SU1337202A1 - Method of cutting cylindrical surfaces - Google Patents

Abstract

The invention relates to mechanical engineering and can be used in the machining of cams of asterisks, cam differentials of vehicles and other parts of offentroid gearing. The aim of the invention is to expand the technological capabilities of the method of cutting cycloidal surfaces and improving cutting conditions by providing processing of their cycloidal surfaces and their equidistant paths when the tool is positioned normal to the machined surface. For this, the workpiece and the tool are reported to have relative rotations, and the oscillating motion is carried out by reciprocating movement of the workpiece with an amplitude defined by the expression I-COS (NU t), where S is the amplitude of the return () atomic-translational movement of the workpiece, mm ; HJ - half the difference between the maximum and minimum radii-vectors of the curve, describing the profile of the treated surface, mm; N is the number of branches of the treated surface, pcs; ui is the angular velocity of the relative angle of the workpiece or tool, rad / s; t is the processing time, s, and the movement of the instantaneous center of rotation of the workpiece along an ellipse. The ratio of the major and minor semiaxes of the ellipse is set equal to the number N. During the processing, the number K. can be changed. f-ly, 17 ill. i (/)

Description

The invention relates to mechanical engineering and can be used in machining, cams of asterisks, cam differentials of vehicles and other parts of off-center gearing.

The aim of the invention is to expand the technological capabilities of the method and improve the cutting conditions by ensuring the processing of associated cycloidal surfaces and equidistant paths to them when the tool is positioned normal to the machined surface.

FIG. 1 shows a scheme for the formation of an epicycloid; in fig. 2 is a diagram of the formation of a hypocycloid5 in Fig. 3 — a diagram of the formation of a curve accompanying the epi (hypo) cycloid and equidistan to it; in fig. 4 is a diagram for constructing centering and actual profiles of cams of differential sprockets; in fig. 5 is a diagram of processing a cam profile in a fixed axis of the workpiece in FIG. 6 - the same, with a fixed axis of the instrument; in fig. 7 is a diagram of processing a cam profile with a tool that performs a swinging motion and is set normal to the surface being machined; Fig. 8 is a diagram for determining the position of the instantaneous center of rotation of the workpiece; in fig. 9 is a diagram of processing the cam profile with a stationary tool installed normal to the surface to be machined due to the additional orientation of the workpiece; in Fig.10, the processing scheme of the associated cycloidal surfaces and equidistant to them; on fig. 11 is a device for carrying out the method; in fig. 12 is a section A-A in FIG. eleven; FIG. 13 is a section BB in FIG. eleven; in fig. 14 is a diagram of the operation of the mechanism for reciprocating movement of the workpiece axis; in fig. 15 is a diagram of the operation of the mechanism which performs the installation of the tool along the normal to the surface to be treated; in fig. 16 - precise and corrected cam profiles for differential sprocket; in fig. 17 - correction scheme of the processed profile.

The method is carried out as follows.

Curves described by different points of a rolling circle along a fixed circle are called cycloidal curves. Depending

B

0

five

0

five

0

five

from the position of the selected point on the rolling circle and its location relative to the fixed circle, one or another kind of cyclic curve is obtained.

The epicycloid (Fig. 1) is described by the point M of the generating circle 1 at its external rolling without sliding. on Fixed Circle 2.

A hypocycloid (Fig. 2) is described by the point M of the generating circle 1 with its internal rolling without sliding along the fixed circle 2.

Let us consider the centers of the generating circle 1 and the fixed circle 2 with a movable radial ray OK, and we will design a point M on this ray. Its projections — the point M — will describe a curve that is usually called a curve — a concomitant epi (hypo) cycloid. Denote the sum of the radii of the movable circle r and the fixed circle R by a, a, R + r, for hypocycloid.

Denote by a. the distance from point M to the center of the moving circle of point K. Consider the cycloidal curves as the trajectory of the point M (fig. 3) located at the end of one of the two links articulated with each other, a, and a, rotating with true angular velocities U ) i. and 10-2. C i i

dem K, whence u) ,, KL (j. Let u), ω, then W.

Depending on the values of K, two groups of curves can be obtained: epicycloid if K 7 O (the same direction of rotation of the links), and hypocycloids if K - O (the different direction of rotation of the links). The projection of the point M to the direction of the link a - the point M - will describe the curve accompanying the epi (hypo) cycloid. The equation of the curve in the polar coordinate system is as follows:

j-COS (N-V)

where cf wt;

N is the number of branches of the obtained curve (as applied to the differential, the number of cams of sprockets of the differential).

