RU2452599C1 - Device for vibration needle hobbing - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to machine building and may be used for deflashing, chamfering and planar machining at milling, multiposition and hybrid machine tools. Proposed device comprises case with its bottom to be secured to machine table and its top to support billets to be machined. Round plate is fitted on said washer by flexible and rigid rings and provided with dead hole to receive rotor journal to run in bearing. Said journal is offset relative to main journals. The latter run in bearings of rotary air engine rotor. Stator is arranged at case center and provided with chamber to feed compressed air acting on rotor vanes.

EFFECT: expanded operating performances, higher quality and efficiency, reduced costs.

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Description

The invention relates to mechanical engineering technology, to methods and equipment for machining by needle milling in order to remove slag from the surface of metals, corrosion products, mill scale, burrs, for cutting metals and is intended for mechanization of deburring, rounding edges and processing planes on milling, multi-position and multioperational machines.

A known method of acupuncture of flat surfaces and a device that implements it, in which the cutting elements of the tool make additional oscillatory reciprocating motion relative to the workpiece [1].

A disadvantage of the known method and device is the insufficiently high precision of processing due to the impact of the drive of the reciprocating vibrational movements, the rapid wear and low tool life due to the large number of moving parts and the extremely complex design of the drive of the vibrational movements, casting doubt on the economic feasibility of using the method and devices.

The objective of the invention is the expansion of technological capabilities, improving the quality and productivity of processing due to the message of the processed workpiece low-frequency, independent of the frequency of rotation of the tool, circular vibrations, increasing the intensification of the process of needle-milling by changing the direction of deflection of the wire elements of the beam at a free length, cutting not only the front , but also by the lateral sides of the wire elements, as well as by increasing the contact zone of the tool with the workpiece, reducing reducing the cost of manufacturing equipment by simplifying the design of the drive of oscillatory movements.

The problem is solved with the help of the proposed device for vibratory acupuncture, comprising a housing, the lower part of which is mounted on a machine table, and the upper part is configured to install workpieces on it, and on the upper part of the housing on a washer made of antifriction material that performs the function a plain bearing, a round plate is installed and movably fixed with the help of elastic and rigid rings, in the center of which from the side of the lower end it is bored blindly e hole in which the rotor neck with an eccentric offset relative to the main necks is mounted on the bearing with the help of an eccentric sleeve, the last rotor on the bearings is based on the stator of a rotary air motor, while compressed air is supplied to the working cavity of the aforementioned stator located in the middle part of the housing, acting on the rotor blades.

Design features of the proposed device are illustrated by drawings.

Figure 1 shows the proposed device, a longitudinal section; figure 2 is a cross section aa in figure 1; figure 3 is a partial cross section bB in figure 1; figure 4 is a view along In figure 2; figure 5 is a top view along W in figure 1; in Fig.6 is a view along D in Fig.1, the neck of the rotor with an eccentric offset E _P relative to the main necks, the sleeve is conventionally not shown; in Fig.7 is a view along D in Fig.1, an eccentric sleeve with an eccentricity E _B , the rotor neck is not conventionally shown; in Fig.8 is a view along D in Fig.1, the connection of the eccentric neck of the rotor with the eccentric sleeve, which allows to establish the minimum eccentricity E _Zmin and the amplitude A _{Zmin of the} oscillatory movement of the plate with the workpieces; in Fig.9 is a view along D in Fig.1, the connection of the eccentric neck of the rotor with the eccentric sleeve, which allows you to set the maximum eccentricity E _Зmax and amplitude A _{Зmax of the} oscillatory movement of the plate with the workpieces; figure 10 - diagram of the needle milling of the flat surface of the workpiece with a face needle cutter using the proposed device; in Fig.11 - element D in Fig.10, the direction of movement of the longitudinal feed of the table with the workpiece fixed on the proposed device coincides with the direction of circular vibrations of the workpiece, the maximum deflection of the wire elements of the beam on the free length is t _max and is directed to the left, while the cutting is performed on the right side wire elements and the maximum thickness of cut chips; in Fig.12 - element D in Fig.10, a bundle of wire elements in the position of changing the direction of movement of the circular vibrations of the workpiece, the wire elements of the beam at a free length are straightened, while cutting is performed by the ends of the wire elements; in Fig.13 - element D in Fig.10, the moment of oncoming movement of the longitudinal table feed with the workpiece fixed in the proposed device and the direction of circular vibrations of the workpiece, the deflection of the wire elements of the beam over the free length is minimum t _min and is directed to the right, while cutting is performed by the left side wire elements and the thickness of the cut chips is minimal.

