Timken Mounting Guide

Download (PDF, 1000.35KB)

Timken Mounting Guide TABLE OF CONTENTS PAGE Product Information. . . . . . . . . . . . . . . . . . . . . . . . 2-7 Wide Inner Ring bearings . . . . . . . . . . . . . . . 2-3 Housed Units. . . . . . . . . . . . . . . . . . . . . . . . . 4-5 Spherical Roller bearings. . . . . . . . . . . . . . . . 6-7 Internal Clearances. . . . . . . . . . . . . . . . . . . . . . . 8-12 Installation of Drawn Cup bearings. . . . . . . . . . . . . 13 How to Inspect a bearing journal or housing bore. . . . . . . . . . . . . . . . . . . . . . . . . 14-16 Shaft and Housing Fits. . . . . . . . . . . . . . . . . . . 17-39 Shaft Design – Needle bearings. . . . . . . . . . . . . . . 40 Housing Design – Needle bearings . . . . . . . . . . . . 41 Shaft and Housing Shoulders. . . . . . . . . . . . . . 42-44 Tables. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45-46 Torrington Shaft Mounting Accessories . . . . . . . . . 47 INTRODUCTION The intent of this mounting guide is to provide the information you need to properly mount Timken® Torrington® ball, roller and needle bearings. For addi­tional assistance please feel free to contact a Timken Authorized Distributor or sales office in your area. For your nearest Timken sales representative, call (800) 223-1954. Outside the U.S. and Canada, call (330) 438-3000. The Timken® Fafnir® line from The Timken Company originated the wide inner ring bearing design for ball bearings which could be easily mounted on straight shafts and positioned without shoulders, locknuts or adapters. The internal bearing construction is basically the same as the deep race, single row radial type with ability to carry radial, thrust and combined loads, while providing low friction qualities which are characteristic of high-grade bearings. The inner ring is generally extended on both sides of the race to provide additional shaft support, and is locked to the shaft by specially designed setscrews or by the Timken-originated, eccentric self-locking collar or concentric collar. The wide inner ring bearings are also available with cylindrical or spherical outside diameters. The cylindrical or straight O.D. type is used for mounting in straight-bored housings. The spherical O.D. type must be mounted in a corresponding spherical seat and is used to compensate for shaft or housing misalignments. FAFNIR WIDE INNER RING BEARINGS WITH LOCKING COLLARS The following series are available with the cam (self-locking) collar. RR Series These bearings feature the flareout, contact type R-seal which encloses a synthetic rubber impregnated washer between two metal caps. Most sizes incorporate the Fafnir Shroud-Seal design. R-seal wide inner ring bearings are available in the following non-relubricatable variations: KR (one seal, cylindrical O.D.), RR Series KRR and KRRB (two seals). Relubricatable versions are: G-KRR, G-KRRB and GN-KRRB (heavy-duty). RA-RR Series The RA-RR series features an extended inner ring and self-locking collar for simple effective shaft retention in a standard series bearing. The newly developed, positive contact, land-riding R-seal provides improved protection against the heavy contamination encountered in many applications. All sizes have a heat stabilized, moisture conditioned 6/6 nylon retainer which has proven extremely effective under conditions of misalignment. RA-RR extended inner ring bearings are available as RA-RR (two-seals, straight O.D. ) and RA-RRB (two seals, spherical O.D. ). Relubricatable versions are GRA-RR and GRA-RRB. RA-RR Series Tri-Ply-Seal Series Tri-Ply Seal bearings are designed for environments where severe conditions and moisture are present. The new one piece Tri-Ply seals incorporate a highly effective seal design molded to an exterior shroud cap. The shroud cap protects the seal lips from fiber wrap and abrasion while enhancing the overall sealing effectiveness of the unit. All units incorporate the self-locking collar and have a nylon retainer. Tri-ply Seal bearings are available in both a non-relubricatable (KPPB) and relubricatable version (G- KPPB). Tri-Ply-Seal Series External Self-Aligning Series The construction of this series permits the inner assembly, which contains an open type ball bearing with spherical O.D. to align in the seat of the mating outer ring. The seat of this outer ring is matched with the spherical O.D. of the ball bearing outer ring providing unrestricted self-alignment which allows the inner assembly to become square and true with the shaft. Self-aligning units are available in both standard SM-S or heavy SMN-S series. RA-DD Series Bearings External Self-Aligning Series The new RA-DD series bearings are extended inner ring type with cam locking collars. They incorporate two close fitting non-contact grease shields to effectively retain lubricant and provide protection against harmful contaminants. The non-contact metallic shields provide