Nasa technical paper 3096 avscom technical report 91 c020 a method for determining spiralbevel gear tooth 1991 geometry for finite element analysis robert f. Determining proper backlash values there are several methods for determining the correct values of each axis. Standard gears are designed with a specified amount of backlash to prevent noise and excessive. Axle shaft removal methods 8 axle shafts from the axle housing 9 differential carrier from the axle housing 10 measure ring gear backlash differential and ring gear from the carrier 12 disassembly. While holding the pinion yoke steady, rotate the ring gear back and forth. And installation instructions west coast differentials. Measuring the backlash is a fairly straightforward task and is a quick way of determining whether a professional.
The proposed velocity compensation method is most efficient only for low operating. Zerobacklash can not be generated with this method. Single rear drive axles, rearrear tandem drive axles and. The operating backlash of meshing gears teeth is affected by many.
Measuring for ball screw backlash and table movement. There are a number of common ways to reduce backlash in gears. Analytical gear inspection is used for checking the individual elements of a gear runout, lead. Mount the ring gear to the carrier carefully, making sure there are no burrs created between the two surfaces. A gear or cog is a rotating machine part having cut teeth or, in the case of a cogwheel, inserted teeth called cogs, which mesh with another toothed part to transmit torque. Length of tape not critical depends on speed of gear checker and diameter of gear. In order to design a gear system with good performance the dynamics of gear system should be considered. Gears are compact, positiveengagement, power transmission elements capable of changing the. The ring gear transfers the power through the axle shafts to the tires. When assembling the gears, please provide the proper backlash between flanks.
Backlash, a clearance between mating gear teeth, is built into speed reducers to let the gears mesh without binding and to provide space for a film of. This is the checklist of gear and gearbox inspection that is to be followed. Excessive or insufficient backlash can result in noise, excessive wear, and damage. Check the backlash by mounting a dial indicator to the housing with the plunger set perpendicular to the ring gear teeth.
Introduction in modern power transmission systems gear mechanisms are widely adopted due to their technical advantages. Proper backlash from the play in the gears are necessary to absorb the deviations of noise and oscillation in order to have smooth rotation. Design engineers across the industry use different anti backlash gear design techniques, some of them are patented as well. Measure gear backlash by mounting a dial indicator so it is similar to a pinion tooth profile, block the gear to prevent its rotation and rock the pinion through the backlash. Return to adjuster on the tooth side of the ring gear and tighten adjuster until it contacts the bearing cup. When the vehicles driveshaft turns, it rotates the pinion gear. There are two ways of measuring gear tooth thickness. Backlash is measured by mounting a dial indicator to the housing with the plunger set perpendicular to the ring gear teeth. You can hold round pins or balls in the space between gear teeth, and measure over the pins to. In this method the gear is held on a mandrel and circular disc of same diameter as the base circle of. We use a toyota differential as an example but this procedure can be applied to any differential. Increase backlash pattern is more than 38 off the toe of tooth. To measure shaft endplay, mount a dial indicator at the end of a shaft and move the shaft in the axial direction. Pdf backlash prediction of a spur gear pair with manufacturing.
Hold the pinion yoke and rotate the ring gear back and forth. There are two ways of measuring gear tooth thickness, however, that require no special equipment. After new cams and gears are installed, backlash for inner cam drive gears 34t must be checked. There are, however, two ways to set pinion depth, neither of which varies by manufacturer. Different backlash pattern markingscorrect and incorrect. Check ring gear bolt s for proper length, use a very small. Place a magnetic base indicator directly on the screw. Basic concepts for methods of inspection of gear parameter. In the cross section perpendicular to the tooth of a straight bevel gear, circular backlash at pitch line j t, normal backlash j n and radial backlash j r have the following relationships. Mounting type range capacity range cost required e. Accuracy of gears testing and inspecting khk gears. Gear backlash is the clearance between two mating gears. This section introduces methods of reducing or eliminating backlash. The pinion gear intermeshes with and turns the ring gear.
Using a wooden rod, press down on the front cam through the. Backlash is necessary to achieve correct operation of the gears and varies with the size of the tooth and the operating conditions. This method can be applied to spur, helical, screw and worm gears. Over the years we have gathered information from gleason gear design manuals, dana spicer instruction manuals, technical bulletins. In this section we learned two methods to measure the. There are a number of methods to measure the back lash for spur and helical gears.
With the pinion gear installed, position ring gear and carrier into housing to check backlash. Accuracy of gears testing and inspecting is a page to learn how to test and check the accuracy of gears. Rotate the punch unit by hand and note the rotational resistance the resistance will become greater with the backlash effectively removed. Suppose gear c is fixed and the arm a makes one revolution. You can check these conditions with the help of a dial indicator. Conventional backlash measurement are usually done after the gears are installed by using one or multiples of the following methods. The same applies to yaxis, just substitute y for x. Measure over pin, two pin method for two and four starts, three pin method for one start. Backlash power point section e tools and production. These include methods like preloading as well as design with gears that eliminate or at least minimize backlash.
