Cage & Needle Roller Assemblies

Transcription

1 Cage & Needle Roller Assemblies NSK cage and needle roller assemblies are high-quality products that offer users higher reliability and greater ease of handling and installation.

2 Adaptable to severe operating conditions, including strong impact load, complex operations, and high temperatures Easy handling 2. High load capacity 3. High limiting speed 4. Long life Unitized design facilitates easy handling and installation. Low cross-section provides high load capacity within the smallest envelope. Properly lubricated, the cage structure guides the rollers precisely enabling high-speed operations. Roller crowning reduces stress on the roller ends and prolongs bearing life. 2

3 NSK cage and roller assemblies consist of a complement of needle rollers held in place by a cage. Their unitized design makes for easy handling and installation. With no inner or outer ring, the low cross-section provides maximum loadcarrying capability within the smallest envelope. Properly lubricated, they can operate at high speeds thanks to the unique cage, which guides the rollers precisely. The controlled contour rollers in cage and roller assemblies have an optimum profile, which reduces end stress, allows operation under moderate misalignment and prolongs bearing life. 2. Specification Number An example of a bearing specification number is as follows: Example: FWF Design and Types The most common cage used in cage and roller assemblies is the M type. M-type cages are either pressed from steel plate or machined. These cages undergo surface hardening after processing to attain high wear-resistance and rigidity. The cages facilitate optimum lubricating conditions because lubricant can be easily replenished. Other cages include those made by precision pressing, welded cages, and polyamide molded cages. Welded cages produced by welding pressed steel are especially suited for mass production. Applying its considerable experience and knowledge, NSK supplies cage and roller assemblies of the highest quality. Codes for the various types of cage and roller assemblies are shown in Table 1. There are many types of cage and roller assemblies other than those in Table 1, including split cages. Code Width (mm) Inscribed circle diameter (mm) Circumscribed circle diameter (mm) For inch bearings, each dimension is expressed with two-digit whole numbers in units of 1/16 of an inch following the code. Cage Type Table 1 Cage and Roller Assembly Codes Code Metric Inch Example 3. Accuracy Standard NSK cage and roller assemblies usually use rollers classified as JIS Class 3 or higher. Roller accuracy is shown in Table 2. M Cage FWJ, FWF WJ Class Tolerance in Average Value of Diameter Table 2 Accuracy of Needle Rollers Diameter Variation in a Single Radial Plane, ( 1 ) Deviation from Circular Form, ( 1 ) Diameter Variation within Gauge Lot, ( 1 ) Units: µm Deviation in Length, ( 2 ) FBN Cage FBN high low VD WP max h13 R max VD WL max L WS Single Row Welded Cage FWJC, FWJW FWJE h h13 Polyamide Cage FBNP Note ( 1 ) Applies at the center of roller s length. ( 2 ) Depends on L w classification. h13 is shown in Table 3. Remarks Deviation between the actual measured diameter at any point over the entire length of roller and the actual maximum diameter at the center of the entire length must not exceed the following values: Class 2: 0.5 µm Class 3: 0.8 µm Class 5: 1.0 µm M Cage FWF W Table 3 Tolerance of Deviation in Length Units: mm FBN Cage FBN W Basic Dimension h13 over incl. over incl. Double Row Welded Cage FDJC, FDJS Polyamide Cage FBNP W

