SU1209042A3 - Transmission mechanism - Google Patents

Abstract

A steplessly variable ball gear has two co-axial rings of balls (A and B), which are so supported by two inner and two outer rolling paths (19-22) formed on moulding rings (12-15) that each ball in one ring touches two rolling paths and two balls in the other ring. The inner and outer rings are axially shiftable with respect to each other. As the distance between both the inner and the outer rings is constant and the rolling paths have concave-curved, preferably circular arc-shaped cross-sections, it can be ensured that the contacts of tangency, required for transmission of torque, between the balls and between the balls and the rolling paths are maintained over a wide variation range.

Description

The invention relates to mechanical engineering, in particular to a transmission mechanism.

The purpose of the invention is to control the range of change of gear ratio,

Fig, 1 shows the mechanism in the neutral position, the cross section; in fig. 2 and 3 - the same, in extreme positions; FIG. 4 shows transmission balls in the direction of the axis of the transmit-5 in FIG. 5 and 6 - geometrical figures according to the principle of operation; in fig. 7 is a horizontal section in FIG. four; FIGS. 8-14 are geometrical figures explaining

one;

transfer operation; in fig. axis axis in FIG. 1,

The transmission mechanism (FIGS. 1 and 2) contains an input shaft 1, a pair of internal ring-shaped tracks 2 and 3 of rotation mounted on it, a couple of ring-shaped tracks 4 and 5 of the rim, separated from the tracks 2 and 3 of the colp, in intervals of 6, Track 4 motionless. Track 5j spatially separated from the road has an axial

ki 4 ,, is free to rotate, but the ability to slip in the pocket and forms an output gold.

The profiles of the four annular tracks 2j 3 and 4, 5 are described by concave generators 7-10, which in the preferred-i variant are arc-shaped curves. The distance - 1P 1e in the axial direction, both between the inner 2 and 3, and the outer 4 and 5 tracks of rotation is constant,

Between the annular lanes are placed two sets of balls 11 and 12; which form coaxial rings. Each ball 11 of one ring is tangent to form 7 of the inner track 2 and form 9 of the outer track 4 and the color of the balls 12 of the other ring. Each ball 12 of the other ring relates to an inner track 3 forming 8, forming 10 outer track 5 and two first ring balls 11.

The Y axis (FIG. 1) is the axis of symmetry for the two axially fixed tracks 9 and 10 of rotation. The shift along the X axis of the inner tracks (Fig. 2) leads to a change in the quantitative parameters, which determine the ratio of the rotational speed of the input shaft 1 to the speed

0

- i

0

0

0

These 5 tracks of rotation, which is the output element, i.e. to a change in gear ratio of the gear mechanism.

FIG. 4 shows two rings 11 and 12, which are visible in the direction of the axis of the mechanism. The movement of the balls is considered in the projection of the X, Y, Z axes and the PJ lines running at equal angles and representing planes that intersect each other on the X axis and in which the centers of the balls move and the relative displacements of the rings of the balls. One of the lines P coincides with the Z axis. The angle between two adjacent planes P is called the central angle p and depends on the number of balls.

2br

P

where n is the number of balls.

If the balls 12 in one ring (FIG. 2) are shifted to the main transmission axis X, then the balls 11 in the other ring will move from the main axis, as shown by dotted lines on (phi, 4). The projection of a line or an imaginary straight line between the centers of two balls 11 and 12 remains constant, which follows from two congruent triangles obtained from the projection of the dotted line S onto a solid line. Since all the balls must be in continuous contact with each other, the forward direction represented by the length of the rod S between the centers of the wigs is always 2R, where R. is the radius of the ball.

If the bottom of the plane P, in which the centers of the balls should move, parallel to each other at a distance of less than 2R., Then the movement possibilities for the centers of the balls while maintaining contact between the balls can be represented by two circles bsH C c of the same size 1 , figs 5), which are thus positioned relative to their respective two planes in order to form the surfaces of an imaginary cylinder Cj, the axis fcoToporo perpendicular to the planes, and in which the imaged rod S will protrude between an arbitrary a point on a single circle and a diametrically opposite point on another circle. The point of tangency of the balls will be the center of gravity of this cylinder.

In fact, the two planes in which the centers of two adjacent balls move are not parallel, but form an angle p. With each other. In FIG. 6, an imaginary cylinder Su and a rod are represented in three different positions between two planes P. The position shown by solid lines corresponds to the neutral position, in which the centers of the two balls are equidistant along the X axis, and the position shown by dotted lines is the extreme position in which the difference between the distances between the centers of the balls from the x-axis is the maximum possible. The position shown by dotted lines and lines corresponds to the intermediate position. The cylinder bbmie shows the rod projections on the X axis in three positions. Thus, the relative displacements of the ball centers are accompanied by axial movements of the cylinder Su, and that the tracks along which the centers of the balls can move in planes P correspond to ellipses in which the surface of the cylinder intersects the planes. One of these ellipses is shown as a figure E (Fig. 6) together with a circle C, representing a cylinder, and this is shown in the form that is obtained when viewed from the end. The half of the minor axis of the ellipse, which is equal to the radius of the circle, is denoted by L, and half of the major axis is denoted by the letter b.