improved high speed and low torque performance such as required for high speed printing press applications. The 6/6 molded nylon retainer has proven extremely effective under conditions of misalignment. These bearings are dimensionally inter­changable and have the same load capacities as the RA-RR series. (Available in 5/8"-1 1/2" shaft sizes.) RA-DD Series WIDE INNER RING BEARINGS WITH SETSCREW LOCKING DEVICE The following series are available with the setscrew locking device with special setscrews that are resistant to loosening during operation. YA-RR series The (G)YA-RR(B)series relubricatable and non-relubricatable bearings are an extended inner ring type with specially designed setscrews. Positive contact land-riding R-Seals provide protection against harmful contaminants and retain lubricant. Setscrew Series bearings are available in both non-relubricatable version YA-RRB and relubricatable version GYA-RRB. Both types have nylon retainers. YA-RR Series ER Series This series offers industry standard mounting dimensions and standard nomenclature for a large variety of sizes of relubricatable, extended inner ring bearings for through-bored housings. All bearings in this series have nylon retainers and are equipped with snap rings which eliminate the need for machining housing shoulders. Positive contact landriding R Seals provide protection against harmful contaminants and retain lubricant. ER bearings are all black oxide coated for corrosion resistance. ER Series FAFNIR WIDE INNER RING BEARINGS WITH CONCENTRIC COLLARS GC-KRRB Series The GC-KRRB wide inner ring bearings are relubricatable with spherical outside diameters, nylon retainers and shroud seals. The metal shroud maintains tight seal contact against the inner ring and shields the rubber seals from damage due to dirt or fiber wrap. The concentric collar is locked to the shaft by two setscrews, located 120° apart, which are mated with threaded holes in the collar and drilled holes in the bearing inner ring. CAM (SELF-LOCKING) COLLAR GC-KRRB Series 1. Observe cam design of the wide inner ring and self locking collar. 2. Mate the cam of the collar with the cam of the wide inner ring. 3. Press the locking collar against the wide inner ring and turn in the direction of shaft rotation until tightly engaged. 4. With drift pin in collar hole, strike in direction of shaft rotation to lock. For Stationary shafts and outer ring rotation, turn collar in opposite direction of rotation. CONCENTRIC COLLAR For simplified installation, the concentric collar is normally assembled to the wide inner ring for shipment. Slip the complete unit on the shaft and tighten both setscrews. 5. Tighten setscrew in collar. Ball Bearing housed units, originated by Timken’s own Fafnir line, are available in a wide variety of types and sizes to accomodate a complete range of operating conditions. These units generally have cast iron housings and are designed for mounting on straight shafts with a slip fit. The self-locking collar and the setscrew inner bearing designs provide ease in mounting, bolt holes in housings take standard bolts for assembling these units to machinery frames. Several series are also available with the concentric locking collar. As most of these units are made with a self aligning feature, it is unnecessary for the user to refine his design in excess of practical limits. If desired, units incorporating prelubricated wide inner ring bearings may be furnished without grease fittings. There are several basic types of housed units available: Pillow Blocks, Flanged Cartridges, Flangette Units, Cylindrical Cartridges and Take-up Units. The type required is generally determined by its application and mounting requirements. Within the basic type selected, numerous variations allow for load factors, shaft sizes, mounting surface dimensions, base to shaft center line heights and lubrication requirements. PILLOW BLOCKS Pillow blocks, the most commonly used type of mounted units, are designed to provide shaft support where the mounting surface is parallel to the shaft axis. The bolt holes are usually slotted for adjustment during mounting. Pillow blocks are supplied in both standard and heavy duty series. Pressed steel and rubber pillow blocks are also available for light duty applications. FLANGED CARTRIDGES Flanged cartridges are used where a shaft passes through the machine frame at a right angle. A four bolt mounting is the most common, however, where the mounting area is restricted, three and two bolt versions are available. A piloted flanged cartridge, also available, provides additional mounting accuracy and support. Flanged cartridges are supplied in both standard and heavy duty series. Iron and rubber flanged cartridges are also available. A complete line of Flangette Units, pressed steel flanged cartridges, provides an economical solution to light duty applications. Two, three and four bolt mountings