The number of branches of the curve is from the following relationship:

N (K-1),

Wj

where K -.

If the working part of the cutting tool — the top of the flat cutter — is combined with the point M and the axial feed is given to a non-rotating workpiece centered at the point O, a cylindrical D-D surface is formed with a guide line in the form of a curve accompanying the epi (hypo) cycloid. We will call this surface a related cycloidal surface and will use this term in the following. If we combine with the point M the axis of a circular cutter, cutter or grinding wheel of radius R, a cylindrical surface Р-Р or Р -Р is formed with a direction line in the form of an equidistant to the curve accompanying the epi (gypsum) cycloid. These surfaces will be referred to as equidiants to the accompanying cycloidal surface.

The cam differential is formed by synthesizing two cam mechanisms with one common follower,

In the automotive industry, the term rusk is adopted for the cam differentials, which will be used later on.

in cam differentials with a radial arrangement of crackers, the profile of the latter is formed by arcs of circles. In this case, the center profile of the crackers when moving the cam describes a curve spaced from the profile of the cam at a distance R ,, equal to the radius of the arc of a circle, the profile of the crackers is the center profile of the cam. The actual cam profile is obtained by constructing an equidistant curve (equidistants) to the center profile, with each center profile corresponding to two actual cam profiles of the outer and inner sprockets (FIG. 4). Curves associated with epi (hyb a) cycloid, and as actual profiles are the distributors for them,

The use of these curves improves the performance of the car, since the gear ratio between the inner and outer stars of the differential gears with a fixed rusk is always equal to one and, therefore, the distribution of torque on the drive wheels when

g

locked differential equally.

In existing machines, the tool axis is, as a rule, fixed, or it performs longitudinal or transverse movement. Therefore, it is practically impossible to ensure the treatment of differential sprockets by the use of the circuit shown in FIG.

To create a kinematic scheme that meets the practical conditions of machine tool operation, we use the transformation of this scheme.

We apply the method of reversibility of movements.

Give the blank, links m and and

extra speed - and

 2

-1 tog

Yes, the link a stops, the workpiece rotates about the axis O with the speed C), the link a rotates around the axis K with the speed (K-1) -u) N-w (FIG. 5),

Thus, when the workpiece rotates around a fixed axis O with an angular velocity U), the center-to-center distance of the tool located at point M and the workpiece is

OM aa

SOB (KH) 5

which corresponds to the curve equation accompanying the epi-hypo-cycloid.

With this processing scheme, the tool axis performs a longitudinal movement in accordance with the dependence

(l-cos (N if)),

where, which is undesirable because of the large mass of instrumental attendants,

This scheme can also be converted (FIG. 6). To do this, make the axis of the tool M fixed, and make the axis O of the workpiece O to make a longitudinal movement in accordance with the same relationship with which the axis M previously moved,

Thus, when the workpiece rotates at a speed (l) around the axis 0, it performs a movement in accordance with the dependence

(l-cos (N-tr)),

where Lf Cot, the center-to-center distance of the tool located at the moving point M, and the workpiece is

OM a, -a ,. cos (N v),

which also corresponds to the equation of the curve accompanying the epi (hypo) cycloid. It should be noted that the direction of rotation of the link HJ does not affect the law of variation of the center-to-center distance and, consequently, the profile of the resulting curve, since the function cos is even.

The processing circuit shown in FIG. 6, it is possible to treat the cams of differential sprockets with a tool having dimensions determined by the radius R of the circular arc of the biscuit profile: a chisel with a cutting edge tucked into the radius R, a milling cutter, a grinding wheel of the radius H, During processing, tool wear occurs, it is edited, regrinding, consequently, a change in radius R. Processing with a tool with a changed radius R will lead to a change in the cam profile of the sprockets, which is limited by the tolerance per part. Since the precision requirements of the sprocket cams are very high, it is necessary to process the tool in accordance with such a scheme. A tool change is often required, which reduces productivity and increases the consumption of the cutting tool.

In addition, the minimum radius of curvature of the sprockets of the differential, and therefore the radius of the tool that can be used for machining sprockets (for milling and grinding), is much larger than the radius R (the arc of the circle of the biscuit profile. Using the tool with the maximum allowable radius increases the rigidity of the AIDS system and increases processing accuracy.

From the foregoing it follows that it is necessary to create such a processing method in which the cam profile of the sprockets would not depend on the radius of the tool. This can be ensured by the location of the tool normal to the surface to be treated, i.e. to ensure such a relative orientation of the product and tool that the normal to the surface being machined always passes through the point and axis of the tool currently being machined.

