RU2615578C1 - Rigid gear for wave transmission of discrete motion - Google Patents

Abstract

FIELD: machine engineering.

SUBSTANCE: rigid gear for wave transmission of discrete motion consists of two pairs of toothed sectors. In the contact areas of the rigid tooth gear, the teeth of the wave coupling sector are made by height variable hi. Identical tooth sectors are locted diametrically opposite, one sector pair in mesh with a flexible gear forms the wave gear transmisstion, and the other - the wave gear coupling. In the interface zones, the sector teeth of the wave coupling have a variable height. Variable teeth height values h_i can be determined by mathematical formulas and dependencies.

EFFECT: increased transmission durability.

2 cl, 4 dwg

Description

FIELD OF TECHNOLOGY

The invention relates to mechanical engineering and instrumentation and can be used in mechanical devices that implement discrete motion of the output link with continuous movement of the input.

BACKGROUND

Known wave transmission with roller, disk and cam generators of internal waves and ring generators of waves of external deformation [1].

The closest technical solution is a step wave transmission [2], which contains a flexible wheel, a wave generator and a hard wheel consisting of four gear sectors, with which the flexible wheel sequentially forms a two-wave gear or wave gear coupling. With the continuous rotation of the wave generator, which provides wave engagement in the area of one pair of gear sectors of the hard wheel, the output link rotates, when the gear is engaged with the second pair of gear sectors of the hard wheel, forming a wave gear coupling with the flexible wheel, the “stand-by” mode is implemented - the output link remains stationary. Thus, with continuous rotation of the input link, a discrete rotation mode of the output link is realized.

The disadvantages of this design solution are high dynamic loads and intensive tooth wear when the transition of the teeth of the flexible wheel with the teeth of the hard wheel from one pair of sectors to another occurs due to the difference in the angular steps of the teeth of the hard wheel sectors. In this case, the instant loading of the teeth of the flexible wheel reduces the bearing capacity and resource of the flexible wheel and the transmission itself.

SUMMARY OF THE INVENTION

The objective of the present invention is to significantly reduce dynamic loads in the areas of interconnection of the teeth of the flexible wheel at the boundaries of the sectors of the hard wheel, reduce wear and increase the durability of the transmission.

The technical result is achieved by the fact that in the contact areas of the hard gear sectors, the teeth of the sectors of the clutch wave are made of variable height h _i , which is determined from the condition that the teeth of the flexible and hard wheels are not jammed from the stop of the tops of the teeth of the wheels upon engagement, which ensures shock-free mating of the teeth of the flexible wheels during the transition of a deformation wave (gearing zone) from one sector of a hard wheel to another.

Thus, the intermittent wave transmission comprises a flexible wheel, an ox generator and a rigid wheel consisting of four gear sectors. The same gear sectors are diametrically opposed, and one pair of sectors, when engaged with the flexible wheel, forms a wave gear transmission, and the other a wave gear coupling. Moreover, in the zones of conjugation of the sectors, the teeth of the sectors of the wave coupling have a variable height. The height of the teeth is determined from the condition that there is no jamming of the teeth of the flexible and hard wheels from the stop of the tops of the teeth of the wheels when entering the mesh depending on the angle of rotation ϕ _{h of} the wave generator.

Variable values of the height h _{i of the} teeth are determined by the following mathematical formulas and relationships:

- окружность впадин жесткого колеса; r _{a гi} - окружность вершин деформированного гибкого колеса; r_сг - радиус срединной линии недеформированного гибкого колеса;

- радиальное перемещение точек срединной линии гибкого колеса; w₀ - радиальная деформация гибкого колеса на большой оси деформации;

,

- расчетные коэффициенты [4]; β - половина угла облегания гибкого колеса генератором волн; h_s - кратчайшее расстояние от срединной линии до вершины зуба гибкого колеса; ϕ_h - угол поворота генератора волн.Where

- circumference of the hollows of the hard wheel; r _{a gi} is the circumference of the vertices of the deformed flexible wheel; r _cg is the radius of the midline of the undeformed flexible wheel;

- radial movement of the midline points of the flexible wheel; w ₀ - radial deformation of the flexible wheel on the major axis of deformation;

,

- estimated coefficients [4]; β - half the angle of the flexible wheel by the wave generator; h _s is the shortest distance from the midline to the top of the tooth of the flexible wheel; ϕ _h is the angle of rotation of the wave generator.

LIST OF FIGURES

In FIG. 1 shows an axial section of a wave transmission of discrete motion.

In FIG. 2 shows a cross section of a wave transmission of discrete motion.

