RU2260506C1 - Device for diamond-abrasive handling of holes - Google Patents

Abstract

FIELD: mechanical engineering.

SUBSTANCE: the invention is pertaining to the field of mechanical engineering and may be used at finishing handling OF interior surfaces of rotation. The device contains a mandrel bearing a diamond-abrasive disk. The mandrel has an linked with the radial holes for feeding of a lubricating-cooling technological substance through pores of the disk. On the mandrel there is a spacer sleeve controlling the height of the diamond-abrasive disk and having radial holes coinciding with the radial holes of the mandrel. Spacers are located on the butts of the disk made out of a fabric porous shell on the elastic porous base. In the capacity of the diamond-abrasive cutting layer use a double-sided diamond-abrasive fixed on the shell. Such design increases productivity and quality of the processing, expands technological capabilities due to possibility to process non-round holes.

EFFECT: the invention ensures an increase of productivity and quality of the processing, expansion of the technological capabilities due to possibility to process non-round holes.

5 cl, 11 dwg, 1 ex

Description

The invention relates to tooling designs according to mechanical engineering technology, intended for use in finishing processing of internal surfaces.

A device for polishing surfaces is known, comprising a housing with a spindle bearing an abrasive wheel, and it is provided with a mandrel with guides perpendicular to the axis of the spindle for moving the housing, made spring-loaded relative to the mandrel and provided with a spring-loaded rod mounted parallel to the guides with the possibility of constant contact with the spindle, while the mandrel equipped with body travel limiters [1].

The disadvantage of this device is low productivity and quality due to insufficient wheel speed, narrow technological capabilities, namely for processing rotating parts, and the inability to process non-circular holes, while the complexity of the design makes the polishing process more expensive. In addition, the design of the tool and the processing method do not allow the supply of cutting lubricants (COTS) directly into the contact zone of the abrasive with the workpiece, which entails an increase in the heat stress of the process and the appearance of microcracks leading to marriage.

A device for polishing surfaces is known, which includes a mandrel bearing an abrasive wheel, and the mandrel is provided with a sleeve, which is the inner ring of a roller radial needle bearing, in which the axes of the outer and inner surfaces are made at an angle α and intersect in the center of symmetry with oblique washers at which the ends made at an angle α to each other, with an abrasive wheel, which is made on a flexible (rubber, rubber, volcanic, etc.) base and which is mounted on the outer ring of the bearing at an angle m α to a plane perpendicular to the axis of rotation, while the angle α is determined by the formula

α <arcsin (V _to / D _to ), deg,

where In _to and D _to - respectively the height and outer diameter of the abrasive wheel, mm [2].

The device is also equipped with a circular ring truncated at an angle α to a plane perpendicular to the axis of rotation, mounted on the end of the circle coaxially with the mandrel axis and a two-arm lever, pivotally in an arm mounted on the mandrel, with one shoulder in contact with the inner surface of the ring, the other shoulder with a screw screwed into the mandrel, and damping spring. In addition, the mandrel is installed at a distance of N from the work surface and rotates with a frequency of N _o , determined respectively by the formulas:

H = 0.5 [(D _to ² -B _to ² ) ^1/2 ] -B _to tgα, mm,

N _o ≥N _d [2πD _k / L _max ], min ^-1 ,

where N _d is the rotational speed of the part, min ^-1 ;

L _max - maximum arc of contact between a circle and a part, mm.

The disadvantage of this device is the design complexity, which increases the polishing process and reduces reliability, as well as the difficulty of adjusting the angle of the circle (requiring replacement of the sleeve, oblique washers and braking mechanism), necessary when optimizing the processing process in production conditions when changing the material being treated - thermal operations, cutting tools, specifications, cutting conditions. Lack of versatility prevents the processing of non-circular holes. In addition, the design of the tool and the processing method do not allow the supply of cutting lubricants (COTS) directly into the contact zone of the abrasive with the workpiece, which entails an increase in the heat stress of the process and the appearance of microcracks leading to marriage.

The objective of the invention is to increase productivity and quality of processing, simplifying and cheapening the design of the tool, expanding technological capabilities that allow processing non-circular holes and the ability to apply lubricant-cooling technological means (COTS) directly to the contact zone of the abrasive with the workpiece, in order to reduce the heat stress of the process and increase the modes cutting.

The problem is solved using the proposed device for diamond-abrasive machining of holes, containing a mandrel bearing a diamond-abrasive wheel, and the mandrel has an axial central hole connected to the radial holes for supplying a lubricant-cooling technological means (COTS) through the pores of the circle, and equipped with a spacer sleeve that determines the height of the circle and having radial holes matching the radial holes of the mandrel, washers located at the ends of the circle, and the circle is made of fabric a porous shell on an elastic porous base, with a double-sided diamond-abrasive skin mounted on the shell as a diamond-abrasive cutting layer.

