授课课题键、花键的互换性（Teaching topic keys, spline interchangeability）

1、授课课题键、花键的互换性（Teaching topic keys, spline interchangeability）The document comes from the network, it is my own collection organized, if have omitted, the error, still asks everyone to correct!The tolerance and cooperation of key and splineTeaching subject: tolerance and cooperation of key and splineO

2、bjective: 1. To understand the types and characteristics of flat key and rectangular spline.2. Master the characteristics of tolerance and coordination of flat and rectangular spline connections; Master the fixed mode of the rectangular spline connection;3. Understand the tolerance and cooperation o

3、f involute spline;4. Learn the annotation of flat key and rectangular spline1. The selection and annotation of the tolerance and cooperation of the flat key connection;2. The selection and annotation of the tolerance and cooperation of rectangular spline linkageDifficult point: the tolerance of rect

4、angular spline linkage and the selection of fitThe main function of bonding and spline in the machine:The gear, pulley, etc. used to connect the shaft and shaft to deliver torque;The key can also play a guiding role when there is an axial relative motion between the shaft and the transmissionType of

5、 key: it can be divided into single key and splineSingle bonds are divided into flat, semicircle and wedge keysThe flat key is the most widely usedThe flat key can be divided into ordinary flat key and direct flat keyOrdinary flat keys are generally used for fixed connections, and the directed flat

6、keys are used for removable connectionsThe shape of the keypad is divided into rectangular spline, involute spline and triangular spline, with the most application of rectangular splineThis section mainly discusses the precision design of the combination of flat and rectangular splineFIG. 8-1 key jo

7、in figure 8-2 single key1. Precision design of flat bond couplingIncludes: 1. Dimensional precision design2. Shape bit precision design3. Precision design of surface roughness1. Design of dimensional precisionThe basic composition of the flat key connection:The parallel bond is composed of key, shaf

8、t keyway and hub keywayAt work, the torque is transmitted through the side of the key and the side of the hub and hub grooveMatching size of flat key connection: b(non-fit size: L (key length), h (key height)T (depth of shaft groove), t1 (depth of hub groove)D (shaft and hub groove diameter)Figure 8

9、-3 pin connectionUse requirements:The lateral transmission of the force requires sufficient effective contact areaThe upper surface of the key has a certain clearance between the hub and hub groove (0.2-0.5).The key is firmly embedded; Easy to installFactors and controls affecting the use of flat ke

10、y connections:1) factors that affect the use of flat key connectionsThe symmetry error of the surface of the hole and axis axisSurface roughness: the surface roughness of the key and keyway2) control the factors that affect the use of the requirementsThe key is standard, so the control of the influe

11、ncing factors is mainly to the keywayFor the tolerance of the size, the tolerance of the non-fit size should be givenThe symmetry tolerance of the center plane of the center plane with the width of the axis and the width of the hub groove is givenThe surface roughness of the key grooves is allowable

12、 to the surface roughness, rather than the surface roughness valueDetermination of tolerance and cooperation of the flat key connection:1) the tolerance band and fit type of key and keyway fit in sizeCoordinate system: base axis systemThe precision of the parallel bond is standardized: the key width

13、 specifies a tolerance zone: h9; There are three kinds of tolerance zonesThree kinds of cooperation are formed: loose, general and relatively tightLoosely coupled connections are generally tighterFigure 8-4 schematic diagram of the tolerance of flat keysTable 8-1 the tolerance and coordination of th

14、e width of key key and width of shaft slot and width of hub groove2) the tolerance zone of the flat key and key wayHigh h: h11Flat bond length L: h14Shaft slot length L1: H14Axial groove depth t and the tolerances of the wheel groove depth t1 be determined by national standard textbooks (see table 1

15、0.3), to facilitate measurement, tagged (d - t) and (d + t1), its deviation according to the corresponding t and t1 selection bias, but (d) the deviation should be taken from number (-)2. Key slot toleranceIn order to ensure sufficient contact area and avoid assembly difficulty in the profile of key

16、 and keyway, the national standard has the following rules for the shape of key and key slots:(1) due to the actual center plane keyway on the radial and axial misalignments, caused the keyway symmetry error, shall, in accordance with the provisions of each wheel shaft groove and the axis of symmetr

