RU2252132C1 - Combination type grinding disc - Google Patents

Abstract

FIELD: machine engineering, possibly effective preliminary and finish working of blanks by means of abrasive disc.

SUBSTANCE: abrasive disc includes body with large-grain abrasive layer rigidly secured to it and spring-loaded movable inserts with small-grain layers. Mechanisms for radial motion of each movable insert include two pneumatic cylinders with mutually normal axes. Cylinders whose axes are parallel relative to axis of disc are joined to wedge type clamp that fixes spring-loaded inserts with small-grain abrasive layers. Invention provides possibility for finish grinding by means of disc with spring-loaded fixed inserts and for dwelling by means of said inserts.

EFFECT: desired accuracy of dimensions, preset macro- and micro-geometry of ground surfaces.

3 dwg

Description

The invention relates to tools for metal processing and can be used at enterprises of the metalworking industry for effective preliminary and final processing of workpieces of machine parts and devices.

Combined grinding wheels are known, including alternating sectors of various grain sizes arranged around a circle (SU, copyright certificates No. 595140, class B 24 D 5/14, 1978; No. 608645, class B 24 D 5/14, 1979). The use of these wheels improves the quality of the machined parts. The reasons that impede the achievement of the technical result indicated below when using known circles include the fact that their designs do not allow to control the sequence of participation in the cutting of elements with different grain sizes.

Known is a combined grinding wheel consisting of a body carrying coarse-grained abrasive layers, retractable inserts bearing fine-grained abrasive layers, and a mechanism for moving the retractable inserts (SU, copyright certificate No. 1255414, class B 24 D 3/34 // B 24 D 17 / 00, 1986). Such a circle makes it possible to perform preliminary, final processing and nursing of workpieces with abrasive layers of different granularity in one operation without changing the circle. The reasons that impede the achievement of the technical result indicated below when using a known wheel include the fact that in the known construction, coarse and fine-grained abrasive layers are rigidly fixed respectively to the body and the sliding inserts of the wheel, which does not allow damping the oscillations of the technological system at the stages of final grinding and nursing and increases the time required to complete these steps to achieve the required macro- and microgeometry of polished surfaces.

The closest method of the same purpose to the claimed invention according to the totality of features is a combined grinding wheel containing a body with a coarse-grained layer rigidly fixed on it, retractable inserts with fine-grained layers rigidly fixed to them, and springs made of material with thermomechanical memory, which are supports of movable inserts and providing their extension when heated (RU, patent No. 21515130 C1, CL B 24 D 5/14, 2000), adopted as a prototype.

Such a circle makes it possible to carry out preliminary grinding sequentially performed in one operation with a coarse-grained layer rigidly fixed to the wheel body, and final grinding, and then nursing with fine-grained layers fixed to inserts mounted on the springs. Grinding with a wheel adopted as a prototype has the advantages of machining with a rigid tool at the preliminary grinding stage, the main of which is high productivity, and processing with damping of the oscillations of the technological system at the stages of final grinding and nursing. The reasons that impede the achievement of the technical result indicated below when using the wheel adopted for the prototype include the fact that when grinding with fine-grained layers fixed to spring-loaded inserts, the shape errors of the surface being polished are copied, obtained at the stage of preliminary grinding and having, as a rule, unacceptably large values due to the magnitude and variation of the cutting forces.

The invention consists in the following. The combined grinding wheel has wedge clamps operating from pneumatic cylinders placed in the wheel casing, allowing the spring-loaded movable inserts with fine-grained abrasive layers to be fixed (rigidly fixed) to the final grinding stage.

The technical result consists in increasing the accuracy of the geometric parameters of the grinding parts.

The specified technical result during the implementation of the invention is achieved by the fact that, as in the known device, the combined grinding wheel comprises a housing with a coarse-grained abrasive layer rigidly fixed on it, movable inserts with fine-grained layers and a mechanism for radial movement of the inserts made in the form of springs. The peculiarity lies in the fact that the mechanism of radial movement of each movable insert includes two pneumatic cylinders, the axes of which are mutually perpendicular, and the cylinders whose axes are parallel to the axis of the circle are connected to a wedge clamp that fixes the movable inserts with fine-grained layers.

The analysis of the prior art by the applicant, including a search by patent and scientific and technical sources of information, and the identification of sources containing information about analogues of the claimed invention, allowed to establish that the applicant did not find an analogue characterized by features identical to all the essential features of the claimed invention. The definition from the list of identified analogues of the prototype, as the closest in the set of essential features of the analogue, allowed us to identify the set of essential distinctive features perceived by the applicant in the claimed device set forth in the claims.

Therefore, the claimed invention meets the condition of "novelty."

