C Combined Needle Roller Bearings C Drawn Cup Roller Clutches C Needle Roller Bearing Accessories The mating shaft and housing are normally used as inner and outer raceways. The unitized design allows for easy handling and installation.
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C Combined Needle Roller Bearings C Drawn Cup Roller Clutches C Needle Roller Bearing Accessories The mating shaft and housing are normally used as inner and outer raceways.
The unitized design allows for easy handling and installation. Controlled-contour rollers reduce end stresses and permit operation under moderate misalignment. A variety of cage designs, styles and materials, as well as multiple roller paths and segmented constructions, meet broad application requirements. Page Introduction. C22 Connecting Rod Guidance Arrangements.
C24 Connecting Rod Applications. This catalog includes the most popular, standardized and non-standard designs. Needle roller and cage radial assemblies have a steel cage that provides both inward and outward retention for the needle rollers.
The designs provide maximum cage strength consistent with the inherent high load ratings of needle roller bearings. Accurate guidance of the needle rollers by the cage bars allows for operation at high speeds. Needle roller and cage assemblies have either one or two rows of needle rollers. Also listed are metric series needle roller and cage assemblies using molded, one piece glass reinforced engineered polymer cages suffix TN. These operate well at temperatures up to.
At such high temperatures oil can deteriorate with time and it is suggested that oil change intervals are observed. Needle rollers with relieved ends used in these assemblies are made of high carbon chrome steel, through-hardened, ground and lapped to close tolerances for diameter and roundness. See the engineering section of this catalog for further discussion of relieved end rollers. Metric series needle roller and cage radial assemblies are supplied with needle roller complements subdivided into groups gages shown in Table 1.
The group limits of the needle rollers are indicated on the package. Labels of identifying colors show the group limits of the needle rollers. The needle roller and cage assemblies of one shipment usually contain needle rollers with group limits of between 0 to -2, and -5 to -7 mm colors red, blue and white.
Information on needle roller and cage assemblies with needle rollers of different group limits will be supplied on request. Needle roller and cage radial assembly must be axially guided by shoulders or other suitable means. Length tolerance H11 is suggested.
If end guidance is provided by a housing shoulder at one end and by a shaft shoulder at the other end the shaft must be axially positioned to prevent end locking of needle roller and cage assembly. The housing and shaft shoulder heights should be 70 to 90 percent of the needle roller diameter to provide proper axial guidance. In order to realize full bearing load rating and life the housing bore and the shaft raceways must have the correct geometric and metallurgical characteristics.
Additional design details for housings and shafts used as outer and inner raceway can be found in the engineering section of this catalog. The only limit to precision of the radial clearance of a mounted assembly is the capability of the user to hold close tolerances on the inner and outer raceways. The suggested shaft tolerances listed in Table 2 are based on housing bore tolerance G6 and apply to metric series radial needle roller and cage assemblies with needle rollers of group limits between P0M2 and M5M7.
Where assemblies are subjected to high centrifugal forces, such as in epicyclic gearing, or inertia forces as in the small end of a connecting rod, the contact pressure between the cage and the raceway guiding surface becomes critical. Consult your Timken representative when cages will be subjected to high induced forces. Special coated or plated cages to enhance life under conditions of marginal lubrication and high induced forces can also be made available.
Connecting rods have two bearing positions: the crank pin or big end and the wrist pin or small end. In the crank pin position there may be severe operating conditions due to centrifugal forces, internal forces, accelerations and high rotational speeds, requiring the use of special needle roller and cage radial assemblies. Similarly, in the wrist pin position the reciprocating inertia loads and high oscillating speeds dictate the use of special cage designs.
Needle roller and cage assemblies for use in crank pin positions have cages with a large outside cylindrical surface to ensure optimum radial guidance in the connecting rod bore. Due to the inherent low weight and strength of the heat-treated cages, the needle roller and cage assemblies are well-suited for high engine speed applications. When necessary, silver plating and copper plating can be applied for optimum performance during operation at high speeds.
Reciprocating inertia loads and oscillating speeds require the cages used in the wrist pin positions to be heat treated and to guide on the wrist pin. These cages are available in a variety of widths to allow the selection of a needle roller and cage assembly with the length of needle rollers to match the connecting rod width.
SIZE SELECTION In most instances selection of a suitable size of a needle roller and cage assembly for typical connecting rod positions may be based on the cylinder displacement of the engine which in turn, dictates the crank pin and wrist pin diameters.
Suggestions based on engine displacements are listed in the following table. Connecting rod guidance is achieved at the crank pin end using a small clearance between the crank webs.
Guidance at the wrist pin end is controlled by a small clearance between the piston bosses. With crank pin end guidance care must be taken that an adequate amount of lubricant is supplied to the crank pin bearing and the surfaces which guide the connecting rod.
For this purpose, grooves in the connecting rod end faces or slots in the connecting rod bore aligned with the incoming lubrication path should be provided.