4 4. Applications to Maximize Performance Mounting In cage and roller assemblies, the shaft and housing are generally used as raceway rings. It is important to satisfy the finish accuracy and hardness requirements in Table 4. Guide width for cage and roller assemblies The tolerances for the guide width, b, are based on cage width, B c, and shown in Table 5 (see Fig. 1). Accuracy and roughness of the raceway surface The shaft and housing bore of cage and roller assemblies In particular, harmful circumferential waviness and a are often used as raceway surfaces of needle bearings in polygonal shape are undesirable. Accuracy and roughness order to achieve the most compact bearing design and for raceway surfaces are shown in Table 4. Since these enhance shaft rigidity, load capacity, and accuracy. values may change depending on the desired Accuracy and roughness of the raceway surface greatly performance, please contact NSK. affect the life, noise, and accuracy of bearings. Therefore, shape, accuracy, and roughness have to be treated with great care. Table 4 Accuracy and Hardness for Shaft and Housing Fillet radius Table 5 Tolerance for Guide Width, b Type Metric Inch Tolerance for b +0.2 B c B c +0.2 Units: mm B c b Fig. 1 Guide Width The fillet radius of the shaft and housing shoulder in contact with the cage end surface should not interfere with the cage itself. Item Shaft Housing Out-of-Roundness Tolerance Cylindricity Tolerance IT3 2 IT3 2 IT3 2 IT3 2 Fitting tolerances for shafts and housing bores Fitting tolerances for shafts and housing bores under various operating conditions are shown in Table 6. Roughness, R a Hardness HRC58 to 64 Appropriate depth of hardened layer required HRC58 to 64 Appropriate depth of hardened layer required Operating Conditions Table 6 Fitting Tolerances for Shafts and Housing Bores High Accuracy, Normal Oscillating Motion High Temperature, Large Shaft Deflection, Mounting Error Fitting Tolerance for Housing Bore G6 G6 G6 Material and heat treatment of raceway furnace The raceway rings and rollers of needle bearings are repeatedly stressed on their relatively small contact surfaces. The materials for raceway rings, rollers, and shafts and housings that function as raceways, must therefore have high hardness, resistance to permanent deformation, and long rolling fatigue life. These materials are also required to be resistant to wear and shock, and have good dimensional stabilization. Common materials used for shafts and housings that function as bearing raceways include the following: Carbon steel for machine construction (for carbonizing) S15CK (JIS G 4051) Chrome molybdenum steel (for carbonizing) SCM415~421 (JIS G 4105) Chrome steel (for carbonizing) SCr415, 420 (JIS G 4104) Nickel chrome steel (for carbonizing) SNC415~815 (JIS G 4102) Nickel chrome molybdenum steel (for carbonizing) SNCM220, 415, 420 (JIS G 4103) JIS: Japanese Industrial Standard Other materials, such as S50C and S55C, can be utilized The hardened layer, which is tempered at a temperature between 160 C and 180 C after hardening, has to develop a martensite structure with an even distribution of very fine carbides. In the case of cemented or induction hardening of the raceway surface, the surface hardness should not only be HRC58 to 64 (HRC60 to 64 is preferable), but also, the hardened layers with Vickers hardness of HV 653 (HRC58) and HV550 (HRC52.3) have to reach appropriate depths. When the values of hardness are below these values, bearing fatigue life significantly decreases. The hardened layer depth (up to HV550) after grinding finish is estimated by using the following equation: t (0.08~0.10) D w where, t: Effective hardened layer depth (mm) D w : Roller diameter (mm) Core hardness is generally HRC30 to 45. Fitting Tolerance for F w 50 mm j5 Shaft F w > 50 mm h5 Shaft inclination Permissible shaft inclinations from elastic deflection by an external force and mounting error are shown in Table 7. When shaft inclination exceeds that in this table, please contact NSK, as it is necessary to change the amount of roller crowning and increase internal clearance. h5 f6 g5 Table 7 Shaft Inclination Cage Width (mm) Permissible Inclination (mm/mm) over incl with through hardening or induction hardening. 5 6

5 M Cage FBN Cage Welded Cage Polyamide Cage ➀ ➁ ➂ ➃ ➄ ➆ ➇ (includes inch design) FBNP-476Z ➇ FBNP ➇ FBNP ➇ FBNP ➇ FBNP ➇ FBNP ➇ FBNP ➇ FBN ➁ FBN ➁ FBN ➁ FBN ➁ FBN E ➁ FBN A-E ➁ FBN ➁ FBN ➁ FBN ➁ FBN ➁ FWF ➀ FWF ➀ FWF ➀ BN ➀ FWF ➀ FWF ➀ FWF ➀ FWF ➀ FWF ➀ FWF ➀ FWF ➀ FWF ➀ FWF ➀ FWF A ➀ FWJS-15209Z ➇ WJ ➂ FWF ➀ FWF ➀ FWF ➀ FWF ➀ BN501622E ➀ FWF ➀ FWF ➀ FWF ➀ FWF ➀ FWF ➀ FWF ➀ FWF ➀ FWF ➀ FWF ➀ FWJC ➇ FWJ ➂ FBNP ➆ FWF Z ➀ FWF Z ➀ FWF ➀ FWF ➀ FWF ➀ FBN W FWF ➀ FWF ➀ FWJ ➂ FWF A ➀ FWF ➀ FWF ➀ FWF ➀ FWF ➀ FBN Z-E ➁ FBNP ➆ FWJ ➂ BN ➃ WJ ➂ FWJ ZB ➂ FWJ Z ➂ FWF ➀ FWF ➀ FWF ➀ FWF ➀ FWF ➀ FWF ➀ FWF ➀ BN E ➀ FWJ ➂ FWF ➀ FWF ➀ FWJE ➄ FWF ➀ 7 8