In this case, the diamond-abrasive skin is taken with different grain sizes on each side and in the form of separate petals, which are fixed to the shell with the formation of an intermittent cutting layer, with each petal attached to the shell from only one end face parallel to the axis.

In addition, the outer diameter of the circle is taken larger than the diameter of the machined hole and the introduction of the circle into the billet hole is carried out using a split conical ring consisting of two ring sectors.

At the same time, the device operates in two modes, in the rough diamond-abrasive machining mode with the petals facing the coarse-grained side to the surface being machined when the circle rotates in one direction and in the finishing mode when the circle is reversed and the circle rotates in the opposite direction, and in the latter case, the petals are turned over account of friction forces with a fine-grained side to the surface to be treated.

In addition, the unsecured part of the petal, in order to better pass the COTS and turn the petals when switching from one mode to another, is cut into several parts in the transverse direction.

Figure 1 shows the proposed device, a General view and a partial longitudinal section; figure 2 is a view along A in figure 1, the circle is configured for roughing; figure 3 is a view along A in figure 1, the circle is configured for finishing; figure 4 is a processing diagram of a circular hole of the proposed device, a longitudinal section; figure 5 is a view along B in figure 4, a partial cross section; 6 is a diagram of the processing of an ellipse hole; 7 is a diagram of the processing of a tetrahedral hole; on Fig is a diagram of the processing of a hexagonal hole; Fig.9 is a diagram of the introduction of a circle into the hole of the workpiece; figure 10 - detachable conical ring for introducing a circle into the hole of the workpiece; figure 11 is a view along In figure 10.

The proposed device is used for finishing diamond abrasive processing of round and non-circular holes. It contains a mandrel 1, on which a diamond-abrasive wheel 2 is mounted. Mandrel 1 has an axial central hole 3 connected to radial holes 4, which serve to supply a lubricant-cooling technological means (COTS) through the pores of the circle directly into the cutting zone.

Circle 2 is equipped with a spacer sleeve 5 that determines its height and has radial holes 6 matching the radial holes 4 of mandrel 1. To maintain the shape of circle 2 in the form of a straight cylinder, it is equipped with washers 7 located at the ends of the circle.

The peripheral surface of the circle 2 is made in the form of a porous fabric shell 8, which is located on an elastic porous base 9 (for example, a rubber sponge, foam rubber, etc.). The porous base 9 was originally taken with a larger diameter than the diameter of the sheath 8, in order to ensure elasticity during assembly.

As a diamond-abrasive cutting layer, a double-sided diamond-abrasive skin is used, which is taken with different grain sizes on each side, and is fixed to the shell 8 in the form of separate petals 10 with the formation of an intermittent cutting layer, i.e. on the peripheral cutting surface of the circle there are depressions 11 not filled with abrasive and allowing the free exit of COTS to the surface of the circle.

Each petal 10 is fixed (for example, glued) to the shell 8 from only one end 12, parallel to the axis of the circle.

In contrast to traditional abrasive processing in the proposed device, the outer diameter of the circle 2 is taken larger than the diameter of the workpiece bore 13 to create elasticity and provide a radial transverse feed S _pop , while the introduction of circle 2 into the workpiece bore 13 is carried out using a split split conical ring 14, consisting of two annular sectors 15 (see Fig.9-11).

Before processing, the ring 14 with the inlet part 16 is inserted into the hole of the workpiece, and after the introduction of the circle into the hole is removed by opening the lock 17 due to the hinge 18, movably connecting the ring sector 15.

The proposed device operates in two modes:

- in the mode of rough diamond abrasive machining with petals facing the coarse-grained side to the surface being machined when the circle rotates in one direction;

- in the finishing mode with reverse and rotation of the circle in the opposite direction, in this case, the petals are turned over due to the friction forces with the fine-grained side to the surface to be treated.

In order to better pass the COTS and flip the petals during the transition from one mode to another, the loose part of the petal 10 is cut into several parts 10 ¹ in the transverse direction.

The assembly and operation of the proposed device is as follows.

A washer 7 is mounted on the mandrel 1 and a sleeve 5 is put on so that the radial holes 6 and 4 are combined. Then a porous elastic base 9 is pressed onto the sleeve, and the contacting surfaces of the washer, bushings and bases 9 are pre-lubricated with glue. A second washer 7 is placed, on the end of which also glue is applied, and the circle is clamped with a nut.

On a pre-radially compressed elastic base 9, a sheath 8 is assembled with diamond abrasive blades assembled with glue on its inner surface. After the glue has dried and the adhesive joints have set, the circle is ready for use. When diamond abrasive blades are worn, the sheath 8 assembly is forcibly replaced with a new one. A diamond skin is highly resistant; one set of a shell with diamond petals mounted on a ⌀ 50 mm circle and a height of 30 mm can process 30 ... 50 thousand holes [3].

The input of the circle into the hole to be machined is carried out when the workpiece and the device are stationary with the help of a conical guide ring 14, which is inserted into the workpiece hole by the entry part 16, and is removed after the introduction of the circle.