The proposed device is designed for high-performance flat vibration needle-cutting, as well as removal of metal slag, corrosion products, mill scale, burrs, rounding edges on milling, multi-position and multi-operation machines with the application of circular vibrational movements of low frequency and amplitude A _З = 0.2 ... 2.0 mm per workpiece.

The proposed device for vibratory acupuncture includes a housing 1, the lower part 2 of which is made with the possibility of fixing on the table of the machine, and the upper part 3 is made with the possibility of installing workpieces 4.

On the upper part 3 of the casing, on a washer 5 of an antifriction material that acts as a sliding bearing, a round plate 8 is mounted and movably fixed with elastic 6 and hard 7 rings. The washer 5 is made of antifriction material, for example, tin-phosphor cast bronze of Br. OF10-1 (according to OST 1.90054-72).

On the periphery, the plate 8 has a protrusion, which allows it to be movably fixed with elastic 6 and rigid 7 rings and screws with a guaranteed clearance Z, which allows the plate to move freely in the horizontal plane. The elastic ring 6, mounted on the inner surface of the hole of the rigid ring 7, is made of rubber, for example, prevents the spent sludge and chips from getting into the mating zone of the plate 8 with the washer 5, while it is a damper and dampens the impact of the rotor on the plate.

In the center of the plate from the side of the lower end, a blind hole 9 is drilled, in which the neck 12 of the rotor 13 with an eccentric offset E _P relative to the main necks of the rotor 14 is installed on the bearing 10 using an eccentric (with an eccentricity Е _В ) sleeve 11 (see Fig. 7) (see Fig.6). The main necks 14 of the rotor 13 on bearings 15 is based in the stator covers of a rotary air motor.

The stator of a rotary air motor is located in the middle of the housing 1 and has an eccentrically offset central hole in which the rotor 13 with blades 16 is located, and the covers 17 and 18 are fixed in the bored holes of the housing and carry the rotor 13 on the bearings 15. Compressed air under pressure 0 , 5 ... 1.0 MPa is supplied through a hose (not shown), nipple 19 and mesh 20, through lateral hole 21 into an eccentrically displaced central hole - the working cavity of the stator, where it expands on the rotor blades, causing rotation of the latter about. The disk 22, adjacent with a minimum gap to the ends of the blades, does not allow premature leakage and bleeding of air from the inter-blade space. The exhaust air is pushed through the opening 23, closed by nets 24. In addition to the side opening 21, there are a number of side openings 25, which serve to effectively fill the cavities of a rotary air motor and interconnected by a longitudinal opening 26, are muffled by plugs 27 from the outside.

и регулировать величину амплитуды А_З колебательного движения плиты с заготовками (см. фиг.8-9). Общий эксцентриситет соединения Е_З может принимать значения от 0 (при равенстве эксцентриситетов Е_Р=Е_В) до максимального, равного сумме Е_Зmах=Е_Р+Е_В, путем изменения положения эксцентриковой втулки относительно эксцентриковой шейки ротора. Таким образом, максимальная амплитуда А_Зmах колебательного движения плиты с заготовками будет равна А_Зmах=2E_Зmax=2(Е_Р+Е_В) (см. фиг.9).The installation on the eccentric displaced with an eccentricity Е _Р neck 12 of the rotor of the eccentric sleeve 11 with the eccentricity Е _В allows to obtain an oscillatory vibrational motion of circular orientation with a vector

and adjust the magnitude of the amplitude A _{Z of the} oscillatory movement of the plate with the workpieces (see Fig.8-9). The total eccentricity of the compound E ₃ can take values from 0 (if the eccentricities are equal, E _P = E _B ) to a maximum equal to the sum of E _Zmax = E _P + E _B , by changing the position of the eccentric sleeve relative to the eccentric neck of the rotor. Thus, the maximum amplitude A _{Zmax of the} oscillatory movement of the plate with the workpieces will be equal to A _Zmax = 2E _Zmax = 2 (E _P + E _B ) (see Fig. 9).

When the rotor of the rotary air motor rotates, the axis of the central hole of the plate, eccentrically shifted by the amount of eccentricity Е _З = Е _Р + Е _В , relative to the main necks of the rotor, will describe a circle with a diameter of A _З = 2Е _З. Together with the eccentric sleeve mounted on the eccentric neck of the rotor, a plate with blanks will make circular vibrational movements. These vibrations will have an amplitude A ₃ and a frequency f equal to the rotor speed.

