RU2464152C2 - Device for static-pulse elastic hardening - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to machine building, particularly, to burnishing, gaging, hardening of metal part inner surfaces. Proposed device comprises mandrel with deforming elements and first hydraulic cylinder to apply static load thereto. It has also second hydraulic cylinder with hammer and waveguide to apply intermittent pulse load to mandrel and hydraulic pulse generator for supply of both hydraulic cylinders. Said also second hydraulic cylinder with hammer and waveguide is arranged on first cylinder rod to allow hammer and waveguide to reciprocate thereon. Deforming element represents a screw helical spring with outer surface shaped to truncated cone with tape angle φ=3…5° and, at least, three, deforming coils. First coil is connected with lead disc while last coil is connected with gaging coil.

EFFECT: expanded performances, higher efficiency and power savings.

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Description

The invention relates to mechanical engineering technology, in particular to methods and devices for burnishing, calibration, deformation pulling and hardening of the metal inner surfaces of the openings of steel and alloy parts by surface plastic deformation with static-pulse loading of the deforming tool.

A device and method for static-pulse burning of holes by a pulling method, containing a cartridge in which a deforming tool is mounted, is provided with a support flange for installing the workpiece, a hydraulic pulse generator for generating a periodic pulse load, a waveguide in the form of a stepped rod with small steps and maximum diameters and brisk in the form of a sleeve, which is mounted on a small diameter step of a stepped rod with the possibility of longitudinal transition They are mounted, and the cartridge is mounted on the waveguide, while the sleeve and the step of the maximum diameter of the step rod are made with cross sections of the same area to transmit a periodic impulse load to the deforming tool along its longitudinal axis, and the ratio of the length of the sleeve to the step length of the maximum diameter of the step rod is unity [1 , 2].

The known device and method is characterized by limited technological capabilities, insufficiently tight fit, insignificant depth of the hardened layer and insufficiently high degree of hardening of the treated inner surface, low efficiency and high energy intensity of the equipment.

The objective of the invention is to expand the technological capabilities of burnishing through the use of a static-pulse load on a special springy deforming element, during the passage of which there are circumferential tensile and radially compressive stresses that can significantly increase the tightness and depth of the hardened layer, increase the degree of hardening and reduce the height of microroughnesses of the processed surface, as well as increasing productivity, efficiency and reducing the energy intensity of the process.

The problem is solved using the proposed device for a static-pulse elastic durning on machines containing a mandrel with deforming elements, a hydraulic cylinder configured to apply a static load P _ST to the mandrel, a hydraulic cylinder in which the hammer and waveguide are located, made with the possibility of application to the mandrel periodic pulsed load P _MI, and a hydraulic pulse generator for the supply of hydraulic cylinders, wherein the cylinder is a periodic pulse duty movably on w Ther cylinder static load and is provided with a waveguide and the striker in the form of sleeves with the possibility of longitudinal movement on said rod, wherein the deforming member is a helical conical spring made of a wire diameter d _PR, with the outer working surface of a truncated cone with the angle φ = 3 ... 5 °, with deforming the turns of at least three, of which a first coil is rigidly connected to intaking disc, and the last - rigidly connected to the caliber plate, wherein the diameter d approximately _ol n ovoloki determined by the formula:

d _PR ≈ 0.33 (P _ST + P _IM ) ^0.7 / (f ^0.4 [σ _FR ] ^0.7 D ^0.4 _zag ), mm;

where d _PR is the diameter of the wire, mm; (P _ST + P _IM ) - the total force of burning out, N; f is the coefficient of friction between the element and the workpiece; depending on the processed material and technological lubricant f = 0.05 ... 0.14; [σ _FROM ] - permissible stress of the material of the wire in bending, MPa; D _ZAG - diameter of the machined hole in the workpiece, mm;

in addition, the angle β of the inclination of the coil of the spring is determined by the formula:

β≈arctg [0.5P / (D _B -i)], deg;

where P is the spring pitch, mm; D _B - outer diameter of the coil of the spring, mm; i - interference, mm.

