RU2320909C1 - Wave spur gear transmission - Google Patents

Abstract

FIELD: invention refers to machine building particularly to mechanical transmissions and may be used in drives of machines and devices.

SUBSTANCE: wave spur gear transmission has body (1), cam-shaped generator of waves (3), separator (5) with radial guides and located in them spurs (7), rigid cogged wheel with spurs (12). Base (6) of spurs (7) and guides of separator (5) fulfilled coaxial-cylindrical with possibility of turning of bases in guides relatively to their common axis located in middle plane of transmission. Elastic drum (10) is located inside separator (5) and is conjugated with ends of bases (6), provided with flats and shoulders oriented in the direction of spurs. Between opposite straight-line edges of base (6) and flats there is guaranteed clearance whose total value is calculated according to formula.

EFFECT: improves working capacity and increase efficiency.

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Description

The invention relates to mechanical engineering, in particular to mechanical gears, and can be used in drives of machines and devices.

Known wave gear cylindrical gear containing a rigid and flexible gears, a wave generator, input and output shafts placed in the housing [1].

Also known is a wave gear cylindrical gear comprising an input shaft located in the housing, a cam wave generator, a separator with radial guides and teeth with bases located therein, radially movable, a rigid gear wheel, a flexible wheel, which is essentially a return flap spring, and the peripheral efforts perceive the prismatic bases of the autonomous teeth, transmitting them to the separator [2].

This transmission has significant disadvantages. Firstly, it is technologically and economically justifiable that it is impossible to “fit” into the current standards for the allowable error in mating the teeth of the hard wheel and the cage, since independently from one another (from different bases), operations are performed to process the grooves of the cage, prismatic bases and the teeth themselves. As a result of the imposition of errors in the location, shape and size of the three mating elements, there is a skew and a violation of the contact of the teeth in the engagement. This reduces their load capacity due to the lack of compensation for errors (self-alignment of the teeth). Secondly, prismatic conjugation with respect to moving elements is always prone to seizing, which reduces the transmission efficiency.

Finally, the design of the flexible wheel - the return spring of the transmission [2] basically determines (lengthens) the axial dimension of the transmission, the body volume is not used effectively, and the metal consumption increases.

In order to eliminate these drawbacks, it is proposed to give the movable (autonomous) teeth of the separator an additional degree of freedom - the possibility of limited rotation around a radial axis located in the middle transverse plane of the transmission. For this, the tooth bases and the separator guides associated with them are cylindrical, and the flexible wheel is in the form of an elastic shell perforated around the circumference with the separator teeth pitch, located inside it and fixed by shoulders at the ends of the bases entering the holes of the flexible wheel.

To limit the arbitrary rotation of the cylindrical bases in order to avoid tooth interference when entering the gear with a hard wheel, two opposed flats are made on the end part of the bases, the shell holes associated with them have two corresponding straight edges, and a guaranteed side clearance is made between flats and edges, and those others are equally oriented with respect to the teeth.

The total value of two lateral clearances δ is determined from 2 conditions: non-intersection of the vertices of the mating teeth (δ _max ) and self-alignment of the teeth depending on the probable value of the accumulated angular error to be compensated (δ _min ).

From figure 2:

from figure 4: δ = l · sinα.

These conditions are met when:

where α is the skew angle of the teeth,

δ is the calculated value of the total clearance,

φ is the angle of the accumulated error of the arrangement of the teeth in the mesh,

l is the length of the flat,

t _x is the chordal pitch of the teeth of the hard wheel on the circumference of the protrusions,

a is the thickness of the top of the tooth,

b is the length of the tooth (the width of the ring gear).

The device of the claimed transmission is shown in figure 1 ... 4: figure 1 - axial section of the transmission; figure 2 is a local section aa (figure 1) indicating the maximum mutual distortion of the teeth before coming into contact; figure 3 is a sectional view of the transmission along the middle plane (BB in figure 1); figure 4 - section bb (figure 3) indicating the data for calculating the gap in the pairing "edge-flat".

In the housing 1 there is an input shaft 2, a generator 3 connected to it, an output shaft 4, a separator 5 connected to it, in radial guides of which bases 6 with teeth 7 are placed, flats 8 and shoulders 9 are made at the ends of the bases, on which a flexible wheel is fixed in the form of a perforated shell 10, the holes in which have straight edges 11, a hard wheel with teeth 12 is connected to the housing 1.

Transmission works like this. The cam of the generator 3, connected to the input shaft 2, moves the base 6 of the teeth 7 along the radial guides of the separator 5, introducing the teeth 7 into engagement with the teeth of the hard wheel 12, and the teeth 7 rotate in a tangential plane, ensuring their optimal position (self-installation) in contact gearing. Flexible wheel-shell 10, relying on the shoulders 9 of the base 6, promotes the return of the teeth 7 from the engagement zone, and also prevents them from unnecessarily arbitrary rotation in this zone, due to the interaction of the edges 11 of the holes in the shell with flats 8 of the base 6. The separator 5 perceives forces from the teeth 7 through their base 6 and transmits torque to the output shaft 4.

The positive effect is to increase the efficiency of the teeth and transmission efficiency, reduce material consumption and greater adaptability and the possibility of reducing the degree of accuracy of the teeth. This is achieved by self-aligning and improving the contact of the teeth in engagement, reducing the tendency to seize the cylindrical tooth bases in the guides, including through the two-dimensional nature of the friction (translational movement with rotation), as well as due to the greater compactness of the transmission.

Information sources

1. Ginzburg EG Wave gears. L .: Engineering, 1969, pp. 12-12.

2. Osipov V.I. and Osipov I.B. Cogwheel gear wave. Copyright Certificate No. 1778390, August 1, 1992

Claims (1)

A cylindrical wave gear train comprising an input shaft located in the housing, a cam wave generator, a separator with radial guides and teeth located therein with radially movable bases, a rigid gear wheel, a flexible wheel — a return spring, characterized in that the tooth bases and separator guides are made coaxially cylindrical with the possibility of rotation of the bases in the guides relative to their common axis located in the middle plane of the transmission (transverse plane kills), moreover, opposite flats are made at the ends of the bases, the flexible wheel is placed inside the separator and is made as an elastic shell with holes evenly spaced around the circumference in the middle plane of the transmission to accommodate the ends of the bases having two opposite straight edges oriented in the direction of the teeth, as well as end shoulders oriented respectively to the flats on the bases, between the edges and flats a guaranteed symmetrical lateral clearance is made, the total value of which δ

where φ is the probable accumulated (total) angular error, l is the length of the flat, t _x is the chordal pitch of the teeth of the hard wheel on the circumference of the protrusions, a is the thickness of the top of the tooth, b is the width of the teeth.

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