Occasionally, bronze or hardened steel washers may be used for end guidance of the connecting rod. At the wrist pin end, the needle roller and cage assembly is located axially between the piston bosses. It may be both economical and effective to machine the connecting rod at the wrist pin end and at the crank pin end to the same width. It is suggested that at the wrist pin end the needle roller length does not overhang the connecting rod width.
Otherwise, the load rating of the needle roller and cage assembly will be reduced. Wrist pin end will get the most effective axial guidance between the piston bosses.
The length of the needle roller and cage assembly and the connecting rod width at the crank pin end should be identical to ensure best possible radial piloting of cage in the bore of the connecting rod. The crank webs are recessed to allow proper axial alignment of the connecting rod. As a rule, it is not necessary to have additional supply of lubricant. Only in engines with sparse lubrication should consideration be given to provide lubricating slots in the connecting rod bores as with crank pin end guidance.
The effective case depth 50 HRC of the raceways should be 0. After hardening, the connecting rods must be stress relieved.
The high speeds of modern production engines dictate the need for crank pin bearings with a relatively large radial clearance. The maximum radial clearance would be a result of the sorting plan shown in Table 3. As shown in the example of the matching scheme, the suggested mounting diameters for the crank pin position are G6 for the connecting rod bore diameters and h5 for the crank pin diameters.
Axial location of the cage is shown on the crank pin end guidance arrangement. Racing and sport engines operate at yet even higher speeds than production engines, requiring 50 percent larger radial clearances in the crank pin bearings. The larger radial clearances should also be used in bores of split connecting rods to avoid the danger of distortion resulting from the unavoidable connecting rod deformation occurring in operation.
Consult your Timken representative for advice on such applications. The radial clearance in wrist pin bearings should be held as small as possible. The minimum clearance should be aimed at 2 mm with the maximum clearance resulting from the proposed sorting plan in Table 3. The maximum clearance should be held as close as possible to 12 mm for all wrist pin bearings based on sorting wrist pins made to a tolerance h5, small end bore diameter tolerance of K6 and needle roller grades as shown in Table 3.
Crank pins: e. Wrist pins: e. It is suggested that the parallelism of the wrist pin axis and the crank pin axis be within a tolerance zone of 0. This catalog includes the most popular standard designs. Also available on request are needle roller and cage assemblies using molded, one piece glass reinforced engineered polymer cages.
Within any one assembly, the needle rollers have a total diameter tolerance of. The limit to precision of the radial clearance of mounted needle roller and cage assemblies is the capability of the user to hold close tolerances on the inner and outer raceways. The tolerance of the overall width of these assemblies is given on the tabular pages of this section.
The cage and needle roller assembly normally uses the shaft and housing as the inner and outer raceways. In order to realize full bearing load rating and life, the shaft and housing must have the correct geometric and metallurgical characteristics. The tables of dimensions for these assemblies list the suggested diameters for the shaft when used as the inner raceway.
These are consistent with ISO h5 shaft raceway tolerances. Additional design details for shafts used as inner raceways can be found in the engineering section of this catalog. Since the housing normally serves as the outer raceway, it should be of sufficient cross section to maintain adequate roundness and running clearance under load.
The tables of dimensions also list the suggested diameters for the housings when used as outer raceways. These are consistent with ISO G6. There are two primary constructions of inch series needle roller and cage assemblies.
The WJ assemblies generally employ larger diameter needle rollers whereas the WJC assemblies normally employ smaller diameter needle rollers. Additional design details for housings used as outer raceways can be found in the engineering section of this catalog.
The suggested mounting diameter tolerances for these needle roller and cage assemblies will provide correct running clearance for most applications. The needle roller and cage assembly must be axially located by shoulders or other suitable means. End locating surfaces should be hardened to minimize wear. For satisfactory operation, minimum axial clearance should be 0. Oil is the preferred lubricant for most applications. In critical applications involving high speeds, ample oil flow must be provided.
Where assemblies are subjected to high centrifugal forces, such as in epicyclic gearing, or inertia forces, as in the small end of a connecting rod, the contact pressure between the cage and the raceway guiding surface becomes critical.
Special plated cages to enhance life under conditions of high induced forces can also be made available.
Catalogo Rolamento Conico Timken
Our expertise in metallurgy, friction management and mechanical power transmission helps them accelerate improvements in productivity and uptime. We supply products and services that can help keep your operations moving forward, whether you need drive train kits for commercial vehicles, durable housings for bearings in dirty environments, couplings that avoid metal-to-metal contact between motors and gearboxes, repair services for rail bearings, steel for an aircraft engine shaft, For example, we offer repair services and equipment monitoring equipment that can alert you to problems before they impact your uptime. Additionally, we offer a broad selection of seals, premium lubricants, lubricators, couplings and chain to keep your operations moving smoothly. Timken engineers designed special housings to withstand tough challenges on the job.
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