RU2108887C1 - Method for knurling internal gear profiles - Google Patents

Abstract

FIELD: plastic metal working, namely knurling internal toothed profiles on tubular parts, particularly at restoring them. SUBSTANCE: method comprises use of worn part as blank 2 with uniform thickness t of fused layer 3 on its outer surface 1. Thickness t is directly proportional to sum l of wear value and allowance S for subsequent working of internal gear profile 4. Blank 2 is heated up to plastic deformation temperature and it is secured to mandrel that is mounted without possibility of rotation. Then blank 2 is deformed by axial effort P equal to $$$, where n - number of intertooth recesses; R - radius of shaped roller 8, mm; R<Mv>1<D> - radius of tooth extensions, mm; $$$- metal yield strength, MPa; $$$- allowance for rolling, mm. Internal toothed surface 4 of blank 2 is deformed lengthwise by means of rotating shaped rollers 9 set in double-section holder 16 and radially arranged on beam lines connecting rotation center 7 of knurled blank 2 with symmetry axis of intertooth recesses. Simultaneously outer cylindrical surface 1 of said blank is step by step knurled crosswise by means of stepped double-row roller unit 11. Deformation is over at temperature of crystallization start. Such method may be used at restoring by hot knurling internal toothed profile of splined sleeve of Cardan joint transmission of motor vehicle GAS-53 and other tubular articles with complex profile. EFFECT: enhanced efficiency. 5 dwg

Description

 The invention relates to the processing of metals by pressure and can be used at repair enterprises when knurling internal gear profiles in tubular parts, in particular, when restoring them.

 The known method, which is implemented in the copyright certificate N 1748986, class. B 21 H 5/02, publ. 07/23/92, bull. N 27 and consists in the redistribution of metal with a non-working inner surface of the driveshaft holes on the worn surface of the splines. However, in this way it is impossible to restore the internal gear profile while maintaining the original dimensions of the part.

 There is also a known method of knurling internal gear profiles, in which, simultaneously with profiling by gear rollers of the inner surface of the tube billet, additionally compress the yew in a stationary matrix of its outer surface. (Aut. St. N 725767, class B 21 H 5/00, publ. 05.04.80, bull. N 13 - prototype).

 However, the known method is applicable for rolling only large-sized parts with internal gearing, such as the gears of the planetary gear drive of the wheels of the combine harvester “Kolos”, having an inner diameter of ⌀ 270 mm. In addition, the disadvantage of this method is the impossibility of manufacturing and restoring tubular parts with internal teeth, for example, driveshaft bushings or hubs of driven clutch disks worn simultaneously on the outer cylindrical but internal gear surfaces.

 The purpose of the invention is the expansion of technological capabilities of the method and improving the quality of knurling of internal gear surfaces.

,
где
n - количество впадин зубьев;
R - радиус профильного ролика, мм;
R₁ - радиус зубчатых выступов, мм;
σ_s - напряжение текучести металла, МПа;
δ - припуск на прокатку, мм;
и одновременно с продольным профилированием внутренней зубчатой поверхности заготовки формирующими профильными вращающимися роликами, набранными в двухсекционную обойму и веерообразно расположенными на лучах, соединяющих центр вращения накатываемой заготовки с осями симметрии впадин зубьев, осуществляют поэтапную поперечную накатку ее наружной цилиндрической поверхности ступенчатым двухрядным роликовым блоком, при этом деформирование заканчивают при температуре начала кристаллизации.The goal is achieved in that in the method of knurling internal gear profiles, which consists in profiling the inner surface of the workpiece while simultaneously deforming it on the outer surface while simultaneously axially moving the workpiece, a worn part uniformly deposited over the outer surface with a deposited layer thickness directly proportional is used as a workpiece the sum of the wear and allowance for the subsequent processing of the internal gear profile, and when deformed to a heated to a temperature of pl -terrorist deformation and not attached to the workpiece having a mandrel rotatably applied axial force P, equal

,
Where
n is the number of tooth depressions;
R is the radius of the profile roller, mm;
R ₁ is the radius of the gear protrusions, mm;
σ _s is the yield stress of the metal, MPa;
δ is the allowance for rolling, mm;
and simultaneously with the longitudinal profiling of the internal gear surface of the workpiece by forming profile rotating rollers, mounted in a two-section cage and fan-shaped located on the beams connecting the center of rotation of the workpiece with the axis of symmetry of the tooth cavities, stagewise transverse knurling of its outer cylindrical surface with stepwise double-row rollers is carried out the deformation is completed at the temperature at which crystallization begins.

 The presence in the proposed method of the invention is proved by the fact that the existing methods of knurling internal gear profiles do not provide for the simultaneous formation of the outer cylindrical and inner gear surfaces with allowances for the nominal size when they are restored, or are suitable only for the manufacture of large tubular parts.

