RU2265765C2 - Face gear-roller drive - Google Patents

Abstract

FIELD: the invention refers to engineering industry and refers to construction of mechanic drives.

SUBSTANCE: movement transmission in a face gear-roller drive from the tooth of a driving-wheel 2 to the tooth of the driven wheel 4 is fulfilled through a pair of rollers 5 and 7. The rollers 5,7 are positioned in a fixed ring 8 and placed on the axle in such a manner that interior roller 5 contacts with the tooth of the driving wheel 2 and the exterior 7 - with the tooth of the driven wheel 4.

EFFECT: expansion of possibilities of using, simplification of a construction.

8 dwg

Description

The present invention relates to the design of mechanical gears and is aimed at increasing their load capacity and increasing the gear ratio in one stage.

Currently, gears with an involute tooth profile are most common.

One of the significant drawbacks of such gears is a low gear ratio in one stage

where z _to - the number of teeth of the wheel;

z _W - the number of gear teeth.

An increase in i is possible by reducing the number of gear teeth z _w However, in involute gears this is almost impossible, because when z _w <16, undercutting of the tooth leg begins.

In practice, for a single-stage gear, the limitation i≤6 is used, because at i> 6, the dimensions of the transmission increase, which leads to the use of multi-stage options and, as a result, to an increase in the metal consumption of the drives.

Known planetary gear [1], consisting of a housing, a leading disk with an end cam, a driven disk having end teeth, a separator fixedly connected to the housing and rollers placed in the slots of the separator. When the drive disk rotates, its end cam acts on the rollers and moves them alternately into the hollows of the driven disk, causing it to rotate.

This transmission can implement significant gear ratios, but has a significant drawback. The roller is in contact with the working surfaces of the drive and driven discs (wheels) rotating at different angular speeds, i.e. during transmission, the rollers do not roll, but slide over the surface of one of the wheels. The slip time is proportional to the gear ratio.

The proposed design of the mechanical gear-roller transmission eliminates a similar disadvantage due to the use of a pair of rollers placed on the same axis.

Figure 1 presents a structural diagram of the mechanical gear-roller transmission. On the shaft 1 is the drive wheel 2, which has two teeth with a helical profile. On the driven shaft 3 is a driven wheel 4 having fourteen teeth of a helical profile. When the rotation of the wheel 2 under the action of the helical surface of the tooth, the inner rollers 5, freely sitting on the axles 6, move in the axial direction of the transmission. Through the axis 6, this movement is transmitted to the rollers 7, which, in contact with the helical surface of the teeth of the wheel 4, makes it rotate. The reciprocating movement of the rollers along the transmission axis is ensured by the location of the axes of the rollers in the longitudinal grooves of the intermediate stationary ring 8. Thus, the rotational movement of the gear with a helical tooth profile is converted into the translational motion of the rollers, which, in turn, is converted into rotational motion of the driven wheel.

The transmission operation scheme is shown in FIG. 2. The scans of the driving 2 and driven 4 wheels are conventionally reduced to the same diameter, although in the diagram (Fig. 1) the diameter of the gear 2 is less than the diameter of the wheel 4.

With the number of gear teeth equal to two, it is necessary to have four rollers (rollers 5 and 7 on the diagram are projected into one).

When the reamer 2 moves to the right, which corresponds to a clockwise rotation of the gear, and when the reamer 4 is stationary, the rollers will move in the same direction, but with a path corresponding to the profile of the teeth of the wheel 4.

In the case of restricting the movement of the roller along the reamers and the possibility of its movement in the perpendicular direction (along the transmission axis), the reamer 4 will move in the opposite direction.

Figure 3 shows a diagram of the interaction of transmission links.

When the reamer gear moves to the right (in the direction of the arrow), the working surface of the gear tooth A _{w H w} will cause the roller 5 to move in the perpendicular direction. The roller 7, located on the same axis as the roller 5, acting on the working surface of the tooth of the wheel A _to B _to , performs a stroke and moves the sweep of the wheel to the left.

At the same time, the second pair of rollers 5, 7 under the influence of the idle tooth surface of the wheel a _to b _k idles, returning to its original position. While moving along the horizontal section K, the apex of the tooth a _k passes over the roller 7 and it touches the working surface of the tooth of the wheel. The subsequent movement of the reamer gear will make this pair of rollers make a working stroke.

The teeth of the wheel and gears should be asymmetric (as shown in the diagram of figure 3) and made taking into account the overlap to ensure the continuity of the transmission. Therefore, the transmission cannot be reversible.

The number of gear teeth can be 1, 2, 3. With one tooth, two alternately loaded rollers are needed, but then the load on the wheels will be asymmetric. With three teeth and six rollers, the dimensions of the transmission increase. The optimal number of teeth will be equal to two with four rollers (figure 2).

Figure 4 shows the ratio of forces acting on the transmission links. When the gear rotates with a driving moment T _w , a circumferential force will act on the roller at the contact point

where d _W - the average diameter of the gear teeth.

Axial force driving roller

where α _W - the angle of inclination of the helix of the gear tooth.

The circumferential force acting on the tooth of the wheel is determined

where α _to - the angle of inclination of the helix of the tooth of the wheel.

In the considered ratio of gear and wheel profiles, their directions of movement are inverse. It is possible to realize movement in one direction (Fig. 5).

In the design of FIG. 1, rolling friction is realized at the contact points of the teeth and rollers, as well as the axes of the rollers and the guide grooves of the fixed ring. However, in the places of contact of the rollers and the stationary ring, sliding friction acts during their rotational and reciprocal motion. Therefore, the contact should be made flat using the flats on the ring (6, where 5 is the gear wheel; 7 is the wheel roller; 6 is the axis of the rollers; 2 is the stationary ring).

The design of the node providing reciprocating motion may be different.

For power transmissions, the scheme shown in FIG. 7 is more applicable, where 5 is a gear roller; 7 - wheel roller; 6 - the axis of the rollers, mounted on a sleeve 9, sliding along a cylindrical guide 10; 11 - guide key.

For the design of the transmission with a similar roller unit, it is necessary to implement a scheme of the coincident direction of movement of the gear and wheel (figure 5).

The principle of operation of the transmission was investigated using geometric constructions, reamers of gears, as well as on the layout (Fig. 8), made in accordance with the structural scheme (Fig. 1). The gear ratio is determined by analogy with the mechanical transmission:

Analysis of the research results showed that this design can implement the gear ratio i = 5; 7; 9; eleven; thirteen; fifteen...

Accordingly, the number of teeth of the driven wheel should be equal to 10; 14; 18; 22; 26; thirty...

Sources of information

1. SU 1587271 A1. Planetary gear. 08/23/1990

2.SU 1364792 A1. Planetary gearing. 01/07/1988.

Claims (1)

End gear containing two coaxial gears, rollers in contact with the teeth of the wheels, placed in a fixed ring with the possibility of reciprocating motion along the transmission axis, characterized in that the movement from the tooth of the driving wheel to the tooth of the driven wheel is transmitted through a pair of rollers placed on the axis so that the inner roller is in contact with the tooth of the drive wheel, and the outer one is in contact with the tooth of the follower.

Images