RU2239541C1 - Built-up petal type abrasive tool for longitudinal-cross polishing - Google Patents

Abstract

FIELD: machine engineering, possibly dimensionless finishing of part surfaces by means of petal type discs.

SUBSTANCE: built-up disc is in the form of pair of petal type abrasive wheels mounted with gap on common shaft in such a way that they are inclined by the same angle relative to plane normal to rotation axis. One wheel is mounted in shaft by means of rolling bearing assembly. Petals of grinding disc are made of double-side grinding cloth in the form of ellipse whose small axis is equal to diameter of wheels and whose large axis is determined depending upon inclination angle of grinding wheels. Such design provides increased axial rigidity of tool and crossed paths of motion of wheels.

EFFECT: enlarged manufacturing possibilities of tool due to working by means of two ends of petals, enhanced efficiency and improved quality of working.

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Description

The invention relates to mechanical engineering, to the machining of metals, and can be used for grinding and polishing the surfaces of parts with their dimensionless final machining with flap wheels.

Known prefabricated abrasive tool made in the form of a pair of abrasive wheels fixed at an angle to each other on a common shaft with an axial clearance [1].

The disadvantages of the known tool are the limited technological capabilities for decorative finishing and finishing of shaped surfaces, as well as difficulties in achieving a wide range of quality of the machined surfaces, while having minimal axial rigidity and working only on one side of the peripheral abrasive surface, it is impossible to achieve high productivity.

Known prefabricated abrasive tool made in the form of a pair of abrasive wheels fixed at an angle to each other on a common shaft with axial clearance, and the tool is equipped with a tension spring located between adjacent ends of the abrasive wheels, which are installed with the possibility of angular rotation [2].

The disadvantages of the known tool are:

- minimum axial rigidity of the tool, not allowing to achieve high performance;

- work on only one side of the peripheral abrasive surface of the tool greatly increases the complexity of processing;

- limited technological capabilities for decorative finishing and finishing of shaped surfaces;

- difficulties in achieving a wide range of quality of the treated surfaces.

All this reduces processing productivity, quality and leads to increased tool consumption.

The objective of the invention is to expand the technological capabilities of the tool by providing the possibility of processing with two ends of the petals of the tool, which is installed at an angle to the axis of rotation, increasing productivity by increasing the axial rigidity of the tool due to the use of abrasive petals in the form of an ellipse, as well as improving the quality of processing due to the cross longitudinal-transverse the intersection of the trajectories of the polishing wheels.

The problem is solved using the proposed prefabricated flap abrasive tool for longitudinally transverse polishing, which is made in the form of a pair of abrasive flap wheels fixed at the same angle to a plane perpendicular to the axis of rotation, on a common shaft with an axial clearance, and one of the circles mounted on the shaft by means of a rolling bearing, and the petals of the circles are made of a double-sided grinding skin in the shape of an ellipse, the small axis of which is equal to the diameter of the circles, and the large axis depends on the angle of circles womb and is defined by the formula

b = D / cosα,

where b is the major axis of the ellipse;

D is the outer diameter of the inclined circles;

α is the angle of inclination of the circles to a plane perpendicular to the axis of rotation, which is determined by the formula

α ≥ arctan (A _o / D),

where A _o is the amplitude of the oscillating cutting zone of inclined circles, which is in relation to the height of the circle Ao≥ B, here B is the height of the circle with a minimum height.

The invention is illustrated by drawings. Figure 1 shows the design of a precast flap abrasive tool for longitudinally transverse polishing, a partial axial section; figure 2 is a General view of the tool, rotated half a turn relative to the position shown in figure 1; figure 3 is a view along a in figure 1; figure 4 is an ellipsoidal petal of a double-sided grinding skin; figure 5 - position of the petals of the circles in the zone of contact with the work surface, circles in the position shown in figure 1; in Fig.6 - the position of the petals of the circles in the zone of contact with the work surface, circles in the position shown in figure 2; 7 is a scan of the tool track on the work surface when it is rotated one revolution.

The proposed prefabricated flap abrasive tool allows for finishing in both longitudinal and transverse directions.

The working cutting element of the tool is an ellipsoidal petal 1 of a double-sided grinding skin. The tool is made in the form of a pair of abrasive flap wheels 2 and 3, fixed at the same angle α to a plane perpendicular to the axis of rotation.

Circles 2 and 3 are mounted on a common shaft 4 with an axial clearance using an oblique washer 5, which defines the angle of inclination of circle 2, a gasket 6, which defines the clearance between the circles, sleeve 7, on which circle 3 is movably mounted, and nuts 8, which are fixedly fixed to the petals 1 circle 2 relative to the shaft 4. The sleeve 7 has an outer surface whose axis is located at an angle α to the axis of the hole. Using the bearing unit 9 on the sleeve 7 is movably fixed circle 3 with the possibility of free rotation. The bearing assembly 9 includes a flange 10, which is mounted on a rolling bearing using spring thrust concentric rings (taken, for example, according to GOST 13940-80 and GOST 13941-80). On the flange 10, with the help of the nut 11, the petals 1 of the moving circle 3 are fixed. In order to intensify the processing, the petals 1 of the circles 2 and 3 are taken from a double-sided grinding skin in the form of an ellipse, the small axis of which is equal to the diameter of the circles in an inclined position, and the large axis depends on the angle of inclination circles and is determined by the formula

b = D / cosα,

where b is the major axis of the ellipse;

D is the outer diameter of the inclined circles;

α is the angle of inclination of the circles to a plane perpendicular to the axis of rotation, which is determined by the formula

α ≥ arctan (A _o / D),

where A _o is the amplitude of the oscillating cutting zone of inclined circles, which is in proportion to the height of the circle A _o ≥ B, here B is the height of the circle with a minimum height.