Pa figs. 4 two adjacent balls 11 and 12 are shaded. Suppose that through the centers of these balls there is a section that is parallel to the XZ plane, as a result of this we will get an image similar to the one shown in FIG. 7, where the two radii R of the balls, arranged in such a way that they are continuation of each other, form an imaginary rod that makes an angle o (with a line that is parallel to the Z axis and protrudes through the center of the ball 11, being the outer generatrix an imaginary cylinder that is visible in the direction of the axis X. The end surface of the cylinder is represented by a line, 2a in length, which passes through the center of the ball 12 and is parallel to

payment

042. “

X axis. The angle c depends on the balls in a neutral position. Thus, the axes of the ellipse (Fig. 6 and 7) can be defined as:

0

five

0

five

0

and R,; sin o

b a / cos (p / 2) o (, / cos (p / 2).

In practice, the displacement of the balls is provided by the displacement in the axial direction of one set of forming rings relative to the other set. It is assumed that the imaginary cylinder C y shifts in the direction perpendicular to its axis and parallel to the axis of mechanism X. Thus, the centers of the balls make a complex movement with radial and axial components along the resulting trajectory of rotation in planes containing the axis of the mechanism.

Theoretically, an arbitrarily large number of curve shapes can be used, but only one curve shape satisfies the requirement that in order to achieve the greatest possible change in the arms of the forces determined by the arrangement of the points of contact of the balls on the rotation tracks, it is necessary to ensure the symmetric movement of these points. contact both in the radial and axial directions - 5. Due to the double symmetric movement of the points of contact of the balls along the raceways, the ratio between oppositely directed displacements in the radial direction 0 and the total displacement in the axial direction of the research institutes of the centers of the two balls must be such that the paths of displacement of the centers of the balls also turn out to be symmetrical.

The required symmetry conditions are satisfied in the case of a cycloid. The cycloid obtained by spinning a circle having a straight line radius is shown in FIG. 8. Opposite

0 directional movements of the centers of the balls along the edges of an imaginary cylinder and their total displacement in the axial direction along with the cylinder, can be described by two halves

cycloid in the bisectral plane

central angle, as shown in FIG. 9, where the axis is parallel to the axis X and perpendicular to the axis of the cylinder.

denoted by X. In the range where y is taken on the X axis, curves can be expressed by the equation

 ) 1 I. a

180

The centers of the balls can be fixed on these homogeneous curves, symmetrical about the Y axis using identical curves that are symmetrical to the first curve, relative to the X axis, shifting one pair of curves relative to another pair of curves along the X axis, as shown by dotted lines in FIG. ten,

These double symmetry curves provide a geometric basis for obtaining rotation track profiles. However, the curves are plotted on a plane forming a goal equal to half the central angle p with planes P into which the centers 0, and 0 of the balls can move. Therefore, the curves must be projected onto one of these planes in order to create the base for the desired Profiles. Coordinates y. These curves should therefore be divided by the cosine of the half of the central angle, which results in the configuration shown in FIG. 11. In the range c y –c, where c corresponds to the selected maximum shift in the radial direction, i.e. in the Y direction, the curves can be expressed by the following equation:

x i / a2- (ycos e / 2) 2 + V cos / 2

, (.-) j.

IV a

180

As follows from the material considered below, the adjustment range of the transmission mechanism is determined by the maximum difference obtained between the distances from the mechanism axis to the points of contact between the balls 11 and 12 and the tracks 8-10 of rotation and the distances from the own axes O ,,, and 0 rotation of the balls 11 and

12 to the points 1 of the sledge, as well as between the radii from the last axes to the point of mutual contact of the balls 11 and 12, by shifting the balls in the rings formed by the balls 11 and

12. The ratio of these distances is greater for the outer tracks 9 and 10 of the rotation than for the inner tracks 7 and 8 of the rotation. Since the maximum difference in distances is determined not only by the number of balls, the angle (X. and size C, but also the radius g of displacement of the main cycloid, the radius g can be used to calculate the adjustment range, if necessary. The radius of displacement of the cycloid as

(| 1A2- (with cos / 2) 2 - m) 180

I

sin- (

with cos

E / 2

)

where g is the value of y for the case when x is c, so that the generalized formula for the shift curve of the centers of the balls in the range с y –c will have the form

x / a 2- (y.cos jB / 2) +

g (cos e / 2 lsin

(cos p / 2 -t)

sin- (--l.)

40

45

50

55

FIG. Figure 12 shows an example of using a radius g of displacement which is smaller than the radius a of an imaginary cylinder.

The shape of the curves found in this solution leads to rotation track profiles that are quite difficult to produce in practice, but the curve segments that are needed as a basis for such profiles are very close to circular arcs, which leads to the possibility of are easy to manufacture. It can be calculated that the maximum deviations have a value that is less than the order of manufacturing inaccuracy, usually adopted during the production of balls. To this it is necessary to add that the effect of inaccuracies in the execution of the curves on the two contacting balls actually neutralizes each other due to the symmetry of the curve.