We take advantage of the fact that the normal pn of the DD curve accompanying the epi- (hypo) cycloid and its equidistant P-P and P-P, which are the actual profiles of the cam of sprockets at a given point M, passes through the point M, forming the DD curve, and through the instantaneous center. P of the workpiece rotation (, phi1. 7.1. The points A of the actual profile of the sprockets of sprockets corresponding to the point M are on the normal nn of the distance R. equal to the radius of the arc of the circumference of the crackers, from the point

M

If point A races

between points M and P, it belongs to the P-P profile of the inner sprocket. If point A is located on the opposite side of

M

then it belongs to the profile

points

R-R outdoor sprocket.

Determine the trajectory of movement of the instantaneous center P of rotation of the workpiece, making a complex movement according to the scheme shown in FIG. 6

It is known from theoretical mechanics that the instantaneous center of the link (in our case, the workpiece) is located at the intersection of the perpendiculars to the directions of the velocities of the points of the link. The speed of any point of the workpiece will be added up from the speed V of the translational axis O of the workpiece and the speed V "of rotation of the workpiece around its axis 0. The resulting speed V is the geometric sum of these two speeds (Fig. 8). We define for two points the product O and M V speeds

V.

For point M

dS dt

dS d ij

dtf dt

dS

-r - .. W

d.if

35

no

(1st

from where

-dt

a j. sin (n},

V, (sin (W-4)} -,

Vj-wOM co; a ,, - aj.cos (N4)). For point 0:

V, (N-aj-sin (N)) u),.

Perform the perpendiculars to the resulting velocities V at the points O and M. The point of intersection of perpendiculars is point R. The triangles OM P and M TB are similar, since their sides are mutually perpendicular. From Dodobi should:

V v

2

PR- ((a. - ujla -a-j coslN-t / T

-ajCos (N. If)),

. sindfv),)

The coordinates of the point P in the ordinate HKU will be equal

Xp KO and Cos (N-),

Ur-Op-K.a with (N-) ()

2- sin (N-4),

,

(N-4) 90 °.

V N P

but

2

Let us prove that for any value of the angle точка the point P belongs to an ellipse with center at the point K, whose small axis is the same as the X axis and is equal to, and the large axis coincides with the y axis and is equal to b: K-a2. The equation of an ellipse has the following form:

x + y 1 and DG

where do we have

We substitute into this equation

Hr-a

cos

: N -c)

2

2

as a result of transformations we get

y N-Ya2 (l-cos4N-4)) N-a2-sin (N-4) This value corresponds to the value of Ur-N-a,;,. sin (n-4).

Thus, the point P with coordinates. Xp a2-cosiN-4)

Ur I-a2-sin (N- f)

belongs to the ellipse with the center at the point K having the semi-axes and. Denote this ellipse by f, the instantaneous center P of the workpiece moves along an ellipse f, the center of which is located at point K, with the semiaxes a. and Naj, and the direction of movement will be opposite to the direction of rotation of the part (Fig. 7). The angle h between the radius-vector of the curve D-D and the normal pn is determined from the following relationship:

 N-a 2-sin (N -tf)

The normal n-n can be represented as a link MP, pivotally connected at point M, with a link along the link moves a slide P connected to a variable-length crank KP (Fig. 7).

To transform this mechanism, we stop the link of M. P. At the same time, the workpiece is oriented in such a way that the normal to the surface D-D and to the surfaces equidistant to it P-P and

p p is always located along the pre-selected direction of the link m P, having the tool axis C on the link

five

0

five

0

0

Mr on

distance

,

-R.

INST

from POINT M and having the ability to move the tool along the link MP, in order to compensate for tool wear, we obtain a processing circuit in which the cam profile does not depend on the radius of the tool (Fig. 9). Comparing the circuits in FIG. 7 and Fig. 9, which allow one to obtain the same profile, we see that in the first case, the workpiece performs a complex rotation-translational motion, and the tool is additionally oriented (makes a swinging motion together with the link M P).

In the second case, there remains a complex rotational-translational movement of the workpiece and an additional orientation of the workpiece (swinging movement

5 together with the link m k), while the tool remains stationary. Swinging movement of the tool is undesirable because of the large mass of tool heads, in addition, in this case it is necessary to provide a kinematic link between the workhead and the tool heads. Therefore, the scheme shown in FIG. 9. Due to the small value of the ra5 measure and the design of the device to the circuit is difficult.

by

2 this

run

Dp its constructive apply the principle of likeness.

Move the slider P to a point (Fig. 10). From the similarity of AM RK and LM P k it follows that the position of the normal nn remains unchanged. Increased link

55

and in the axis

times and, respectively, half-aj and N-a, A times, we obtain a scheme similar to the processing scheme shown in FIG. 9.

