Systems and Components

Transcription

1 new LINEAR SYSTEMS AND COMPONENTS SELF-ALIGNING LINEAR BEARINGS & PILLOW BLOCKS TM LINEAR SYSTEMS AND COMPONENTS TECHNICAL INTRODUCTION PRECISION HARDENED AND GROUND SHAFTING Linear Ball Bearing, Shafting, Pillow Block an Slie System Features Bearing Design Consierations System Design Consierations Application Examples EXCEL INCH SELF-ALIGNING BEARINGS AND PILLOW BLOCKS Inch EXCEL Close an Open Bearings 230 Inch EXCEL Single Close an Open Pillow Blocks 23 Inch EXCEL Twin Close an Open Pillow Blocks 232 Inch Flange Mount Single an Twin Pillow Block 233 POWERTRAX LBB BEARINGS LBB Precision Close an Open Bearings Stainless Bearings 236 Instrument Bearings an Shafting 237 Seal Specifications 238 LUBRICATION 239 Inch Precision Harene Shafting 240 Nook Shaft - Precut/Stocke Shafting 243 Precision En Machining 244 SUPPORT RAILS AND SUPPORT BLOCKS Low Profile 244 Stanar Profile 245 Shaft Support Blocks 246 SLIDE SYSTEMS & ACCESSORIES Series 00, 200 & MM Slie 247 Reference Number System 248 Carriage Plates 249 Series 2, 3, 2, 22, 32, 3, 23 an 33 Slie Systems Series 22 an Series 302 an 32 Slie System MM Slie System 258 Motor Aapters an Bellows Boots 259 METRIC EXCEL SELF-ALIGNING BEARINGS, PILLOW BLOCKS AND PRECISION LINEAR SHAFTING EXCEL Close an Open Bearings 260 EXCEL Single an Twin Close Pillow Blocks 26 Metric Precision Linear Shafting 262 PowerTrax Linear Systems an Components nookinustries.com 29

2 POWERTRAX SELF-ALIGNING LINEAR BEARINGS & PILLOW BLOCKS TM 220 nookinustries.com

3 LINEAR BEARING TYPES AND LINEAR SHAFTING POWERTRAX Nook Inustries manufactures a full range of linear slie systems an slie systems components. The PowerTrax line of linear components inclues soli shell LBB linear bearings, self-aligning EXCEL linear bearings, HG Harene an Groun Shafting, Pillow Blocks an complete slie systems. LINEAR BEARING TYPES EXCEL LINEAR BEARINGS Designe to fit into precision bores, these bearings are self aligning an offer long life. Precision harene an groun bearing plates with conforming ball tracks are containe in a mole thermoplastic housing. LBB These bearings are use in lower loa applications where self alignment is not require. The precision fit between the bearing an shaft is built into the bearing as a result of the soli steel shell. These bearings utilize a mole plastic ball retainer assemble insie a harene an groun shell. ILBB INSTRUMENT SERIES Similar in construction to LBB linear bearings, Instrument Series Linear Bearings are small iameter, high precision bearings with stainless steel shells. When matche with Instrument Series Linear Shafting, ILBB Linear Bearings provie high performance with.000 to.0003 inch clearances. ILBB Linear Bearings are use in light loa, high precision applications where low friction guiance is require such as meical an semiconuctor equipment. OPEN SERIES BEARINGS For applications requiring fully supporte shafts, open bearings are available in both LBB an EXCEL types. In an open bearing, one ball circuit is remove to allow the mounte bearing to translate along a supporte shaft. SEALS LBB an EXCEL bearings are available in seale an unseale versions. ILBB bearings are unseale. MATERIALS Nook PowerTrax linear bearings use a combination of high performance thermoplastic, chrome-steel bearing balls, an either a one piece harene steel shell or precision groun harene steel bearing plates. (SEE FIG. EXCEL MAXIMUM SPEED When use in high spee or high impact environments, EXCEL bearing capacities shoul be e-rate as shown in the chart. Divie the rate loa by the loa factor to etermine the appropriate bearing size. (SEE FIG. 2 FIG. EXCEL SELF-ALIGNING LBB SERIES STAINLESS STEEL SERIES INSTRUMENT SERIES FIG.2 OUTER SHELL Plastic Resin NYLON-66 Harene Black Oxie Stainless IMPACTS & VIBRATIONS Without external impacts or vibrations Without significant impacts or vibrations Without external impacts or vibrations BALLS Harene Chrome Harene Chrome Harene Chrome LINEAR SHAFTING MATERIAL Nook PowerTrax HG Shafting, mae from high quality alloy steel, is manufacture an stocke for immeiate shipment in our Clevelan, Ohio facility, in iameters from 5 to 80mm an /4 to 4 inches. Stainless shafting is available from /4 thru 2 inch iameter. Stanar iameters can be cut to your specifie length an shippe within 24 hours of receipt of your orer. Contact Nook Inustries, Inc. for availability of special iameters. CASE HARDNESS PowerTrax HG alloy shafting is inuction harene to Rc Stainless steel shafting is harene to Rc Instrument Series Shafting is harene to Rc The case epth on all PowerTrax HG Shafting is precisely controlle for optimal performance. The extremely har surface minimizes wear an is resistant to nicks an scratches. (SEE FIG. 3 on following page BEARING PLATE Harene N/A N/A BALL RETAINER N/A N/A Nitrile Acetal Resin Acetal Resin 440C 440C N/A Acetal Resin SPEED Velocity 50 ft/min Velocity > 50 ft/min an 90 ft/min Velocity > 90 ft/min ACCELERATION (G Acceleration < 0.5G Acceleration > 0.5G an.0g Acceleration >.0G an 2.0G END RINGS Black Oxie Stainless Stainless INTERNAL SEALS ~.5.5 ~ ~ 3.5 Nitrile N/A N/A FACTOR (ƒ nookinustries.com 22