The essence of the proposed device is illustrated by drawings.

Figure 1 presents a diagram of the processing of holes by surface plastic deformation - elastic mandrel with static-pulse loading of the spring mandrel, the position of the device before processing, the deforming element in a free unloaded state; figure 2 - diagram of the processing of the holes of the proposed device, the position of the device at the end of processing, the deforming element in a compressed static and pulsed load state; figure 3 is a General view of the design of the mandrel with a spring-loaded deforming element, a partial longitudinal section, a deforming element in a free unloaded state; figure 4 - the same deforming element in a compressed static and pulsed load state; figure 5 - spring deforming element in a free unloaded state before processing; Fig.6 is a springy deforming element in a loaded static and pulsed force in a compressed state in the hole being processed during processing; in Fig.7 - springy deforming element loaded with static force, in the expanded state, is located in the hole to be processed during processing (the dashed line shows the position of the deforming element loaded with the total static and pulsed force); in Fig.8 - element A in Fig.3, a variant of the prefabricated mandrel and its fastening to the rod of the cylinder of static load; Fig.9 is a section bB in Fig.8.

The proposed device is intended for finishing by surface plastic deformation (PPD) with calibration and hardening of the metal inner cylindrical surfaces of 1 holes with a diameter D _{ZAG of} workpieces 2 of steel and alloys with an elastic deforming tool - mandrel 3, to which a static load P _ST is applied using a hydraulic cylinder 4 and pulse R _IM load using a power hydraulic cylinder 5, in which are located the firing pin 6 and the waveguide 7.

The workpiece 2 is installed on the base plate 8 of the machine 9.

The device consists of a deforming tool - mandrel 3 (see Fig.3, 4), containing one or more (not shown) deforming elements 10 mounted on the rod 11 of the cylinder 4 of a static load.

The mandrel is designed for surface plastic deformation of through holes and is made with a front guide sleeve 12, providing mutual orientation of the workpiece and tool and fixed on the rod 11 with a nut 13.

The deforming element 10 is a helical conical spring made of wire, made, for example, according to GOST 9389-75, diameter d _PR , with an outer working surface in the form of a truncated cone with an angle φ = 3 ... 5 °, with deforming coils in an amount not less than three, of which the first turn 14 is rigidly connected to the intake disk 15, and the last turn 16 is rigidly connected to the calibrating disk 17.

The material of the wire of the deforming coil of the spring (for example, hard alloy VK15, VK15M) provides high wear resistance of the tool and high bending strength. At low tool loads, VK8 alloy can be used.

On Fig and 9 presents a more technological version of the prefabricated design of the mandrel and its mounting to the rod 11. The shank of the rod 18, on which are installed: a deforming element, a guide sleeve, a nut and other parts of the mandrel, has a flange 19 with two flats. The dorn is inserted with a shank into the groove 20 of the central stepped hole of the rod, rotated 90 ° relative to the central axis and fixed in it.

Parts of the mandrel: the rod, the shaft, the guide sleeve, the distance bushings (not shown) are made of carbon steels hardened to a hardness of HRC 40 ... 45. When assembled, the radial runout of the deforming elements relative to the guides does not exceed 0.02 _... 0.05 mm. This requirement is fulfilled due to the high accuracy of the manufacture of mandrel parts. Particular attention is paid to the stem and shaft (their radial runout should not be more than 0.01 ... 0.02 mm), distance bushings and deforming elements - springs (their face and radial runout relative to the base hole should not exceed 0.005 ... 0.01 mm )

There is no calibrating tape on the spring element, but for large hole diameters (> 75 ... 150 mm) it can be used, its width is chosen depending on the material and the wall thickness of the workpiece ([5], p. 399).

