SI21810A - Internal gearing pair with s-gearing - Google Patents

Abstract

The internal gearing pair with S-gearing is a gearing pair, resulting from a gearwheel with internal cogs (1) and a gearwheel with external cogs (2) featuring lateral cog profiles, which according to the Gearing Act conforms to a curved semi-symmetrical S-shaped fitting track (5 or 6). The geometrical shape of the fitting track is first determined by the slope in its centre alphaC = 20 degrees +/- 2 degrees and increasing curve factor between the centre and the ends. Typical and predefined are the point at the beginning of fitting, the point at the end of fitting and the centre of the fitting curve, which coincides with the kinematic pole (C) of the gearwheel pair. The distance between the starting point of fitting (A) and the final point of fitting (E) on one side, as well as the centre of the wormwheel gearing (9) on the other corresponds to the module value. Their distance from the vertical axis of symmetry of the gearwheels (10) depends on the angle alphaE = 38 degrees +/- 1 degree, which results between the straight line E-C, or on the other side the straight line A-C with the axis of symmetry of the wormwheel gearing (9). All gearwheels of the same module, which correspond to such a fitting line can be manufactured by using the same tools. These gearwheels can fit together and uniformly convey power and rotation between parallel shafts. A typical application are gearing pumps.

Description

Inner gear pair with S-tooth

The subject of the invention is an inward gear pair shown in Fig. 1, comprising an inward gear (1) and an outward gear (2) whose teeth are in contact with a convex-concave fit of the flanks. This fitting of the teeth is conditioned by the “S” shaped box, hence the name. The movement (rotation) is transmitted between the inward gear (1) with the teeth turned in the center direction and the outward gear (2) with the teeth facing in the opposite direction - outwards. It can be described by the speeds of kinematic circles (3) and (4), which must be the same, and their kinematic axis goes through point C. In the case where the rotation is transmitted from the outward gear (2) to the inward (1) in the clockwise direction direction, the gear wheel rotates about the O ₂ axis in the direction indicated by the arrow (8) and the driven gear around the Oi axis in the direction indicated by the arrow (7). Then the tooth contact at the point P and the transfer of forces at this point through the slide (5). Harvesting starts at the start point (A), goes beyond the point (C) and ends at the end point of the harvest (E). To transfer the load when rotating in the opposite direction, there is a contact between the teeth after the bar (6). Before the harvesting of one pair of teeth at point Pe ends, the next (adjacent) pair of teeth at point Pa must already be in contact, as can be seen in Figure 2.

Scope and core of the problem

Inside gear pairs fall within the area of machine elements and the narrower gearbox area. They are used for planetary gearboxes from the largest to the smallest dimensions, as a rule they are an integral part of automatic gearboxes, they are used for power transmission in robotics, they are useful for oil gear pumps for lubrication of internal combustion engines, etc.

Commonly known and used inward gear pairs generally have an evolutionary tooth shape for all areas. Also, the evolutionary inward gear pairs have a concave-convex fitting of the flanks of the teeth, but their median curvature radius is small at the start of harvesting (within rolling circles), so the specific load in the flanks of the flanks of the area is greater, the greater the specific slip, the lubrication is worse, therefore, the friction is greater and the wear is greater.

The main problems of all gears, including those that use inward gear pairs, are fracture toughness, flank endurance, wear, and friction energy losses. Important modern problems of all gearboxes include the noise that the gearboxes make when transmitting power.

Detailed descriptions of inward gear pairs can be found in the extensive literature in the field of machine elements, e.g. :

- Niemann, G., Winter, H.: Maschinenelemente Bd.ll, Springer Verlag, Berlin, Heidelberg, NewYork 1989;

- Tovvnsed, D. P.: Dudley's Gear Handbook, McGraw-Hill, New York 1992;

- Dudley, D.W.: Practical Gear Design, Technomic Publishing Co., Lanchaster, Basel 1994

- and others.

Description of the new solution

The invention will be described by way of example with pictures showing:

1. Inner gear pair consisting of an inner and outer gear (Figure 1)

2. The detail of Figure 1, which shows the course of the track and the two points of contact of the gear and driven gear teeth (Figure 2)

The essence of the new solution is the shape of the flanks of the teeth of the inner and outer gears, so that the flanks of the teeth have a concave-convex touch when transferring motion and load over the longer section of the bar, as shown in Figure 2 in points (P _A ) and (Pe). This means that at the tooth contact, the flank of one tooth has a concave (convex) shape and its pair has a convex (convex) shape. The concave-convex touch of the flanks of the teeth allows a larger contact surface, so the specific load on the flanks is lower and the endurance of such gears is greater. Such flank alignment is also true for evolutionary inward gear pairs, but in such gears, especially if the number of gear teeth is small, a clear slip occurs in the flanks of the flanks within the rolling circles, and the length of the bar in the area is shorter and therefore smaller the surface of the flanks of the teeth through which movement and loading in this section are transmitted. This means that the flanks of the teeth of evolutionary gears in the area of active touch are more subject to wear than the flanks of the teeth in our solution, in which the active parts of both flanks are almost equally long. The active part of the inner gear side is indicated by (11) in Figure 2 and the active part of the outer gear side by (12). With the new tooth shape, there is relatively less slippage and more rolling between the flanks of the teeth, thus reducing friction losses.