4 POWERTRAX LINEAR SHAFTING AND LINEAR SLIDE SYSTEM FEATURES FIG. 3 SURFACE FINISH PowerTrax HG shafting is centerless groun to a consistently smooth surface finish of 4 microinches rms or less. Excellent surface finish an harness maximize the efficiency an life of linear bearings. STRAIGHTNESS PowerTrax HG shafts are straight within of an inch per foot cumulative when shippe from the factory. Hanling or machining of shafting can cause the material to ben. PREDRILLED &TAPPED HOLES PowerTrax HG alloy shafting is stocke with raial holes rille an tappe to accept a continuous shaft support rail. Continuous support prevents shaft eflection when use to support heavy loas or for long travel lengths. Raial holes can be supplie in stainless steel shafts from /2" to 2" iameter. PRECISION END MACHINING PowerTrax HG shafting can be supplie pre-machine to application requirements. Sen a etaile sketch or blueprint for a prompt quotation. See page 22 for escriptions of machining offere by Nook Inustries. Templates for machining are available on our website HARDENED SHAFT CROSS SECTION END nookinustries.com HORIZONTAL LENGTH TOLERANCE PowerTrax HG shafting cut to your specifie length will have a stanar length tolerance of +/32" up to 2" an ±/6 above. Closer tolerances are available for an aitional charge. Non-precision chamfere ens are stanar on all cut shafting. SHAFT SUPPORTS Aluminum support components for en mounting or continuously supporting PowerTrax HG shafting are available for inch sizes /2" to 2". SELF-ALIGNING PILLOW BLOCKS PowerTrax Pillow Blocks simplify mounting of PowerTrax Linear Bearings. They are available with EXCEL Bearings to fit shafts from /4 to 2 inch an 0 to 50mm. PowerTrax Pillow Blocks provie the precision bearing bores necessary for linear bearing installation. MOUNTING TOLERANCES The PowerTrax Pillow Block mounting surface to centerline imension is hel to ±0.00 inch. Bearings will self-align up to ±/2. MATERIALS All PowerTrax Pillow Blocks are manufacture from precision machine, thick walle, extrue aluminum. PILLOW BLOCK SEALS PowerTrax Pillow Blocks are supplie complete with lip seals. The seale pillow block keeps lubricant in an irt an ebris out resulting in smoother operation an longer bearing life. LINEAR SLIDE SYSTEMS SERIES 00 SLIDE SYSTEMS PowerTrax Series 00 slie systems are pre-assemble an reay to mount. Series 00 slies consist of combinations of PowerTrax Linear Ball Bearing Pillow Blocks, HG shafting, carriage plates an shaft supports. Aluminum carriage plates inclue threae steel inserts at key mounting locations. SERIES 200 SLIDE SYSTEMS PowerTrax Series 200 slie systems are assemble slies which inclue: Linear bearing pillow blocks Integrate en supports HG linear shafts Carriage Plate PowerTrac Ball Screw assembly Many options are available for these slie systems. Different screw styles an leas, protective boots, special motor mounts an custom carriage plate machining is available. Contact Nook Inustries, Inc. for assistance. MM SLIDE MINI SLIDE SYSTEMS PowerTrax MM Slies are metric-imensione compact slie units. They utilize lightweight aluminum components an inclue an integrate carriage/pillow block assembly for a reuce overall height. A wie variety of screw iameters, leas an nut styles are available. These systems inclue: EXCEL linear bearings Integrate en supports HG linear shafts Carriage/pillow block assembly Lea screw assembly

