RU2359790C1 - Threading method of ring gear of rigid wave gear with intermediate rolling bodies - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: method is implemented by form-generating method and includes roughing and smoothing. It is used toll in the form of rolling element, which is introduced into toothing with gear ring shape with providing of displacements and its values, corresponding particular gearing. Additionally roughing is implemented by hard-alloy end-milling cutter with maximal removal of work material, implemented with maximal hardness, and smoothing - by grinding wheel for one blank installation on manufacturing equipment, herewith cutter diametre is implemented less of grinding wheel diametre, which is selected equal to diametre of rolling elements of wave gear.

EFFECT: accuracy increasing and manufacturing content reduction.

2 dwg

Description

The invention relates to the field of manufacturing gears, and in particular to methods of manufacturing teeth using cutting tools, and can find application in cutting gears of a hard wave transmission wheel with intermediate rolling bodies.

A known method of manufacturing parts of the transmitting node of the differential speed Converter "gearbox-bearing" (Pat. RF 2287417, IPC V23P 13/00. BI No. 32 - 2006). The method includes preparing parts from tool steel workpieces and then performing specified curved surfaces on them using program-controlled movements of the cutting tool. Moreover, the execution on the prepared parts of the specified curved surfaces is carried out with a carbide tool. Defined curved surfaces can be performed using a numerically controlled milling machining center. For machining billets of steels with a hardness of more than 65 Rockwell units, a spherical end mill can be used as a carbide cutting tool.

The disadvantage of this method is the high cost of manufacturing parts with curved surfaces, due to the high cost of technological equipment, tools and highly qualified staff.

There is also known a method of cutting the inner ring gear of a wave transmission with intermediate bodies on EDM machines with wire cutting. (Khokhryakov B.G. Cutting out complex parts (wave reducers with intermediate links) on EDM machines. Difficult implementation experience. Magazine "Engine" No. 4/2001). Processing is carried out due to electroerosion of the material of the workpiece and occurs in one operation. As a tool, copper wire is used.

The disadvantage of the method of using EDM machines for wire cutting for cutting the internal gear rim of a hard wheel of a wave transmission with intermediate bodies is the high complexity and cost, due to the high cost of equipment, tools and high qualification of staff, as well as low values of accuracy and roughness of the working surfaces of tooth profiles.

The closest adopted for the prototype is a method of cutting a gear rim of a hard wheel on coordinate machines. The roughing operation, with the minimum hardness of the workpiece material, is performed by the end mill on the coordinate boring machine. The finishing operation, with the maximum hardness of the workpiece material, is carried out with an end grinding wheel of small diameter on a coordinate grinding machine. Thus, roughing and finishing operations are performed on different technological equipment. An analytically obtained profile of the depression between the teeth of a hard wheel of a wave transmission with intermediate bodies is replaced by a broken curve composed of segments of arcs with constant radii R, the center of which is located on the axis of symmetry of the depression at a distance A from the center of the hard wheel. For every two points of the profile of the cavity (tooth) symmetrical with respect to the axis of the profile, certain values of R and A are obtained. Setting a permissible deviation from the calculated profile, several (4-5) combinations of R and A are obtained that determine the coordinates of the arcs replacing the profile of the cavity between adjacent teeth (Yangulov BC - About one of the methods of manufacturing and control of the gear ring of a planetary gear with intermediate bodies. VINITI bibliographic index. Deposited scientific works, 1985, No. 6, p.118).

The disadvantages of this method are the low accuracy of the tooth profile and the high complexity and cost of cutting the gear rim of a hard wheel of wave transmissions with intermediate rolling bodies.

The task: to increase the accuracy of tooth profiles, reduce the complexity and cost of cutting the gear rims of the hard wheels of wave gears with intermediate rolling bodies.

This problem is solved as follows. A method of cutting a gear rim of a hard wheel of a wave transmission with intermediate rolling bodies comprises a rough operation and a finishing operation with the maximum hardness of the workpiece material. Roughing is carried out with an end mill made of hard alloys, and finishing with a grinding wheel on one technological equipment.

The invention is illustrated by drawings, which depict:

- figure 1 is a cross section of a wave transmission with intermediate rolling bodies;

- figure 2 is a process of cutting a gear rim of a hard wheel.

The input link of the transmission (Fig. 1) is an eccentric generator - 1, installed with an eccentricity a _ω , relative to the center of the hard wheel - 2 and the cage - 3. When the generator rotates, its outer surface reciprocates the rolling bodies - 4 in the radial grooves of the cage - 3. Rolling bodies - 4 are in contact with the working surfaces of the gear rim of the hard wheel - 2.

, где Z - число зубьев. Величина возвратно-поступательных перемещений тел качения в пазах обоймы составит 2a_ω.The output link of the transmission may be a ferrule or a hard wheel. The gear ratio of the gear will be equal to the number of teeth or rolling elements of the output link, respectively. For example, assume that the output link is a hard wheel. In this case, in one rotation of the generator by an angle of 2π, the hard wheel will rotate by an angle

where Z is the number of teeth. The magnitude of the reciprocating movements of the rolling bodies in the grooves of the cage will be 2a _ω .