In FIG. 3 shows a design diagram for determining tooth height.

In FIG. 4 shows the construction of adjacent gear sectors of a hard wheel.

DETAILED DESCRIPTION OF THE INVENTION

In FIG. 1 shows an axial section of a wave transmission of discrete motion. In the housing 1 and the cover 2, a flexible wheel 3 is mounted on bearings 7, made in the form of a glass and is an output link of the transmission; inside the wheel 3 there is a disk wave generator, consisting of disks 4 mounted on an eccentric shaft 5; the hard wheel 6 is fixed in the housing 1. The disks 4 of the wave generator give the flexible wheel 3 the shape of a two-vertex oval (Fig. 2). The hard wheel 6 is made of four gear sectors 8, 9, 10 and 11. A pair of sectors 8 and 9, located diametrically opposite, made the same and has gear rims with angular tooth steps equal to the angular tooth pitch of the flexible wheel 3. Another pair of sectors 10 and 11, also located diametrically opposite, made identical and has gear rims with angular tooth pitch different from the angular pitch of the teeth of the flexible wheel 3. The gear sectors 8 and 9 of the hard wheel 6 in the mating zones have teeth of variable height ( Fig. 4).

The transfer works as follows. When the wave generator rotates, the flexible wheel 3 in meshing with sectors 10 and 11 forms a two-wave transmission (the output link carries out movement), and in meshing with sectors 8 and 9 it forms a wave coupling (the output link is stationary). Thus, the output link 3 performs intermittent movement. When the wave generator passes through the interface zone of the sectors due to the variable height of the teeth of the sectors of the clutch, an unstressed transition of the deformation wave of the flexible wheel 3 is ensured and thereby an unstressed alternation of the driving modes and the “standstill” of the output link is provided. The methodology for calculating the tooth height h _i (Fig. 3) is based on the basic principles of the classical theory of involute gearing, using the condition of no jamming of the teeth of the flexible and hard wheels from the stop of the tops of the teeth of the wheels when entering the gearing depending on the angle of rotation ϕ _{h of} the wave generator [3] .

As an example, table 1 shows the values of the height of the teeth of the sector of the wave clutch of the hard wheel with the following geometric parameters of the wave transmission of discrete motion: the number of teeth of the sector of the wave clutch z _m = 21, the number of teeth of the sector of the wave transmission z _w = 22, the number of teeth of the flexible wheel z _g = 86, engagement modulus m = 0.4 mm, half of the angle of inclination of the flexible wheel by the wave generator β = 30 °.

Information sources

1. Kostikov Yu.V., Timofeev G.A., Fursyak F.I. New in the design of wave gears // Bulletin of higher educational institutions. Engineering. 2012. No. 12. S. 42-49.

2. Step wave transmission. A.S. USSR No. 1260598, class F16H 1/00, 27/04, publ. 09/30/86 // BI 1986. No. 36.

3. Timofeev G.A., Podchasov E.O. The study of jamming in gears of non-power wave transmissions // News of Higher Educational Institutions. Engineering. 2016. No4. S. 16-21.

4. Shuvalov S.A., Volkov A.D. Deformation of a flexible gear wheel of a wave transmission by two disks // News of Higher Educational Institutions. Engineering. 1971. No. 10. S. 44-49.

Claims (4)

1. A hard disk of a wave transmission of discrete motion, consisting of two pairs of gear sectors, identical and diametrically opposed, one pair of gear sectors forming a wave gear with a flexible wheel, and the other pair of sectors, a wave gear coupling, characterized in that in local areas relative to the boundary lines between the sectors of the hard wheel, the teeth of the sectors of the wave clutch have a variable height h _i , determined from the condition that there is no jamming of the teeth of the flexible and hard wheels from the stop in gear teeth at the entrance to the mesh depending on the angle of rotation ϕ _{h of} the wave generator. 2. The hard wheel of the wave transmission of discrete motion according to claim 1, characterized in that the variable values of the height h _{i of the} teeth are determined by the following mathematical formulas and dependencies:

Where

- circumference of the hollows of the hard wheel; r _{a gi} is the circumference of the vertices of the deformed flexible wheel; r _cg is the radius of the midline of the undeformed flexible wheel;

- radial movement of the midline points of the flexible wheel; w ₀ - radial deformation of the flexible wheel on the major axis of deformation;

- estimated coefficients; β - half the angle of the flexible wheel by the wave generator; h _s is the shortest distance from the midline to the top of the tooth of the flexible wheel; ϕ _h is the angle of rotation of the wave generator.

Images