed in claiml wherein the said polyamide hub is made of PA 6.6 + 50 % glass fiber.
3. A clutch release bearing as claimed in claims 1 and 2 wherein the said bearings balls supported with cage.
4. A clutch release bearing as claimed in claims 1 to 3 wherein the said ball bearing having both side rubbers seal.
5. A clutch release bearing as claimed in claims 1 to 4 wherein the inside diameter of the said hub is lubricated with thermal grease.

6. A clutch release bearing as claimed in claims 1 to 5 wherein Wax / Heat plug provided in the said hub to indicate the bearing status for temperature rise of the bearing.
7. A clutch release bearing as claimed in claims 1 to 6 wherein a Belleville spring is fitted at gap between the outer ring face and below the bend edge of cover.
8. A clutch release bearing as claimed in claims 1 to 7 where in the said fork plate is made of hardened steel strip.
9. A clutch release bearing as claimed in claims 1 to 8 wherein a Sheet metal cover fitted with polyamide hub sleeve by using wave spring & circlip for locking arrangement of cover & hub with four pegs provided in moulded hub to restrict the slippage of the said sheet metal cover.