6 ➀ ➁ ➂ ➃ ➄ ➅ ➇ BN ➀ BNE ➂ FWF ➀ FWF ➀ FWF ➀ FWF ➀ FWF A ➀ FWF ➀ FWF ➀ FBNP Z ➇ BN E ➀ FWF ➀ FWF ➀ FWF HSC ➀ BN ➂ FWJ A ➃ BN ➀ WJ ➂ FWF ➀ BN502311A-E ➀ FWF ➀ FWJC A ➇ FWF ➀ FBN W FBN ➁ FWF ➀ FWJ ➃ FWJE ➄ FBNP Z ➇ FWF ➀ FWF ➀ FWF ➀ FWF ➀ FWF ➀ FWF ➀ FWF ➀ FDJC FWF ➀ FWF ➀ FWF ➀ FWF ➀ FWF ➀ FWJN ➂ FWJ ➂ FWJ B ➂ FWJ H ➂ BN ➀ FWJ Z ➂ BN ➀ BN502526W ➇ WJ ➂ WJ ➂ FWF ➀ FWF ➀ FBN ➁ BN E ➀ BNE ➂ FWF ➀ FWJC ➇ FBNP ➇ FWF ➀ FWJ ➂ BN ➀ FWF ➀ FWF ➀ FWJW ZA ➅ BN E ➀ BN ➀ BN E ➀ FWJ Z ➃ BN ➀ FWF ➀ FWF ➀ FWF ➀ FWJ A ➂ FWF A ➀ FWJ ➃ FWF ➀ FWF ➀ BN ➀ FWF ➀ FWF ➀ FWF ➀ FWF ➀ 9 10

7 ➀ ➁ ➂ ➃ ➄ ➅ ➆ ➇ ➈ ➉ FWF ➀ FWF ➀ BN ➂ FWF ➀ BN503036A ➀ FWF ➀ BN ➀ BN ➀ BN ➀ BN ➂ BN ➂ BN ➂ FWF ➀ BN ➂ BN ➀ BN503002A ➀ BN503002E ➀ BN503002G ➀ FWJ ➃ WJ ➂ WJ ➂ WJ ➂ FBNP Z ➇ FBN WA FWF ➀ FWJ ➂ FWJ ➂ FWJ ➂ FWF W ➉ FWJE ➄ FWJW ➅ FWF ➀ FBNP Z ➇ FWJ ➂ FWF ➀ BN ➀ BN ➀ BN ➂ BN503230A ➂ BN ➀ BN ➀ FBNP ZA ➇ FWJ ➃ WJ ➂ WJ ➂ FBNP Z ➈ FWF YG ➀ FWF ➀ FWF ➀ FWJ ➂ FWJC A ➆ FBN ➁ FBN ➁ FWF ➀ FBN Z ➁ BN ➃ FWF ➀ BN ➃ FWF ➀ FWF ➀ FWF ➀ BN503502A ➀ BN ➂ BNE ➂ BNE ➂ FWJ Z ➂ FBNP ZA ➇ BN ➀ FWF Z ➀ BN ➀ BN ➀ FWF ➀ BN ➀ BN ➀ BN ➀ FWF ➀ FWJ ZA ➃ FWJ ➂ FWJ ➂ FWF ➀ FWF ➀ FWF ➀ FBNP ZA ➇ 11 12

