GB-T3478.1-1995标准（英文版）

National Standard of the Peoples Republic of ChinaStraight Cylindrical Involute Splines Modules, Basic Rack Profiles, and TolerancesGB/T 3478.1 1995Superseding GB 3478.1-83This standard is identical to Part I “Generalities”, ISO 4156 1981 “Straight Cylindrical Involute Splines Metric Modules Side Fit Generalities, Dimensions, and Inspection”. 1. Subject Contents and Application ScopeThis standard specifies the module series, basic rack profiles, tolerances, and side fit classifications for straight cylindrical involute splines. This standard applies to the straight cylindrical involute splines with standard pressure at 30 and 37.5 (module at 0.510mm) and side fit at 45 (module at 0.252.5mm). 2. Normative Reference GB 1800Tolerance and fitting generalities - standard tolerances and basic deviationsGB 10095Accuracy of involute cylindrical gearsGB/T 3478.5Straight cylindrical involute splines - Inspection methods3. Terms, Symbols, and DefinitionsThe terms, symbols, and definitions adopted in this standard are shown in Table 1 and Figure 1 (30 pressure angle flat root is hereafter referred to as 30 flat root, 30 pressure angle fillet root is hereafter referred to as 30 fillet root, 37.5 pressure angle fillet root is hereafter referred to as 37.5 fillet root, and 45 pressure angle fillet root is hereafter referred to as 45 fillet root). Table 1Terms, Symbols, and DefinitionsNo.TermSymbolDefinition1Spline jointThe coaxial elements that interconnected via the spline teeth in equal spacing and with same number of teeth on the internal and external cylindrical surfaces for transmission of torque or motion. The spline on the internal cylindrical surface is called as internal spline and the spline on the external cylindrical surface is called as external spline. 2Involute splineThe spline with involute tooth profile. 3Root arcMin curvature radius of root arc Internal spline External splineRiminReminThe transitional curve connecting the involute tooth profile with root circle. 4Flat root splineThe spline in which the involute tooth profiles at both sides of one same tooth space are connected with the root circle respectively via a length of transitional curve. Table 1 (Continued)No.TermSymbolDefinition5Fillet root splineThe spline in which the involute tooth profiles at both sides of one same tooth space are connected with the root circle respectively via a length of transitional curve. 6Modulem7Number of teethZ8Reference circleThe basic circle for calculation of spline dimensions, on which the pressure angle is taken as the standard value. 9Reference diameterD10PitchpThe arc length between two neighboring teeth at one side on the reference circle, calculated by the circumference ratio multiplying module m. 11Pressure anglePressure angle at any point of tooth profile is the sharp angle between the spline radial line at such point and the tangent line of tooth profile at such point. 12Standard pressure anglepThe specified pressure angle on the reference circle. 13Base circleVirtual circle of expanded involute tooth profile 14Base circle diameterDb15Major diameter Internal spline External splineDeiDeeDiameter of root circle (major circle) for internal spline and diameter of top circle (major circle) for external circle16Minor diameter Internal spline External splineDiiDieDiameter of top circle (minor circle) for internal spline and diameter of root circle (minor circle) for external circle17Involute end circleThe circle at end point of internal spline tooth profile for involute spline, which, in together with the minor circle, forms the control limit of the involute tooth profile.18Involute end circle diameterDFi19Involute start circleThe circle at start point of external spline tooth profile for involute spline, which, in together with the major circle, forms the control limit of the involute tooth profile.20Involute start circle diameterDFe21Basic tooth space widthEThe circular tooth space width on reference circle of internal spline, of which the value is half of the pitch. 22Actual tooth space widthMaxMinEmaxEminThe actual circular tooth space width of one tooth space measured on the reference circle of internal spline. 