RU2239538C1 - Combination type needle-grinding method - Google Patents

Abstract

FIELD: machine engineering, possibly finish needle-abrasive working of blanks of different materials having trend for flaw occurring.

SUBSTANCE: method is realized with use of tool having grinding wheel and device for mounting it on mandrel; discs having peripheral openings for mounting U-shaped bundles of wire pile; flanges for fixing discs on mandrel. Grinding wheel has separate diamond-abrasive beams secured to outer surface of tore-like elastic envelope. Outer diameter of worn grinding wheel may be restored until diameter less than diameter of discs with wire pile by double interference value of tool forcing to part due to supplying compressed air into elastic envelope.

EFFECT: enhanced efficiency, improved quality of working, increased useful life period of tool without readjustment of it, possibility for restoring outer diameter of disc during operation.

3 cl, 8 dwg

Description

The invention relates to mechanical engineering technology, in particular to the processing of materials by needle cutting and grinding with adjustable tool diameter and the angle of inclination of the cutting layer relative to the axis of rotation, and can be used at engineering enterprises for effective finishing of workpieces made of various metals predisposed to defect formation.

A known method and device for its implementation for cleaning surfaces from corrosion products, scale, etc., containing a drive disk with tufts of pile alternately placed around its circumference and installed in the through holes of the disk abrasive cylinders [1].

The disadvantages of the known method and device are the narrow specialization, which limits its use for processing bodies of revolution, while the free rotation of the abrasive cylinders only due to friction forces does not allow to intensify the processing process, in addition, as the abrasive wears, the cylinders will be pressed against the workpiece with less effort surface due to the properties of the clamping springs, and the device does not allow the full use of the cutting properties of the abrasive, which requires a very high speed of rotation (p the order of several thousand revolutions with such small cylinder diameters) of the disk that it is difficult to carry out for dynamic reasons, thereby reducing productivity and processing quality.

The objective of the invention is to increase productivity, machining quality and durability of the tool due to the rapid restoration of the outer diameter of the grinding wheel and the axially offset cutting layer.

The problem is solved by the proposed combined method of needle grinding, in which the workpiece and assembly tool containing a grinding wheel with a device for mounting it on the mandrel, disks having peripheral holes for mounting U-shaped bundles of wire pile, and flanges for fixing the disks on the mandrel rotational movements and feed movements along the surface to be treated, and the restoration of the worn out outer diameter of the circle is carried out on the go, without stopping the process, due to compressed air supply to the elastic shell to a diameter less than the diameter of the wire-wound disks by twice the interference with which the tool is pressed against the workpiece, while the grinding wheel consists of separate diamond-abrasive bars mounted on the outer surface of the toroidal elastic shell.

Moreover, to intensify the process and impart greater rigidity to the toroidal elastic shell, its inner surface is divided by partitions into compartments communicating with each other, and restrictive washers are installed from the ends of the shell.

In addition, in order to increase the length of the arc of contact of the tool with the workpiece, the circle and discs are mounted on the mandrel at an acute angle α to a plane perpendicular to the axis of rotation, using oblique washers located at the ends of the tool, while the angle α is assigned by the formula:

α <arctan (A _w / D),

where A _w is the amplitude of the oscillating cutting layer of the circle, which is taken no more

A _W < _{H W} ;

D and _W - respectively the outer diameter and height of the grinding wheel.

Figure 1 shows the construction of a prefabricated tool for implementing the proposed method, a partial longitudinal section; figure 2 schematically shows the proposed method of combined needle grinding, view A in figure 1; figure 3 is a section bB in figure 1; figure 4 is a partial longitudinal section of a tool with the most worn out circle; figure 5 - section bb in figure 1; figure 6 is a diagram of the assembly of the needle cutter; 7 is a scan of the trace of a combined tool on a machined surface; on Fig is a diagram of the interaction of the needle cutter with the workpiece.

The proposed combined method of needle grinding is used for joint and sequential processing by needle milling and grinding, which is carried out by a peripheral axially offset cutting layer of a combined needle grinding tool.

Combined needle grinding tool contains a grinding wheel 1 and a needle needle 2, mounted on the same mandrel 3 (Fig.1-4).

The grinding wheel 1, which is prefabricated, consists of separate diamond-abrasive bars mounted on the outer surface of the toroidal elastic shell 4. To give greater rigidity to the toroidal elastic shell 4, its inner surface is divided by partitions 5 into compartments 6 communicating with each other [2]. Such a mounting device for the assembly of the grinding wheel 1 allows you to quickly, on the fly, restore the worn out outer diameter of the steep by supplying compressed air P _cr to the elastic shell 4 from the condition of increasing the diameter D _w to sizes smaller than the diameter D _{and the} needle cutter 2 by twice the interference N with which the tool pressed against the part (Fig. 8).

The diamond-abrasive bars of circle 1 are taken on a flexible, for example, rubber base, and their fastening to a toroidal elastic shell 4 is carried out by one of the known methods, for example by gluing by vulcanization, etc.

A toroidal elastic shell 4 is mounted on the mandrel 3 with restrictive washers 7, oblique washers 8 and secured by a nut 9 with a washer 10.

Actuation of the operating state of a toroidal elastic sheath 4 is carried out by applying to the shell 11 through the side and central openings 12 disposed in the mandrel 3, and fitting the pin (not shown) under the pressure of compressed air P _{compression channel.}

Acupuncture 2 consists of disks 13, which have peripheral holes 14 for fastening U-shaped bundles of wire pile 15, and flanges 16 for fixing disks 13 on mandrel 3 (Figs. 1, 4, 5-6).

Each U-shaped bundle 15 of wire pile is mounted on the disk 13 so that the section of its bend is placed between a pair of holes 14, and its free ends pass through these holes and are located radially with respect to the axis of the mandrel 3. The distance between the axes of each pair of holes of the disk 13 does not exceed twice the diameter d of the hole [3].