are available along with a relubricable version. CYLINDRICAL CARTRIDGES Cylindrical cartridges, like flanged cartridges, provide shaft support where the shaft axis is perpendicular to and passing through a machined housing which is generally very thick. The outside diameter of the cylindrical cartridges permits mounting with a press fit into a straight, through-bored housing. Cylindrical cartridges have a machined spherical bearing seat to provide initial shaft alignment in standard duty applications. Synthetic, conductive rubber cylindrical cartridges are also available for applica­tions where low cost, light duty, low noise operation is essential. TAKE-UP UNITS Take-up units are used where shaft adjustment and belt tightening devices are required, such as conveyor applications. Frames for take-up units provide for either side or top mounting. Take-up units are available in cast iron for standard duty and pressed steel for economical, light duty applications. FAFNIR SELF-LOCKING COLLAR INSTALLATION Most Timken Fafnir housed units come equipped with the self-locking collar to facilitate the mounting of wide inner ring bearings. This self-locking collar eliminates the need for locknuts, washers, shoulders, sleeves, and adapters. The locking collar has a counterbored recess which is made purposely eccentric to the bore. The collar recess and the end of the bearing inner ring with which it engages are both machined so that they act as mating cams when on the shaft. When the collar is engaged to the inner ring, it grips the shaft tightly with a positive binding action that increases with use. No adjustments of any kind are necessary. 1. Slip the shaft through the pillow block or other Fafnir housed unit which incorporates the wide inner ring bearing. Be certain the bearing is aligned in position along the shaft to eliminate any possibility of cramping loads. 2. Fasten the unit securely to the base using the proper bolt size. 3. Place the self-locking collar on the shaft with its cam adjacent to the cam on the end of the bearing’s inner ring. Turn the collar in the direction of shaft rotation. The eccentric recessed cam will slide over and engage the corresponding cam on the bearing inner ring. 4. Using a lightweight hammer and a drift pin inserted in the drift pin hole strike in the direction of shaft rotation to positively engage the collar. The wide inner ring is now locked to the shaft. 5. As a final step, fully tighten the setscrew. It exerts a wedging action to hold the collar always in the engaged position, even under shock load. This Fafnir design will operate effectively after the cams are tightly locked in most cases with no setscrews at all. FAFNIR SETSCREW LOCKING BEARING Steps 1 and 2 can be repeated from the Self Locking Collar Installation above. To lock the setscrew bearing, simply tighten each inner ring set­screw to the recommended torque listed by shaft size. See chart below. Recommended Shaft Size in/mm Torque in lbs. (n • m) 1/2­11/16 3/4 -1 11/16 -1 3/4 17 mm 20-25 mm 30-45 mm 35 in lbs 80 in lbs 155 in lbs 4 (n • m) 9 (n • m) 18 (n • m) 113/16 -2 3/16 50-55 mm 275 in lbs 31 (n • m) It may be necessary to rotate the shaft to provide an easy access of the setscrew wrench to the setscrews. To disassemble, loosen the setscrews. CONCENTRIC COLLAR For simplified installation of Fafnir housed units equipped with concentric collar bearings, the collar is normally assembled to the wide inner ring for shipment. Slip the complete unit on the shaft following steps 1 and 2 described for the self-locking collar procedure, and tighten both setscrews. MOUNTING PROCEDURES – TORRINGTON SPHERICAL ROLLER BEARINGS Depending on the size of bearing and the application, there are different methods for mounting rolling bearings. In all methods, however, certain basic rules must be observed. Cleanliness Choose a clean environment. Work in an atmosphere free from dust or moisture. If this is not obtainable, and sometimes in the field it isn’t, the installer should make every effort to insure cleanliness by use of protective screens, clean clothes, etc. Plan the work Know in advance what you are going to do and have all necessary tools at hand. This reduces the amount of time for the job and lessens the chance for dirt to get into the bearing. Inspection and preparation All component parts of the machine should be on hand and thoroughly cleaned before proceeding. Housings should be cleaned, including blowing out the oil holes. Do not use an air hose on bearings. If blind holes are used, insert a magnetic rod to remove metal chips that might have become lodged there during fabrication. Shaft shoulders and spacer rings contacting the bearing should be square with the shaft axis. The shaft fillet must be small enough to clear the radius of the bearing. On original installations, all component parts should be checked against the detail specification prints for