To verify the compliance of the claimed invention with the condition “inventive step”, the applicant conducted an additional search for known solutions in order to identify signs that match the distinctive features of the claimed device from the prototype. The search results showed that the claimed invention does not follow explicitly from the prior art for the specialist, since the influence of the transformations provided for by the essential features of the claimed invention on the achievement of the technical result is not revealed from the prior art determined by the applicant.

The described invention is not based on a change in quantitative features, the presentation of such features in relationship, or a change in their appearance.

Therefore, the claimed invention meets the condition of "inventive step".

The drawings show: in Fig.1 is a General view of a combined grinding wheel, combined with a local incision; figure 2 is a section aa in figure 1; figure 3 is a longitudinal section of a circle with extended inserts bearing fine-grained layers.

The combined grinding wheel comprises a housing 1 with a coarse-grained abrasive layer 2 rigidly fixed thereon, movable inserts 3 with fine-grained abrasive layers 4, pneumatic cylinders, the cavities of which are made in the ring 5, and pistons 6 are connected to the movable inserts 3 and rely on the springs 7 (Fig. 1); pneumatic cylinders, the cavities of which are made in the housing 1, and the pistons 8 are connected to a wedge, forming a wedge clamp, a sleeve 9 with a piston groove 6; faceplates 10; screws 11 (figure 2).

Combined grinding wheel works as follows.

When removing the main allowance (for pre-treatment) grinding is carried out with a coarse-grained abrasive layer 2 (Fig. 1), fixed motionless on the circle body 1, in the modes corresponding to preliminary grinding with a hard tool. Mortise feed is carried out by the feed mechanism of the grinding machine. In this case, inserts 3 with fine-grained layers 4 are “recessed”, i.e. their working surface is at some distance from the working surface of the circle body with a coarse-grained layer and does not apply to the workpiece. The fixation of the movable inserts 3 in the "recessed" position is due to the pressure of compressed air supplied to the cavity "B" (figure 2) of the pneumatic cylinders, the axes of which are perpendicular to the axis of the circle.

After removing the main part of the allowance, the supply of compressed air in the cavity “B” (FIG. 2) of the pneumatic cylinders is stopped and the inserts 3 with fine-grained layers 4 due to the action of the springs 7 on the pistons 6 are moved radially outside the coarse-grained layers 2. In this case, the compressed air is supplied in the cavity “B” (FIG. 3) of pneumatic cylinders, the axes of which are parallel to the axis of the circle. Under air pressure, the pistons 8 move to the right and jam the pistons 6, rigidly fixing the inserts 3 with the fine-grained layers 4 in the extended position. With their help, the rest of the allowance is removed in the modes corresponding to the final grinding. The radial (mortise) feed of the grinding wheel during processing with fine-grained layers is carried out from the drive of the transverse feeds of the grinding machine.

When moving to the nursing stage, the supply of compressed air to the “B” cavity (Fig. 3) of the pneumatic cylinders is stopped, the inserts 3 with fine-grained layers 4 are released and are able to oscillate on the springs 7 in the radial direction, thereby damping the oscillations of the technological system.

The grinding cycle of the proposed circle consists of the following stages: preliminary and final grinding and nursing. In this case, preliminary grinding is performed by a coarse-grained abrasive layer, rigidly fixed to the circle body, and aims to remove the main part of the allowance. The final grinding is carried out by rigidly fixed inserts with fine-grained abrasive layers, providing the required accuracy of the size and shape (macrogeometry) of the polished surfaces. At the nursing stage, inserts with fine-grained layers are used, connected with the circle through elastic elements, which allows damping vibrations in the technological system and providing the required microgeometry of the machined surfaces of the parts.

Thus, the above information indicates the following conditions are met when using the claimed device:

- a tool embodying the claimed device in its implementation, is intended for use in industry, namely in mechanical engineering in the processing of metals by cutting;

- for the claimed device in the form described in the independent clause of the claims, the possibility of its implementation using the means and methods described in the application or known prior to the priority date is confirmed;

- a tool embodying the claimed invention in its implementation, is able to ensure the achievement of the perceived by the applicant technical result.

Therefore, the claimed invention meets the condition of “industrial applicability”.

Claims (1)

A combined grinding wheel comprising a body with a coarse-grained abrasive layer rigidly fixed on it, movable inserts with fine-grained layers and a mechanism for radially moving the inserts made in the form of springs, characterized in that the mechanism for radial movement of each movable insert includes two pneumatic cylinders whose axes are mutually perpendicular moreover, the cylinders, the axes of which are parallel to the axis of the circle, are connected to a wedge clamp fixing the movable inserts with fine-grained layers.

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