The scheme presented on the fkg. 10, defines a method for treating the concomitant cycloidal surface of D-D and its equidistant P-P and P-P surfaces.

The proposed method allows to treat the associated cycloidal surfaces and equidistants to them with higher accuracy, without applying any corrective mechanisms, in contrast to the known, where

The method can be implemented with a device (Fig. 11) containing a fixed housing 3, in which a movable housing 6 is mounted on the coaxial rods 4 and 5. The common axis of the rods 4 and 5 is the axis m. the drive 7 of rotation through the belt drive and gears 9-12, shaft 13 (FIG. 12). The axis of rotation of the shaft 13 is the axis K. The distance between

accompanying cycloidal surfaces can be regarded as corrected trochoidal surfaces ..

The treatment of the accompanying cycloidal-15 ° and K is equal to a ,. Inside the shaft surfaces it is possible due to the reciprocating movement of the axis O of the workpiece in accordance with

13 with eccentricity aj / 2 performed

on the bore 14, in which the shaft 15 is mounted in bearings.x, the axis of rotation of the shaft 15 is the axis O, inside the shaft 15 with eccentricity a n / 2 there is a bore 16, On one side of the shaft 15 also with eccentricity a / 2 the neck 17 is made; the spindle is installed in the bearings in the bore; The axis of the bore 16, the neck 17 and the axis of rotation of the spindle 18 is the axis; The shaft is assembled in such a way that the axes are m. K, o, O are located in one plane; the O and O axes are placed between the axes M and K; The distance between the axes K and O is equal to a. The gear wheel 19 is fixed on the casing 6, the axis of which coincides with the axis K of the shaft shaft 13. On the shaft 13 the carrier 20 is rigidly attached, in the bore 21 of which the bearings are mounted 22, on which gears 23 and 24 are rigidly fixed, Gear 23 engages with fixed wheel 19, and gear 24 - with gear wheel 25 fixed rigidly on shaft 15, Assembly of gear wheels 19, 23-25, drove 20 with shafts 13 and 15 is made in such a way that the axis K, O and the axis of the shaft 22 is located in the same plane. The gears 24 and the logs 25 have the same number of teeth, Z -Z The number of teeth of the wheel 19

dependence (l-cos (K uj-t)) with simultaneous uniform rotation of the workpiece around its axis 0.

With the proposed method of processing, the profile of the associated cycloidal surfaces does not depend on the radius of the tool, which is always achieved by placing the normal along the pre-selected direction and the possibility of moving the tool axis along the same direction. The location of the normal is always along the pre-selected direction is possible, due to the additional orientation of the workpiece, carried out by moving the instantaneous center of rotation of the workpiece along an ellipse,. in which the ratio of the major and minor axes is equal to the number of branches of the treated surface.

This processing method provides the possibility of correcting the profile of the associated cycloidal surfaces, which is necessary to eliminate possible deviations from the profile shape due to errors in the manufacture of the device implementing this method, as well as changes in the conditions of processing modes associated with the change in the deformation of the AIDS system. The profile is corrected by changing the ratio of the major and minor semiaxes of the ellipse along which the point P moves relative to the point. At the same time, the normal to the surface does not lie along the previously selected direction and, therefore, the tool axis is not normal to the surface to be machined. The deviation of the tool axis from the normal to the machined surface will result

(W

7202 °

to the correction of the profile of the accompanying cycloid surface.

The method can be carried out by the device (Fig. 11, comprising a stationary body 3, in which a movable body 6 is mounted on coaxial rods 4 and 5. The common axis of rods 4 and 5 is the axis m. In case 6, a rotationally driven rotational drive 7 is installed via a belt drive 8 and gears 9-12, shaft 13 (FIG. 12). The axis of rotation of shaft 13 is axis K. The distance between

.

° and K equals a ,. Inside the shaft

13 with eccentricity aj / 2 performed

on the bore 14, in which the shaft 15 is mounted in bearings.x, the axis of rotation of the shaft 15 is the axis O, a bore 16 is made inside the shaft 15 with eccentricity a 2/2, a neck is made with eccentricity / 2 on one side of the shaft 15 17, In the bore 16, the spindle 18 is installed in the bearings, the axis of the bore 16, the neck 17 and the axis of rotation of the spindle 18 is the axis O. The shaft is assembled in such a way that the axes are m. K, o, O are located in one plane; the axes O and O are located between the axes M and K; the distance between the axes K and O is equal to a. The gear wheel 19 is fixed to the housing 6, the axis of which coincides with the axis K of the shaft of the shaft 13. On the shaft 13 the carrier 20 is rigidly attached, in the bore 21 of which the bearings 22 are mounted the gears 23 and 24 are rigidly fixed, the gear wheel 23 engages with the fixed wheel 19, and the gear 24 with the gear wheel 25 fixed rigidly on the shaft 15, the assembly of gear wheels 19, 23-25, drove 20 with the shafts 13 and 15 in such a way that the K, O and axis of the shaft 22 are located in the same plane. The gears 24 and the wheel 25 have the same number of teeth, Z -Z The number of teeth of the wheel 19 in