23Effective tooth space widthMaxMinEVEVmaxEVminEqual to circular tooth thickness of one ideal full tooth that fitted along the full tooth length (without clearance nor interference) on the reference circle of external spline. 24Basic tooth thicknessSThe circular tooth thickness on reference circle of external circle, of which the value is half of pitch. Table 1 (Continued)No.TermSymbolDefinition25Actual tooth thickness Max MinSmaxSminThe actual circular tooth thickness of one spline tooth measured on the reference circle of external spline. 26Effective tooth thickness Max MinSVSVmaxSVminEqual to circular tooth space width of one ideal full tooth that fitted along the full tooth length (without clearance nor interference) on the reference circle of internal spline.27Effective side play(full tooth side play)CVThe effective tooth space width of internal spline deducted by the effective tooth thickness of fitted external spline, of which the positive value means clearance and negative value means interference. 28Theoretical side play(One tooth side play)CThe actual tooth space width of internal spline deducted by the actual tooth thickness of fitted external spline. 29Tooth profile allowanceCFThe radial distance that the involute tooth profile is beyond the engagement part in the spline joint. 30Total toleranceT+Sum of machining tolerance and composite tolerance 31Machining toleranceTAllowable variation of actual tooth space width or actual tooth width.32Composite deviationComposite toleranceComposite of form and position deviations of spline tooth (or tooth space)Allowable composite deviation33Pitch cumulative deviationPitch cumulative toleranceFpFpMax absolute difference between the actual arc lengthy and theoretical arc length between any two tooth flanks at same side of reference circle. Allowable pitch cumulative deviation.34Tooth profile deviationTooth profile tolerancefpfpThe normal distance between two theoretical tooth profiles containing the actual tooth profiles in the working part of tooth profile (inclusive of tooth profile allowance part, but exclusive of top chamfer)Allowable tooth profile deviation35Tooth alignment deviationTooth alignment toleranceFFThe reference circle arc length between two theoretical tooth traces containing the actual tooth traces within the spline length scope. The tooth trace means the intersection line between the reference cylindrical surface and tooth face. Allowable tooth alignment deviation36Space between two bars MRiThe inner space between two length bars when measuring actual tooth space width of internal spline with two length bars, which is generally referred to as value M. 37Bar spanMReThe outer space between two length bars when measuring actual tooth thickness of external spline with two length bars, which is generally referred to as value M.38Length of common normal lineAverage length of common normal lineWTwo outer tooth faces at intervals of K teeth are tangent to one of two parallel planes respectively, of which the vertical distance between two parallel planes is referred to as length of common normal line. The number of teeth between such two parallel planes must be indicated. The actual average length of common normal line measured on one same spline. 39Basic dimensionThe dimensions given in the design, which are the basis for tolerance designation. 40Auxiliary dimensionThe dimensions for manufacture and control only when needed. Note: Its allowable to measure the Fp and F in vicinity of reference circle. SV and S (Actual)EV and E (Actual)EV and E (Actual)Internal splineExternal splinea30 Flat RootSV and S (Actual)EV and E (Actual)Internal splineExternal splineb30 Fillet RootOptionalSV and S (Actual)EV and E (Actual)Internal splineExternal splinec37.5 Fillet RootFigure 1Involute Spline JointSV and S (Actual)OptionalEV and E (Actual)Internal splineExternal splined45 Fillet RootFigure 1 (Continued)4 Basic Parameters4.1 The basic parameters are shown in Table 2. 4.2 The standard pressure angle D is the tooth profile angle of basic tooth profile. 