The concave-convex contact of the flanks of the teeth is conditioned in our case by such a girder, which is curved over the entire length of the gully and is shown in magnified scale in Figure 2. This girder consists of two curved parts, namely, the first part extends from the point (A ), where the start of picking is, to the kinematic pole (C), where the turning point is. The second part goes from point (C) to point (E), where harvesting ends. The bushing (5) shown in Figures 1 and 2 satisfies the conditions of power transfer in the selected direction of rotation of the right flank of the tooth of the inward gear and the left flank of the tooth of the outward gear. The symmetrical slider (6) corresponds to the transfer of power down the left flank of the inward gear and the right flank of the outward gear.

The general definition of a girder derives from the Tooth Shape Act, according to which each point (P) on the girder (Figure 2) is said to be such a form of flanks on the inward gear and such a flank of teeth in the outlet gear that the common normal "n" in at this point, it passes through the kinematic pole (C). This means that every shape of the box also has its own tooth shape.

Slot S of the tooth, which is drawn on an enlarged scale in Figure 2 and in such a position that when one pair of flanks stops at point P _E , it proceeds from the starting point A, through the kinematic pole C, to the exit point E. It consists of two equal parts AC and CE, which are semi-symmetrical and rotated so that points A and E lie with respect to the kinematic pole C diametrically. The tangent to the slider in the kinematic pole (C) forms with respect to the center line (9) as ac = 20 ° ± 2 °. The curvature of the track at an individual point, which is defined as the reciprocal of the corresponding radius of curvature, must continuously increase from point (C) to point (E) and, on the other hand, to point A, the minimum curvature of the track and the greatest curvature radius is at point (C) the maximum curvature and minimum curvature radius are at points (A) and (E). The curvature center of the pick-up point (E) lies on the EC line and the corresponding curvature radius must be equal to or less than the EC distance. The position of the starting point (E) is determined by its perpendicular distance (ζ) from the center of the wheels (9) and by a parallel distance (ξ) from the center of the wheels (10). The distance (C) is generally equal to the value of the module, and the parallel distance (ξ) is conditioned by the angle a _E , which is 38 ° ± 1 °.

An advantage of the invention is the concave-convex fitting of the flanks of the teeth as shown e.g. after point (P _A ) or point (P _E ) Figure 2. A concave convex fit is the entire length of the track from point (A) to point (E), except in the area of the kinematic pole (C) where the curvature of the track is curved, at here the flank fit is convex convex. The concave-convex fitting of the flanks of the teeth allows a smaller specific load on the flanks of the teeth, which makes the inward gear pairs with semi-symmetrical and progressively curved gearbox more durable, have better lubrication conditions, and therefore the wear of the flanks of the teeth is lower and the yield of rotation is better. An advantage of the invention is that the active side length of the inner gear (11) is almost equal to the active length of the outer gear side (12), which means that the movement between the flanks of the teeth is made more by rolling and less by sliding.

An important advantage of the invention is that the fitting of the concave convex flanks of each pair of teeth is very conformal, which allows the tooth load to gradually increase in the case of lubricated and precision gears due to the thicker oil layer, so that the transfer of load from one pair of teeth to another is softer and the running of such gears is quieter and less noisy.

Claims (2)

PATENT APPLICATION 1. The inward gear pair with S-gear is characterized by the fact that the slots (5) and (6) belonging to the gearing pair of gears of the inner and outer gears are semi-symmetrical, progressively curved starting at the kinematic pole (C) where the curvature is smallest to the starting point (A) or to the end point (E), where the curvature is greatest, so that these bars have the shape of the letter "S" to enclose the tangent (t) to the box in the kinematic pole (C) with the center of the pinion (9) angle (Xc ⁼ 20 ° ± 2 °, starting point (A) and end point (E) are, as a rule, spaced from the center of the gear (9) by the value of the module and their distance from the vertical center of the gears (10) with an angle (Xe ⁼ 38 ° ± 1 °, surrounded by the EC line or, on the other hand, the AC line with the center of the pinion (9). 2. The use of an S-toothed gear pair according to claim 1 in gear pumps, characterized in that the gear pump comprises a functional pair of gears (1) and (2) formed in accordance with a semi-symmetrical, progressively curved track (5) or ( 6) according to claim no. 1.