Field of Invention:
The present invention relates to the field of Mechanical Engineering and especially in field of automotive industries i.e. in rotary equipments/pivoted. All the Moving parts should have minimum friction to get the maximum torque which is availed by the use of the Bearings.
Prior Art:
Vehicles require bearings in almost all their parts be it the steering wheel or the seats or wheels or the engine or tilt cabin. They come in a variety of sizes and types to suite the function. Modern technology and new designs aid the vehicle in betterperformance.
Emphasizing space, weight and performance considerations, optimum quality control manufacturing conditions are used to provide the precise bearings required by the automobile industry. These bearings are widely used for various vehicles for transmission and rotation.
The concept behind a bearing is very simple. Things roll better than they slide. The wheels on the car are like big bearings. If Car has something like skis instead of wheels, then it would be a lot more difficult to push down the road. That is because when things slide, the friction between them causes a force that tends to slow them down. But if the two surfaces can roll over each other, the friction is greatly reduced.
Bearings reduce friction by providing smooth metal balls or rollers, and a smooth inner and outer metal surface for the balls to roll against. These balls or rollers "bear41 the load, allowing the device to spin smoothly.
Bearings typically have to deal with two kinds of loading, radial and thrust. Depending on where the bearing is being used, it may see all radial loading, all thrust loading or a combination of both.
US 5275493, explains the bearing which includes a series of spaced bearing surfaces so as to distribute load amongst a series of spaced bearing surfaces thereby increasing the load carrying capacity of the assembly. The bearing surfaces are formed of a high PV material. The bearing assembly can be either a radial bearing for supporting radial loads or a thrust bearing for supporting thrust loads.
In US4501534, apparatus and a method are disclosed for providing a lubricant film within a sleeve bearing for prolonging bearing life. A rotating shaft is supported by a sleeve bearing and power is supplied to the rotating shaft. That the shaft is operated at a minimum speed to establish a lubricant film between the shaft and the bearing upon startup prior to being operated at a reduced rotational speed. Once the lubricant film is established, this film is maintained during reduced speed operation and bearing life is prolonged.
A swivel mounting is made as a double-row roller bearing and has an outer ring with a first outer track and a second outer track, a first inner ring with a first inner track, and a second inner ring with a second inner track which is located axially
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next to the first inner ring. Two sets of rollers roll between the outer tracks of the outer ring and the inner tracks of the inner rings. The swivel mounting is constructed such that the outer ring with the first inner ring and the second inner ring forms one axial slide bearing at a time is explained in the Patent No. US7021612.
US 2007206891, explains the Hydrodynamic bearings providing reduced friction are provided. The bearings include a load-transferring element and a porous bearing pad spaced from the load-transferring element. The load-transferring element is provided with a high-viscosity lubricant. The porous bearing pad is saturated with a low-viscosity lubricant. The high-viscosity lubricant and the low- viscosity lubricant are drawn into the clearance space by hydrodynamic action to form a bi-component lubricant film. The bi-component lubricant film includes a high-viscosity film layer and a low-viscosity film layer, which provide reduced viscous dissipation as well as proper cooling and lubrication. US patent 6874859 describes the shaft/roller unit for tracked vehicles which has a long life and resistance to wear is formed by a shaft which has a shoulder in its central portion, perpendicular to its axis, and onto which two wholly hardened steel half-rollers are fitted, one on each side of the shoulder, with ttie interposition of antifriction bushings, the half-rollers grasping the shoulder and, when they have been welded together along a mating contact and locating surface, forming a unitary roller which has a predetermined axial position on the shaft and can withstand considerable axial stresses.
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The Silent bushes avoids the need for metal bearing bushes between the pivot shaft and housing and it also eliminates the need of lubrication at the regular intervals in addition to avoiding metal to metal contact between the shaft and housing. This eliminates the passage of noise and vibration from one another to a great extent. Such busing sometimes also acts as self aligning bearings to accommodate the angular misalignments between the housing hole and shaft centre line on assembly. It also some time used to withstand the shear during earthquake and upsets.
These silent bushes have some limitation with the hinge angle/pivot angle, they take permanent set or failure. The rubbery material that is bonded between the outer and inner sleeve of such bushings or bearings, are present to take the shear mode of the deformation. They can take the deformation up to + 5 degree in hinge mode in either direction of the free condition.
When the hinge action goes beyond this degree of deformation they undergo mechanical slip with respect to the shaft or housing, thus causing the mechanical friction/wear, ultimately leading to the rattling of the hinge and subsequent failure or rupture of the system.
