splined connection

Abstract

This utility model pertains to general mechanical engineering, primarily to kinematic linkage systems, and can be used to increase the reliability and durability of any technical devices designed to transmit torque using splined connections. The technical result of this utility model is to improve the reliability and durability of splined connections, and consequently, the entire technical device, by increasing the alignment accuracy and permissible shaft misalignment. This technical result is achieved by a splined connection comprising a splined shaft and a mating splined sleeve with an involute tooth profile, in which the splined shaft teeth are barrel-shaped in the axial direction. Unlike the known splined connection, the outer diameter of the splined shaft teeth is provided with projections that flexibly engage the splined sleeve's splined grooves.In this case, the projections on the outer diameter of the teeth of the splined shaft are made in the form of a narrow belt, having a fit with a gap of 0.005 to 0.015 mm along the grooves of the splines of the sleeve.

Description

[0001] The utility model relates to the field of general mechanical engineering, primarily to kinematic linkage systems, and can be used to increase the reliability and durability of any technical devices whose design involves the transmission of torque using splined connections.

[0002] Spline shafts are used in designs to transmit torque due to the action of the drive shaft, by means of contact along the side surfaces of the teeth, on the driven shaft.

[0003] When assembling splined shafts, due to the presence of deviations in separately manufactured parts, runouts, misalignments and distortions occur, which must be compensated for.

[0004] Modern designs utilize several shaft alignment options. For example, shaft alignment in the radial direction can be accomplished according to OST 1 00086-73 (Industry Standard. Involute Toothed (Splined) Joints. FSUE "VNII "Center", Moscow, 1974). Alignment can be accomplished in two ways:

[0005] along the side surfaces (p. 2 OST 1 00086-73) - centering by S. The splines are manufactured using a cutter or a milling cutter, the manufacturing accuracy of the side profiles of the teeth is low (S3a, S4, S3h6), there are large lateral gaps in the connection (gaps in the connection can reach values ​​of up to 0.36 mm), as a result, this manufacturing method does not provide the required accuracy of shaft alignment in the radial direction.

[0006] by outside diameter Da (p. 3 OST 1 00086-73) - centering by D. The diameter of the internal spline roots is produced using broaches, ensuring the specified accuracy (according to OST 1 00086-73). The diameter of the external spline tops is ground (to a roughness of Ra 0.80-1.6) to ensure the specified locating accuracy. This method - in a splined connection - ensures a more accurate fit, while the production of internal splines requires the use of expensive equipment (broaches), which is also more labor-intensive.

[0007] This shaft positioning method is acceptable for limited shaft misalignment. However, increasing shaft misalignment increases spline wear and reduces service life, while greater shaft misalignment increases the risk of seizure and failure.

[0008] Another, closest positioning solution is to manufacture a gear ring with the diameter of the tops machined along the radius.

[0009] For example, this alignment option is found in the gearbox-compressor junction of the D049R gas turbine engine, where torque from the turbocharger is transmitted to the gearbox via a splined shaft. The splines used in the shaft connection are gear engagements with an equal number of teeth, where the outer teeth on the coupling half are rounded (Fig. 3). This tooth configuration ensures precise shaft alignment by aligning the gullies of the inner teeth with the tops of the outer teeth, which are machined to a radius (rounded).

[0010] To ensure basing in this way, a part with internal splines is manufactured using a broaching machine, while the manufacturing accuracy of the spline cavity diameter is not high, and the positioning accuracy and the required radial clearance at the shaft junction in such splined connections are ensured by finishing by grinding the tops of the outer tooth to the actual diameter of the inner tooth cavity.

[0011] Parts manufactured in this way can only be used as a set and are not interchangeable.

[0012] A disadvantage of this method is that compensating for large angular misalignments requires increased lateral clearance in the tooth engagement. Increasing the permissible misalignment or changing the spline length requires further increasing the lateral clearance. Therefore, this tooth design has a limited maximum permissible misalignment.

[0013] A design similar to the D049R engine is used in toothed couplings complying with GOST 50895-96 (Toothed Couplings. Specifications. State Standard of Russia, Moscow, IPK Publishing House of Standards, 1996, p. 9, pp. 4.4 and 4.5). Unlike the D049R engine unit, these couplings utilize a barrel-shaped tooth shape, which compensates for distortions without increasing lateral clearances.

[0014] However, the disadvantage of this design is that such tooth radial machining requires a high tooth with the original contour for gear engagement (GOST 13754-78). Teeth for splined connections have an original contour with a smaller tooth height and are not suitable for this type of machining, so this configuration is applicable to a limited range of design solutions.

[0015] If we consider the variant in which there are no gaps (Fig. 4), then in case of distortions, the teeth cut into the mating part in two planes - in one plane along the tooth gullet (Fig. 5, location A), and in the plane perpendicular to it along the lateral surface (Fig. 5, location B). The basing methods according to OST1 00086-73, due to the presence of lateral gaps (when centering by d) or radial clearance (when centering by s), make it possible to compensate for the distortion in only one plane, since they have either only lateral gaps or only radial ones.

