RU2440883C1 - Method of vibration honing - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to cutting of hard-to-process metals and may be used in finish diamond-abrasive machining, for example, honing of bores. Honing is performed by device comprising body and diamond abrasive hones that reciprocate and rotate. Sleeve-like body is rigidly fixed on spindle mandrel and provided with bored cylindrical holes along its periphery. Said holes accommodate plungers to reciprocate therein. Every plunger is equipped with pivot arranged at its center to support rocker with coil compression springs to create radial operating pressure of hone holder on machined surface. Plungers with rockers and bar holders are subjected to lengthwise vibrations by compressed air feed through manifold and channel in pulley hub into cylinder head section. Plunger goes down unless cylinder cross section is aligned with said orifice and is forced up by compressed spring. Plunger vibration frequency is controlled by pulley rpm.

EFFECT: higher precision, efficiency and quality, simplified design.

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Description

The invention relates to the cutting of difficult-to-process metals and can be used for finishing, finishing diamond abrasive processing, for example, when honing holes.

There is a method of vibration honing and a device that implements it, which contains a vibrator mounted to interact with the tool body and made in the form of a thrust bearing with a separator, the working surface of one of the detachable parts of which is made cam [1].

The disadvantage of this method and device is the unreliability of the structure, expressed in that, with certain combinations of cutting conditions and forces, dimensions of the cam part profile, stiffness of the pressing springs, etc. the balls of the thrust bearing will slip along a smooth ring with the cage, without causing vibrations. Moreover, the method and the device does not allow you to adjust the magnitude of the amplitude of oscillations and inefficient.

A known method and device for vibration honing, containing a vibrator, mounted to interact with the tool body and made in the form of a thrust bearing with a cage, the working surface of one of the detachable parts of which is made cam, while the said detachable part is made in the form of a sleeve and is fixedly mounted on the tool body, and the separator is placed on the body with the possibility of rotation [2].

The disadvantage of this method and device is the possibility of failure and unreliability of the structure, expressed in the fact that with certain combinations of profile sizes of the wavy end face of the vibrator sleeve, the stiffness of the spring compressing this sleeve, significant cutting forces, and others, the balls located in the cavity will not overcome the protrusions and will slip along the smooth ring of the vibrator bearing together with the mentioned sleeve, without subjecting the tool to vibrations. In addition, the device does not allow you to smoothly control the amplitude of the oscillation, which is extremely important when choosing the optimal value of the latter for these specific processing conditions. The device is not characterized by high performance and quality processing.

A known method and device for vibration honing, containing a vibrator made in the form of a thrust bearing and installed with the possibility of interaction with the bar holders carrying honing bars, and it is equipped with washers installed on each side of the bearing in the amount of two pieces with non-parallel ends made at an angle α / 2 with the ability to smoothly control the angle of inclination from zero to α, rods made in the form of leaf springs, a sleeve with an outer diameter D, while the thrust bearing made double, mounted at an angle α to the plane of rotation with the help of washers, and the sleeve is pressed into the middle ring of the double bearing and connected by rods to the bar holders for the latter to communicate vibrational movement with amplitude A _r determined from the relation A _r = Dcosα [3].

The disadvantages of the known method and device are small amplitudes of vibrational movements and the inability to control the frequency of vibrations, which directly proportionally affect the productivity and quality of processing.

A known method and device for diamond-abrasive machining of holes with static-pulse loading, comprising a housing and bar holders carrying external diamond abrasive bars, it is provided with a sleeve rigidly fixed to the housing with longitudinal grooves for the bar holders, sinusoidal flat springs onto which the bar holders rest on the inner surface and which are rigidly fixed at one end to the housing and pivotally connected to the ring included in the drive for changing the outer diameter meter, and the ring is equipped with fingers in contact with the bayonet grooves made in the housing at an angle to the longitudinal axis, and a handle passing through the groove in the sleeve, a waveguide with levers acting on the ends of the bar holders and located in the grooves of the housing and the sleeve, coil compression springs acting on the opposite ends of the bar-holders, and the striker located in the central longitudinal hole of the housing coaxially with the waveguide [4, 5].