5 BEARING DESIGN CONSIDERATIONS POWERTRAX BEARING DESIGN CONSIDERATIONS APPLICATION VARIABLES To etermine the best linear bearing prouct or system for your application it is necessary to know: Amount of loa How the loa is applie Length of stroke COEFFICIENT OF FRICTION PowerTrax linear bearings exhibit an extremely low coefficient of friction ranging from to Coefficients of static an rolling friction are use to estimate the force require to overcome frictional resistance. The formulas for etermining static an rolling frictional resistance are: Static Friction: F s = L x f s Rolling Friction: F = L x f WHERE: F s = Static frictional resistance (lbs F = ynamic frictional resistance (lbs L = applie raial loa (pouns f s = coefficient of static friction f = coefficient of rolling friction The tables show the coefficients of friction for PowerTrax Linear Bearings operating on harene an groun shafts of recommene iameters. (SEE FIG. 4 There are other variables that affect the ynamic frictional resistance of linear bearings. These variables inclue: Lubrication Dry linear bearings exhibit the lowest coefficient of friction. Friction values for lubricate bearings are higher ue to the presence of lubricant surface tension. Seals Non-linear seal rag occurs because of the geometry an the materials use in the bearing seals. Contamination Foreign particles restrict free rolling of the bearing balls an will contribute to an increase in ynamic frictional resistance. LUBRICATION A lubricant formulate for rolling friction shoul be use with PowerTrax Linear Bearings. In applications where operating spees are low an loas are light, PowerTrax linear bearings can be use without lubrication at a reuce life. However, to protect the highly polishe bearing surfaces from corrosion an wear, a lubricant is recommene. Where linear spees are high, a light oil shoul be use an provision for re-lubrication shoul be mae to avoi operating the bearings ry. For typical applications, a meium to heavy oil has goo surface ahesion an affors greater bearing protection. Linear Bearings 2" iameter an above may use high pressure FIG.4 Coefficients of Static Friction (f s TYPE OF BEARING LUBRICATION ANY Coefficients of Rolling Friction (f TYPE OF BEARING LUBRICATION NONE OIL 00% 00% lithium grease such as Shell Alvania #2 for moerate spee applications. Lubricants containing aitives such as molyisulfie or graphite shoul not be use. Nook Linear Lube LBL- liqui is a goo, all purpose lubricant for use with linear bearings. See page 239 for more information. MAXIMUM AND NORMAL RATINGS The require esign life, the shaft harness, an a bearing ynamic loa rating affect the loa that can be applie to a PowerTrax linear bearing. Two ynamic loa ratings are given for each bearing size base on the rotational orientation of the bearing. Normal Loa Rating The Normal Loa Rating is use in applications where the orientation of the ball tracks relative to the loa cannot be controlle. The Normal loa rating is base on a loa impose irectly over a single ball track. The Normal loa rating shown in the specification tables is slightly greater than woul be mathematically calculate base on one track loaing because it assumes that the loa is share to some egree by one or more of the ajacent ball tracks. IN % OF RATED 75% 50% 25% IN % OF RATED 75% 50% 25% GREASE nookinustries.com 223