2t

two times the number of gear teeth 23,. On the neck 17 of the shaft 15 in the bearings mounted lever 26,

- a bore 27 of which has a shaft 28 in bearings, on which a wheel 29 and gear 30 are rigidly fixed. The wheel 29 engages with a wheel 55, rigidly fixed on a shaft 17 of shaft 15, Gear 30 is meshed with a wheel 32, rigidly connected to spindle 18,

Thus, the neck 17 of the shaft 15 is connected to a gear spindle 18 consisting of gear 31, wheel 29, gear 30 and wheel 32, with a total gear ratio (i N) equal to the number of branches of the work surface. The spindle 18 holds the holder 33 with the workpiece 34, so that the axis of rotation O of the spindle is also the axis of rotation of the holder 33 and the workpiece 34. In the movable body 6 there is a crank 35, the axis of rotation of which is the axis. The crank 35 is kinematically connected to the shaft 13 of a gear train consisting of 12, 36 and 37 wheels with a common gear ratio. The distance between the axes M and K is La. On both sides (in Fig. 11 shown on one side), on crank 35, there are pins 38 fixed at a distance R

N + 1 ,, -L 3,2 FROM the axis to

crooked. On

The pins 38 are hinged with gear-2c or 39, which engage with internal gears 40 rigidly connected to housing 6. The number of teeth of internal gear 40 is twice the number of gear teeth 39, Z 2 Zjg. Gear 39 x distance

N-1, p a. from the axis of gears tough

thirty

A device for implementing the method works as follows. The shaft 13 rotates at a constant speed (K-LO) from the rotational drive 7, where N is the number of branches of the surface to be treated. The carrier 20 rotates with the shaft 13. Herewith, the gear wheel 23 runs around the fixed wheel 19 and transmits the rotation to the shaft 15 through the gear pair 24 and 25. The gear ratio between the shafts 13 and 15. Fig. 14 schematically shows the two positions of operation of the mechanism. In the initial position of the axis M, K, O and O, the axis 41 is positioned with the common axis P.

Assembly is made in such a way

that the axis of the fingers 38, the axis P and K are 35 in one plane, the flat lines show the initial positions of the shaft 15 with the axis o, the spindle 18 and the eccentric shaft 1 7 belonging to the shaft 15 with the common axis 0. The dashed line shows intermediate positions of the shaft 15 s. The axis O, spindle 18 and 17 of the neck 17

40

laid in the same plane, with the axis P located between the axis of the fingers 38 and the axis k. On axles x 41, articulated sliders 42 are mounted, which move in straight lines in the grooves 43 of the fixed housing. The longitudinal axis of the grooves 43 in the initial position is in the same plane with the axes K, M and k (in Fig. 1, 1 is the plane of the drawing). Axis C tooling (N.W) around axis K of shaft 13,

with the axis O- when turning the shaft 13 at an angle (N ×). Shaft 15 makes a complex movement. Its axis O rotates with the speed shaft 15 rotates at the true speed (-N-U)). When turning the shaft 13 at an angle (N-t), the axis O occupies the position 0 |. Since the shafts 13 and 15 rotate at opposite speeds, but equal in magnitude to the speeds, the shaft 13 rotates through an angle (-and). The common axis O of the neck 17, the spindle 18, the workpiece 34 takes

This 44 is located on the longitudinal axis of the grooves 43 at a distance -R

AND EAST from the M axis and has the ability to move in the direction of the longitudinal axis of the grooves 4 in order to adjust for the size depending on the tool diameter. Surface treatment with the help of the proposed device can be carried out or with correction of the processed surface profile, or without correction, position 0 .. as eccentric- When processing with a correction on the lever, | / 2 then and 0, .0. ./2, 26 set in the radial direction, i.e. an isosceles triangle, a flat ruler 45 ″ Lever 26 Consequently, the O axis is reciprocating relative to the 0 axis. The chamfer moves in the direction

0

2c

20212

The lever 26 is carried out by an additional crank 46 with a finger 47 fixed at a distance g from the axis of the additional crank 46. The crank 46 is connected kinematically with the shaft 13 by a gear pair 12 and 36 with a gear ratio. Between flat ruler 45 and crank 46, force closure is performed by means of a spring 48 (Fig. 13).

