RU2350454C1 - Device for strengthening of spherical surfaces - Google Patents

Abstract

FIELD: technological processes; tool.

SUBSTANCE: device that comprises body with deforming elements available in it, striker and wave guide, to which periodical pulse load is applied. Body is arranged as hollow with thread, where bushing with collar is installed. Deforming elements are arranged in the form of disk springs having solid flat peripheral end surface and conic surface with radial slots and central hole. Disk springs are assembled in packet with location of radial slots in staggered order relative to each other and convex conical ends towards each other and are installed between bushing collar and wave guide.

EFFECT: technological resources are expanded, efficiency is increased, and prime cost of device is reduced.

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Description

The invention relates to mechanical engineering technology, in particular to devices and methods for finishing and hardening processing of spherical surfaces of parts, for example, automobile ball fingers, of steels and alloys by surface plastic deformation (PPD) with a pulsed loaded tool.

A known method and device for processing incomplete spherical surfaces of parts of the PPD, in which the workpiece and the deforming tool are notified of rotational movement, and the deforming device is informed of rotation along a circle lying in a plane offset from the center of the processed spherical surface, while the angular velocity of the deforming device is associated with angular velocity ratio ω workpiece _yn >> ω _d, moreover, given the mathematical relationship between effort n immersion and force burnishing [1].

The device and method is characterized by low efficiency, high energy intensity, not sufficiently large depth of the hardened layer and a low degree of hardening of the treated surface.

The objective of the invention is to expand the technological capabilities of PPD through the use of pulsed loading of a deforming tool that allows you to control the depth of the hardened layer, the degree of hardening and surface microrelief, as well as improving the quality, accuracy and productivity of processing through the use of a multi-element deforming tool.

The problem is solved with the help of the proposed device, which serves to harden spherical surfaces and contains a housing with deforming elements located therein, a striker and a waveguide, to which a periodic pulse load generated by a hydraulic pulse generator is applied, and a sleeve with a shoulder is mounted on the hollow body on the thread and deforming elements made in the form of disk springs having a continuous flat peripheral end surface and conical with an angle of inclination on a _CB to the central axis, a surface with radial grooves and a discontinuous central hole, while the cup springs are stacked with radial grooves staggered relative to each other and convex conical ends to each other, and installed between the collar of the sleeve and the waveguide.

The essence of the device for hardening spherical surfaces is illustrated by drawings.

Figure 1 presents the scheme of surface plastic deformation processing of a workpiece of an automobile ball finger installed in a special device based on a conical surface, the proposed device at the time of pulse loading of deforming elements - disk springs; figure 2 - the same at the time of removal of the load from the deforming elements - Belleville springs and removal of the striker from the waveguide; figure 3 - section a - a in figure 1; figure 4 - section B - B in figure 3, the moment of loading of the deforming elements; figure 5 - section b - In figure 4; figure 6 - section B - B in figure 3, the moment of free state (without loading) of the deforming elements.

The proposed device is used for surface plastic deformation (PPD) for hardening spherical surfaces 1 with a periodic pulsed load of deforming elements 2, while the workpiece 3, for example, an automobile ball finger, is given a rotational movement V _З , and for the deforming elements - a rotational movement V _And and longitudinal the supply of S _PR in order to supply and preload them to the center of the spherical surface.

The housing 4, which is a hydraulic cylinder, is hollow, and a sleeve 5 with a collar 6 is mounted on the thread on it. In the housing 4 are a striker 7 and one of the stages of the waveguide 8, and in the sleeve 5 there is a second stage of the waveguide 8 and deforming elements 2, which are installed between shoulder 6 and waveguide 8.

The waveguide 8 through the firing pin 7 is affected by a periodic pulsed load P _IM generated by a hydraulic pulse generator (GGI) (not shown), which is connected to the housing 4 [2-4].

The deforming elements 2 are made in the form of Belleville springs and have a continuous flat peripheral end surface 2 ^P and a conical 2 ^K with an angle of inclination a _CB to the central axis of the surface with radial grooves and a discontinuous central hole. Thus, the conical part 2 ^{K of the} Belleville spring is divided by radial grooves into petals, cantileverly located relative to the peripheral surface 2 ^P and bent at an angle a _CB relative to the central axis.

Belleville springs 2 are stacked with radial grooves staggered relative to each other by convex conical ends to each other, and are installed between the shoulder 6 of the sleeve 2 and the waveguide 8.