8 ➀ ➁ ➂ ➃ ➄ ➅ ➇ ➈ ➉ FBNP ➇ FWJ A ➂ BN ➃ BN ➃ FWF ➀ FWF ➀ FBNP ZA ➇ WJ ➂ WJ ➂ WJ ➂ FWJ Z ➂ FWJ Z ➂ BN ➀ BN ➀ FWFD ZW ➉ FWJE B ➄ FDJC BN ➀ BN ➉ BN503930A ➂ BN ➀ BN503903A ➀ FBNP ➈ BN ➃ FWF ➀ FWF A ➀ FWF ➀ FWF ➀ FWJ ➃ FWJ C ➂ FBNP A ➇ BN ➁ FWJE ZF ➄ FWJE ZF-DL ➄ FWF ➀ FWJ ➂ FWJ DL ➂ FWF ➀ FWF A ➀ FWF ➀ BN ➀ FWF ➀ BN ➀ BN ➀ FBNP Z ➈ BN ➀ BN ➅ WJP ➂ FBN ➁ FWF ➀ BNE ➂ FWF ➀ FWJ ➂ BN ➀ BNE ➂ WJ ➂ WJ ➂ WJ ➂ BN504424C ➀ BN504411A ➀ FDJS Z FWF ➀ FWF ➀ FDJC FBNP Z ➇ BN ➃ FWJ ➃ BN ➉ FWF ➀ BN ➀ BN ➀ BN ➀ FWF W ➉ FWJC ➄ FWF ➀ FWF ➀ FWF ➀ BN ➀ FWF ➀ FBN Z ➁ FWJW Z ➅ FDJS Z BN ➉ FWF ➀ 13 14

9 ➀ ➁ ➂ ➅ ➆ ➉ FWJC ➆ FWF ➀ FWF ➀ BN ➀ FWF ➀ BN ➀ FWF A ➀ BN ➀ WJ ➂ BN ➀ FDJC BN ➀ FWF ➀ BN ➀ FWF A ➀ FWF ➀ BN ➀ BN ➀ WJ ➂ BN ➀ WJ ➂ WJ ➂ BN ➀ WJ ➂ BN ➀ BN505026A ➀ BN505026D ➀ FWF WZ ➉ BN ➀ WJ ➂ BN ➀ WJ ➂ WJ ➂ FDJS FDJS FWJW ZA ➅ FWJW ZA ➅ BN ➀ FWF ➀ FWF ➀ FWF ➀ FWF C ➀ WJ ➂ WJ ➂ FWF ➀ FWF Z ➀ FDJC FWF W ➉ FWF Z ➀ FWJW ZA ➅ FWF ➀ FWF ➀ FWF W ➉ FWF ➀ FWF ➀ FWF ➀ FWF ➀ BN ➀ BN506018HSC ➀ WJ ➂ FBN ➁ BN ➀ WJ ➂ WJ ➂ BN ➉ FBN ➁ FWF A ➀ FWF ➀ BN ➀ FBN A ➁ FBN ➁ WJ ➂ FWF ➀ FWF ➀ FBN ➁ FWF ➀ BN ➉ FWF W ➉ FWF ➀ BN ➀ FBN ➁ FBN ➁ 15 16

10 (Split Cage) ➀ ➁ ➂ ➄ ➆ Split Cage ➇ ➉ FWF ➀ WJ ➂ WJ ➂ BN ➀ BN ➀ FBN ➁ FBN ➁ FWF A ➀ FWF ➀ FWF ➀ FWF ➀ FWF ➀ BN ➀ WJ ➂ WJ ➂ FWF ➀ WJ ➂ WJ ➂ WJ ➂ FWJE ➄ FWJE Z ➄ FWF ➀ BN509012HSC ➀ BN ➀ FWJC ➆ BN509507A ➀ FWJC Z ➆ BN ➀ FWJC ➆ BN ➀ FWF ➀ BN ➉ FWF ➀ BN ➀ WJ ➂ WJ ➂ FWF ➀ FWF ➀ FWF ➀ BNF502204B ➀ BNF ➉ BNF ➀ FBNPF ZA ➇ BNF ➉ BNF ➉ FWJEF Z ➄ FBNF A ➁ BNF ➀ FBNF W BNF ➉ BNF ➉ BNF ➀ BNF ➀ BNF ➀ BNF ➀ FBNPF Z ➇ BNF ➉ BNF ➀ FBNPF Z ➇ BNF ➀ BNF ➀ FWJCF Z ➆ FWJCF ➆ BNF ➀ FBNPF ➇ BNF ➀ BNF ➀ FWJCF Z ➆ FDJSF Z BNF504101A ➀ BNF ➉ BNF ➀ FBNF ➁ FBNF ➁ BNF ➉ BNF ➉ BNF ➉ BNF505102A BNF506501A ➉ FDJCF Z BNF507502A ➉ BNF ➉ BNF ➉ 17 18