The diameter d _PR wire is approximately determined from the strength conditions by the formula:

d _PR ≈ 0.33 (P _ST + P _IM ) ^0.7 / (f ^0.4 [σ _FR ] ^0.7 D ^0.4 _zag ), mm;

where d _PR is the diameter of the wire, mm; (P _ST + P _IM ) - total (static P _ST plus pulsed P _IM ) force of burning out, N; f is the coefficient of friction between the element and the workpiece; depending on the processed material and technological lubricant f = 0.05 ... 0.14; [σ _IZ ] - permissible stress of the material of the wire in bending, MPa, for the hard alloy VK15 - [σ _IZ ] = 1800 MPa; D _ZAG - diameter of the workpiece bore hole, mm.

The magnitude of the interference is affected by the angle β of the inclination of the coil of the spring, which is determined by the formula:

β≈arctg [0.5P / (D _B -i)], deg;

where P is the spring pitch, mm; D _B - outer diameter of the coil of the spring, mm; i - interference - the main technological parameter of the process is the difference between the diameter of the machined hole and the diameter of the billet hole before machining, mm.

If we consider one coil of the spring in the free state (see Fig. 5) and the same coil - in the loaded state (see Fig. 6), then you can see that, changing its position, close to the transverse plane with a constant outer diameter of the coil springs D _B , the outer diameter of the spring, and therefore the diameter of the hole increases by the value of - i. Therefore, the amount of interference i is affected by the angle β of the inclination of the coil spring turns, the spring pitch and the outer diameter of the coil spring.

A distinctive feature of the proposed device is that on the deformable element - the spring acts sleeve 7 located on the rod 11 and sliding on it. The sleeve 7 is located in the hydraulic cylinder 5 (FIGS. 1, 2) and is a waveguide to which a periodic pulsed load P is applied to _them by the hammer 6. The hammer 6 is also located in the hydraulic cylinder 5 and has the shape of a sleeve. The hydraulic cylinder 5 has the possibility of longitudinal movement along the rod 11, consistent with the longitudinal movement of the mandrel in the hole being machined, and operates from a hydraulic pulse generator (GGI) (not shown) [3, 4]. The waveguide 7 and the firing pin 6 are made in the form of bushings of the same diameter.

The proposed device is used for surface plastic deformation processing by the burning of the inner surfaces of the holes. This operation is performed by moving with an interference fit of the tool — the mandrel through the workpiece’s machined hole, and static and impulse, periodic loads are applied to the mandrel along the axis of the tool and the machined hole.

The workpiece 2 is installed in the base plate 8, for example, a press or a vertical broaching machine (for example, mod. 7B65) and the mandrel is inserted into the pre-machined hole of the workpiece with the lead-in part.

Processing begins with the inclusion of a longitudinal feed S _PR , which is due to the constant action on the mandrel of the rod 11, which, in turn, is affected by the main static load P _ST developed by the hydraulic cylinder 4. At the same time, the hydraulic cylinder 5, which generates an additional periodic pulse load P _IM .

A periodic impulse load P _is carried out using a striker 6, acting on the end of the waveguide 7, made in the form of bushings located on the rod 11. A hydraulic pulse generator (not shown) is used as a mechanism for pulse loading of the tool [3, 4].

Static loading P _CT and longitudinal feeding S _{PR of the} mandrel are carried out using a hydraulic loading cylinder 4, the piston 21 and the rod 11 of which are connected to the mandrel.

The pulse load is carried out by a hydraulic cylinder 5, which operates from a hydraulic pulse generator (not shown). The waveguide 7 in the form of a sleeve is installed in the hydraulic cylinder 5 on the rod 11 with the possibility of longitudinal axial movement and is located between the striker 6 and the deforming element 10.

The initial impulse generated in the striker 6 at the moment of impact on the waveguide 7, reflected from the free end of the striker with the opposite sign, reaches the waveguide, one part of it is reflected again in the striker, and the other goes into the waveguide and propagates in the direction of the loaded surface. Having reached the loaded surface, the last part of the pulse is distributed on the transmitted and reflected. Passing deformation waves with equal lengths of the striker and the waveguide do not overlap and do not break, but follow each other, in addition, when the contact areas of the cross sections of the striker and the waveguide are equal, the impact energy is most fully realized in contact with the loaded medium.