4.3 The module m is classified into two series, totaling 15 types. The series 1 should take precedence. Table 2 Basic ParametersmmBasic Tooth Space Width E and Basic Tooth Thickness SPitchSeries 2Series 1Module mTooth*Table 2(Continued) mmModule mTooth*Basic Tooth Space Width E and Basic Tooth Thickness SPitchSeries 2Series 1*For easy comparison, this table gives the sizes of spline tooth in various modules, with standard pressure angle D at 30, number of teeth at 30, and scale at 1:1. 5 Basic Tooth Profiles5.1 This standard specifies four basic tooth profiles based on three types of tooth profile angles and two types of roots, which are shown in Figure 2. 5.2 The basic tooth profile of the involute spline refers to the normal tooth profile of the basic rack. The basic rack refers to the ideal deviation-free spline in infinite diameter. 5.3 The basic tooth profile is the basis for determination of involute spline size. 5.4 The datum line is one straight line traversing the basic tooth profiles, based on which the size of the basic tooth profile is determined. 5.5 The root arc radius of basis tooth profile of internal spline Fi and root arc radius of basis tooth profile of external spline Fe are both of fixed value. Note: For the splines fabricated by various generating methods, the curvature radius of their root arcs is varying. The curvature radius at the tangent point between the arc and the minor circle of external spline (or major circle of internal spline) is the minimum value and it increases gradually along the arc and reaches the maximum value in vicinity of involute start point of external spline (or involute end point of internal spline). 5.6 The tooth profile allowance for all basic tooth profiles CF is 0.1m. 5.7 Its allowable to use the basic tooth profiles of flat root and fillet root on the internal splines and external splines in mixed manner. Datum lineBasic tooth profile of external splineBasic tooth profile of internal splinea30 Flat RootDatum lineBasic tooth profile of internal splineBasic tooth profile of external splineb30 Fillet RootDatum lineBasic tooth profile of external splineBasic tooth profile of internal splinec37.5 Fillet RootFigure 2Basic Tooth ProfilesDatum lineBasic tooth profile of internal splineBasic tooth profile of external splined45 Fillet RootFigure 2 (Continued)6 Dimension Series6.1 The calculation equation for dimensions of splines is shown in Table 3. 6.2 The basic dimension series of major diameter of external splines are shown in Table 4, Table 5 and Table 6. The modules in parentheses are secondary modules. If the dimensions shown in the table cant meet the demands of product structures, the allowable number of teeth may be out of the provisions in this table, provided that the geometrical parameter relationship and the tolerance fits specified in the standard must be maintained, in order to facilitate the utilization of standard cutting tools. Table 3Calculation Equation for Dimensions of SplinesItemCodeEquation or ExplanationDiameter of reference circleDmZDiameter of base circleDbmZcosDPitchpmBasic dimensions of major diameter of internal spline 30 flat rootDeim(Z+1.5) 30 fillet rootDeim(Z+1.8) 37.5 fillet rootDeim(Z+1.4) 45 fillet rootDeim(Z+1.2) (See Note (1)Lower deviation of major diameter of internal spline0Tolerance of major diameter of internal splineChoose from IT12, IT13, or IT14Min diameter of involute end circle of internal spline 30 flat root and fillet rootDFiminm(Z+1)+2CF 37.5 fillet rootDFiminm(Z+0.9)+2CF 45 fillet rootDFiminm(Z+0.8)+2CFBasic dimensions of minor diameter of internal splineDiiDFemax+2CF (See Note (2)Limit deviation of minor diameter of internal splineSee Table 25. Basic tooth space widthE0.5mTable 3(Continued)ItemCodeEquation or ExplanationMin effective tooth space widthEVmin0.5mMax actual tooth space widthEmaxEVmin+(T+) (See Chapter 8 and Table 721)Min actual tooth space widthEminEVmin+Max effective tooth space widthEVmaxEVmin-Upper deviation of effective tooth thickness of external splineesvSee Table 23 and Figure 3Basic dimensions of major diameter of external spline 30 flat root and fillet rootDeem(Z+1) 37.5 fillet rootDeem(Z+0.9) 45 fillet rootDeem(Z+0.8)Upper deviation of major diameter of external splineesv/tanD (See Table 24)Tolerance of major diameter of external