The silent bushes are made to take both axial and radial load. The intermediate bush between the inner and shaft in turn should be much more than the torsional shear force. But it is impractical to incorporate the market available antifriction combination bushes in the available boundary dimensions of these silent bushes, as such designs are not prevalent. Hence there exist an new design to over come the above said drawbacks and limitations.
The present invention comprises of a special antifriction combination bearing that can take radial load and biaxial loads which could be accommodated within boundary limits and not damage the packing material that isolates the torsional and radially transmitted noise and vibration that originates from the shaft to the housing.
Summary of the Invention:
A silent bush with integral biaxial combination antifriction bearing comprises of a special antifriction combination bearing that can take radial load and biaxial loads which could be accommodated within the boundary limits and not damage the packing material that isolates the torsional and radially transmitted noise and vibration that originates from the shaft to the housing.
In one of the embodiment of the invention, the bearing constitute a ball bush which is equal to one needle bearing and two thrust bearing back to back that can be built by two combi-bearings that commercially available.
Description:
A ball bearing is a common type of rolling-element bearing, a kind of bearing. The term ball bearing to mechanical engineers usually means a bearing assembly which uses spherical bearing balls as the rolling elements. To laypeople the term often means an individual ball for a bearing assembly. The remainder of this entry uses the term ball for the individual component and "ball bearing" or just "bearing" for the assembly.
Ball bearings typically support both axial and radial loads and can tolerate some misalignment of the inner and outer races. Also, balls are relatively easy to make cheaply compared to other kinds of rolling elements. Ball bearings tend to have lower load capacity for their size than other kinds of rolling-element bearings due to the smaller contact area that spherical shapes provide. Radial
A radial ball bearing uses axially symmetric inner and outer races that are shaped so a radial load passes radially through the bearing. Most radial designs also support modest axial loads.
Axial
An axial ball bearing uses side-by-side races. An axial load is transmitted directly through the bearing, while a radial load is poorly-supported, tends to separate the races, and anything other than a small radial load is likely to damage the bearing. Types of Bearings
There are many types of bearings, each used for different purposes. These include ball bearings, roller bearings, ball thrust bearings, roller thrust bearings and tapered roller thrust bearings. Ball Bearings
Ball bearings, as shown below, are probably the most common type of bearing. They are found in everything from inline skates to hard drives. These bearings can handle both radial and thrust loads, and are usually found in applications where the load is relatively small.
In a ball bearing, the load is transmitted from the outer race to the ball, and from the ball to the inner race. Since the ball is a sphere, it only contacts the inner and outer race at a very small point, which helps it spin very smoothly. But it also means that there is not very much contact area holding that load, so if the bearing is overloaded, the balls can deform or squish, ruining the bearing. Roller Bearings
Roller bearings like the one illustrated below are used in applications like conveyer belt rollers, where they must hold heavy radial loads. In these bearings, the roller is a cylinder, so the contact between the inner and outer race is not a point but a line. This spreads the load out over a larger area, allowing the bearing to handle much greater loads than a ball bearing. However, this type of bearing is not designed to handle much thrust loading.
A variation of this type of bearing, called a needle bearing, uses cylinders with a very small diameter. This allows the bearing to fit into tight places. Ball Thrust Bearing
Ball thrust bearings like the one shown below are mostly used for low-speed applications and cannot handle much radial load. Barstools and Lazy Susan turntables use this type of bearing. Roller Thrust Bearing
Roller thrust bearings like the one illustrated below can support large thrust loads. They are often found in gearsets like car transmissions between gears, and between the housing and the rotating shafts. The helical geprs used In most
transmissions have angled teeth - this causes a thrust load that must be supported by a bearing. Tapered Roller Bearings
Tapered roller bearings can support large radial and large thrust loads. Tapered roller bearings are used in car hubs, where they are usually mounted in pairs facing opposite directions so that they can handle thrust in both directions. Cylindrical roller bearings
Cylindrical roller bearings with snap ring grooves are full complement, self- retaining units comprising solid inner and outer rings, rib-guided cylindrical rollers and sealing rings. The outer rings have grooves for retaining rings. The inner rings are axially split, 1 mm wider than the outer rings and are held together by a steel strip that is rolled into place. Cylindrical roller bearings with snap ring grooves are locating bearings. These bearings are highly rigid and can support axial forces in both directions as well as high radial forces. Due to the full complement design of these bearings, they have the largest possible number of rolling elements and thus extremely high basic dynamic and static load ratings. Due to their kinematic conditions, however, they cannot achieve the high speeds that are possible when using cylindrical roller bearings with cage.
