RU2481186C1 - Device for finishing spheres - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to machine building and may be used for finish abrasion of single solid spheres. Machined sphere is arranged between two pairs of tubular laps with their axes located in one plane. First pair of laps has vertical rotational axis, servo drive fitted on upper lap axle and ball-screw gearing for programmed variation of sphere compression resultant force in vertical direction. Position of second pair axis is adjusted by deflection from horizon plane there angle α defined by formula α=45°-µ, where µ is angle of spherical radius of second pair laps. In lapping by servo drive programs, every turn of sphere occurs together with one of opposed laps pair.

EFFECT: higher precision.

2 cl, 3 dwg

Description

The invention relates to the field of abrasive finishing and can be used in the manufacture of spherical rotors of non-contact suspensions of gyroscopes and other spherical parts with high requirements for accuracy of shape.

There are several three-spindle installations for spherodovodka continuous spheres, one of which is taken as a prototype (USSR AS No. 185231, class B24B 1/00, 1964). In these installations, the sphere to be spherical is fixed by three tubular lapping, the axes of which are located in the same plane. The angle between the axes of the lapping is 120 °. The rotation of the lapping leads to the rotation of the sphere, which is processed by abrasive paste due to slippage between the sphere and lapping. The advantage of the installation in a wide strip of removal, which allows to reduce the amount of allowance to eliminate the initial non-sphericity. The lack of installation in the relatively low accuracy of the shape of the sphere at the level of 0.15 μm (non-circularity), due to the unevenness of the removal inside the stripe and the long duration of coverage of the entire surface of the sphere with strips. This time of material removal from the entire surface of the sphere is one of the main characteristics of precision spherical finishing.

Using the proposed device, it becomes possible to solve the problem of spheriodovka single continuous spheres with high accuracy, with a shape error of 0.01-0.02 microns due to the rapid coverage of the entire surface of the sphere with wide strips of strips, uniform distribution of strips of strips on the surface and alignment of strips inside strips of removal. To do this, use servos, which according to the program control the movement of the sphere in the process of spherical watering. The scheme of the proposed device is presented in figure 1, which indicates:

1, 2, 3, 4 - tubular lapping;

5 - processing traces with the largest removal thickness:

6 - servomotors;

7 - ball screw transmission.

Two pairs of oppositely located laps fix the sphere. Lapping 2, 4, forming the first pair of oppositely located lapping, mounted on the same vertical axis, rotate at the same speeds, which vary according to the servo program. A servo motor 6 and a ball screw transmission 7 are installed on the axis of the upper lapping. According to the servo program, the resulting compression force F of the sphere in the vertical direction changes. The center of the sphere is controlled by moving the lower lapping along the vertical axis. Lapping 1 and 3, forming the second pair, are located on the same axis, the position of which is adjustable and is determined by the angle of inclination to the horizon plane α = 45 ° -µ, where µ is the spherical radius of the lapping of the second axis. Subject to this equality, the equality of the oppositely directed forces T ₁ T ₃ applied to the 1st and 3rd lapping, and the rotation of the sphere together, without slipping, with lapping of the vertical axis, a stripping width of Vp equal to 90 will be removed from the surface of the sphere ° in an angular measure. The survey in these bands will be symmetrical with respect to the center of the sphere if the relative velocities of the 1st and 3rd laps are equal. By using such stripping strips with symmetrical stripping, it is possible to increase the accuracy of spherical spotting. Figure 2 shows the location of three strips of removal, representing spherical belts with a width of 90 °, oriented along three mutually perpendicular axes of the sphere. This is one of the best options for the fastest and most uniform coverage of the entire surface of the sphere with strips. In FIG. 2 are indicated:

8-6 identical areas with two layers of removal;

9-8 identical areas with three stripping layers having a triangular shape.