6 POWERTRAX BEARING DESIGN CONSIDERATIONS Maximum Loa Rating The Maximum loa rating assumes that the loa is applie miway between two ball tracks as illustrate below. In this orientation the loa is istribute over the maximum number of bearing balls. (SEE FIG. 5. FIG. 5 NORMAL MAXIMUM LIFE DETERMINATION The Normal an Maximum loa ratings are base on a Rc 60 shaft harness an a travel life of two million inches. For linear bearing system operating at less than full rate loa, the Loa-Life Curve may be use to etermine the travel life expectancy. (SEE FIG. 6 SHAFT HARDNESS If shafting other than stanar alloy PowerTrax HG shafting is use, the Shaft Harness Curve establishes a shaft harness correction factor, Rh. When calculating the equivalent loa, this factor compensates for the effect of harness. (SEE FIG. 7 EQUIVALENT An equivalent loa value can be calculate when sizing linear bearings for applications at conitions other than maximum rating. Equivalent Loa Formula: L e = L a / (R L x R h WHERE: L e = Dynamic Equivalent Loa (The minimum bearing capacity to meet esign life requirements L a = Applie Loa (Actual Loa R L = Loa Life Ratio Factor (from chart R h = Shaft Harness Ratio Factor (from chart BEARING INSTALLATION In most installations, PowerTrax linear ball bearings are esigne to slip-fit into the housing bore an secure by one of the following means: Between an internal housing shouler an a threae cap. Between external retaining rings. Between internal snap rings in the bore of the housing. The bore iameter require to maintain recommene bearing/ shaft clearance is given in the EXCEL linear bearing information section. The bore oes not affect clearance between an LBB bearing an a shaft. (SEE FIG. 8 FIG. 8 Between an internal housing shouler an a threae cap. FIG. 7 Between external retaining rings. Between internal snap rings in the bore of the housing. FIG. 6 LIFE RATIO FACTOR R L TRAVEL LIFE (IN MILLIONS OF INCHES SHAFT HARDNESS RATIO FACTOR R h SHAFT HARDNESS (ROCKWELL C 224 nookinustries.com

7 SYSTEM DESIGN CONSIDERATIONS POWERTRAX ASSEMBLY EXCESSIVE FIT Oversize shaft iameters or misalignment between the installe bearings can cause preloa between the shaft an the bearing. Preloa conitions shoul be correcte before operating the bearing. If, in an assemble unit, the shaft can freely rotate relative to the bearing, then the fit is at the maximum or less. SYSTEM DESIGN CONSIDERATIONS SYSTEM CONFIGURATION PowerTrax Linear Slie Systems are available in a variety of configurations. The following factors shoul be consiere when choosing the slie system which best suits an application. SINGLE OR DOUBLE SHAFT SYSTEMS The majority of applications require ouble shaft systems in orer to restrain the loa in two planes. Single shaft systems may be use for hanging or vertical loas where rotation of the bearing aroun the shaft is allowable. FULLY SUPPORTED OR UNSUPPORTED SHAFTS Fully supporte systems are use to eliminate shaft eflection. Full shaft supports must be attache to a machine mounting base. Openstyle bearings use with this system are sensitive to loa orientation. En-supporte systems are generally use to span a gap or where some eflection is allowable. This system uses close-style bearings that achieve higher loa capacities. The shaft must be selecte so that eflection oes not excee self-alignment capability of the bearing. LINEAR BEARING PILLOW BLOCKS Two bearings must be use to support a loa on a shaft. Single blocks allow for custom spacing an wier loa bearing stances. Twin pillow blocks have a compact, one-piece esign. CARRIAGE PLATES Carriage plates are esigne in two styles for linear system packages. Carriage is esigne for two pairs of single bearing blocks. Carriage 2 is esigne for two twin bearing blocks an has a shorter over all length. BEARING/SHAFT SIZE For fully supporte systems the bearing size neee for the application is etermine by the loa an life requirements. For en-supporte systems, both the bearing iameter that meets loa an life requirements an the shaft iameter that results in an allowable eflection must be etermine. The correct choice of shaft/bearing iameter is the larger of the two. CONDITIONS Linear systems require at least three bearings to efine the plane of motion. It is necessary to ientify an unerstan which of following loa conitions affect the application: Centere Loas Offset loas Sie Loas Vertical Loas Gravity effects Reaction Forces (i.e., cutting tool reaction. Dynamic loaing (acceleration, eceleration an inertial loas nookinustries.com 225