Next, the rotation of the workpiece V _s , the rotation of the circle V _to and the longitudinal feed S _ol for processing the hole along the entire length are included. Radial cutting S _pop diamond-abrasive grains is provided due to the elasticity of the circle.

Processing holes proposed device consists of two transitions. The first transition - roughing is performed when the circle rotates in one direction, when the petals face the coarse-grained side to the surface to be treated. Switching to the second transition - finishing is carried out by changing the direction of rotation of the circle, while the petals are turned, like the pages of a book, by turning the fine-grained side to the surface to be treated.

The device allows you to use one of the most effective ways to supply SOTS and feed it under pressure through the central hole of the mandrel and the pores of the circle directly into the contact zone of the abrasive with the workpiece, reducing the heat stress of the process, which allows to increase the cutting conditions. The easy penetration of COTS into the contact zone is also facilitated by: a porous fabric shell, a discontinuous peripheral diamond-abrasive surface of the circle and transverse cuts of the petals, dividing them into parts 10 ¹ .

When processing round holes, the axis of rotation of the circle is combined with the axis of the machined hole of the workpiece (see figure 4-5). However, having the property of elasticity and the ability to change its external configuration, the axis of the circle can be shifted relative to the axis of the workpiece and it becomes possible to process non-circular holes (see Fig.6-8).

Example. A through hole of a flange of 7 50 H7 ^(+0.025) mm and a length of 40 mm was ^{processed on an internal grinding} machine mod. 3K228V. The workpiece material is steel 45, hardened, hardness HRC 45. The method of fastening the workpiece is in the cartridge. Technological system: machine tool - tool - workpiece is quite rigid. The roughness parameter of the treated surface is Ra 0.32 μm. The circle is made of ⌀ 64 mm, 30 mm high on a foam basis, the petals of the skin are grit on the one hand 14A12, on the other - 14A4. The allowance is 0.05 mm, the rotational speed of the circle is 13,000 min ^-1 (V _k = 34 m / s), the rotation speed of the workpiece is 191 min ^-1 (V _k = 0.5 m / s), the longitudinal feed is S _pr = 0.05 m / s. Coolant - 5% aqueous solution of emulsol in water. The petals of the skins were impregnated with a composition containing 40% paraffin, 55% PVC grease and 5% graphite in order to better flip the petals when switching from one mode to another and lower the temperature.

To obtain the necessary accuracy and roughness, it took half the time than with traditional processing.

The device improves productivity and processing quality, simplifies and reduces the cost of tool design, expands technological capabilities and allows you to process non-circular holes.

Sources of information

1. A.S. USSR 622647, MKI V 24 V 5/02. Device for polishing surfaces. B.M. Nikiforov and R.P. Chauzov. Application No. 2150282 / 25-08, decl. 07/01/75, publ. 09/05/78. Bull. No. 33 is a prototype.

2. RF patent No. 2202461, MKI 7 V 24 V 29/00, 45/00. Device for polishing surfaces. Stepanov Yu.S., Afanasyev B.I., Borodin V.V., Fomin D.S. Application 2001123492/02, declared 08.21.2001, publ. 04/20/2003 Bull. Number 11.

3. Reference technologist-machine builder. In 2 vols. T.1 / Ed. A.G. Kosilova and R.K. Meshcheryakova. - 4th ed., Revised. and add. - M.: Mechanical Engineering, 1986. P.443.

Claims (5)

1. Device for diamond-abrasive machining of holes, containing a mandrel bearing a diamond-abrasive wheel, characterized in that the mandrel has an axial central hole connected to radial holes for supplying a lubricant-cooling technological means (SOTS) through the pores of the circle and is equipped with a spacer a sleeve that determines the height of the circle and having radial holes matching the radial holes of the mandrel, and washers located at the ends of the circle, while the circle is made of porous fabric shell elastically porous substrate, and as a diamond abrasive cutting layer used sided diamond-abrasive cloth, fastened to the shell. 2. The device according to claim 1, characterized in that the diamond-abrasive skin is used of different grain sizes on each side and in the form of separate petals that are attached to the shell with the formation of an intermittent cutting layer, with each petal mounted on the shell with only one end face parallel to the axis. 3. The device according to claim 1, characterized in that the circle is made with an outer diameter larger than the diameter of the hole to be machined, while the introduction of the circle into the workpiece hole is carried out using a split conical ring consisting of two ring sectors. 4. The device according to claim 2, characterized in that it is designed to operate in two modes: the petals facing the coarse-grained side to the surface to be machined, while the circle rotates in one direction - in the rough diamond-abrasive treatment mode and the petals inverted with the fine-grained side to of the treated surface, due to friction forces during reverse and rotation of the circle in the opposite direction - in the finishing mode. 5. The device according to claim 4, characterized in that the loose part of the petal is cut into several parts in the transverse direction for better passage of the COTS and the flipping of the petals when switching from one mode to another.

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