With the selected parameters of the spherical belts and their location, it is easy to calculate that 88% of the surface area of the ball is covered by two strips of removal, 12% of the area is the total area of triangular regions covered by three strips of removal. In order to achieve such an arrangement of the strips on the surface of the sphere, in addition to three rotations of the sphere by 360 °, it is necessary to perform 5 additional rotations of the sphere to change its orientation relative to the axes of lapping. Each rotation of the sphere in the device occurs in conjunction with one of the lapping pairs. All other rotations of the sphere, characterized by slippage with all four lapping, are also possible in the proposed device, but are undesirable because they inevitably lead to uneven removal from the surface of the sphere. Uneven and increased removal from the surface of the sphere occurs when the rotation of the sphere slows down, which occurs when the sphere slides with all four lapping. During joint rotations of a sphere with lapping, one should evaluate the stability of these joint rotations, which is greater, the greater the difference in the forces compressing the sphere. The values of the forces and speeds at which these turns occur with sufficient stability are presented in the graphs of Fig. 3, and are entered into servo programs that control the process of sphero-surfacing for a long cycle of sphero-primer with a duration determined by the wear of the abrasive paste or the achievement of the required precision of the spherical polishing. Figure 3 presents 8 rotations of the sphere, which make up a small cycle spherical. These cycles are repeated until the completion of the large spherical cycle. The rotation of the sphere 360 ° around the vertical axis is carried out at the 1st, 3rd and 7th turns of the sphere. These three rotations, oriented along three mutually perpendicular axes of the sphere, cover the entire surface of the sphere with strips. The angular velocities ω ₁ , ω ₃ of the 1st and 3rd lows at these turns are directed in opposite directions. Their values are specified in the process of setting up the device. The rotation of the sphere by an angle of 90 ° is carried out at the 2nd, 4th, 5th and 8th turns, of which the 5th turn is made around the vertical axis, and the remaining turns are made around the 2nd axis, inclined to the horizon plane at an angle α. The 6th turn is produced at an angle of 270 ° around the 2nd axis. To go from turning around the vertical axis to turning around the 2nd axis, increase the forces T ₁ , T ₃ , reduce the force F and equalize the angular velocities ω ₁ , ω ₃ of the 1st and 3rd lows. In addition to the forces F, T ₁ , T ₃ , the angular velocity Ω of rotation of the 2nd and 4th laps is introduced into the servo program, which coincides with the speed of the sphere when it is rotated through 360 °. The maximum values of the velocity Ω are chosen based on the diameter of the sphere and the conditions for its processing. It should not be too large, in which conglomerates and the appearance of marks on the surface of the sphere are possible. The speeds of the joint rotation of the sphere with the 2nd axis, on the contrary, should be quite large, since they affect the productivity of the process of spherical finishing.

The proposed device is designed for removal in the form of wide strips of removal with a width equal to 90 ° in an angular measure. Therefore, in addition to the quick and uniform coverage of the sphere with strips of strips and the uniform distribution of small cycles of spherical finishing, consisting of 8 turns, it is necessary to solve the problem of alignment of strips inside the strips. To this end, during each rotation, the forces compressing the sphere and its rotation speed do not change. However, this is not enough, since the lengths of the lapping arcs located in planes perpendicular to the axis of rotation of the sphere, and participating in the spherical flow, vary significantly and reaches a maximum in tracks 5 in figure 1.

The absence of patterns for calculating the removal thickness inside the removal strip leads to the need to configure the device to align the removal thickness inside the removal strip. Such a setting is possible, since at the same time it is possible to change the forces F, T ₁ , T ₃ and their ratio, the spherical radius µ of the lapping located on the 2nd axis, the width of the lapping edge, the angular velocities ω ₁ , ω ₃ of the 1st and 3rd go lapping. Simultaneously with the adjustment, designed to align the thicknesses of the strips inside the stripping strip, they solve the problem of equalizing contact pressures along the edges of the lapping, located on the 2nd axis. In statics, with a fixed sphere and fixed lapping of the 2nd axis, forces T ₁ , T ₃ act on the sphere, which are directed along the 2nd axis and which create constant contact pressure along the lapping edge. The maximum values of contact pressures determine the quality of the treated surfaces (roughness, risks, punctures). Therefore, in all cases of removal, one should strive for constant contact pressures close to its maximum values, which will increase the productivity of the spherical process at a given accuracy of spherical delivery. To this end, additional forces or moments of force should be applied to lapping 1 and 3 in order to compensate for the friction forces arising in the process of spherical flashing, and to preserve the constant contact pressure along the flanges of the flashing during spherical flashing. The location of the axes of the 2nd and 4th lapping on the same vertical axis also helps to equalize contact pressures and increases the stability of the movement of the sphere.

The technical and economic efficiency of the invention consists in increasing the productivity of spherical cultivation and in increasing the accuracy of the shape of the processed sphere.

It is not possible to calculate the economic effect due to the lack of statistically sound initial and comparative data.

Claims (2)

1. Device for honing a sphere located between the edges of tubular lapping, the axis of rotation of which are located in the same plane, characterized in that it is made with two pairs of oppositely located lapping, fixing the sphere, and the first pair of lapping has a vertical axis of rotation and mounted on the axis of the upper lapping the servo-drive and ball screw transmission to change the resulting compression force of the sphere in the vertical direction, and the position of the axis of the second pair of lapping is regulated by the deviation from the horizontal plane that an angle α, defined by the formula α = 45 ° -μ, where μ - lapping angle of the spherical radius of the second pair. 2. The device according to claim 1, characterized in that it contains servos that change the resulting compression force of the sphere and the angular rotational speeds of the laps according to the program, ensuring each rotation of the sphere together with one of the pairs of oppositely located laps.

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