The disadvantages of the known method and device are very complex and expensive equipment, which is required to implement the processing method, it is especially not profitable for small series of products, in addition, the hydraulic pulse generator used in this device has an original design and requires special development and manufacture while narrow technological capabilities, not high productivity and processing quality limit the application of the method and device.

The objective of the invention is the expansion of technological capabilities, increasing productivity, accuracy and quality of diamond abrasive processing by applying vibrations to the longitudinal reciprocating movement of diamond abrasive bars using the simplified design of a pneumatic oscillation excitation generator, based on the use of pneumatic plungers with an optimal vibration frequency adjustable by an additional mechanism.

The problem is solved by using the proposed method of vibration honing, including a message to a device having a housing and bar holders, bearing, located outside with the possibility of expanding the diamond-abrasive bars, reciprocating and reciprocating movements, and the casing is a sleeve rigidly fixed to the Central hole on a spindle mandrel, while the housing has circumferentially, circumferentially, longitudinally bored cylindrical holes in which plungers with the possibility of reciprocating-longitudinal movement are laid down, with each plunger in the middle part having a hinge on which a beam is installed longitudinally, bearing compression coil springs at its ends, providing a clamp and radial working pressure of the bar holder with a diamond-abrasive bar to the work surface, except Moreover, the aforementioned plungers with rocker arms and bar holders are subjected to longitudinal vibrations due to the supply of compressed air from the network through the manifold, the channel in the pulley hub, in the upper part of the cylinder, while the plunger moves down until the cross section of the cylinder coincides with the hole that releases compressed air into the atmosphere, and the pre-compressed spring located at the bottom of the cylinder and pushing the plunger up contributes to the upward movement of the plunger, and the frequency of the plunger vibrations is regulated pulley speed.

The essence of the method is illustrated by drawings.

Figure 1 shows a diagram of vibration honing of a billet hole with the proposed method, which is implemented by the presented device, a longitudinal section; figure 2 is a cross section bB in figure 1; figure 3 is a General view of the device, side view; figure 4 is a view, a bottom view of figure 3.

The device with which the proposed method is implemented is intended for fine finishing processing of holes in the honing mode with the application of oscillating vibrations A in the longitudinal direction to the diamond-abrasive bars 1, while the spindle 2 is informed of the rotational motion V _AND with the reversal of the direction of rotational motion and the longitudinally moving S _PR , as in traditional honing.

The proposed method and device comprises a housing 3, which is a sleeve having a central longitudinal hole with which it is rigidly fixed to the spindle with a bolt 18. The housing has circumferentially longitudinally bored cylindrical holes 4. The number of peripheral holes is selected for structural reasons and depends from the technical conditions of the vibro-honing process of the workpieces and can be performed from 2 to 6 or more.

In the cylindrical openings of the housing with the possibility of reciprocal-longitudinal oscillatory movements with amplitude A, plungers 5 are located, which are supported from the bottom (according to FIG. 1) by coil compression coil springs 6.

The plungers 5 in the middle part have a hinge 7 with an axis 8, on which a rocker 9 is longitudinally mounted, bearing compression coil springs 10 at their ends, which provide pressing and radial working pressure P of the bar holder 11 with a diamond-abrasive bar 1 to the work surface. To place the hinge 7 on the middle part of the plunger 5 in the middle part of the housing, a groove is cut against each cylinder. Due to the rocker arm swinging on the hinge axis, the diamond-abrasive block evenly lies along the entire length to the work surface.

The fastening of diamond-abrasive bars on the bar holders is carried out externally by traditional gluing, as the most reliable, minimally time-consuming and easily feasible.