[0016] Thus, when centering splined connections according to OST 1 00086-73, if misalignment occurs, the cutting action and increased wear are inevitable. Moreover, to increase the maximum permissible misalignment or to increase the spline length, it is necessary to directly increase the radial clearance (for centering by s) or the lateral clearance (for centering by d). This allows for an increase in the permissible misalignment in one plane (Fig. 6), but also increases the cutting action in the other plane.

[0017] This problem is partially solved by the locating method used in the D049 coupling design. The rounded tops of the external spline teeth better compensate for shaft misalignment by allowing the external spline teeth to roll over the internal spline teeth in the same plane. However, in the perpendicular plane, the spline condition remains identical to the locating method according to OST1 00086-73, i.e., the grooves remain.

[0018] Existing design solutions for shaft alignment using splined connections have a number of problems. These include: limited permissible angular misalignment of shafts and springs, the need to increase lateral clearances when this misalignment is high, and the need for expensive equipment for machining tooth profiles.

[0019] The closest thing to a utility model is a splined connection comprising a splined shaft and a splined sleeve mating thereto, with an involute tooth profile, in which the splined shaft teeth are barrel-shaped in the axial direction (Patent No. 2486100, published June 27, 2013, Bulletin No. 18, IPC B63N 11 / 00). The disadvantage of this splined connection is its inability to accurately center the connected parts, as well as to accurately maintain the direction of their relative axial movement. As a result, under heavy loads, local deformation of the side surfaces of the shaft grooves by the sleeve splines occurs, forming depressions that impede the axial movement of the sleeve along the shaft.

[0020] The technical result to which the utility model is aimed is to increase the reliability and durability of the splined connections, and therefore the entire technical device, by increasing the accuracy of the basing and the magnitude of the permissible shaft distortions.

[0021] The technical result is achieved by a splined joint comprising a splined shaft and a mating splined sleeve with an involute tooth profile, in which the splined shaft teeth are barrel-shaped in the axial direction. Unlike the known splined joint, the outer diameter of the splined shaft teeth is provided with projections that movably engage the splined sleeve gullets. The projections on the outer diameter of the splined shaft teeth are designed as a narrow band, having a fit with a clearance of 0.005 to 0.015 mm across the splined sleeve gullets.

[0022] The utility model is illustrated by drawings.

[0023] Fig. 1 - longitudinal section of the splined connection;

[0024] Fig. 2 - view of the barrel-shaped tooth;

[0025] in Fig. 3 - view of the rounding of the external splines;

[0026] in Fig. 4 - view of the spline connection when cutting teeth in case of distortions;

[0027] in Fig. 5 - view of the spline connection when teeth are cut in with distortions in two planes;

[0028] Fig. 6 - view of a splined connection showing the influence of the spline length on the gap size;

[0029] Fig. 7 - view of tooth surface treatment.

[0030] The claimed splined connection (Fig. 1) with an involute tooth profile comprises a splined shaft 1 and a splined sleeve 2 mated therewith. The teeth 3 of the splined shaft 1 have a barrel-shaped form in the axial direction (Fig. 2). On the outer diameter of the teeth 3 of the splined shaft 1, projections 4 are formed, which movably contact the gullies of the splines 5 of the sleeve 2. The projections 4 can be made in the form of a narrow belt having an exact fit in the gullies of the splines 5 of the sleeve 2 (a gap from 0.005 to 0.015 mm), and serving as a centering one and ensuring high accuracy of shaft locating in the radial direction. At the same time, the presence of a barrel-shaped form of the external teeth of the splines allows for the required lateral clearances to prevent jamming and localization of the contact patch in case of shaft distortions, since in the presence of projections 4 in the form of a centering belt, a high value of angular distortions can be allowed.

[0031] The base surfaces in a splined connection are the cylindrical surfaces of the shaft and sleeve, so their final processing (grinding) is straightforward and requires no special equipment. The side surfaces A, B, and E (Fig. 7) of the internal and external splines can be machined using a broaching tool or a cutter. The gullet of the external splines—surface G (Fig. 7)—and the centering ring surface B (Fig. 7) on the internal splines are ground to ensure the required fit accuracy (roughness Ra 0.80). This simplifies the process of cutting internal splines.

[0032] The splined connection ensures precise centering of the sleeve relative to the shaft. The sleeve is centered on the shaft using the outer diameters of the shaft and the projections.

[0033] Thus, this utility model proposes basing a splined connection by manufacturing a narrow short belt on internal splines, and manufacturing a tooth cavity with high precision, ensuring an accurate fit in the splined connection, while to compensate for high angular distortions and ensure localization of the contact spot, the external teeth are made in a barrel shape.

[0034] As a result, by increasing the accuracy of the alignment and the magnitude of the permissible shaft misalignments, the utility model allows for an increase in the reliability and durability of the splined connections, and thus the entire technical device.

Claims

1. A splined connection comprising a splined shaft and a splined sleeve mated thereto, with an involute tooth profile, in which the teeth of the splined shaft are barrel-shaped in the axial direction, characterized in that projections are made on the outer diameter of the teeth of the splined shaft that movably contact the cavities of the splines of the sleeve.

2. A splined connection according to paragraph 1, characterized in that the projections on the outer diameter of the teeth of the splined shaft are made in the form of a narrow belt having a fit with a clearance of 0.005 to 0.015 mm along the grooves of the splines of the sleeve.

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