The deformation element of the mandrel works as follows.

During the working stroke under the action of only the static load P _{CT, the} deforming element enters the hole in the first turn with the intake disk and the surface plastic deformation process will take place, as in the case of conventional traditional mandrels.

When the striker strikes the waveguide, in addition to the action of a static load, a pulse R _IM load begins to act on the deforming element (Fig. 6). The waveguide slides along the rod and moves the calibrating disk along the rod, while the spring of the deforming element is compressed, because the intake disc remains stationary relative to the rod, abutting against the guide sleeve. The pulse load P _IM on the deforming element will overcome the resistance of the spring P _PR and the coils, approaching, will radially affect the machined surface of the hole. As shown in Fig.6, the spring is compressed, reduced in height and the coils occupy a transverse position relative to the longitudinal axis of the hole being machined. Circumferential tensile and radially compressive stresses arise, which can significantly increase the depth of the hardened layer, increase the degree of hardening and reduce the height of the microroughness of the treated surface.

At the end of the action of the pulse load on the deforming element, its spring will be unclenched under the action of its own force P _PR and the static load P _ST acting on the rod (Fig.7). Moreover, the calibrating disk of the deforming element will remain in place, supported by the waveguide, and the intake disk will move down along with the movement of the rod.

The proposed mandrel effectively increases the diameter of the hole due to plastic deformation of the surface of the hole by the coils of the spring of the deforming element. This hardens the surface layer to a greater depth than with conventional burnishing, improving the quality of the treated surface, there is a decrease in the length of the mandrel.

The deforming element, made in the form of a spring, will smoothly and gradually, and not abruptly, perceive a pulse shock load, which significantly reduces vibration and, as a result, the waviness of the treated surface.

After the termination of the pulse load, the spring comes to its original position, increases in height and the turns are located at a distance of step P from each other (Fig.7). At the same time, the last turn 16 with the calibrating disk 17 remains in place, and the middle, first 14 and intake disk 15 go down (according to Fig. 7) under the action of the spring's own elastic force P _PR and static load P _ST .

Thus, with each hit of the striker on the waveguide, the coils of the springy deforming element will approach and radially act on the surface being treated, creating tensile and radially compressive stresses. Moreover, the height of the element is minimal, and the spring pitch P = 0. In the time intervals between impacts, the spring will restore its original height and the coils of the springy deforming element will be parted at a distance of step P from each other.

The depth of the hardened layer of the proposed device increases and reaches 1.5 ... 2.5 mm, which is significantly (3 ... 4 times) more than with traditional static burnishing.

The greatest degree of hardening is 25 ... 30%. As a result of static-pulse processing, in comparison with traditional burnishing, the effective depth of the layer, hardened by 20% or more, increases by 2 ... 2.6 times, and the depth of the layer hardened by 10% or more, by 1.6 ... 2, 2 times.

Example. Processed by the proposed device a hole with a diameter of 40 mm; billets of material - steel 18HGT GOST 4543-74, hardness HB 207-228, weight - 6.75 kg. The treatment was performed with a mandrel with a deforming spring element - a spring, 40 mm in diameter, 6 mm wire diameter, a deforming element in a compressed state of 24 mm, a spring pitch of 20 mm, made of VK15 hard alloy, and an angle of φ = 4.5 °.

Processing was carried out on a modernized press using a special GGI - a hydraulic pulse generator. The modernization concerned the installation on the press, on the rod of an additional hydraulic cylinder with a waveguide and a striker, carrying out additional periodic pulsed loading of the mandrel tool.

Cutting fluid - sulfofresol. Burning speed S _PR = 4.5 m / min. The greatest value of the impact energy developed by the GGI, A = 285 J (impact force 265 kN, impact speed 7.4 m / s), with a shock frequency of f = 5 ... 15 Hz. The interference fit was i = 0.3 ... 1.5 mm per diameter. Static loading was carried out by force up to P _CT = 42 kN.