Each plunger with a rocker arm, a bar holder and a diamond-abrasive bar is subjected to reciprocal-longitudinal vibrations with amplitude A. Compressed air is supplied by the pressure of the _SJ from the pneumatic network through the fixed nozzle 12 to the rotating channel 13 through the manifold 14. The collector is a ring covering the hub 15 of the pulley 16 and having an internal groove connecting the fitting to the channels. The channels 13 in the rotating hub 15 of the pulley 16 are drilled by the number of cylinders. Once in the upper part of the cylinder, the compressed air moves the plunger down (according to FIG. 1), compressing the spring 6 until, when the pulley hub rotates, the cross section of the cylinder coincides with the outlet 17 releasing the compressed air into the atmosphere. Upward movement of the plunger carries pre compressed spring 6, located at the bottom of the cylinder and the ejector plunger up, plunger wherein the frequency of vibration is controlled speed V _W of the pulley 16. Commercially available compressed air supply structure rotating pulley to the hub, which houses pnevmokanaly allows adjustment actuation frequency plungers with diamond abrasive bars. The pulley 16 is mounted on the spindle 2 using a rolling bearing 19 and a sliding bearing in the form of a sleeve 20.

The proposed design of the pneumatic oscillator vibrate rotationally driven pulley V _H V-belt transmission 16 by an additional motor (not shown), it allows to obtain a different pattern on the nature of the microrelief on the surface of the workpiece honinguemoy hole. In order to simplify the kinematics of the design of the drive of the oscillation excitation generator, as an additional option, a stepper motor (not shown) was used.

Work on the proposed method is as follows.

A device for operating the proposed vibration honing is mounted on a spindle of a honing or drilling machine equipped with an additional motor for rotating a pulley of a pneumatic vibration excitation generator. Compressed air of strictly defined pressure 3 ... 6 KPa is supplied to the collector, because the speed of movement of the honing bars and, to some extent, the response frequency, depends on the magnitude of the air pressure, based on the fact that an increase in pressure implies an increase in the rotation speed of the pulley of a pneumatic vibration excitation generator.

Compressed air through the manifold and the channel in the hub fills the cylinder and moves the plunger and the diamond-abrasive block fixed to it with the rocker arm and bar holder to the lower position, while the pushing spring located under the plunger is compressed.

When combining the cylinder with the outlet 17, the compressed air in the upper part of the cylinder is vented to the atmosphere and the plunger with the bar is pushed upward by the spring. The vibration frequency of the bars depends on the ratio of the spindle rotation frequencies and the rotation speed of the pulley of the pneumatic vibration excitation generator, as well as on the direction of their rotation.

The minimum frequency of vibration of the bars will be when the directions of rotation of the spindle V _{And the} rotation of the pulley V _H coincide.

The maximum vibration frequency of the bars will be in the opposite direction of rotation of the spindle V _AND and the rotation of the pulley V _H , and the higher their rotation frequency, the higher the frequency of vibration of the bars.

Thus, diamond-abrasive honing occurs with vibrational longitudinal longitudinal loading of the bars, which significantly improves the quality of the processed surface and increases productivity several times.

As an example, the bore of a cylinder liner 130-1002021 was machined on a vertically honed machine of the mod. ZM83S equipped with a honing head with a pneumatic vibration excitation generator and AC6 80/63 50M1 diamond abrasive bars (GOST 25594-83) - 6 pcs .; a panel with an electric contact sensor - SP-231; Auto Caliber 8M-17729-02. The material of the processed billet-casting of the cylinder liner is special cast iron having a chemical composition (in%): C 3.2 ... 3.4; Si 2.0 ... 2.3; Mn 0.5 ... 0.8; Cr 0.25 ... 0.40; Ni 0.10 ... 0.25; P <0.20; S <0.15; Fe is the rest. Mechanical properties of cast iron: 170 ... 241 HB; σ _B > 206 N / mm ² ; σ _IZ = 432 N / mm ² . The diameter of the machined hole is 100.50 ... 100.56 mm; roughness - Ra = 0.32 μm. After assembling the honing head for precise positioning, the bars were worked in by grinding in paste on the honing machine through the hole of the honed (defective) sleeve with the equality of the peripheral speed V _AND and the longitudinal speed S _PR . Lapping paste was an abrasive powder of green silicon carbide with a grain size of 5, mixed with grease in a ratio of 1: 2. The paste was applied with a brush to the diamond bars. Break-in of diamond bars was carried out until the contact area reached 90%. The lapping time of the bars was 14.5 minutes. Modes of diamond abrasive processing: V _And = 19 m / min; S _PR = 37.7 m / min.

