RU2282528C1 - Oscillating combination type working method - Google Patents

Abstract

FIELD: combination working of metals by friction surface hardening and surface-plastic striking pulse deforming, possibly finishing surfaces.

SUBSTANCE: method comprises steps of using combination type tool having mandrel carrying mounted in it along the same axis device for working by balls and device for friction surface hardening. Tapered washers are mounted in pairs on ends of combination type tool. Washer-gasket is placed between devices. Device for working by balls has left and right lids mutually joined along their periphery through elastic shell with seats for balls; set of spacing washers arranged between said devices. Device for friction surface hardening includes disc made of material with low heat conductivity. At working process change of tool oscillation amplitude is gradually controlled.

EFFECT: enlarged manufacturing possibilities, improved quality and efficiency of working, increased wear resistance of tool.

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Description

The invention relates to a combined treatment of friction surface hardening of metals and surface-plastic shock-pulse deformation and can be used for finishing, finishing processing of surfaces subject to intense wear, steel and cast iron precision machine parts.

Known is a combined method of processing with a tool containing a grinding wheel with its fastening elements on the mandrel and a device coaxially mounted with it for processing metal surfaces with balls [1].

The disadvantages of the known method of combined processing are: the need for an additional surface hardening operation, for example, quenching by high-frequency currents (HFC), cementation and quenching in gas furnaces, etc. This requires additional expensive equipment, tools and time; reduces the productivity, accuracy and quality of the processing process.

The objective of the invention is the expansion of technological capabilities of the method by providing periodic, combined and sequential exposure to the machined flat and rotating surfaces by friction surface hardening before impulse-impact plastic deformation by a combined tool with axially displaced 1 working surface, which allows to improve quality and accuracy, reduce the complexity of processing and increase performance, and also provide noise absorption, reduced ball wear, lower reduction of drive power loss.

This is achieved using the proposed method of oscillating combined processing of surfaces of revolution, including reporting rotational motion to the workpiece and rotational motion and feed motion along the machined surface to a combined tool located at an acute angle α to a plane perpendicular to the axis of rotation, using a combined tool containing a mandrel with coaxially balls mounted on it for treating metal surfaces and friction devices ion surface hardening, equipped with fastening elements on the mandrel, slanting washers and a washer-spacer installed between the mentioned devices arranged in pairs from the ends of the combined tool, while the device for treating metal surfaces with balls is made with left and right covers connected at the periphery of the elastic shell with sockets under the balls, and each socket is made in the form of a tube with rolled ends, in which the ball is installed with the possibility of free movement, and the size a set of spacer washers between the said covers, the total height of which is not less than the height of the elastic shell, and the device for frictional surface hardening contains a disk of material with a low coefficient of thermal conductivity and with a working surface on its periphery, located at an acute angle α to a plane perpendicular to the axis rotation, while smoothly controlling the change in the oscillation amplitude of the combined tool by changing its angle using oblique washers and washers adki, and the said angle of inclination α is determined by the formula:

arc tg (V _beats / D) ≥α≥arc tg (V _fr / D),

where In _beats - the height of the elastic shell with balls, mm;

D is the outer diameter of the tool, mm;

α is the acute angle of inclination of the tool to a plane perpendicular to the axis of rotation, deg;

In _FR - the height of the disk for friction surface hardening.

Figure 1 shows a diagram of the proposed method of oscillating combined processing and the design of the tool for implementing the method, rotated to a maximum angle α; figure 2 is a section aa in figure 1; figure 3 - more technologically advanced for assembly version of the design of the right cover; figure 4 is a tool rotated by a minimum angle α = 0.

A method of oscillating combined processing is that rotary motions and a feed motion along the surface to be machined are reported to the workpiece and the combined tool.

A tool that implements the proposed method contains a disk 1 for friction surface hardening with elements of its fastening on the mandrel 2 and a device 3 for co-processing metal surfaces with balls coaxially mounted with it.

The fastening elements of the tool are made in the form of oblique washers 4 in the amount of four pieces, two from each end of the combined tool to provide an axially displaced cutting layer by installing the disk 1 and device 3 at an angle to a plane perpendicular to the longitudinal axis, with the possibility of smooth adjustment of the oscillation amplitude A _fr by changing the angle of inclination of the disk 1 and the device 3. The spacer washer-gasket 5 and the nut 6 are also fasteners and serve for the reliable installation of the components of the combined and strument on the mandrel 2.

The device 3 for treating metal surfaces with balls contains a left 7 and a right 8 covers, peripherally connected by an elastic shell 9, in which nests for balls 10 are made, each socket consisting of a tube 11 with rolled ends, in which the ball 10 freely moves.

To ensure the state of "expansion" of the elastic shell 9, which is attached by known methods, for example, vulcanization, to the ends of the covers 7 and 8, between the covers there is a set of spacer washers 12, the total height of which is not less than the height of the elastic shell 9.

To reduce drive power losses, as well as reduce wear of the sockets 11 and balls 10, the axis 13 of each socket 11 is located at an angle β to a straight line 14 connecting the longitudinal axis of the mandrel 2 with the center of the outlet opening of the socket 11.

The angle β depends on the diameter of the tool, because they select it such that at the moment of contact of the ball 10 with the surface to be machined, the axis 13 of each socket 11 is directed at right angles to it when processing flat surfaces or normal to the tangent when processing surfaces of revolution.

For a more technologically advanced assembly and adjusting the tension of the shell 9, a design option for the right cover is provided (Fig. 3), which is made integral and consisting of a ring 15, a flange 16 connected by screws 17.

Processing device 3 with deforming balls 10 according to the proposed method is as follows.