The disks 13 are mounted with an offset from one another so that the U-shaped tufts of the pile 15 of one of them are located between the tufts of the other. The distance l between the axes of the holes 14 of two adjacent disks 13 located along the length of the mandrel 3 is equal to half the distance L between the axes of the pair of holes 14 in the disk.

Disks 13 are installed at an acute angle α to a plane perpendicular to the axis of rotation, due to oblique washers 8 located at the ends of the tool, while the angle α is assigned by the formula:

α <arctan (A _w / D),

where A _w is the amplitude of the oscillating cutting layer of the circle, which is taken no more

A _W < _{H W} ;

D and _W - respectively the outer diameter and height of the grinding wheel.

Assembling a tool that implements the proposed method is as follows.

The wire from the bay is cut and bundles are dialed with a diameter close to the diameter of the hole 14. Then, the bundles are bent and threaded into adjacent holes 14 of the disk 13, after which they are bent again in the radial direction of the disk. Then, the disks 13 are put on the mandrel 3 all the way into the flange 16 and the oblique washer 8, pre-installed on the mandrel 3, and fixed on the opposite side through the sleeve 17 with another oblique washer 8, followed by tightening with the nut 9. The disks 13 are mounted on the mandrel 3 in such a way that the tufts of pile on one disk are located between the tufts of pile on a adjacent disk. The oblique washers 8 are located with a maximum thickness in diametrically opposite places from each end of the tool.

Work on the proposed method is as follows.

The tool is mounted on a mandrel, which is reported rotation, and is brought to the work surface. The ends of the wire pile, interacting with the treated surface, carry out micro-cutting. With a small overhang of the pile (15 ... 20 mm), the tool works like an acupuncture.

Following surface treatment by needle milling, abrasive finishing is carried out. The tool rotates with a peripheral speed of at least V _and = 60 ... 70 m / s and is pressed with a constant force of 600 ... 1000 N to the workpiece, for example (with reference to circular needle grinding) rotating with a peripheral speed of V _s = 0.02 ... 0.08 m / s. The longitudinal feed of the tool relative to the part is S _ol = 0.6 ... 1.5 mm / rev.

When the circle 1 is worn out and its outer diameter D _w decreases with the height of the diamond-abrasive bars h _max (for a new circle) up to h _min (for the most worn out), the circle is restored on the go, without stopping the process, by supplying compressed air to the elastic the shell is up to a diameter smaller than the diameter of the wire-pile disks by twice the tightness N with which the tool is pressed against the workpiece.

Studies have shown that the proposed method, when combining a high speed of rotation and sinusoidal oscillation in the longitudinal direction of the thermal field, intensifies the processing process due to an increase in the length of the arc of contact between the tool and the workpiece, the presence of the angle of intersection of the trajectory of the grinding wheel and the needle cutter with the direction of the initial roughness, causing the trace network and the nature microgeometry as in honing, grinding honing with the imposition of vibrations (Fig.7). The grinding wheel self-sharpening conditions are improved.

The use of the proposed technical solution allows high-performance and high-quality removal of significant allowances, i.e. work in difficult conditions, increase the efficiency of use of the tool as a whole, as well as parts of it - needle cutters with reliable fastening of the wire pile by increasing the packing of the pile and the rigidity of the needle cutter.

The combined method of needle grinding is simple to implement, and the tool is reliable in operation, uncomplicated in design and extends the technological capabilities of processing due to the combination of needle milling and grinding, reduces auxiliary time, increases processing productivity by 2 ... 2.5 times, improves the quality and roughness of the processed surface .

Sources of information

1. A.S. USSR 1493248, MKI A 46 V 7/08 // 24 V 45/00. Device for surface treatment. Perepichka E.V. and Skalko N.S. Application No. 3984461 / 31-12, application. 12/04/85, publ. 07/15/89, Bull. No. 26 is a prototype.

2. French patent 2 654 027, MKI B 24 V 9/14. A surface treatment tool that automatically takes the appropriate shape. Application 11/06/1989, publ. 10/05/1991, VINIPI No. 19.

3. A.S. 1 431 726, MKI A 46 V 7/10. Cylindrical brush. Abugov L.G. and other Application No. 4109194, application. 06/17/86, publ. 10.23.88, Bull. Number 36.

Claims (3)

1. A combined method of needle grinding, in which the workpiece and assembly tool containing a grinding wheel with a device for mounting it on a mandrel, disks having peripheral holes for mounting U-shaped bundles of wire pile, and flanges for fixing the disks on the mandrel, indicate rotational movements and feed movements along the surface to be treated, characterized in that a grinding wheel is used, consisting of separate diamond-abrasive bars fixed to the outer surface of a toroidal pack a different shell, while restoring the worn out outer diameter of the circle on the go without stopping the process due to the supply of compressed air into the elastic shell to a diameter less than the diameter of the wire-pile disks by twice the tightness with which the tool is pressed against the part. 2. The combined method according to claim 1, characterized in that to intensify the process and give greater rigidity to the toroidal elastic shell, its inner surface is divided by partitions into compartments communicating with each other, and restrictive washers are installed from the ends of the shell. 3. The combined method according to claim 1 or 2, characterized in that to increase the length of the arc of contact of the tool with the workpiece, the circle and discs are mounted on the mandrel at an acute angle α to a plane perpendicular to the axis of rotation, using oblique washers located at the ends of the tool, the value of the angle α is determined by the formula α <arctg (A _w / D), where A _w is the amplitude of the oscillating cutting layer of the circle, which is chosen no more than A _w < _{H w} ; D and _W - respectively the outer diameter and height of the grinding wheel.

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