The values of technological factors (vibration frequency of the bars, amplitude A, and feed value) were chosen in such a way as to ensure the multiplicity of vibration exposure when processing the elementary area of the treated surface in the range of 6 ... 10. A further increase in the frequency of the oscillating effect slightly affects the processing efficiency.

The value of the force of static preloading of the bars to the treated surface was P> 25 ... 40 N.

The proposed method and device allowed to increase productivity by 1.5 ... 2 times, to exclude the operation of semi-diamond-abrasive processing due to the improvement of surface roughness by 1 ... 2 classes. At the same time, the consumption of diamond-abrasive tools decreased by 20%.

Vibration load in combination with rotational and reciprocating movements of the device creates a cross-movement of diamond-abrasive grains and periodically changes the cutting and friction force.

Thanks to this, material removal and chip formation are facilitated, grain self-sharpening is improved, and variable forces are actively redistributed in the cutting plane and the friction force is reduced several times.

Cross vibrational motion with static loading increases the number of actively working diamond-abrasive grains and intensifies the cutting of protrusions of surface irregularities. At the same time, a wear-resistant regular microrelief is formed on the treated surface with the cross direction of the patterns and roughnesses of small and uniform height.

The proposed method and device can improve the modes and productivity of processing several times without compromising the quality of the processed surface. In addition, under such conditions, tool life increases two or more times compared with resistance in traditional diamond abrasive processing, material removal and chip formation are facilitated, and energy consumption for cutting and friction is reduced.

The proposed method and device extends the technological capabilities of vibration honing, increases the productivity, accuracy and quality of diamond abrasive processing by applying vibrations to the longitudinal reciprocating movement of diamond abrasive bars using a simplified design of a pneumatic oscillation excitation generator based on the use of pneumatic plungers with an optimal vibration frequency regulated by an additional mechanism.

The method is expedient and effective to use when processing workpieces of low rigidity from hard-to-work materials and alloys.

Information sources

1. A.S. USSR No. 356108, cl. B24B 33/00, 1970.

2. A.S. USSR No. 1530418, cl. B24B 33/00, 1987.

3. RF patent No. 2146593, MKI 7 V24V 33/00, 33/02 // V24V 1/04. Device for vibration honing. Stepanov Yu.S., Afanasyev B.I. and other Application No. 98115880/02; 08/17/1998; 03/28/2000. Bull. No. 8.

4. RF patent No. 2291043. IPC V24V 33/02; B24B 33/08. Device for diamond abrasive processing with static-pulse loading. Stepanov Yu.S., Kirichek A.V., Afanasyev B.I. and other Application 2005124502/02, 08/01/2005; 01/10/2007; Bull. No. 1 is a prototype.

5. RF patent No. 2290292. IPC V24V 1/00; B24B 33/02; B24B 33/08. The method of diamond abrasive processing with a static-pulse loaded. Stepanov Yu.S., Kirichek A.V., Afanasyev B.I. and other Application 2005124415/02, 01/08/2005; 12/27/2006; Bull. No. 36 is a prototype.

Claims (1)

The method of vibration honing, comprising a message to a device having a housing and bar holders that support externally rotatable diamond-abrasive bars, reciprocating and reciprocating movements, characterized in that they use a housing, which is a sleeve rigidly fixed to the center hole on the spindle mandrel, and having circumferentially circumferentially longitudinally bored cylindrical holes in which the plungers are arranged with the possibility of reciprocating-longitudinally on movements, each of which has a hinge in the middle part, on which a beam is mounted longitudinally, bearing compression coil springs at its ends, which provide a clamp and radial working pressure of the bar holder with a diamond-abrasive bar to the surface to be treated, while the said plungers with rocker arms and the bar holders are subjected to longitudinal vibrations due to the supply of compressed air from the network through the manifold, the channel in the pulley hub to the top of the cylinder, and the plunger moves down until until the cross section of the cylinder coincides with the hole that releases compressed air into the atmosphere, and the pre-compressed spring located at the bottom of the cylinder and pushing the plunger up contributes to the upward movement of the plunger, and the frequency of vibration of the plungers is controlled by the speed of the pulley.

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