The lever 26 has a radial direction of the groove 49. When processing the profile without correction, the ruler 45 is removed from the lever 26. The finger 50, which enters the groove 49, is attached to the body 6, not allowing the lever 26 to rotate about the axis O, but leaving the possibility of returning translational movement of the lever 26, together with the spindle 18.

A device for implementing the method works as follows. The shaft 13 rotates at a constant speed (K-LO) from the rotational drive 7, where N is the number of branches of the surface to be treated. The carrier 20 rotates with the shaft 13. Herewith, the gear wheel 23 runs around the fixed wheel 19 and transmits the rotation to the shaft 15 through the gear pair 24 and 25. The gear ratio between the shafts 13 and 15. Fig. 14 schematically shows the two positions of operation of the mechanism. In the initial position of the axis M, K, o and O is located30

35

40

45

by growth (N.W) around the axis K of the shaft 13,

with the axis O- when turning the shaft 13 at an angle (N ×). Shaft 15 makes a complex movement. Its axis O rotates with the speed shaft 15 rotates at the true speed (-N-U)). When turning the shaft 13 at an angle (N-t), the axis O occupies the position 0 |. Since the shafts 13 and 15 rotate at opposite speeds, but equal in magnitude to the speeds, the shaft 13 rotates through an angle (-and). The common axis O of the neck 17, the spindle 18, the workpiece 34 takes

 position 0 .. Since eccentricities, | / 2, then 0, .0. ./2, i.e. the triangle is isosceles. Therefore, the axis O reciprocatingly moves in the direction

1313

M K. From the triangle O .O.K we define side 0; K:

ar

() cos (N-tf) + ji.coslN-t,). cos (n-if)

Consequently, the center-to-center distance between the M and O axes at the indicated position of the mechanism is

(N-4)

This equation coincides with the equation of the curve of the accompanying fungi-pocycloid. Since the neck 17 belongs to the shaft 15, it rotates around its own axis O also with a speed (-NU.). The neck 17 is kinematically connected with the spindle 18 by a gear 3-1, 29, 30 and 32 with a total gear ratio () equal to the number of branches of the curve being processed. Consequently, the spindle 18 with the workpiece 34 rotates around the axis O with a speed (-w). The scheme shown in FIG. 14 fully corresponds to the theoretical processing scheme shown in FIG. 6, which allows processing of related cycloidal surfaces and equidistant paths to them. When the crank 35 rotates at a speed (NUI), the gear 39 runs around the internal gear 40 rigidly coupled to the housing 6, rotating at the same time with the true angular velocity (-N-uj). At the same time, the P axis shreds in an ellipse (Fig. 15). The size of the minor axis is

N + 1

N-1

R-p-

2

 The size of the major semiaxis is R + + p A-N-a2. The slider 42, pivotally fixed on the axis P, moves along the rectilinear groove 43 of the stationary body 3, forcing the body 6 along with the workpiece 34 to swing relative to the axis of the m.

Crank 35, pins 38, gears 39 and 40, axes 41, sliders 42 and guide grooves 43 are the mechanisms for turning the movable body 6. Thanks to it, the cutting angles are constant during machining. This mechanism rotates the body 6 together with the workpiece 34 relative to the axis M in such a way that the normal to the surface being processed always passes through the machining

1b

20

Da and N-K axis

2b

72021

current point and axis

With the tool.

Dimensions laid down in the construction of the device: between the axes K and M a, between the axes M and K - a, the location of these axes in the same plane; moving the axis O of the workpiece 34 in this plane in accordance with the dependence of OM a, -aj cos (K- (j; rotation of the workpiece 34 around the axis O with speed (-wj; movement of the common axis P of the axes 41 in an ellipse with semi-axes

with the center of the ellipse, whereby the direction of interchange is opposite to the direction of rotation of the workpiece 34, the movement of the sliders 42 pivotally fixed on axes 41 along the rectilinear guide grooves 43 of the stationary body 3, which causes the body 6 to swing with the workpiece 34 relative to the axis M The location of the C axis of the tool C on the longitudinal axis of the grooves 43 with the possibility of moving along it is all fully consistent with the processing method (Fig. 10), which allows the processing of accompanying cycloidal surfaces and equidistant r to them.