splineSee Table 25Max diameter of involute start circle of external splineDFemax(See Note (3) of which hs is shown in Figure 2. Basic diameter of minor diameter of external spline 30 flat rootDiem(Z-1.5) 30 fillet rootDiem(Z-1.8) 37.5 fillet rootDiem(Z-1.4) 45 fillet rootDiem(Z-1.2)Upper deviation of minor diameter of external splineesv/tanD (See Table 24)Tolerance of minor diameter of external splineChoose from IT12, IT13 or IT14.Basic tooth thicknessS0.5mMax effective tooth thicknessSVmaxS+esvMin actual tooth thicknessSminSVmax (T+) (See Chapter 8 and Table 721)Max actual tooth thicknessSmaxSVmax Min effective tooth thickness SVminSmin + Tooth profile allowanceCF0.1 m (See Note (1)Note: (1) Its allowable to choose flat root for 37.5 and 45 fillet root internal splines. In such case, the basic dimension of major diameter of internal spline Dei shall be greater than the min diameter of involute end circle of internal spline DFimin. (2) For all spline side-fitted classifications, the value DFemax shall be taken based on the H/h fit. (3) This equation is deduced from the machining theory of rack cutting tools. (4) The tooth profile allowance is varying for other fit classifications, except the CF of H/h fit classification is equal to 0.1m. Table 4Table of Basic Dimension Series for Major Diameter of 30 External SplineDee = m (Z+1)Number of TeethModuleTable 4 (Continued) ModuleNumber of TeethTable 5Table of Basic Dimension Series for Major Diameter of 37.5 External SplineDee = m (Z+0.9)ModuleNumber of TeethTable 5(Continued) Number of TeethModuleTable 6Table of Basic Dimension Series for Major Diameter of 45 External SplineDee = m (Z+0.8)ModuleNumber of TeethTable 6(Continued)Number of TeethModule7 Tolerance GradesThis standard specifies four tolerance grades: grade 4, grade 5, grade 6, and grade 7.8 Tolerances8.1 Total tolerance (T +) The calculation equation for total tolerance of tooth space width and tooth thickness is as below (in unit of um): a. When the tolerance grade is grade 4, the calculation equation is 10 i1) + 40 i2)b. When the tolerance grade is grade 5, the calculation equation is 16 i1) + 64 i2)c. When the tolerance grade is grade 6, the calculation equation is 25 i1) + 100 i2)d. When the tolerance grade is grade 7, the calculation equation is 40 i1) + 160 i2)Note: 1) For the tolerances based on the diameter of reference circle D, the tolerance unit i is: When D500mm, i=0.45+0.001DWhen D500mm, i=0.004D+2.12) For the tolerances based on the basic tooth space width E or basic tooth thickness S, the tolerance unit i is: i=0.45+0.001E or i=0.45+0.001SOf which, D, E, and S are in unit of millimeters. 8.2 Composite tolerance The composite tolerance is determined based on the comprehensive influences of the pitch cumulative deviation, tooth profile deviation, and tooth alignment deviation on the spline fit. In consideration that any individual deviation may not appear in form of maximum value on one same spline at one time and three individual deviations may not influence the spline fit without mutual compensation, the composite tolerance is calculated in accordance with following equation: In unit of umThe value in Table 721 is calculated based on the tooth alignment tolerance under the condition that the spline length is half of the diameter of its reference circle. In event of different length, the value is adjustable when necessary, but the total tolerance (T + ) remains the same. 8.3 Machining tolerance TThe machining tolerance is the difference between the total tolerance (T + ) and composite tolerance , namely (T + ) . 8.4 Pitch cumulative tolerance FpThe calculation equation for pitch cumulative tolerance Fp is as below (in unit of um): a. When the tolerance grade is grade 4, the calculation equation is . b. When the tolerance grade is grade 5, the calculation equation is . c. When the tolerance grade is grade 6, the calculation equation is . d. When the tolerance grade is grade 6, the calculation equation is . Of which, L is half of circumference of reference circle, namely L = mZ/2, in unit of mm. 8.5 Tooth profile tolerance ff8.5.1 The calculation equation for tooth profile tolerance ff is as below (in unit o