17、y degree of toleranceThe tolerance level of symmetry is selected by GB/T 1184-1996, which is generally 7-9(2) when the ratio of the key length L to the key is greater than or equal to 8, the parallel degree of the two working sides of the key width b should be specified in the lengthWhen b is less t

18、han or equal to 6mm, the tolerance level is level 7; When b is greater than 8 36mm, the tolerance level is 6. When b is greater than 40mm, the tolerance level is level 53. Surface roughness of keywayThe maximum value of the matching surface Ra is 1.6-3.2. The maximum value of non-matched surface Ra

19、is 6.3It can be rated 7-9 according to GB/t1184-1996 tolerance value of shape and location tolerance4. Example of axis marking:Marking groove depth d - t and toleranceLabel slot width b and toleranceLabel symmetry toleranceLabel surface roughnessFigure 8-5 axis mark5. Example of logo of wheel hub:La

20、bel hub deep d + t1 and toleranceLabel slot width b and toleranceLabel symmetry toleranceLabel surface roughnessFIG. 8-6 label of wheel hubThe tolerance and cooperation of rectangular spline bondCompared with bonding, its centring precision is high, good guide and strong bearing capacity, so it is w

21、idely used in mechanical productionThere are many kinds of spline bonds, but the most widely used is the rectangular spline1. The use requirements, geometric parameters and centering methods of rectangular spline1) geometric parameters of rectangular splineMain dimensions: path d, large diameter d,

22、key and keyway width B;The number of keys is even: 6, 8, and 102) use requirements:Figure 8-7 rectangular splineA) internal and external key requirementsB) side transmission force requires sufficient and large effective contact areaC) for sliding spline keys, there is a certain gap between the insid

23、e and outer spline keysD) the accuracy of the spline3) centring method: the path is fixedThe rectangular spline bond is composed of multiple surfaces, the main structural dimensions have large diameter (D), the path (D) and the key width (B). These parameters also have matching dimensions and non-ma

24、tching dimensionsFrom the perspective of standardization, no matter which type of size, the tolerance and cooperation national standard can be adoptedIn the combination of rectangular spline, it is very difficult to combine the large diameter D, path D, and key width B of the external splineBecause

25、the three dimension will have made errors, and even if these three dimensions are done very accurate, but also between its corresponding surface can have position error, in order to guarantee the use of performance, improve the processing technology, just choose a combination of surface as the main

26、matching surface, for its high accuracy, to ensure that the nature and centering precision, the surface is called the centering surfaceBecause of the hardness of the combination surface of the spline, it is usually required to heat treatment during processingTo ensure the accuracy and shape of the s

27、urface of the centering surface, it is necessary to make the grinding process after heat treatmentAccording to the processing technology, the path is easy to grind, which is easy to guarantee high machining accuracy and surface hardness, which can improve the wear resistance and service life of the

28、splineTherefore, the standard of rectangular spline is determined by using the pathSpline hole of large diameter and difficult to grinding on the side of the keyway, for this a few non centering size can lower tolerance grade, but due to lateral transfer torque by key, therefore the lateral size on

29、the key requirements of tolerance grade higher2. The precision design of the rectangular spline joint1) design of dimensional precision:Internal and external spline size tolerance zone: see table 11-7Coordinate system: base hole systemThe selection of mating type: the main reason for the relative mo

30、tion of the spline in the internal and external spline: table 11-7A) the relative motion requires frequent application of sliding fit;B) without relative motion requirements, the application of fixed cooperation;C) the accuracy of centering is high, and the fixed coordination is applied. Require low

31、, usable sliding fitLarge diameter is a centering diameter, corresponding combination of internal and external spline D surface should be larger gap, so the H10 prescribed standards/a11, both general purpose and precision transmission with spline, is only this kind of cooperation2) determination of

32、internal and external spline location toleranceA) the limiting dimensions of the path d are adhered to the principle of inclusion:The shape of its surface is tolerableTolerance principle of tolerance and size toleranceB) the location of the spline is subject to the principle of maximum entity (batch

33、)The position tolerance of spline is integrated to control the angular position of each key of the spline, the symmetry error of each key to the axis, and the parallel error of each key to the axisIt adheres to the principle of maximum entity(the location tolerance is shown in the textbook table 10.7)C) the symmetry tolerance of key and keyway and to