8 POWERTRAX SYSTEM DESIGN CONSIDERATIONS Apply the actual loa to the appropriate loa conition in the figure below to calculate the resulting bearing loas. (SEE FIG. 0. FIG F4Z 2 L FZ F4Z 3 2 F2ZF3Z 2 CENTERED F Z = L +( L X 2 ( L X 3 F 2Z = L ( L X 2 ( L X 3 F 3Z = L ( L X 2 + ( L X 3 F 4Z = L +( L X 2 + ( L X 3 ACCELERATION FORCES Use the equation in the following figure to etermine the aitional forces evelope ue to acceleration. If impact or impulse loas are anticipate, these forces must also be consiere when selecting the appropriate bearing size. (SEE FIG. FIG. AT THE TIME OF ACCELERATION AND SLOW DOWN. L Thrust V Spee t t 2 t3 t Time Direction of progress 3 0 FY F2Y L FX 2 FZ F4Z F2X F4X F2ZF3Z FZ F4Z F3Z F2Z FYF2Y F3YF4Y OFFSET F Z = L +( L X 2 ( L X 3 F 2Z = L ( L X 2 ( L X 3 F 3Z = L ( L X 2 + ( L X 3 F 4Z = L +( L X 2 + ( L X 3 SIDE MOUNTED F Y = F 4Y =( L X 3 2 F Z = F 4Z = L + ( L X F 2Z = F 3Z = L ( L X VERTICAL MOUNTED F X = F 4X =( L X F Y = F 4Y =( L X F X + F 4Y = F 2X + F 3X F Y + F 4Y = F 2Y + F 3Y 0 At the time acceleration starts: F = F 4 = L ( + 2 V x 4 g x t x 0 F 2 = F 3 = L ( 2 V x 4 g x t x 0 At constant velocity: F = F2 = F3 = F4 = 4 L At the time it slows own: SHAFT DEFLECTION Shaft eflection shoul be consiere when choosing the proper bearing an shaft iameter for en-supporte systems. Deflection is irectly relate to the iameter of the shaft, the unsupporte length of the shaft, an the type of shaft en mounting that is use. Typical Shaft En Mounting. (SEE FIG. 2 F = F 4 = L ( 2 V x 4 g x t 3 x 0 F 2 = F 3 = L ( + 2 V x 4 g x t 3 x 0 Gravitational acceleration: g = 384 in./sec 2 = 9.8 m/sec 2 Simple - the en allows some of the shaft eflection slope through the fastening point. Fixe - the ens are constraine from eflection. NOTE: Fixe en mounting can be accomplishe by capturing the shaft en with a length of engagement equal to or greater than /2 times the shaft iameter. FIG.2 FIXED SIMPLE 226 nookinustries.com