The major Application of the Industrial, Automotive, Instrumental Bearings are roller bearings because of its rigidity, smooth action, easy availability. Rolling bearings generally comprise two bearing rings with integral raceways. Rolling elements are arranged between the rings and roll on the raceways.
Rolling elements can be balls, cylindrical rollers, needle rollers, tapered rollers or barrel rollers. The rolling elements are generally guided by a cage that keeps them at a uniform distance from each other and prevents them coming into contact with each other. In needle roller bearings and ribless spherical roller bearings, the cage also ensures that the rolling element axis is positioned correctly. Where bearings can be dismantled, the cage holds the rolling elements together and gives easier fitting of the bearings. For particular applications, rolling bearings with a full complement of balls, cylindrical rollers or needle rollers may be used.
The standard material for sheet metal cages is steel, while brass is also used for some applications. Solid cages are made from brass, steel, laminated fabric and other materials. Cages made from thermoplastic materials are also widely used, especially those made from polyamide reinforced by glass fibre. Rings and rolling elements are predominantly made from through hardened chromium steel, although case hardening steel is also used. Special bearings for extreme operating conditions - load, speed, temperature, corrosion - are made from temperature-resistant and/or corrosion-resistant steels, plastic, ceramics or other materials.
Rolling bearings are available in open versions or with seals on one or both sides. The most common types of seals are gap seals and lip seals. Every roller bearing design has characteristic features that make it especially suitable for specific bearing applications. It is not possible to draw up generally valid rules for the selection of the bearing type as several factors usually have to be considered and weighed up. In addition to load and speed, attention must also normally be paid to influences such as temperature, lubrication, vibrations, fitting, maintenance etc. In many cases, at least one of the main dimensions of the bearing - usually the bore diameter - is already defined by the design of the adjacent construction.
Rolling bearings for predominantly radial loads are described as radial bearings. Most radial bearings can support combined loads, e.g. deep groove ball bearings, angular contact ball bearings, tapered roller bearings or spherical roller bearings. Cylindrical roller bearings N, NU, most needle roller bearings, drawn cup needle roller bearings and needle roller and cage assemblies can only support radial loads.
Rolling bearings for predominantly axial loads are described as axial bearings. Axial spherical roller bearings and single direction axial angular contact ball bearings can support combined axial and radial loads. The other types of axial bearings are only suitable for axial loads.
If there is little radial space available, bearings with a low cross-sectional height must be selected, such as needle roller and cage assemblies; needle roller bearings with or without an inner ring, deep groove ball bearings and spherical roller bearings of certain series.
If there is little axial space available, bearings series including single row cylindrical roller bearings, deep groove ball bearings or angular contact ball bearings are suitable for radial and combined loads. For axial loads, axial needle
roller and cage assemblies, axial needle roller bearings or axial deep groove ball bearings are used.
The most important feature of the bearing is how the bearings guide a shaft. There are bearings that allow axial displacements, bearings that guide a shaft in one or both axial directions and bearings that allow angular adjustment and thus tolerate misalignment of the adjacent construction.
The bearing size is determined primarily by the magnitude and types of load - dynamic or static - the bearing load carrying capacity and the requirements for operating life and operational reliability of the bearing arrangement. Rotating bearings are subjected to dynamic stresses. Bearings are subjected to static stresses if there is only very slow relative motion between the bearing rings, if swivel motion occurs or if loads occur in a stationary condition. Where external dimensions are identical, roller bearings can in general be subjected to higher loads than ball bearings. As a result, ball bearings are usually used for small and moderate loads, whilst roller bearings are frequently used for higher loads and larger shaft diameters. Thin section bearing
Thin section bearings have high precision, are very quiet and have high load carrying capacity. These ball bearings are available in three different designs and have an extremely small, predominantly square cross-section. Within each series, the cross-section remains constant even for larger shaft diameters and housing bores. The bearings gre therefore also described as Constant Section (CS), This special feature distinguishes thin section bearings from conventional bearings as standardized in ISO series.
It is therefore possible to select a larger cross-section and thus use a bearing with higher load carrying capacity without the need to change the shaft diameter as well. Thin section bearings allow designs to be achieved that are extremely light and require little space.
The present invention eliminates the limitation of the hinge angle of the rubbery material that cause the permanent set of the material and deploy the anti frictional properties.
