The latter construction weakens the shaft to a considerable degree because of the slots cut into it and consequently, reduces its torque-transmitting capacity. Splined shafts are most generally used in three types of applications: 1 for coupling shafts when relatively heavy torques are to be transmitted without slippage; 2 for trans- mitting power to slidably-mounted or permanently-fixed gears, pulleys, and other rotating members; and 3 for attaching parts that may require removal for indexing or change in angular position. Splines having straight-sided teeth have been used in many applications see SAE Paral- lel Side Splines for Soft Broached Holes in Fittings ; however, the use of splines with teeth of involute profile has steadily increased since 1 involute spline couplings have greater torque-transmitting capacity than any other type; 2 they can be produced by the same techniques and equipment as is used to cut gears; and 3 they have a self-centering action under load even when there is backlash between mating members. The general practice is to form the external splines either by hobbing, rolling, or on a gear shaper, and internal splines either by broaching or on a gear shaper. The internal spline is held to basic dimensions and the external spline is varied to control the fit. Involute splines have maximum strength at the base, can be accurately spaced and are self-centering, thus equalizing the bearing and stresses, and they can be measured and fitted accurately.
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The latter construction weakens the shaft to a considerable degree because of the slots cut into it and consequently, reduces its torque-transmitting capacity.
Splined shafts are most generally used in three types of applications: 1 for coupling shafts when relatively heavy torques are to be transmitted without slippage; 2 for trans- mitting power to slidably-mounted or permanently-fixed gears, pulleys, and other rotating members; and 3 for attaching parts that may require removal for indexing or change in angular position.
Splines having straight-sided teeth have been used in many applications see SAE Paral- lel Side Splines for Soft Broached Holes in Fittings ; however, the use of splines with teeth of involute profile has steadily increased since 1 involute spline couplings have greater torque-transmitting capacity than any other type; 2 they can be produced by the same techniques and equipment as is used to cut gears; and 3 they have a self-centering action under load even when there is backlash between mating members.
The general practice is to form the external splines either by hobbing, rolling, or on a gear shaper, and internal splines either by broaching or on a gear shaper. The internal spline is held to basic dimensions and the external spline is varied to control the fit.
Involute splines have maximum strength at the base, can be accurately spaced and are self-centering, thus equalizing the bearing and stresses, and they can be measured and fitted accurately. Tables for these splines have been rearranged accordingly.
The Standard has only one fit class for all side fit splines; the former Class 2 fit. Class 1 fit has been deleted because of its infrequent use. The major diameter of the flat root side fit spline has been changed and a tolerance applied to include the range of the and the standards. The Standard recognizes the fact that proper assembly between mating splines is dependent only on the spline being within effective specifications from the tip of the tooth to the form diameter.
Therefore, on side fit splines, the internal spline major diameter now is shown as a maximum dimension and the external spline minor diameter is shown as a minimum dimension. The minimum internal major diameter and the maximum external minor diameter must clear the specified form diameter and thus do not need any additional control.
The spline specification tables now include a greater number of tolerance level selections. These tolerance classes were added for greater selection to suit end product needs.
The selections differ only in the tolerance as applied to space width and tooth thickness. Copyright , Industrial Press Inc. Therefore, any compensation that must be made for operations that take place during processing, such as heat treatment, must be taken into account when selecting the tolerance level for manufacturing.
The standard has the same internal minimum effective space width and external maxi- mum effective tooth thickness for all tolerance classes and has two types of fit. For tooth side fits, the minimum effective space width and the maximum effective tooth thickness are of equal value. This basic concept makes it possible to have interchangeable assembly between mating splines where they are made to this standard regardless of the tolerance class of the individual members.
For instance, assigning a Class 5 tolerance to one member and Class 7 to its mate will provide an assembly tolerance in the Class 6 range. The maximum effective tooth thickness is less than the minimum effective space width for major diameter fits to allow for eccentricity variations. In the event the fit as provided in this standard does not satisfy a particular design need and a specific amount of effective clearance or press fit is desired, the change should be made only to the external spline by a reduction or an increase in effective tooth thickness and a like change in actual tooth thickness.
The minimum effective space width, in this standard, is always basic. The basic minimum effective space width should always be retained when special designs are derived from the concept of this standard.
Terms Applied to Involute Splines. Some of these terms are illustrated in the diagram in Table 6. Active Spline Length La is the length of spline that contacts the mating spline. On sliding splines, it exceeds the length of engagement. Actual Space Width s is the circular width on the pitch circle of any single space considering an infinitely thin increment of axial spline length.
Actual Tooth Thickness t is the circular thickness on the pitch circle of any single tooth considering an infinitely thin increment of axial spline length.
Alignment Variation is the variation of the effective spline axis with respect to the reference axis see Fig. Base Circle is the circle from which involute spline tooth profiles are constructed. Base Diameter Db is the diameter of the base circle. Basic Space Width is the basic space width for degree pressure angle splines; half the circular pitch.
The basic space width for The teeth are proportioned so that the external tooth, at its base, has about the same thickness as the internal tooth at the form diameter.
This proportioning results in greater minor diameters than those of comparable involute splines of degree pressure angle. Circular Pitch p is the distance along the pitch circle between corresponding points of adjacent spline teeth. The diametral pitch determines the circular pitch and the basic space width or tooth thickness.