The dimensions a, a, R (, and the number of cams of asterisks are determined by drawings of differential sprockets. The instrument radius value (Kinst is determined by the minimum value of the radius of curvature of the sprocket profiles described by equidistant curves to the curve accompanying epi (hypo) cycloid. Size the coefficient is chosen from design considerations.

40 The device allows the treatment of both internal surfaces and external surfaces. FIG. 10, the instrument depicted by the solid line processes the outer surface, and the instrument, depicted by the dotted line, the inner surface. In one revolution, the workpiece is processed And the cams of the sprocket differential. Processing with the help of the proposed device can be carried out on a lathe — by placing the tip of the cutter on the longitudinal axis of the straight grooves 43 (in FIG. 9 - axis nn) and giving the cutter a feed along the axis O of the workpiece 34. When

55. By aligning the tip of the tool with the axis M, a concomitant cycloidal surface D-D is formed. When the cutter's vertex is offset relative to the M axis by some amount along the pn axis, then

thirty

equidistants are formed to this surface, Р-Р and р-р. Processing can be carried out on both the milling and intra-grinding machines, placing the axis C of the tool 4A on the longitudinal axis of the straight grooves 43 and giving the tool rotation. When placing the tool axis C on the pn axis so that the periphery of the tool passes through the axis M, a concomitant cycloidal surface D-D is formed. When the tool axis C is displaced relative to this position by some value along the pn axis and the tool periphery does not pass through the M axis, equidistants to this surface P-P and P-P are formed. Since the normal pp to the surface (DD; Р-Р; Р-Р) at the point being processed (m, A) is always about:; Goes through this point and the tool axis, it is possible to use the tool with the maximum allowable diameter determined by the minimum radius of curvature of the profile. This increases the rigidity of the AIDS system. After dressing the grinding wheel and reworking the cutter, the tool radius changes. Having shifted the tool axis C along the pn axis by the amount of change of the radius in the direction of the workpiece, continue processing. Repeated use of the tool reduces its consumption. During turning, milling and grinding processing, due to the location of the tool along the normal to the machined surface, the cutting angles are constant, which reduces the roughness of the machined surface.

Surface treatment with the device can be conducted without correcting the shape of the guide line of the cylindrical surface being machined and with the correction of the shape of the guide line of the cylindrical surface being machined.

When reciprocating, the movement of the cheek 17 in the direction of the K is the lever 26 along with the cheek 17 also moves in the direction of the K, but since it is hinged on the neck, it has the ability to rotate about the axis 0. When machining without correction, the lever 26 does not Relatively, axis 0. In this case, the finger 50, whose axis is in the same plane with the axes K and m 5, is fixed on the housing 6 and enters the radial groove 49 of the lever 26, depriving the lever 26 of one degree of arches, i.e. obstruction to rotation about the axis O, the ruler 45 is removed from

lever 26. Provision for the possibility of correction is necessary in order to eliminate possible deviations from the shape of the profile due to errors in the manufacture of the device itself, as well as changes in the conditions of processing modes associated with changes in the deformation of the AIDS system. The correction, the shape of the guideline of the cylindrical surface to be machined in the proposed device can be made in two ways.

In the first method, the finger 50 is removed from the housing 6, and the ruler 45 is mounted on the lever 26. When the additional crank 46 is rotated, the finger 47 is in constant contact with the ruler 45, which is provided by the spring 48, and the lever 26 is wobbled

with respect to axis 0. Since the crank rotation speed is N times the rotational speed of the workpiece, W rotates the lever 26 per revolution of the workpiece. When the lever 26 rotates around the axis O, the gear wheel 29, the gear wheel 31, receives an additional angular speed, direction which depends on the direction of rotation of the lever. Accordingly, the additional angular velocity

receives gear 34 through gear 30 and wheel 32. Additional rotation of workpiece 34 causes correction of the shape of the guide line of the cylindrical surface being machined

(Fig. 16).

The solid line in FIG. 16 shows the exact cam profile of the sprocket sprocket and the dotted lines show the adjusted profiles. B points

ilj II., Ill, etc., which correspond to the depressions and protrusions of the cams, the exact profile coincides with the corrected ones, as the angular coordinates

“180 ° 360 ° Nata of these points Oh, ---, --- and

etc. correspond to the rotation of the additional crank 46 at the angles O, 180, 360 °, etc. With such positions of the crank 46, the axis of the finger 47 is in the same plane with the axis O and the axis of the crank 46, there is no rotation of the lever 26 relative to the axis O, there is no additional rotation of the workpiece 34,

Ventually, and correction. FIG. 16 shows two adjusted profiles - a and b. When placed in the initial position of the finger 47 (shown in Fig. 11 by a solid line), profile a is obtained on one side of the crank. When positioned in the initial position of the finger 45 (shown by the dotted line), the profile b is obtained from the other stozone from the crank. Changing the magnitude g of the crank 46 changes the amplitude of the change in the speed of the workpiece 34 and, accordingly, the magnitude of the correction. With the rectilinear surface of the ruler 45, the rotational speed of the workpiece 34 varies sinusoidally. Using a ruler 45 with a profile surface, a change in the speed of the vras, of the preform 34, according to other laws, is obtained, and therefore, the correction value is adjusted on the entire profile.