The guaranteed gap Z between the plate and the rigid ring 7, allowing free movement of the plate in the horizontal plane, must be at least two amplitudes - Z> 2А _З , mm.

The device operates as follows.

The device is applicable for flat needle milling when working with both the end face and the periphery of the tool, but this description applies to flat face needle milling on a vertically milling cantilever machine, for example, mod. 6R11MF3-1.

To install and fix flat prismatic blanks, an electromagnetic rectangular plate in accordance with GOST 17519-81 or a permanent magnet plate in accordance with GOST 16528-81, which is installed on the plate of the proposed device, or other known machine tool device, for example, vice can be used [2, p. 66 ... 110].

The insertion load acting normal to the workpiece surface to be machined is ensured by the vertical movement of the machine table. The choice of the loading load and the cutting depth depends on the specific processing conditions and technical requirements for the surface to be treated.

With flat needle-milling, the workpiece, together with the table, makes reciprocating longitudinal movements S _PR and transverse feed S _POP for each double stroke of the table, while the tool is given a rotational movement V _AND .

When the rotor of the rotary pneumatic engine rotates, the top plate of the device with the blanks will describe a circle with a diameter of A ₃ relative to the vertical axis, i.e. make circular vibrational vibrations with an amplitude of A ₃ (mm) and a frequency f (Hz) equal to the rotor speed, depending on the pressure value of the compressed air supplied to the engine.

As a result of superimposing on the reciprocating longitudinal movements of the machine table with the workpieces with a speed S _{PR of} circular vibrational oscillations with an amplitude of A _Z (mm) and a frequency f (Hz) of the plate, a cross-movement of the workpiece under the bundles of wire elements 28 of the needle mill 29 is created (see Fig. 10 ) relative to the tool velocity vector V _AND, and the magnitude and direction of the total cutting speed and the position of the cutting bundles of wire elements periodically change (see Figs. 11-13).

If the direction of movement of the longitudinal table feed is fixed with the workpiece fixed in the proposed device with the direction of circular vibrations A _{3 of the} workpiece (see Fig. 11), the deflection of the wire elements of the beam at a free length l is maximum t _max and is directed to the left (according to Fig. 11), while cutting is done on the right side of the wire elements and the thickness of the cut chips will be maximum.

With the transverse movement of the workpieces under the action of circular vibrations A _{3 of the} workpiece (see Fig. 12), the wire element beam will go through the deflection direction and the wire elements of the beam at a free length l will be straightened, while the cutting will be carried out by the ends of the wire elements.

At the moment of oncoming movement of the longitudinal table feed with the workpiece fixed in the proposed device and the direction of circular vibrations A _{3 of the} workpiece, the deflection of the wire elements of the beam at a free length l is the minimum t _min and is directed to the right (according to Fig. 13), while the cutting is performed by the left side of the wire elements and minimum chip thickness.

The operation of the device for vibration acupuncture of flat surfaces is as follows.

Before starting, they correct the working surface of the wire pile. As a pile, a steel spring wire with a diameter of 0.5 ... 1.0 mm from steel 65 G. is used. The working surface of the beams is corrected by grinding them in assembled form.

In the process of processing the surface of a longitudinally moving workpiece, the device is pressed against it with an interference fit, as with traditional needle-milling. The force impact on the surface to be treated is carried out by wire elements in contact with the workpiece and having the largest free length l and deflection t. The wire elements adjacent to them elastically compress them, slightly increasing the concentrated total effect on the surface to be treated.

When circular vibrational motions are applied to the workpiece, the direction of movement of the workpiece relative to the needle cutter changes and the bundles of wire pile begin to work both front and side, and the metal removal rate and processing width change in one direction. At the same time, metal removal and chip formation are facilitated, the self-sharpening of the wire pile is improved, and variable forces are actively redistributed in the cutting plane, as a result of which self-oscillations are completely suppressed and the friction force is reduced up to 2 times. In addition, this allows to increase the number of actively working cutting elements of the wire pile and to intensify the cutting of the allowance and protrusions of irregularities of the workpiece surface being machined.

The device is advisable to use when cleaning (without removing chips) and finishing (with removal of chips) processing of workpieces on milling and cleaning machines.

