RU2304039C2 - Grinding machine tool - Google Patents

Abstract

FIELD: mechanical engineering.

SUBSTANCE: grinding machine tool comprises housing and diamond abrasion segments mounted on the housing by means of fastening members. The housing is provided with T-shaped radial grooves made on its face and central longitudinal and threaded openings. The fastening members are made of blocks set in the grooves of the housing for permitting radial movement. The cross-section of the blocks is shaped so that to be mating to the block groove. The inner face of the blocks is inclined at an acute angle. The blocks are provided with radial and peripheral plates for receiving radial and peripheral segments. The ring expansion spring is mounted from the free end of the housing. The central longitudinal opening receives the plunger whose outer side cooperates with the inner face of the blocks.

EFFECT: expanded functional capabilities.

6 dwg, 1 ex

Description

The invention relates to mechanical engineering technology, to the processing of materials by cutting, to grinding, namely to the manufacture and operation of a precast diamond-abrasive tool with an intermittent cutting surface, working with the end face and periphery of the circle, and can be used mainly in engineering plants in the processing of metals and alloys, in particular for intensive machining of blind holes, end faces, thrust threads of compression screws of rolling mills, etc.

A prefabricated end abrasive wheel is known, in which circumferential discontinuous concentric protrusions are made on one end of the casing, and corresponding circumferential concentric grooves are used on the abrasive segments for contacting with said protrusions when assembling the circle, and a flange in the form of a disk with cutouts and radial rays, which is attached to the body with bolts [1].

The known design of a prefabricated end abrasive wheel has narrow technological capabilities, does not have the ability to restore the outer working diameter in order to maintain stability of the machining quality under constant cutting conditions, and does not allow to optimize the machining process in production conditions when the material being processed, chemical-thermal operation, and tool cutting elements change , technical conditions, cutting conditions, requires complex refinement of abrasive segments (execution of circumferential end ntric grooves), which increases the cost of manufacturing the tool.

The objective of the invention is the expansion of technological capabilities, reducing the cost of processing and improving quality through the use of intermittent end-grinding tools with the possibility of radial movement of diamond-abrasive segments in the processing process, which allows to optimize the processing process in production conditions.

The problem is solved using the proposed intermittent end-grinding tool containing a housing and mounted on it by means of fastening elements diamond-abrasive segments, moreover, the housing is made with radial T-shaped grooves at its end and with central longitudinal and threaded holes, and the fastening elements are diamond-abrasive segments - in the form of radial movement installed in the said grooves of the body and having a cross-sectional shape corresponding to the shape of the groove, pads with an inner end located at an acute angle α to a plane perpendicular to their longitudinal axes, and with radial and peripheral plates rigidly fixed on two mutually perpendicular surfaces, designed to install diamond-abrasive segments made respectively radial and peripheral, while the tool is equipped with the sides of the free end of the housing with an annular tension spring mounted on hooks fixed to peripheral plates to shift the pads to the center and strument and a plunger mounted in a central longitudinal housing bore and having disposed at an acute angle α to the longitudinal axis of the outer surface for contact with the inner end blocks and transmitting them by the thrust screws disposed in the central threaded hole of the housing.

Features of the design of the tool are illustrated by drawings.

Figure 1 presents the proposed intermittent end face grinding tool, a longitudinal section; figure 2 is a General view from the left along A in figure 1; figure 3 is a transverse section B - B in figure 1; figure 4 is a General view of the tool and the diagram of the diamond abrasive machining of the thrust thread of the pressure screws of the rolling mills; figure 5 - section b - In figure 2; Fig.6 is a variant of the design of the tool with a shank in the form of a cone and with the possibility of adjusting the outer diameter from the side of the working end.

The proposed tool is used for diamond abrasive machining of cylindrical outer and inner surfaces, as well as the ends of blind holes, the threaded thread of the pressure screws of rolling mills, etc.

An intermittent circular grinding tool consists of a housing 1 with a central landing neck 2 for mounting and fixing the tool on a spindle (not shown). At the base end 3 there are made radial T-shaped grooves 4, in which pads 5 are provided with the possibility of radial movement, having in cross section a shape corresponding to the shape of groove 4.

On two open mutually perpendicular surfaces 6 and 7 of blocks 5, radial 8 and peripheral 9 plates are rigidly fixed, on which radial 10 and peripheral 11 diamond-abrasive segments are mounted. Plates 8 and 9 serve for the perception of axial P _o and radial P _p cutting forces, provide high axial and radial rigidity to the tool and have significantly higher strength characteristics compared to the strength of diamond-abrasive segments.

The tool is equipped with an annular tension spring 12 located on the free end side of the housing 1, which is mounted on hooks 13 fixed on the inner surface of the peripheral plates 9. The purpose of the annular tension spring 12 is to reduce the pads 5 to the center of the tool.