The second method of correcting the shape is directed to ush, the line of the cylindrical surface being machined is to change the distance p between the axis of the finger 38 and the axis P of the axis 41 in the mechanism for rotating the housing 6, for which gear 41 provides for adjusting the location of the axis 41. When the value of p changes the ratio of the major and minor semiaxes of the ellipse varies, along which the axis P is shifted and, consequently, the trajectory of its ellipse.

FIG. 17 shows the trajectories of two points belonging to; their gear 39. Point A is located at a distance p from the axis of the papa 38, and point B is located at a distance p from

I

finger axes 38. By aligning the axis P with point A, we will ensure the installation of the tool along the normal to the surface being treated and we obtain the exact cam profile of the sprocket, which is shown in FIG. 14 solid line .. In the initial position, t n. when turning the crank 35 at an angle; J-4 0, as well as when the crank 35 rotates through an angle of l80 °, 360 °, etc., which corresponds respectively to the troughs and protrusions of the cams, points A and B are located in the same plane with the axes M and K, angle 4 v , 0, the normal passes through the points M and K. Consequently, in these positions, the change in p does not affect the installation of the tool along the normal to the machining of the surface and

five

0

five

0

Profile correction is applied. When the crank 35 is rotated through an angle (N-v) other than 0 °, 180 °, 360 °, etc., points A and B occupy a different position. The angle, which is the angle between the radius-vector of the curve and the normal to the curve at a given point, determines (see Fig. 10) the additional orientation of the workpiece (rotated together with the link M to around the axis M).

This rotation combines the normal pn to the curve with the direction of the longitudinal axis of the grooves 43 of the stationary body 3, on which the tool axis C is mounted. By aligning the axis P with point B, we get a different orientation of the workpiece (the rotation together with the link KK around the axis M is not at the required angle, but at a different angle v, In this case, the normal pn does not coincide with the longitudinal axis of the grooves 43, therefore, the tool C axis is not normal to the surface to be machined, which leads to the correction of the profile being machined.

The combination of two correction methods expands the possibilities of correction and increases the precision of machined surfaces.

Claims (2)

Invention Formula 55 To the method of cutting cycloidal surfaces, according to 35 to which the relative vrash, eni and oscillatory motion, about tl and h - w w; and with the fact that, in order to expand technological capabilities 4C and improve the cutting conditions by ensuring that the associated cycloidal surfaces and the equidistant ones are treated with them when the tool is positioned normal to the machined 4t of the surface, the relative oscillatory motion is carried out reciprocatingly mixing the workpiece with an amplitude determined by the expression 50  l-cos (N-w -t) de I a, the amplitude of the reciprocating movement of the workpiece, mm; half the difference between the maximum and minimum radius vectors of the curve describing the profile of the machined surface, mm; N is the number of branches processed surface; (J is the angular velocity of the relative rotation of the workpiece or tool, rad / s; t is the processing time, s, and the movement of the instantaneous center of rotation of the workpiece along an ellipse, whose ratio is large and small losei equal to the number of branches of the treated surface. 2. The method according to claim 1, characterized in that, in order to increase the accuracy and obtain modified associated surfaces and equidistant paths to them, in the process of processing, the ratio of the major and minor axes of the ellipse is changed. / 7 4 GUAH7LU C {7 / r (// 7JC / rf / ffOfffff T f f / / rffi / e FI.1  fftfcfff / rac / a Corri / frff / rf / ffufcfff ee // f7ff ifCf / f ffi / Fie.2 M VCC rJL / fy / / 77C / V C / Y / e / Y y / rr fAf // ff / (agl FIG. i e / 77 / yo ff Ph.5  / ft / V Fie.b . Fi8.7 FIG. 8 Fi.e 0 .ro ; / 12 12 29 M Gz 0t / a / 4 qjusiS Editor E. Sligan Compiled by V.Semenov Tehred M.Didyk 4080/13 Circulation 974 Subscription VNIITGI State Committee of the USSR for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, yj Proektna, 4 FIG 17 Proofreader