In conjunction with the number of teeth, it also determines the pitch diameter. See also Pitch. Effective Clearance cv is the effective space width of the internal spline minus the effective tooth thickness of the mating external spline. Effective Space Width Sv of an internal spline is equal to the circular tooth thickness on the pitch circle of an imaginary perfect external spline that would fit the internal spline without looseness or interference considering engagement of the entire axial length of the spline.
The minimum effective space width of the internal spline is always basic, as shown in Table 3. Fit variations may be obtained by adjusting the tooth thickness of the external spline.
Alignment Variation Effective Tooth Thickness tv of an external spline is equal to the circular space width on the pitch circle of an imaginary perfect internal spline that would fit the external spline without looseness or interference, considering engagement of the entire axial length of the spline.
Effective Variation is the accumulated effect of the spline variations on the fit with the mating part. External Spline is a spline formed on the outer surface of a cylinder. Fillet is the concave portion of the tooth profile that joins the sides to the bottom of the space. Fillet Root Splines are those in which a single fillet in the general form of an arc joins the sides of adjacent teeth.
Flat Root Splines are those in which fillets join the arcs of major or minor circles to the tooth sides. This circle along with the tooth tip circle or start of chamfer circle determines the limits of tooth profile requiring control. It is located near the major circle on the internal spline and near the minor circle on the external spline. Form Clearance cF is the radial depth of involute profile beyond the depth of engagement with the mating part. It allows for looseness between mating splines and for eccentricities between the minor circle internal , the major circle external , and their respective pitch circles.
Internal Spline is a spline formed on the inner surface of a cylinder. Involute Spline is one having teeth with involute profiles. Lead Variation is the variation of the direction of the spline tooth from its intended direction parallel to the reference axis, also including parallelism and alignment variations see Fig.
Note: Straight nonhelical splines have an infinite lead. Length of Engagement Lq is the axial length of contact between mating splines.
Machining Tolerance m is the permissible variation in actual space width or actual tooth thickness. Major Circle is the circle formed by the outermost surface of the spline.
It is the outside circle tooth tip circle of the external spline or the root circle of the internal spline. Major Diameter Do, Dri is the diameter of the major circle. Minor Circle is the circle formed by the innermost surface of the spline. It is the root cir- cle of the external spline or the inside circle tooth tip circle of the internal spline. Minor Diameter Dre, Di is the diameter of the minor circle.
Nominal Clearance is the actual space width of an internal spline minus the actual tooth thickness of the mating external spline. It does not define the fit between mating members, because of the effect of variations.
Out of Roundness is the variation of the spline from a true circular configuration. Parallelism Variation is the variation of parallelism of a single spline tooth with respect to any other single spline tooth see Fig.
Pitch Circle is the reference circle from which all transverse spline tooth dimensions are constructed. Pitch Diameter D is the diameter of the pitch circle.
Pitch Point is the intersection of the spline tooth profile with the pitch circle. Unless otherwise specified, it is the standard pressure angle. Profile Variation is any variation from the specified tooth profile normal to the flank. Spline is a machine element consisting of integral keys spline teeth or keyways spaces equally spaced around a circle or portion thereof.
Stub Pitch Ps is a number used to denote the radial distance from the pitch circle to the major circle of the external spline and from the pitch circle to the minor circle of the internal spline. The stub pitch for splines in this standard is twice the diametral pitch. Total Index Variation is the greatest difference in any two teeth adjacent or otherwise between the actual and the perfect spacing of the tooth profiles. The numerator in this fractional designation is known as the diametral pitch and controls the pitch diameter; the denominator, which is always double the numerator, is known as the stub pitch and controls the tooth depth.
For convenience in calculation, only the numerator is used in the formulas given and is designated as P. Diametral pitch, as in gears, means the number of teeth per inch of pitch diameter. Table 1 shows the symbols and Table 2 the formulas for basic tooth dimensions of involute spline teeth of various pitches.
Basic dimensions are given in Table 3. Table 1. Dre N In selecting the number of teeth for a given spline application, it is well to keep in mind that there are no advantages to be gained by using odd numbers of teeth and that the diameters of splines with odd tooth numbers, particularly internal splines, are troublesome to measure with pins since no two tooth spaces are diametrically opposite each other. Types and Classes of Involute Spline Fits. Dimensional data for flat root side fit, flat root major diameter fit, and fillet root side fit splines are tabulated in this standard for degree pressure angle splines; but for only the fillet root side fit for Side Fit: In the side fit, the mating members contact only on the sides of the teeth; major and minor diameters are clearance dimensions.
The tooth sides act as drivers and centralize the mating splines. Major Diameter Fit: Mating parts for this fit contact at the major diameter for centralizing. The sides of the teeth act as drivers. The minor diameters are clearance dimensions. The major diameter fit provides a minimum effective clearance that will allow for con- tact and location at the major diameter with a minimum amount of location or centralizing effect by the sides of the teeth.
The major diameter fit has only one space width and tooth thickness tolerance which is the same as side fit Class 5.
ANSI B92.1 PDF
Digital transformation may be the most frequently misunderstood and misused term in business discourse ansi b The tolerances are depending on mounting conditions, shaft I z or tooth flank centering Ansi b This applies both to spline connections with involute flanks as for spline connections with straight flanks. The tool machines and extensive hobbing and cutting tools available to us, allow us to achieve external and internal spline connections according to the standards NBN-DIN — BS-AGMA or NF on gear blanks of which the dimensions fall within the limits of our manufacturing capabilities.
ANSI B92.1-1996 Involute Splines and Inspection