9 SYSTEM DESIGN CONSIDERATIONS AND APPLICATION EXAMPLE POWERTRAX DEFLECTION CALCULATION Use the formula: D = N x W x L 3 WHERE: N = value from fig.3 W = loa in pouns L = length (in inches of unsupporte shaft section CALCULATE MISALIGNMENT ANGLE PowerTrax linear bearings allow for /2 egree misalignment. To etermine the amount of misalignment ue to shaft eflection use the formula: θ = sin - (D/L WHERE: θ = angle in egrees D = shaft eflection L = length (in inches of unsupporte shaft section. If misalignment is greater than /2 egree, then: APPLICATION EXAMPLES Application # PACKAGING LINE An appliance manufacturer nees to move proucts in boxes so that they can be presente to a transfer conveyor after final assembly. Specifications: The boxes weigh 200 pouns The unit reciprocates 8 times per minute 4.5 inch stroke 365 ays per year, ten year esign life. Slightly corrosive environment What is the proper size EXCEL Bearing which will satisfy this application? ANALYSIS: Configuration: There is enough space available for four linear bearings. The system will use stainless steel shafting with a harness of Rc 55. The loa can be centere between four stanar Excel linear bearings Reuce the Length of the shaft. Use a larger shaft iameter. FIG.3 N VALUE FOR NOOK SHAFTS SHAFT DIAMETER (in. SIMPLE FIXED / x x 0-9 Travel Life: 4.5 in./stroke x 8 strokes/min. x 60 min./hr x 24 hrs/ay x 365 ays/year x 0 years = 89,000,000 inches. Loa-Life Ratio Factor (R L : Base on the compute travel life an the loa-life curve R L =.22. Shaft Harness Ratio Factor (R h : For PowerTrax HG Stainless shafting with a harness of Rc 55, R h =.70. 3/8 75 x x 0-9 Applie Loa (L a : Per bearing, L a = 200/4 = 50 lbs. /2 3/4 226 x x x x 0-9 Equivalent Loa (L e : Substituting in the loa formula an solving for L e = 50 / (.22 x.70 = 325 pouns 4. x x 0-9 -/ x x x x x x x x 0-0 SELECTION: From the EXCEL Bearing loa tables, the smallest bearing which excees this loa rating is the 3/4 inch bearing. However, if the application is such that the bearing coul be oriente for maximum capacity, then the 5/8 inch bearing coul be use. The Parts List Is: 4 XLEC2 EXCEL Linear bearings 2 PowerTrax HG Stainless shafting, 9.25 inch minimum length 2 PowerTrax NSB-2 En supports nookinustries.com 227

10 POWERTRAX APPLICATION EXAMPLE Application #2 SCANNER POSITIONING A vision system scanner is mounte to the center of the carriage of a vertically mounte slie system. The customer wants to use one inch open pillow blocks to guarantee a long life. Specifications: Scanner weight is 00 pouns The center of gravity is offset 4 inches from the carriage plate The ajustment istance is 36 inches Minimal eflection esire Han ajustment with future automation planne A travel life of 0 million inches is esire ANALYSIS: Configuration: A stanar system with carriage plate an fully supporte shafts will assure minimal eflection. Loa per Bearing: The loa is centere an offset four inches. Use the equations from the loa conition figure Vertically Mounte to etermine the worst case force through a bearing. The istance from the loa to the centerline of the shaft ( 2 is or 5.87 inches. The bearing spacing ( 0 is set by the carriage plate; 0 = 7 inches. Base on a esign factor of 2, the loa per bearing is 74 pouns. This is far below the rate value of a one inch open bearing. NOTE: When using open-style bearings, if the irection of loaing force is through the opening of the bearing, it is necessary to e-rate the bearing capacity by 50%. SELECTION: PowerTrax Series 33 consisting of a ouble shaft fully supporte system with Carriage an four (4 single bearing blocks. The Parts List Is: 33-6-L36 FIG.4 / LIFE Lines inicate limiting loa for given shaft size Loa on most heavily loae bearing (lbf = (F Dia /2 Dia Dia 3 /4 Dia /2 Dia 3 /8 Dia Shaft Size ( inches 5 /4 Dia Require Travel Life (millions of inches 228 nookinustries.com