To carry out the finishing treatment, it is necessary that the hardness and tensile strength of the material of the wire elements of the pile be higher than these parameters of the material of the workpiece by 1.5 ... 2 times, the ratio l / i, where i is the smallest inertia radius of the cross section of the wire elements, should be within 50 ... 100, and the coefficient K _{p the} density of the wire pile in the range of 0.7 ... 0.9; while the tightness should be 0.7 ... 1.5 mm.

The peripheral speed for finishing processing is 2 ... 5 m / s, other modes of operation of the device are determined empirically.

Production tests were carried out using the proposed device for vibratory flat needle milling installed on a vertically milling cantilever machine mod. 6R11MF3-1.

Flat prismatic blanks from a hot-rolled strip of steel 20 with a total mass of up to 10 kg were installed on a plate with permanent magnets in accordance with GOST 16528-81, which in turn was installed on the proposed device. Processing was carried out with a vibration frequency f = 10 ... 50 Hz and a magnitude of the amplitude of vibrational vibrations A _B = 0.2 ... 2.0 mm. The circular vibration drive included a rotary pneumatic engine, similar to the design of a mod pneumatic wrench motor. I-51 A, with a power of 6.7 kW, which allows you to smoothly adjust the rotor speed over a wide range from 600 ... 3000 min ^-1 .

The values of technological factors (vibration frequency, magnitude of the amplitude of vibrational vibrations) were chosen in such a way as to ensure the multiplicity of vibrational impact on the elementary area of the treated surface in the range of 6 ... 10. A further increase in the frequency of exposure leads to the appearance of large inertial forces and self-oscillations.

Tests of the device during the finishing processing of billets showed that it cuts off scale from the surface to be treated together with a hardened layer; in the process of vibrational needle-milling, the treated surface is not hardened, the pressure of the device against the workpiece surface is 200 ... 600 N per 10 mm of the working surface of the device, and the tangential component of the cutting force is 150 ... 550 N.

For finishing and cleaning using the proposed device, it is necessary to observe the condition: p / σ _B = 1.5 ... 2.0; where p is the pressure during acupuncture, MPa; σ _B is the tensile strength of the material of the workpiece, MPa.

The choice of the appropriate pressure p depends on the physicomechanical properties of the material of the wire pile, on the rigidity and density of the latter, as well as on the interference fit [3].

When finishing metal processing with the proposed device, the hardness of the treated surface does not increase, as a result, the quality of processing, the roughness of the processed surface improves, as well as the processing productivity and durability of the tool, its installation and dismantling are simplified.

The proposed device extends the technological capabilities of needle-milling, improves the quality and productivity of processing by reporting the workpiece to low-frequency, circular oscillations independent of the frequency of rotation of the tool, intensifies the process of needle-milling by changing the direction of deflection of the wire elements of the beam over a free length, cutting not only the front ones, but also by the lateral sides of the wire elements, as well as by increasing the contact area of the tool with the workpiece d, reduces the cost of manufacturing tooling by simplifying the design of the drive oscillatory movements.

Information sources

1. RF patent No. 2294819, IPC B23C 3/00. The method of pulsed acupuncture of flat surfaces. Stepanov Yu.S., Kirichek A.V., Kharlamov G.A., Tarapanov A.S., Afanasyev B.I., Vasilenko Yu.V., Fomin D.S., Samoilov N.N. Application 2005129374/02, 09/20/2005; 03/10/2007. Bull. Number 7.

2. Reference technologist-machine builder. In 2 vol. 2 / Ed. A.G. Kosilova and R.K. Meshcheryakova. - 4th ed., Revised. and add. - M.: Mechanical Engineering, 1985, S. 66-110.

3. Gavrilenko I.G. A method of combining preliminary and final needle-milling stripping of cylindrical parts. // Automation and modern technology, 1992, No. 9. - S. 27-30.

Claims (1)

A device for vibratory needle-milling, comprising a housing, the lower part of which is adapted to be mounted on the machine table, and the upper part with the possibility of installing workpieces on it, characterized in that on the upper part of the housing there is a washer made of antifriction material that acts as a sliding bearing, a round plate is installed and movably fixed with the help of elastic and rigid rings, in the center of which a blind hole is bored from the side of the lower end, in which on the bearing with entrikovoy neck sleeve mounted rotor with an eccentric offset from the main journals, intended for a rotor based on bearings in the stator of the rotary air motor, and a stator located in the middle of the chassis and configured to working chamber for supplying compressed air acting on the rotor blade.

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