 The originality of the proposed method consists in longitudinal profiling of the internal gear surface with fan-shaped rollers, combined with a phased transverse knurling of the outer cylindrical surface of the workpiece with a two-row roller block in a single technological method.

 In FIG. 1 shows a restoration scheme by knurling of a gear part using an example of a fork of a universal joint transmission of a truck by the proposed method; in FIG. 2 is a section AA of FIG. one; in FIG. 3 is a diagram for calculating the amount of wear-compensating metal; in FIG. 4 is a diagram for calculating the longitudinal rolling force; in FIG. 5 is a diagram for calculating the lateral rolling force.

 The method is as follows.

 On the outer surface 1 of the workpiece 2 (Fig. 1), metal 3 is deposited with a thickness of 1, sufficient to compensate for wear And (Fig. 3) and create an allowance S for machining the toothed hole 4 after crimping along the outer surface 1.

The thickness of the deposited layer t is found from the equality of the volume V _{1 of the} deposited metal 3 to the volume V _{2 of the} worn metal 5, taking into account the allowance 8 for machining.

The volume V _{1 of the} weld metal 3 is determined from the formula
V ₁ = π (2r _o + t) • t • L,,
Where
r ₀ is the outer radius of the part, mm;
L is the length of the toothed surface of the hole 4, mm;
The total volume V _{2 of the} metal 5 necessary for the shaping of the toothed hole 4 is described by the expression
V ₂ = πbL (2R ₁ -b + a),,
Where
b is the sum of the wear value And and the allowance S for machining the tooth profile of the hole 4, i.e. b = And + S,
L is the length of the toothed surface of the hole 4, mm;
R ₁ is the radius of the protrusions, mm;
a is the depth of the depressions, mm.

,
После наплавки предварительно нагретую до температуры пластической деформации (900... 950^oC) заготовку 2 закрепляют на оправке 6, не имеющей возможности вращения, связанной с силовым гидроприводом. При перемещении заготовки 2 вдоль оси 7 в направлении стрелки P профильные ролики 8 входят во впадины зубьев, одновременно с этим включается привод токарно-винторезного станка, передающий вращение через патрон 9 и приводную обойму 10 накатным двухрядным роликом 11, расположенным на концентричной с осью 7 окружности.Equating this expression with the volume V _{1 of the} weld metal 3, we find the required thickness t

,
After surfacing, the preform 2 preheated to a temperature of plastic deformation (900 ... 950 ^o C) is fixed on the mandrel 6, which does not have the possibility of rotation associated with a hydraulic power drive. When moving the workpiece 2 along the axis 7 in the direction of the arrow P, the profile rollers 8 enter the troughs of the teeth, at the same time the drive of the screw-cutting machine is turned on, transmitting rotation through the cartridge 9 and the drive clip 10 by a knurled double-row roller 11 located on a circle concentric with the axis 7 .

 As the workpiece 2 moves, the rolling rollers 11 with conical 12, 13 and cylindrical 14, 15 surfaces redistribute the metal in succession in two stages from the outer pre-welded cylindrical surface 1 onto the surface of the worn gear hole 4 with simultaneous longitudinal profiling of this surface with fan-shaped rollers 8, drawn in two-section ferrule 16 and rolling mandrel 17 rolling in the opposite direction of the workpiece 2. As a result, uniform quality occurs idents increment tooth thickness along the entire length L.

The forming process is completed at a temperature of 750 ... 800 ^o C With the reverse movement, the profile rollers 8 come out of the troughs of the gear hole 4, the workpiece 2 is removed from the mandrel 6, the knurling process is completed.

 Increasing the strength parameters of rigging and reducing the power parameters of the equipment is achieved through the use of the principle of separation of the action of the rolling force into components along the X and Y axes.

The force P _N (the design diagram is shown in Fig. 4), acting during longitudinal rolling, is determined by the formula
P _N = σ _s • F,,
Where
σ _s is the yield stress of the metal, MPa;
F is the contact area of the working surface of the roller 8 with the workpiece 2, mm ² .

,
где
n - количество впадин зубьев;
R - радиус профильного ролика 8, мм;
R₁ - радиус зубчатых выступов заготовки 2, мм;
σ_s - напряжение текучести металла, МПа;
δ - припуск на прокатку, мм;
Усилие поперечной прокатки P_X (фиг. 5) рассчитывают по формуле:

,
где
F - площадь контакта рабочей поверхности накатного ролика 11 с наружной поверхностью 1 заготовки 2, мм²;
R₂ - радиус накатного ролика 11, мм;
h - ширина контактирующей части ролика 11 с поверхностью 1, мм;
r - внешний радиус заготовки 2, мм;
Δr - величина уменьшения внешнего радиуса r, мм.The final formula for determining the axial force P required to move the workpiece 2 during the longitudinal rolling process has the form

,
Where
n is the number of tooth depressions;
R is the radius of the profile roller 8, mm;
R ₁ - the radius of the tooth protrusions of the workpiece 2, mm;
σ _s is the yield stress of the metal, MPa;
δ is the allowance for rolling, mm;
The transverse rolling force P _X (Fig. 5) is calculated by the formula:

,
Where
F is the contact area of the working surface of the rolling roller 11 with the outer surface 1 of the workpiece 2, mm ² ;
R ₂ is the radius of the rolling roller 11, mm;
h is the width of the contacting part of the roller 11 with the surface 1, mm;
r is the outer radius of the workpiece 2, mm;
Δr is the magnitude of the decrease in the outer radius r, mm

 The above calculations are necessary for the correct choice of power equipment and for the design of tools and equipment with strength indicators providing the process of surface plastic deformation.