Processing showed that the roughness parameter of the machined surface of the holes decreased to Ra = 0.5 ... 0.07 μm with the initial Ra = 5 ... 6.5 μm, productivity increased by more than three times compared to traditional mandrelling and preliminary deployment, used at the base enterprise of OAO Livhydromash. The energy intensity of the process decreased by 2.1 times. The depth of the hardened layer reached 1.7 ... 2.2 mm. The highest degree of hardening was 21 ... 26%. As a result of static-pulse processing, the effective depth of the layer hardened by 20% or more increased by 1.8 ... 2.4 times, and the depth of the layer hardened by 10% or more by 1.7 ... 2.1 times.

The proposed device extends the technological capabilities of durning due to the influence of a static-pulse load on a special springy deforming element, during the passage of which circumferential tensile and radial compressive stresses arise, which can significantly increase the tightness and depth of the hardened layer, increase the degree of hardening and reduce the height of microroughnesses of the treated surface.

The proposed device allows to increase the productivity of the burning process, to carry out processing with high interference, high efficiency and minimum energy consumption of the equipment.

Information sources

1. RF patent No. 2312757. IPC V24V 39/02. Device for static-pulse burning of holes by pulling. Stepanov Yu.S., Kirichek A.V., Soloviev D.L. Afanasyev B.I., Fomin D.S., Selemenev K.F. Application No. 2006116871/02. 05/16/2006; 12/20/2007 - a prototype.

2. RF patent No. 2312754. IPC V24V 39/02. The method of static-pulse burning of holes by pulling. Stepanov Yu.S., Kirichek A.V., Soloviev D.L. Afanasyev B.I., Fomin D.S., Selemenev K.F. Application No. 2006115432/02. 05/04/2006; 12/20/2007.

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 No. 2090342. IPC ⁶ V24V 39/04. Lazutkin A.G., Kirichek A.V., Soloviev D.L. Water hammer device for processing PPD parts. 95122309/02. 12/21/95. 09/20/97. Bull. No. 26.

5. Reference technologist-machine builder. In 2 vols. T.2 / Ed. A.G. Kosilova and R.K. Meshcheryakova. - 4th ed. reslave. and add. - M.: Mechanical Engineering, 1986. S.397 ... 410.

Claims (1)

A device for static-pulse elastic durning on machines containing a mandrel with deforming elements, a hydraulic cylinder configured to apply a static load P _ST to the mandrel, a hydraulic cylinder in which the hammer and waveguide are located, configured to apply a periodic pulsed load P _IM to the mandrel, and a hydraulic pulse generator for powering the hydraulic cylinders, characterized in that the hydraulic cylinder of the periodic impulse load is movably located on the rod of the hydraulic cylinder of the static load and equipped with a waveguide and a striker in the form of bushings with the possibility of their longitudinal movement on the said rod, while the deforming element is a helical conical spring made of wire with a diameter d _PR , with the outer working surface in the form of a truncated cone with an angle φ = 3 ... 5 ° , with deforming turns in an amount of at least three, the first turn of which is rigidly connected to the intake disk, and the last is rigidly connected to the calibrating disk, while the diameter d _{PR of the} wire is determined by the formula:
d _PR = 0.33 (P _ST + P _IM ) ^0.7 / (f ^0.4 [σ _FR ] ^0.7 D ^0.4 _zag ), mm;
where d _PR is the diameter of the wire, mm; (P _ST + P _IM ) - the total force of burning out, N; f is the coefficient of friction between the element and the workpiece; depending on the processed material and technological lubricant f = 0.05 ... 0.14; [σ _FROM ] - permissible stress of the material of the wire in bending, MPa; _Holes D - diameter of the machined hole in a workpiece, mm;
the angle β of the inclination of the coil of the spring is determined by the formula:
β = arctan [0.5P / (D _B -i)], deg;
where P is the spring pitch, mm; D _In - the outer diameter of the coil of the spring, mm; i - interference, mm.

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