RU2198086C1 - Buildup abrasive wheel - Google Patents

Abstract

FIELD: machine engineering, namely designing of buildup grinding tools with possibility for feeding cutting fluid. SUBSTANCE: buildup abrasive wheel includes abrasive discs and spacing washers between them mounted on mandrel having central cavity and radial openings. Central cavity of mandrel is separated in addition by means of lengthwise partition in order to form two axial ducts for supplying two different type cutting fluids. One axial duct is open to abrasive discs through radial openings and circumferential grooves on outer surface of mandrel in zones of mounting abrasive discs. Second axial duct is communicated with cavities between abrasive discs through radial openings of mandrel, circumferential grooves on inner surface of openings of spacing washers and through radial holes of spacing washers. Such wheel allows to feed cutting fluid to grinding zone through pores of grinding wheel and in the form of pressure oscillating jet at using buildup lengthwise-intermittent abrasive wheels with axially shifted cutting layer. EFFECT: improved design, enhanced lubrication of cutting zone. 3 cl, 3 dwg

Description

 The invention relates to mechanical engineering and machine tool engineering, namely, to the construction of a prefabricated grinding tool with the possibility of combined supply of a lubricant-cooling technological mixture (SOTS) through the pores of the grinding wheel with an axially-displaced cutting layer and a pressure fluid oscillating jet.

 Known prefabricated grinding wheel, which allows the supply of cutting fluid (coolant) to the grinding zone through the axial cavity of a mandrel rotating at a speed ω, radial channels connected to the cavity and from there to the grinding zone, in addition, a plate auger with radius r with a helical surface formed by a curve described by the above equation [1].

 A disadvantage of the known prefabricated wheel is the impossibility of ensuring the effectiveness of the coolant in the combined method of supplying the coolant to the grinding zone and the inability to use it when working precast longitudinally discontinuous grinding wheels with an axially offset cutting layer.

 A known design of a prefabricated abrasive wheel, which is equipped with plates installed between the covers at the base of the abrasive elements and two conical covers installed with axial movement in the cover for supplying coolant, while the surfaces of the conical covers form a second channel for supplying another coolant [2].

 The disadvantages of the prefabricated abrasive wheel are the complex design of the tool and coolant supply system, the impossibility of ensuring the effectiveness of the coolant for traditional wheels, the narrow specialization of use is only for prefabricated abrasive elements of the wheels and the impossibility of using it when working prefabricated axially-discontinuous grinding wheels cutting layer.

 The objective of the invention is to ensure the effectiveness of the action of SOTS with a combined method of supplying SOTS to the grinding zone through the pores and a pressure oscillating jet with prefabricated longitudinally discontinuous circles with an axially offset cutting layer.

 The problem is solved using a precast abrasive wheel, which allows you to use a combined method of supplying a lubricant-cooling technological mixture (COTS) to the grinding zone, which refers to prefabricated longitudinally discontinuous circles with an axially offset cutting layer, consisting of abrasive disks and spacer washers between them mounted on a mandrel with radial holes, while the mandrel cavity is additionally divided by a longitudinal partition with the formation of two axial channels for supplying two heterogeneous SOTS. In addition, one axial channel is connected by radial holes and circumferential grooves made on the outer surface of the mandrel at the installation sites of the abrasive disks, with abrasive disks. The second axial channel of the mandrel is connected by radial holes, circumferential grooves made on the inner surface of the holes of the spacer washers, and radial holes made in the spacer washers, with cavities between the abrasive disks.

 In FIG. 1 shows a precast abrasive wheel longitudinally discontinuous, with an axially displaced cutting layer, consisting of abrasive disks and spacer washers mounted on a mandrel; figure 2 is a section aa in figure 1; in FIG. 3 - section BB in figure 1.

 The design of a prefabricated abrasive wheel refers to prefabricated longitudinally-discontinuous circles with an axially offset cutting layer, which allows for the implementation of a combined method of supplying a lubricant-cooling technological mixture (COTS) to the grinding zone.

 The combined abrasive wheel consists of abrasive disks 1 and spacer washers 2 between them, mounted on the mandrel 3 at an angle α to a plane perpendicular to the axis of rotation of the tool. The angle of inclination of the discs 1 is set and adjusted by oblique washers 4, installed in pairs from the external ends of the assembly circle. The disks 1 are mounted on the mandrel with nuts 5.

 The Central cavity of the mandrel 3 is additionally divided by a longitudinal partition 6 with the formation of two axial channels 7 and 8 for supplying two dissimilar SOTS. The sealing of channels 7 and 8 is provided by seals 9 and a screw plug 10.

 SOTS with good lubricating properties (oil) is fed into one axial channel, for example, 7, connected by radial holes 11 and circumferential grooves 12, made on the outer surface of the mandrel 3 in the places of installation of the abrasive disks 1, with abrasive disks and from there through the pores into grinding zone.

 SOTS, with good cooling properties, is fed into the second axial channel 8, connected by radial holes 13 and circumferential grooves 14, made on the inner surface of the hole of the spacer washers 2 and from there through the radial holes of the 15 spacer washers with oscillating jets in the cavity between the abrasive disks 1 into the zone cutting.

 Combined abrasive wheel works as follows.

 The assembled assembled abrasive wheel is balanced in a known manner and corrected.