In the central longitudinal hole of the housing 1 there is a plunger 14 having a conical outer surface 15, which is at an acute angle α to the longitudinal axis, in contact with the inner ends of the blocks 5. The plunger 14 receives and transfers to the blocks 5 the axial force R developed by the screw 16 when screwing the latter into the central threaded hole of the housing 1. The screw 16 allows, using a clinoplunger mechanism consisting of a plunger 14 and blocks 5, to radially spread the diamond-abrasive segments and thus restore initial outer diameter of the tool.

The inner end of the pads 5, with which they are in contact with the plunger 14, is made at an acute angle α to a plane perpendicular to the longitudinal axis of the pads 5.

The workpiece is informed of the rotational movement V _s , and the proposed tool is rotational motion V _and , the longitudinal feed S _CR and the feed rate S _pop .

Compensation of wear of the segments is carried out thanks to the radial feed of the blocks with the segments due to the additional axial movement of the plunger and the extension of the blocks from the T-shaped grooves of the housing.

The tool can be made with a tapered shank (see Fig.6). This design allows you to adjust the radial movement of the segments from the side of the working end. For this purpose, a central hole is made in the plunger 14, and the screw 16 is made in the form of a threaded plug with a turnkey internal hex hole.

The proposed tool with a radial adjustment drive allows you to evenly affect the diamond-abrasive segments and get the machined surface with high accuracy.

Intermittent working diamond-abrasive surface, large segment areas and high axial stiffness of the proposed tool allow grinding at feeds of 5 ... 6 times and with cutting depths of 4 ... 5 times greater than the feed and cutting depth with continuous conventional grinding without fracture segments.

Example

Abrasive processing of a two-stage hole with a diameter of 190 and 170 mm and the ends of the sleeve with the proposed tool installed in the tool holder on the support of the lathe of the mod was carried out. 16K20T1. The basing and fixing of the sleeve was carried out in a three-jaw self-centering cartridge. The abrasive operation was carried out by the developed intermittent end-circular grinding tool, consisting of eight radial and eight peripheral abrasive segments made of 24A25NSM16K7 material with a workpiece speed V _s = 20 m / s (n = 2000 min ^-1 ) and a longitudinal feed speed S _pr = 5600 mm / min (2.8 mm / rev). The diameter of the new precast tool is 150 mm; rectangular radial abrasive segments of the SP type (GOST 2464-82) with dimensions of 60 × 25 × 125 with preliminary processing according to the shape of the segments were used, peripheral abrasive convex-concave segments of type 1C (GOST 2464-82) with dimensions of 60 × were used 40 × 75 × 85 × 60.

Productivity increased 2.4 times, tool life increased by 30% compared to internal grinding with traditional wheels. The maximum roughness value achieved during the processing by the proposed tool is R _a = 0.8 μm, a reduction of the initial roughness by a factor of 2.5 is possible.

The proposed tool reduces the risk of burns by reducing the heat stress of cutting due to the discontinuity of the contact zone of the tool with the workpiece and interrupted cutting, has increased wear resistance due to the uniform loading of all segments, allows the use of standard diamond-abrasive segments, makes it possible to intensify the processing by joint end face grinding, adjustment and restore the outer working diameter without stopping the process.

These advantages allow you to increase productivity, quality and reduce the cost of processing internal and end surfaces.

The advantage of the tool is the ability to smoothly control the external working diameter, which makes it easy to optimize the processing process in production conditions when changing the material being processed, chemical-thermal operation, cutting elements of the tool, technical conditions, cutting conditions.

The discontinuity of the contact zone contributes to a better penetration of the cutting fluid (coolant) into the treatment zone. Processing with a prefabricated tool allows the coolant to be fed into the area between the segments, which dramatically increases the efficiency of the cooling, dispersing and plasticizing action of the coolant due to facilitating its access to the contact zone between the tool and the workpiece.

Information sources

1. A.S. USSR 1281393, MKP ⁴ V24V 7/06. Prefabricated end abrasive wheel. Churikov A.I., Gusev V.G., Trishin V.M. and other Application No. 3839027 / 31-08, decl. 01/02/85; publ. 01/07/87, Bull. No. 1 is a prototype.

Claims (1)

An intermittent circular grinding tool containing a housing and diamond-abrasive segments mounted on it by means of fastening elements, characterized in that the housing is made with radial T-grooves at its end and with central longitudinal and threaded holes, and the fastening elements of diamond-abrasive segments are in installed in the said grooves of the housing with the possibility of radial movement and having a cross-sectional shape of the reciprocal shape of the groove of the pads with an inner end located under a sharp hl α to the plane perpendicular to their longitudinal axes, and with radial and peripheral plates rigidly fixed on two mutually perpendicular surfaces, designed to install diamond-abrasive segments made respectively radial and peripheral, while the tool is equipped with a housing located on the side of the free end ring tension spring mounted on hooks fixed to peripheral plates for shifting the pads to the center of the tool, and a plunger set in price tral longitudinal housing bore and having disposed at an acute angle α to the longitudinal axis of the outer surface for contact with the inner end blocks and transmitting them by the thrust screws disposed in the central threaded hole of the housing.

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