ADVANTAGES OF THE INVENTION OVER THE EXISTING BEARINGS:
1. It is more compact, offer rugged design features.
2. It has highly integrated, unitized.
3. It has least number of part varieties i.e. 3 sleeves, rubber seal, balls.
4. It can face independently face axial and biaxial loads. 4a.Isolates noise between shaft and body
5. It is cost effective and wide applications
The invention is clearly explained with the help of the following drawings: Figure 1: Prior Art of the bearing design Figure 2: Combi bearing with isolator elastomer bush Figure 3: Radial bearing with isolator elastomer bush Figure 4: Present invention showing the unitized ball bearing.
Detailed Description of the Drawings:
Figure 1 shows the existing arrangement of the bearing with polymer material bushes in two numbers on either end of the bearing (off position) to bear with axial and biaxial load. The main drawback of the bearing is short life of the
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Polymer material due to sudden impact or distortion may cause the polymer material to wear and give very low bush life.
Figure 2 shows the combination of the deep groove ball bearing arrangement with the ball on either off sides with the polymer cushion material over the periphery of the ball to prevent from distortion. The limiting factor of such bearing is that the angle of movement of the hinge may cause the polymer material to wear and thereby cause the metal contact between the shaft and ball which may some time breaks the ball and cause breakage of the bearing. Figure 3 shows the specially designed cylindrical ball which can with stand axial and radial combination loads on off sides to prevent the displacement in case of sudden shock or impact. The advantage is being the less elastomer material and they are very expensive.
Figure 4 shows the arrangement of the three sleeved bearing, inner, intermediate and outer sleeves. The outer sleeve (1) is same as the prevailing bearings. The inner sleeve (2) is made of the thin ferrous material having a bell mouth flange on one end and another which is made on the assembly. The radius of the bell mouth flange is slightly greater than the ball (3) that are being used in the construction of the anti friction bearing. The intermediate sleeve<4)is also having a bell mouthed shape at both ends, but swaged into a stepped cylinder at the ends. The end shapes of the both the inner and intermediate sleeve constitute two pairs of inner race and outer race of angular ball bearings of pressure angle of required choice, with an angle between 30 - 45 degrees. The degree of
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pressure angle depends on the axial loads proportion to that of the radial load coming from the bushes.
The outer (1) and intermediate (4) sleeves are bonded together to form a single assembly by the filling of the rubbery material (5) that is going to act as isolator or cushion. The hardness of the inner and intermediate sleeves can be selected according to the swaging operation that interlocks them with full complement balls interposed upon.
The effect of the assembly with the inner sleeve {2), intermediate sleeve (4) and the balls (3) which are in large numbers so as to reduce the contact stress matching the sleeve hardness, constitute the ball bush which is equal to one needle bearing and two thrust bearing back to back that can be built by two combi bearings that are commercially available in the market. Further the accompanied drawings will clearly explain the invention.

We Claim:
1. A silent bush with integral biaxial combination antifriction bearing comprises of a special antifriction combination bearing that can take radial load and biaxial loads which could be accommodated within the boundary limits and not damage the packing material that isolates the torsional and radially transmitted noise and vibration that originates from the shaft to the housing.
2. The antifriction bearing as claimed in claim 1 wherein there is at least three sleeve arrangements.
3. The antifriction bearing as claimed in claim 2, where in the outer and intermediate sleeves are bonded together to form a single assembly by the rubber material.
4. The antifriction bearing as claimed in claim 3, where in the rubber material acts as cushion or isolator for noise and vibration.
5. The anti friction bearing as claimed in claim 1, wherein the inner sleeve is made of thin ferrous metal sheet having a bell mouth flange on the one end and another which is made on the assembly.
6. The anti friction bearing as claimed in claim 5, wherein the radius of the bell mouth flange is slightly more than that of the ball that is being used in the construction of the anti friction bearing.
7. The anti friction bearing as claimed in claim 2, where in the intermediate sleeve also has a bell mouth shape at both ends, but swaged into a stepped cylinder at the ends.
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8. The anti friction bearing as claimed in preceding claims , wherein the end shapes of the inner and intermediate sleeve constitute two pairs of inner race and outer race of angular ball bearings of pressure angle between 30 to 45 degrees.
9. The anti friction bearing as claimed in claim 8, wherein the pressure angel depends on the axial loads proportion to that of the radial load coming on the bushes.
10. The anti friction bearing as claim in preceding claims wherein the hardness of the inner and intermediate sleeves are selected per the swaging operation that interlocks them with full complement balls interposed.
11. The use of antifriction bearing as claimed in preceding claims to reduce the contact stresses matching the sleeve hardness to match with the commercial sets of combi-bearings.
12. The antifriction bearing substantially as herein described with reference to the accompanying drawing.