FIG. 13 is an image corresponding to FIG. 11, where the trajectories of the centers of the balls are arcs of a circle C and Co, having radii of fc / and Cj, respectively, at the same distance from the minor axis or axis X, and at the same distance X (- and the corresponding sides of the Y axis, which coincides with the major axis of the solid line of the ellipse E corresponding to the imaginary cylinder in its neutral position. In addition, a simplification is made in Fig. 13, which is that the dotted ellipse representing the extreme position imaginary cylinder, crosses the y axis at points near the base of the projection onto the axis X of the imaginary rod S forms the minor axis of the ellipse at neutral position. The projection of the rod onto the axis X in the extreme position of the cylinder is denoted by d.

If the shift occurs to the left and not to the right in the situation shown in FIG. 13, the centers of the balls will follow the continuation of arcs of a circle with respect to the arc Cjj down to the y – c line, which intersects the Y axis, and with respect to the arc Cj - up to the line.

If the center of the right ball (Fig. 1, in the process of moving the ellipse right, moves downwards, rather than upwards, as shown, and in the case of a shift to the left, moves upwards, the other two arcuate trajectories C; and Cs move in such a way that a picture is formed Mirroring the situation of arcs C ,, and Cj as shown in Fig. 14. In the process of relative displacements, one set of arcs is displaced in the direction of the X axis relative to another set. The centers of the balls will be constantly located at their respective points of the mutual feathers Cross sections between upper and lower arcuate paths.

As seen in FIG. 14, the maximum relative shift of the set of arcs is d. Based on the ellipse formula, the formula for determining d can be compiled using the axes of the ellipse and the values with

d 2a V 1 - cVb2

The following three equations with three unknown quantities are R, X and Y ,. can be derived from the data in FIG. 13

R2 (Yc + с) 2 + xi: + (X R2 (Y, - с) 2 + a {+ d) 2

c + a);

Hence the coordinates of the center ball | and the radius of the arc of a circle C, is expired as

Xe (2a2-2S2-dp / (ad-4a) YC (2X.-d + d4 / 4c

R (Yp + s) + XI

When profiles are formed with radius R; R + R | As shown in FIG. 1.5, the displacement of the inner and outer tracks relative to each other will provide the required elliptical path of movement of the centers of the balls and thereby ensure that the contact between the balls and the raceways and between the balls will be maintained.

FIG. 15, the radius R ,, is also marked as was done in the case shown in FIG. 6. Half the length of the projection of the imaginary rod, shown by the solid line in FIG. 4 equals (i (and from here

R

 cos about (

sin (p / 2)

Thus, all dimensions of the transmission mechanism can be calculated from the above equations.

When all the balls have the same dimensions, the tracks of rotation in the gear mechanism have 1e 7 and 8, 9 and 10, which are symmetrical, in pairs. The greatest change in the gear ratio range can be obtained in the case when the four tracks of the rotation have double symmetrical generators 7 and 8, 9 and 10.

The transmission mechanism operates as follows.

The rotation of the input shaft 1 is transmitted to the inner ring-shaped tracks 2 and 3, which, by means of two sets of balls 11 and 12, rotate the outer track 5, which is the output element. By shifting tracks 2 and 3 from the neutral position to the right and left position, a stepless change in the gear ratio is provided.

at ij 05.

(Rig.5

///

FS / g

Phie.e

BUT

FIG.

Jfv /

(Put.O

27g / g //

ll

y / ". X5

L

fPuS. /

Compiled by G. Kuznetsova Editor Y. Sereda Tehred.NadKorrektor V. But ha

Order 315/62 Circulation 880 Subscription

VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow, - Zh-35, Raushsk nab. 4/5

Branch PPP Patent, Uzhgorod, st. Project, 4

Claims (5)

1. A TRANSMISSION MECHANISM, containing two sets of balls that form coaxial rings, and supporting them in this form, a pair of internal and a pair of external ring-shaped tracks of rotation, mounted with the possibility of axial movement of one relative to the other within predetermined limits and located coaxially with the rings of balls, the latter installed with the possibility of rotation relative to the common main axis with the relative rotation of the tracks of rotation, each ball in one ring is paired with two balls in the other ring and vice versa It is mounted to an additional rotation about its own axis passing through the center of tlichayuschiysya in that, to regulate the change gear ratio range, the races distance in the axial direction between both internal and external rotation paths continuously. 2. The mechanism according to p. 1, characterized in that the profiles of the paths of rotation are described by concave generators, in which the axis of rotation of the balls intersect the internal and external tracks or their imaginary extensions going inward at the points of contact of the balls with the named track of rotation, the distance of each last points from the main axis and its own axis of rotation § changes opposite to the relative displacement of the pairs of tracks of rotation, and the ratio of these distances is greater for external tracks of rotation than for internal tracks of rotation. 3. The mechanism according to paragraphs. 1 and 2, characterized in that the generatrices of the rotation paths are arcuate curves. 4. The mechanism according to paragraphs. 2-3 with two sets of balls having the same dimensions, characterized in that in each pair of oppositely rotating paths the generators are symmetrical. 5. The mechanism according to claim 4, characterized in that the four tracks of rotation have double symmetrical generators. SU, 1209042