Use the appropriate dye or marking compound to complete. How to set up your rear gear correctly racingjunk news. This video demonstrates how to measure differential pinion to ring gear backlash. Setting backlash is done using a dial indicator to measure the free movement of the ring gear. Check depth with depth gauge or use topping hob with same pitch and pressure angle. Take a bar and press between the base and the table in both directions. Use gaskets to get backlash feel as close to unmounted condition as possible. Backlash, a clearance between mating gear teeth, is built into speed reducers to let the gears mesh without binding and. Runout can be checked with a master gear see previous paragraphs on functional gear inspection. A backlash compensation scheme using an openloop modification of the input trajectory was proposed in ref. Bevel gears are cut to have a definite amount of backlash when correctly assembled together. Increase backlash by loosening the bearing adjuster on the tooth side of the ring gear several notches.
There is a cross section in the normal direction of the tooth surface n, and a cross section in the radial direction perpendicular to the axis, t. Unless otherwise specified, it is measured at the tightest point of the mesh. Gear, incremental harmonics balance method ihbm, nonlinear dynamics, backlash 1. Nonlinear dynamics of a spur gear pair with timevarying. Backlash between the ring and pinion gear is set after the pinion gear is installed and adjusted. An elementary guide to gear inspection gear solutions. It can also be checked by indicating over aball or pin in atooth space. So reducing the amount of backlash will lead to a more accurate gearmotor. Within a differential are two gears, a ring gear and a pinion gear. Geared devices can change the speed, torque, and direction of a power source. Methods that provide the proper backlash to the gears are as follows. Backlash is strictly the axial free motion of the ball screw to the ball nut, it is not rotational how to measure for backlash. Pin measurement provides an accurate and convenient method of determining tooth thickness of a gear of any diameter within the capacity of the available micrometers.
Gear drive cams 19992006 twin cam except 06 dynaglide 2 checking cam gear backlash. Backlash checking backlash is the distance through which a gear can be rotated to bring its nonworking flank in contact with the teeth of mating gear. Side bearing preload is adjusted while performing the backlash check. Is there any increase in the backlash between the gears mesh. After these bearing preloads have been adjusted, its good practice to check the gear tooth pattern. Then loctite the pinion nut and tighten to 15 inchpounds rotating torque with used bearings or 25 inchpounds with new bearings. For purposes of measurement and calculation, backlash is defined as the amount by which a tooth space exceeds the thickness of an engaging tooth. First of all, a purely torsional model is introduced which has two degrees of freedom. Gears almost always produce a change in torque, creating a mechanical advantage, through their gear ratio, and thus may be considered a simple. This work investigates dynamics of a helical gear pair involving backlash and anglevarying mesh stiffness. Checking timing gear backlash typical gears marked same as the original as far as sizes are. In mechanical engineering, backlash, sometimes called lash or play, is a clearance or lost motion in a mechanism caused by gaps between the parts.
The programmatic method described here is the most reliable. Measuring gear teeth gear teeth can be measured using special tooth calipers, or by meshing with special precision master gears, or with profile testers. In general, backlash in gears is play between mating teeth. The radial backlash in the plane of axes can be broken down into the components in the direction of. The traditional method of inspecting a gear for correct size is the measurement over pins or balls with a micrometer. Kit installation instructions please read completely before installation t his installation guide was written to provide the novice and professional with easy guidelines for differential setup. Determine your method of removing backlash become familiar with your backlash removal method look and feel for backlash in the gears can you see the gear backlash. In fact, one of the more common sources of inaccuracy in gearmotors is due to gear backlash. Single rear drive axles, rearrear tandem drive axles and front drive steer axles revised 0218. Unfortunately, most of you are going to have to do it the hard way, but just in. A typical set of gears comes with a marking compound. Dykem should appear on pitch line approximately i of the face length straight bevel gear. To clearly define quality inspection procedures to the gear department customer service. The following is an example of a programmatic method for determining the three backlash values for the xaxis.
Article describes gear backlash and the gear backlash prevention, and the anti backlash gear design techniques. What are the primary differences between the agma 2001 and the iso 6336 methods. We will discuss the spring loaded scissor gear technique here. It can be defined as the maximum distance or angle through which any part of a mechanical system may be moved in one direction without applying appreciable force or motion to the next part in mechanical sequence. Input gear with your hand and correlate this backlash to the unmounted backlash found in step 3. Numerical values of backlash are measured at the tightest point of mesh on the pitch circle. This compound is used to show what the pattern actually is on the ring gear while adjusting the backlash. The amount of play between the ring and pinion gears is referred to as gear backlash. Pdf backlash compensation in gear trains by means of.
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