 In the process of grinding COTS with good lubricating properties, for example, oil enters through one axial channel 7, passes through radial holes 11 and enters circumferential grooves 12 made on the outer surface of mandrel 3 at the places of installation of abrasive disks 1. Here, the oil is subjected to centrifugal force ejected through the pores of the abrasive discs 1 directly into the cutting zone, providing an effective lubricating effect in the cutting zone.

 An emulsion with good cooling properties (but worse lubricating properties compared to oil) enters the second axial channel 8, passes through the radial holes 13 and enters the circumferential grooves 14 made on the inner surface of the hole of the spacer washers 2. Once in the grooves 14 of the fast-rotating washers 2, the emulsion under the action of centrifugal force is ejected through the radial holes 15 of the spacer washers 2 by oscillating jets in the cavity between the abrasive disks 1 into the cutting zone.

 The implementation of the combined method of supplying SOTS using the proposed developed design of a precast longitudinally discontinuous circle with an axially offset cutting layer, consisting of abrasive disks and spacer washers between them mounted on the mandrel, can significantly increase the efficiency of the applied SOTS.

 The oil entering through the pores of the abrasive disks 1 directly into the cutting zone creates lubricating films on the abrasive grains, significantly reduces the coefficient of friction of the grain and the binder on the material of the workpiece, which leads to a decrease in the friction forces of cutting and temperature in the processing zone.

 It is known that not only the oscillation of the cutting zone, due to the inclination of the abrasive discs at an angle α [3], but also the interruption of the cutting zone in the longitudinal direction, make it possible to tighten cutting conditions, increase vibration resistance and reduce grinding heat stress.

 Therefore, following the oscillating movement of the longitudinally discontinuous cutting zone by abrasive disks, powerful emulsion oscillating in the longitudinal direction are directed onto the surface to be treated, having a good cooling effect and a high speed of movement relative to the workpiece.

 The high relative speed of the oscillating motion in combination with the high cooling effect of the emulsion eliminates burns and other surface defects at high grinding conditions.

 Thus, the proposed precast abrasive wheel is longitudinally discontinuous with an axially-displaced cutting layer, which implements a combined method of supplying COTS to the grinding zone, which ensures its oscillation and the effectiveness of the action of COTS.

We spent processing holes holes on the internal grinding machine mod. 3K228V. The workpiece material is steel 45 GOST 1050-74, HB 260, machining diameter 130 mm, length 60 mm, cutting tools - abrasive disks PP 100x13x20 24A 10 VM1 10 K5 / P40-15 (where: P40-15 - grain size of pore formers from perlite) GOST 2424-83. Processing modes: workpiece speed - 40.8 m / min (100 rpm), tool rotation speed - 31.4 m / s, tool rotation speed - 6000 rpm, minute longitudinal feed S _pr = 5390 mm / min, cross feed of a circle - 0,012 mm / dv.hod.

The number of single abrasive disks in the assembly grinding wheel was 3 pcs., The oscillation amplitude of the wheel was set to A _A = 6.5 mm, the angle of inclination of the disks to a plane perpendicular to the axis of rotation was α = 3 ^o 42 ', the axial clearance Z between the abrasive disks was Z = 6.5 mm was installed using spacer washers with radial holes.

 Lubricating and cooling technological mixture: passed through the pores of abrasive disks - industrial oil; served between abrasive disks - an emulsion. Processing was carried out in 20 passes.

Abrasive machining with a combined longitudinally discontinuous circle with an axially displaced cutting layer, which implements a combined method of supplying COTS to the grinding zone, made it possible to increase the feed rate by a factor of 2.5 by a double stroke, at which a high-quality treated surface with the required roughness is obtained (R _a = 0.63 microns) without defects, burns and microcracks.

The time spent on processing - T _o = 0.42 min compared with T _o = 1.17 min - when grinding with a regular wheel, allows us to conclude that the invention improves productivity by 2.5-3 times and provides an oscillating and efficient the effect of SOTS with the combined method of supplying SOTS.

Sources of information
1. USSR author's certificate 1673418, MKI V 24 V 55/02. The method of supplying cutting fluid to the grinding zone. Yu.S. Danilov, N.D. Gavrilov, A.A. Simdyankin. Application 4737513/08, application. 09/15/89, publ. 08/30/91. Bull. 32 is a prototype.

 2. Copyright certificate of the USSR 1034885, MKI V 24 V 55/02. Prefabricated abrasive wheel. V. G. Gusev. Application 3391121 / 25-08, application. 02/05/82, publ. 08/15/83. Bull. thirty.

 3. Copyright certificate of the USSR 1611714, MKI B 24 V 45/00. Device for attaching the grinding wheel. Yu.M. Ermakov, Yu.S. Stepanov and B.I. Afanasyev. Application 4429371 / 31-08, application. 05.24.88, publ. 12/07/90. Bull. 45.

Claims (3)

 1. Combined abrasive wheel for the combined supply of a lubricant-cooling technological mixture (COTS) into the grinding zone, containing abrasive disks and spacer washers between them, mounted on a mandrel with a central cavity and radial holes, characterized in that the central cavity of the mandrel is additionally divided by a longitudinal partition with the formation of two axial channels for supplying two dissimilar SOTS.  2. The circle according to claim 1, characterized in that one axial channel is connected by radial holes and circumferential grooves made on the outer surface of the mandrel in the places of installation of the abrasive disks, with abrasive disks.  3. The circle according to claim 1 or 2, characterized in that the second axial channel of the mandrel is connected by radial holes, circumferential grooves made on the inner surface of the hole of the spacer washers, and radial holes made in the spacer washers, with cavities between the abrasive discs.

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