Petals 1 circles 2 and 3 are not interchangeable, as they have holes of different diameters.

The tool is installed on a circular, inside, or surface grinding machine, and the workpiece in the appropriate device. The rotation is reported to the shaft V, the tool is tightened with the transverse feed S _pop and the longitudinal feed to the workpiece, and during circular and intra-grinding work, the workpiece is rotated. For a full revolution of the tool shaft, the circle 2 smoothly changes its angular position to the left and to the right of the normal by the angle α with respect to the work surface.

The circle 3, movably mounted with a rolling bearing on the shaft 4, is rolled over the machined surface and, thanks to its inclination in the contact zone with the workpiece, makes oscillating oscillatory movements along the longitudinal axis of rotation.

Moving along the surface of the workpiece machined by circle 2, the movable circle 3 in the contact zone cuts off microroughnesses in the direction perpendicular to the risk-scratches cut by circle 2 (see Fig. 7). Due to the inclination of the circle and the interference by S _pop , the main force on the surface to be treated is carried out by the parts of the petals located on the periphery and having the greatest deflection (see FIGS. 5 and 6). The direction of the deflection of the petals varies depending on the angular position of the circle. If the contact zone of the circle with the workpiece is located to the right of the normal (see Fig. 5), then the deflection direction is to the right, while the petals work to the left abrasive end, if the contact zone is to the left of the normal, then the deflection direction is to the left, and the petals work to the right abrasive butt.

In connection with what has been said during this longitudinal-transverse polishing, the proposed tool manages to remove large allowances (for example, up to 0.3 mm) when using coarse-grained abrasive skins (grain size 16-80) and high cutting speeds (15-35 m / s).

This process is actually a form of grinding and is effective for preparing surfaces for fine polishing and before metal coating.

Longitudinally-transverse polishing with a prefabricated flap wheel with parametric oscillation is intended to reduce the surface roughness parameter (to Ra = 0.1 ... 0.8 μm) without eliminating deviations in the shape of the parts.

The greatest effect of the use of oscillating longitudinal-transverse polishing is achieved during decorative finishing and finishing of shaped surfaces, for example polishing of cylindrical and conical surfaces, processing of molds, dies, etc., polishing curved surfaces of automobile bodies, refrigerators, etc. for painting.

Polishing with the proposed tool is carried out mainly according to one cutting pattern, which is based on the use of high cutting speeds (10 ... 40 m / s), approaching the grinding speed. The peripheral speed of a circle during oscillating polishing of parts made of steel, nickel and chromium 20 ... 35 m / s; from copper, brass and bronze 16 ... 25 m / s; from aluminum, zinc and lead 12 ... 20 m / s.

However, low speeds S _{pr the} movement of the workpiece (which is typical for flat polishing) contribute to improving the quality of processing.

The most applicable for the proposed tool are circles made of electrocorundum and silicon carbide skins on a fabric and paper base with a grain size of 8-M40, as well as diamond and elbor skins with a grain size of 12-MZ on an elastic bond, while the latter are highly resistant.

For the operation of this tool, circles made of water-resistant diamond-abrasive skins are used when processing parts made of steel, cast iron and brass, and an emulsion is used as a cooling liquid; from non-waterproof skins - mineral oils.

The proposed prefabricated flap tool for longitudinal and transverse polishing with parametric oscillation expands technological capabilities by providing the possibility of processing with two ends of the petals that make up the circles, improves productivity and quality of processing by installing circles at an angle to the axis of rotation and free installation of one of the circles, increasing axial stiffness due to the use of abrasive blades in the form of an ellipse.

Sources of information

1. A.S. 689823 USSR, MKI B 24 D 5/00. Prefabricated abrasive tool. 1977.

2. A.S. 1692824 USSR, MKI B 24 D 13/00. Prefabricated abrasive tool. A.V. Chemersky and V.N. Cheshev. No. 4700372/08, declared 04/18/89, publ. 11/23/91. Bull. No. 43 is a prototype.

Claims (1)

Assembled flap abrasive tool for longitudinally transverse polishing, made in the form of a pair of abrasive flap wheels fixed at the same angle to a plane perpendicular to the axis of rotation, on a common shaft with an axial clearance, characterized in that one of the circles is mounted on the shaft by a rolling bearing, and the petals are made of a double-sided grinding skin in the form of an ellipse, the small axis of which is equal to the diameter of the circles, and the large axis depends on the angle of inclination of the circles and is determined by the formula b = D / cosα, where b is the major axis of the ellipse; D is the outer diameter of the inclined circles; α is the angle of inclination of the circles to a plane perpendicular to the axis of rotation, determined by the formula α ≥ arctg (A _o / D); A _about - the amplitude of the oscillating cutting zone of inclined circles, located with the height of the circle in the ratio of A _about ≥ B; In - the height of the circle with a minimum height.

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