Belleville springs have the ability to self-center on the workpiece, since they are installed in the sleeve 5 according to the inner diameter of the sliding fit with a gap.

Belleville springs can be made (according to GOST 3057-79) of steel 60C2A with different distances between radial grooves and different sizes of deforming elements in contact with the workpiece. The more radial grooves a Belleville spring has, the less its rigidity and resistance to deflection and the smaller the contact area of the deforming elements with the work surface.

When moving the striker 7 from bottom to top, according to FIGS. 1-2, the Belleville springs 2 absorb the periodic impulse load P of _the waveguide, due to which the lower springs move up, and their petals bend, straighten and approach the plane of the peripheral surface, and the diameter of the holes d _about Belleville springs 2 is reduced to d ₁ , d ₂ ... and so on, where the index 1, 2 ... is the numbering of the springs in the package, starting from the top, in contact with the shoulder 6.

The total longitudinal periodic pulsed load P _them striker along the waveguide is perceived by the whole package of Belleville springs and is evenly distributed to each spring. This means that each Belleville spring with its petal has a strengthening effect with a pulse load P _IM ^N directed to the surface to be treated (see figure 4).

Periodic pulsed P _IM load is applied in the direction of longitudinal feed and, thanks to the design features of the Belleville springs, they are directed to the work surface.

The periodic impulse load P _IM must be greater than the total force required for the deformation of the Belleville springs, and the force necessary for hardening. The removal of the waveguide and the striker after impact in the initial position (according to Fig.1-2, down) is due to the elasticity of the disk springs and return them to their original free state. In order to mitigate the impact of the waveguide on the body during the removal of the waveguide, a damper 9 is installed at the end of the body, for example, in the form of a rubber ring.

As a result of the impact of the striker on the end face of the waveguide and the waveguide on the end face of the disk spring package, the latter act on the surface to be machined with the cyclicity set by the hydraulic pulse generator. The ability to rationally use the energy of shock waves is determined by the size of the springs.

As a result of the impact of the striker 7 at the end of the waveguide 8, shock and oppositely directed pulses of the same amplitude and duration arise in the striker and the waveguide, each of which will affect the surface being treated with a cycle equal to double the duration of the pulses. Having reached the surface to be treated, the shock pulse is distributed on the passing and reflecting. The passing pulse forms the dynamic component of the strain force.

The sharp edges of the deforming elements of the springs directly in contact with the workpiece spherical surface 1 are rounded with a radius of R = h / 2, where h is the thickness of the Belleville springs, mm.

The deforming elements of each spring without load make a rotational movement along its circumference with a diameter d _о lying in a plane that is offset from the center О of the spherical surface being machined by an amount depending on the design features of the workpiece. The incomplete spherical surface of the workpiece being processed forces the longitudinal axis of the device to be set at an angle α relative to a plane perpendicular to the longitudinal axis of the workpiece.

The accuracy of the shape of the processed spherical surface of the workpiece by the proposed device increases and decreases the roughness due to self-centering and self-installation of Belleville springs along the workpiece during its beating and vibration.

The depth of the hardened layer of the proposed device reaches 0.5 ... 1.5 mm, which is significantly (1.5 ... 2 times) more than with traditional PPD. The greatest degree of hardening is 15 ... 25%. As a result of processing the proposed device in comparison with traditional PPD, the effective depth of the layer, hardened by 20% or more, increases by 1.5 ... 2.2 times, and the depth of the layer hardened by 10% or more - by 1.3 ... 1, 6 times.

Example. To assess the quality parameters of the surface layer hardened by the proposed device, experimental studies of the processing of an automobile ball finger using the proposed device are carried out. The workpiece of the ball upper finger 2101-2904187, installed in a special electromechanical device, was strengthened on the machine mod. 16K20 using the proposed device using GGI [2-4]. The blank is made of steel 20X GOST 1050-74. Belleville springs are made in accordance with GOST 3057-79 from steel 60S2A. Sulfofresol (5% emulsion) was used as the cooling lubricant.

Processed a sphere with a diameter of 32.7 ± 0.1; the initial roughness parameter Ra = 3.2 μm, achieved - Ra = 0.63. The values of technological factors (impact frequency, feed rate, rotation speed of the workpiece and tool) were chosen in such a way as to ensure the multiplicity of impact on the elementary area of the treated surface in the range of 6 ... 10. A further increase in the multiplicity of the deforming effect leads to softening.