 An example of a specific implementation of the method of knurling internal gear profiles is carried out for the simultaneous restoration of hot knurling of a finely modular (m = 2.5; z = 22) serrated slotted hole with a diameter of protrusions of ⌀ 54 mm and a hollow of ⌀ 62 mm, a length of 145 mm and an outer cylindrical surface under the bearing ⌀ 70 mm in diameter of the drive shaft sleeve 53-22.02.157-01 of the automobile GA3-53 from steel 30X GOST 4543 - 71.

Surfacing on the outer surface of the wear-compensating metal was carried out on a UD-209 shafting machine for welding shafts with wire 1.5 Sv - 18 HGSA GOST 2246 - 70. Surfacing modes: current strength J = 100 ... 120 A, arc voltage U = 28. .. 33 B, surfacing speed V _n = 12 ... 15 m / h.

The pre-heated to 950 ^o C in the HDI I3 - 2.4 / 100 installation of the deposited worn-out sleeve was deformed on the rolling unit of the workshop manufacture with a hydraulic drive mounted on the tool post of the lathe of the lathe 1 M 63, by rolling across between six knurls while calibrating the gear slotted holes with rollers with a force of 200 kN and a feed of 0.05 mm / s. The drive of the knurls was carried out from the spindle of the lathe with a rotational speed of the part 100 min ^-1 .

 The quality of the product obtained was evaluated by measuring the dimensions of the rolled billet and examining its structure. As a result of plastic deformation of the worn-out drive shaft sleeve, metal was redistributed from the outer deposited surface to worn ones, while ensuring uniform allowance on all surfaces while maintaining the initial diameter of the outer surface and the geometric shape of the part.

 Microstructural studies of the working surfaces of the driveshaft bush showed that high-temperature plastic deformation strengthens the surfaces of gear splines, which is mainly characterized by an increased density of structural components.

 In addition, the specified method restored the spline hole (z = 10) of the hub of the driven disk 14.160.1142 of the KAMAZ - 740 engine clutch of steel 40 KhGTR GOST 4543 - 71, which also ensured the quality of the product obtained after rolling.

 Thus, the use of the invention allows to achieve the following results.

 1. The method of knurling internal gear profiles provides simultaneous restoration of both the outer cylindrical and internal gear surfaces due to the transverse knurling of the outer surface, combined with longitudinal profiling of the hole with calibrating rollers, which expands the technological capabilities of the method and increases the productivity of the process.

 2. Manufactured according to the results of power calculations given in the description of the method, the rolling unit provides a stable level of quality of the obtained product in accordance with the requirements of technical documentation. In addition, the reduction in the required power indicators of the equipment allows the use of a screw-cutting lathe for rolling.

 3. Due to surface-plastic deformation combined with calibration, the microhardness of the teeth of the spline hole at a depth of 0.1 mm increases by 37%, which ensures guaranteed durability of the splined connection of the cardan gear restored by the proposed method.

 The implementation of the potentials of the present invention allows to simplify the manufacturing process and the restoration of tubular parts having an internal gear profile by combining operations, to expand the technological capabilities of knurling by increasing the diameter range of the machined gear holes, and also to improve the quality of knurled surfaces without changing the initial geometric shape of the part.

Claims (1)

The method of knurling internal gear profiles, which consists in profiling the inner surface of the workpiece with simultaneous deformation of it along the outer surface while simultaneously axially moving the workpiece, characterized in that the worn part is used as a workpiece uniformly deposited on the outer surface with a deposited layer thickness directly proportional to the sum of the wear values and allowance for the subsequent processing of the internal tabbed profile, and when deformed to plastic heated to a temperature axial force Р equal to

where n is the number of tooth cavities;
R is the radius of the profile roller, m;
R ₁ is the radius of the gear protrusions, mm;
σ _s is the yield stress of the metal, MPa;
δ is the allowance for rolling, mm,
and simultaneously with the longitudinal profiling of the internal gear surface of the workpiece by forming profile rotating rollers mounted in a two-section cage and fan-shaped located on the beams connecting the center of rotation of the workpiece with the axis of symmetry of the tooth cavities, stepwise transverse knurling is carried out from its outer cylindrical surface by a stepped double-row roller this deformation is completed at the temperature of the onset of crystallization.

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