In the proposed method, cutting the profiles of the ring gear is performed by a tool in the form of a rolling body, which is engaged with the profiles of the ring gear to ensure movements and their values corresponding to a particular gear. Obviously, the tool rotates at an angular speed that provides the necessary cutting speed. The workpiece must rotate at a speed corresponding to the reduced speed of the output gear link, for which a rigid wheel is cut.

, относительное возвратно-поступательное перемещение инструмента и заготовки составит 2а_ω. Скорость относительного перемещения - V=a_ωsinφ, задают при помощи кривошипа, длина которого равна эксцентриситету передачи а_ω. Угол поворота кривошипа φ жестко связан с углом поворота заготовки φ₁-φ=Zφ₁.This is achieved provided that the rotation of the workpiece at an angle equal to

, the relative reciprocating movement of the tool and the workpiece will be 2a _ω . The relative displacement velocity, V = a _ω sinφ, is set using a crank whose length is equal to the eccentricity of the transmission a _ω . The angle of rotation of the crank φ is rigidly connected with the angle of rotation of the workpiece φ ₁ -φ = Zφ ₁ .

Roughing is performed by carbide (end mill) with the maximum removal of the workpiece material. Further, without removing the workpiece from the table, only replacing the cutter on the grinding wheel and changing the angular velocity of the tool, carry out the finishing operation. This reduces the manufacturing errors of the gear profiles of the hard wheel associated with the installation and basing of the part.

The technological equipment includes a spindle - 5, a table - 6 and a bed (not shown). The spindle consists of a shaft - 7, on which the tool is mounted - 8 (milling cutter or grinding wheel). The shaft has a drive - 9 for rotating the tool. The spindle is mounted on the machine bed in the guides, providing its reciprocating movement relative to the workpiece - 10. The reciprocating movement of the spindle is carried out by the -11 drive. The workpiece is installed on the table, which provides its translational movement along three axes, for adjustment, and rotational, consistent with the reciprocating movements of the spindle. Coordination of the movement of the workpiece and the spindle can be achieved in several ways, for example, using the kinematic run-in chain, as well as in gear shaping or gear hobbing machines.

The design of technological equipment involves its development on the basis of modular construction. All the main components can be used from serial metal-cutting machines, which will reduce the cost of manufacturing a gear wheel. The simplicity of settings and the operation of technological equipment makes it possible for mid-level specialists to work. The complexity of processing the gear rim of a hard wheel of a wave transmission with intermediate bodies will decrease by several times due to a decrease in the number of passes of the tool (compared to the prototype) and due to the use of more productive methods of cutting metals (compared to analogues).

Processing the gear rim of a hard wheel are as follows. The workpiece - 10 is mounted on the table - 6, then combine the axis of the workpiece and tool. After that, the table is moved in the radial direction (relative to the axis of the workpiece) by an amount equal to R _Σ = 0.5 (D _g + D _W ), where D _g , D _W - the diameters of the generator and the rolling elements of the gear. In this case, it is necessary to fulfill the following condition, the crank providing reciprocating movements of the spindle must be set so that its angle φ for the cut cavity is equal to zero, i.e. cutting starts from the top of the tooth. Then include the drive rotation of the tool and the drive, or drives, to ensure the break-in of the hard wheel and tool. The machining of the ring gear in both operations is carried out on a workpiece with working hardness (more than 60 units on the Rockwell scale). After cutting the ring gear with an end mill, it is replaced with a grinding wheel. Without removing the workpiece from the table, change the speed of rotation of the tool and repeat the processing cycle. The allowance for the finishing operation is determined by the fact that the diameter of the cutter (made) is less than the diameter of the grinding wheel, which is chosen equal to the diameter of the rolling elements (wave) transmission.

Thus, the method of cutting the gear rim of the hard wheel allows you to: improve the accuracy of manufacturing the gear rim of the hard wheel, because roughing and finishing operations are carried out without reinstalling the workpiece, and the roughness of the working surfaces of the teeth due to the execution of the finishing operation by grinding; to reduce the cost of the process of cutting the gear rim of the hard wheels of wave transmissions with intermediate bodies due to the possibility of using technological equipment made of aggregates and modules of serial metal-cutting machines, an inexpensive tool, maintenance personnel of average skill, due to the simplicity of the settings and operation of the machine; reduce the complexity of the process of cutting the ring gear by using more productive methods of cutting metals and reducing the number of passes of the tool.

The technical result of the invention: improving the accuracy of manufacturing tooth profiles and the roughness of the working surfaces of the teeth, reducing the cost and complexity of manufacturing the gear rim of a hard wave transmission wheel with intermediate rolling bodies.

Claims (1)

A method of cutting a gear rim of a hard wheel of a wave transmission with intermediate rolling bodies by the rolling method, including roughing and finishing, characterized in that they use a tool in the form of a rolling body, which is engaged with the profiles of the gear rim to ensure movements and their values corresponding to a particular gear while roughing is performed by carbide end mill with the maximum removal of the workpiece material, made with maximum hardness, and finishing is performed by grinding cial round blanks in one set on the process equipment, and operate the cutter diameter smaller than the diameter of the grinding wheel, which is selected equal to the diameter of the rolling bodies of the wave transmission.

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