Workpiece rotation speed V _З = 10 m / min (n _З = 100 min ^-1 ); the speed of the deforming elements - V _And = 50 m / min (n _And = 500 min ^-1 ); longitudinal feeding S _PR devices was carried out manually until a gap was created between the deforming elements and the machined surface z = 0.3 ... 0.6 mm.

The required roughness and accuracy of the spherical surface was achieved in T _m = 0.75 min (against T _m ^bases = 2.75 min according to the basic version with the traditional rolling treatment at the Oryol Steel Mill OSPAZ). The control was carried out by an indicator bracket with an indicator ICh 10 B cells. 1 GOST 577-68 and on the profilometer mod. 283 type AII GOST 19300-86. No defective parts were found in the processed batch (equal to 100 pieces). The deviation of the treated surface from sphericity was not more than 0.02 mm, which is permissible.

The magnitude of the force of the pulsed action of the springs on the treated surface was P _ИМ = 255 ... 400 kN. The depth of the layer hardened by pulsed processing is 3 ... 4 times higher than with traditional rolling.

The hardened layer during traditional rolling is formed under conditions of long-term action of large static forces. Using the proposed device, a similar depth of the hardened layer is achieved as a result of a short-term impact on the deformation zone of a prolonged energy pulse.

Studies of the stress state of the hardened surface layer by pulsed processing showed that the maximum residual stresses are close to the surface, as when chasing, which is favorable for most of the interfaced parts of mechanisms and machines. Comparison of the depth of the dressed and hardened layer, the stress gradient and the hardening gradient shows that the depth of the stressed layer is 1.1 ... 1.3 times greater than the depth of the riveted layer, which is consistent with the theory of surface plastic deformation. Processing showed that the roughness parameter of the machined spherical surfaces decreased to Ra = 0.32 ... 0.63 μm with the initial value Ra = 3.2 ... 6.3 μm, the productivity increased more than three times compared to traditional rolling. The energy intensity of the process decreased by 2.2 times.

Microvibrations during processing favorably affect the working conditions of the tool - Belleville springs. The imposition of a small amplitude oscillatory motion leads to a more uniform distribution of the load on the tool, causes additional cyclic movements of the contact surfaces of the tool and the workpiece, facilitates the formation of a hardened surface. Fluctuations contribute to a better penetration of the cutting fluid (coolant) into the treatment area. When vibration is applied, the deforming surface of the tool periodically “rests”, which helps to increase its resistance. Processing under vibration conditions dramatically increases the efficiency of the cooling, dispersing and plasticizing action of the coolant due to the facilitation of its access to the contact zone of the tool and the workpiece.

The proposed device extends the technological capabilities of pulsed processing by surface plastic deformation by controlling the depth of the hardened layer and the microrelief of the spherical surface by using a device and a special tool with a large number of deforming elements, which allows to increase productivity and reduce manufacturing costs due to the simplicity of design.

Information sources

1. RF patent 2031770, MKP ⁶ V24V 39/04, 39/00. A method of processing incomplete spherical surfaces of parts by surface deformation. Gavrilin A.M., Samoilov N.N. 5045958/27; 04/14/92; 03/27/95. Bull. No. 9 is a prototype.

2. RF patent 2098259, MKI ⁶ V24V 39/00. Lazutkin A.G., Kirichek A.V., Soloviev D.L. Method of static-pulse treatment by surface plastic deformation. No. 96110476/02, 05.23.96; 12/10/97. Bull. Number 34.

3. Kirichek A.V., Lazutkin A.G., Soloviev D.L. Static-pulse processing and equipment for its implementation // STIN, 1999, No. 6. - S.20-24.

4. RF patent 2090342. Lazutkin A.G., Kirichek A.V., Soloviev D.L. Water hammer device for processing parts by surface plastic deformation. 1997. Bull. Number 34.

Claims (1)

A device for hardening spherical surfaces, comprising a housing in which deforming elements, a firing pin and a waveguide are arranged, capable of applying a periodic pulsed load generated by a hydraulic pulse generator, characterized in that the housing is hollow with a thread on which a sleeve with a shoulder is installed, deforming the elements are made in the form of cup springs with a continuous flat peripheral end surface and a conical surface made at an angle to the central B with the radial grooves and discontinuous central hole, wherein the Belleville springs are recruited into the bag with an arrangement of radial grooves staggered with respect to each other and convex conical end faces to each other and are mounted between the sleeve collar and the waveguide.

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