dimensional accuracy. Shaft and housing should be carefully checked for size and roundness. Shaft and housing finish Shaft surfaces on which the bearing will be mounted must be clean and free from nicks or burrs. For an application with stationary housing and rotating shaft, it is suggested the bearing seat on the shaft be ground to 63 RMS maximum. If it is impractical to use a ground finish, a machined finish of 125 RMS is acceptable in many cases, but the amount of interference fit should be slightly increased. Consult our Engineering Department for recommendations. For a stationary outer ring which is required to float (i.e. slide axially in the housing), a housing surface finish of 63 RMS maximum is suggested. Where the outer ring is not required to float, a surface finish of 125 RMS maximum is generally satisfactory. DON’T REMOVE THE BEARING FROM ITS WRAPPER UNTIL ACTUALLY READY TO MOUNT IT. MOUNTING STRAIGHT BORE BEARINGS Heat expansion method Most applications require a tight interference fit on the shaft. Mounting is simplified by heating the bearing to expand it sufficiently to slide easily onto the shaft. Two methods of heating are in common use: 1. Tank of heated oil. 2. Induction heating. The first is accomplished by heating the bearing in a tank of oil having a high flash point. The oil temperature should not be allowed to exceed 250° F. A temperature of 200°F is sufficient for most applications. The bearing should be heated at this temperature, generally for 20 or 30 minutes, until it is expanded sufficiently to slide onto the shaft very easily. The induction heating method is particularly suited for mounting small bearings in production line assembly. Induction heating is rapid, and care must be taken to prevent bearing temperature from exceeding 200° F. Trial runs with the unit and bearing are usually necessary to obtain the proper timing. Thermal crayons (such as Tempilstics*) which melt at predetermined temperatures can be used to check the bearing temperature. While the bearing is still hot, it should be positioned squarely against the shoulder. Lockwashers and locknuts, or clamping plates, are then installed to hold the bearing against the shoulder of the shaft. As the bearing cools, the locknut or clamping plate should be tightened. In cases of outer ring rotation, where the outer ring is a tight fit in the housing, the housing member can be expanded by heating. The oil bath is shown in Figure 1. The bearing should not be in direct contact with the heat source. The usual arrangement is to have a screen several inches off the bottom of the tank. Small support blocks separate the bearing from the screen. It is important to keep the bearing away from any localized high-heat source that may raise its temperature excessively, resulting in race hardness reduction. Figure 1: Heat Expansion Method OIL BEARING BEARING SUPPORT BLOCK BEARING HELD FROM BOTTOM BY SCREEN FLAME BURNER Flame-type burners are commonly used. An automatic device for temperature control is desirable. If safety regulations prevent the use of an open heated oil bath, a mixture of 15% soluble-oil in water may be used. This mixture may be heated to a maximum temperature of about 200° F., without being flammable. The bath should be checked from time to time to insure its proper composition as the water evaporates. The bath leaves a thin film of oil on the bearing sufficient for temporary rust prevention, but normal lubrication should be supplied to the bearing as soon as possible after installation. Be sure all of the soluble-oil in water solution has been drained away from the bearing. Arbor press method The alternative method of mounting, generally used only on smaller sizes, is to press the bearing onto the shaft or into the housing. This can be done by using an arbor press and a mounting tube as shown in Figure 2. The tube can be of soft steel with inside diameter slightly larger than the shaft. The O.D. of the tube should not exceed the maximum shoulder height. The tube should be faced less than the recommended housing shoulder diameter in the tables of dimensions. Coat the shaft with light machine oil to reduce the force needed for the press fit. Carefully place the bearing on the shaft making sure it is square with the shaft axis. Apply steady pressure from the arbor ram to drive the bearing firmly against the shoulder. Never attempt to make a press fit on a shaft by applying pressure to the outer ring, or a press fit in a housing by applying pressure to the inner ring. * Registered Trademark, Tempil Corp.
If you liked this, please tell us:
  • Facebook
  • Twitter
  • email
  • Print
  • Add to favorites
  • Google Bookmarks
  • RSS
This entry was posted in Bearings and tagged , , , , . Bookmark the permalink.


Your email address will not be published. Required fields are marked *


Captcha Captcha Reload

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>