Under the action of centrifugal forces arising from the rotation of the shell 9, the balls 10 protrude above its periphery. By setting the longitudinal feed to the tool and the rotation of the workpiece in the case of processing bodies of revolution, they process surfaces of any given size. In the case of processing flat surfaces, the combined tool is mounted on the spindle of a surface grinding machine and machined as with traditional flat grinding with the periphery of the wheel.

A device for friction surface hardening, consisting of a disk 1 of a material with a low coefficient of thermal conductivity and with a working surface at its periphery, is installed coaxially with the device 3 with deforming balls. The disk 1 is also located on the mandrel 2 at an acute angle α to the plane perpendicular to the axis of rotation, using oblique washers 4 mounted and arranged in pairs from the ends of the tool, and washers 5 installed between the devices.

Processing the proposed method with a combined oscillating tool assembly is as follows.

A workpiece such as a body of revolution is clamped in a chuck, for example, of a grinding, turning or other machine, and a combined tool on the mandrel of the grinding head or in a device with an individual drive. The tool rotates with a peripheral speed V = 65 ... 70 m / s and is pressed with a constant force P = 0.65 ... 1.0 kN to the workpiece that rotates (in the case of processing cylindrical surfaces) with a peripheral speed of 0, 02 ... 0.08 m / s. The longitudinal feed of the tool relative to the workpiece is (0.1 ... 0.2) V _fr , where V _fr - the height of the disk 1 for friction surface hardening, mm

The length of the line of contact of the tool with the workpiece (In _FR ) is 5 ... 8 mm. During friction of the tool and the workpiece in the zone of their contact, the surface of the workpiece being pulsed is heated to a temperature of 800 ... 1000 ° C. A lubricating coolant (coolant) is supplied to the treatment zone, which provides quick cooling of the hardened surface. As a result of hardening, structures of white layers with a thickness of 0.1 ... 0.15 mm with increased microhardness of 7 ... 10 GPa arise on the surface of the workpiece. In the zone of frictional sliding contact, a certain amount of heat (most of it) goes into a rapidly rotating tool. Therefore, titanium alloy or stainless steel having low thermal conductivity (λ = 21.9 ... 25.5 W / m · K) is chosen as the material of the disk. When moving the contact zone in the axial direction due to the inclination of the working disk, the heated working surface of the tool instantly transitions to the cooled surface of the workpiece (Fig. 1). This leads to a cyclical change in temperature on the surface of the hardened workpiece and, accordingly, to an increase in the depth of the hardened layer to 0.15 ... 0.22 mm. By changing the angle of inclination, and therefore by changing the oscillation amplitude A _{fr of the} disk, the depth and microhardness of the hardened layer can be adjusted.

When A _FR <B _{FR, the} increase in the depth of the hardened layer is insignificant, but there is a high probability of overheating of the tool. When the value of A _FR > In _{beats, a} further slight increase in the thickness of the hardened layer leads to an increase in vibration, deterioration in the quality of processing. Therefore, the angle of inclination α is determined by the formula:

arc tg (V _beats / D) ≥α≥arc tg (V _fr / D),

where In _beats - the height of the elastic shell with balls, mm;

D is the outer diameter of the tool, mm;

α is the acute angle of inclination of the tool to a plane perpendicular to the axis of rotation, deg;

In _FR - the height of the disk for friction surface hardening, mm

Thus, during joint processing with a combined tool, the disk 1, mounted at an angle to the axis of rotation, in contact with the peripheral axially displaced peripheral working layer, hardens the surface layer of the workpiece to a greater depth, and the deforming balls 10, protruding above the periphery of the shell 9 of the device 3, strike hardened treated surface and reduce the height of microroughness. In this case, a final microprofile of regular roughness is obtained with a relatively small number of working balls 10.

The axially displaced working layer of the disk 1 strengthens the workpiece by heating it, and the deforming balls ensure the continuity of plastic deformation of the heated surface of the product, which eliminates vibration and vibration of the tool and reduces the roughness of the processed surface.

As the friction disk 1 wears out, it decreases in diameter and it is necessary to restore its original size. To partially adjust the size of the outer diameter in the radial direction and restore the original size, it is rotated in a plane passing through the axis of rotation by a certain angle. This adjustment is possible when replacing the washer gasket 5 with two oblique washers 4 (not shown).

With significant wear of the disk 1 and the device of shock-pulse deformation 3, as well as when finding the optimal processing conditions, use the angle α of the tilt of the tool (figure 4) using mutual rotation of the oblique washers 4 relative to each other.

The proposed method of oscillating combined processing with a tool consisting of a reinforcing disk and a device with deforming balls is distinguished by noise absorption due to the use of an elastic shell, reduced wear of the balls and reduced drive power losses.

Example. On the internal grinding machine mod. 3K228B was simultaneously hardened and machined by pulse-impact plastic deformation through hole with a diameter of 60 N7 ^(+0.03) mm and a length of 60 mm. The roughness parameter of the treated surface is Ra = 0.63 μm. The workpiece material is steel 45 in a normalized state. The working disk for friction surface hardening is made of VT-5 titanium alloy with a working surface width of 5 mm and an outer diameter of 50 mm. The rotational speed of the tool was taken 13000 min ^-1 , the rotation frequency of the workpiece is 200 min ^-1 . A longitudinal feed was set at 5390 mm / min. The angle of the new tool is α = 10 °. The amplitude was 8 mm. The pressure of the friction disk on the workpiece created by the transverse feed mechanism of the machine is 0.8 kN. Coolant was supplied to the treatment zone as industrial I-12A oil. The shell is rubber, 15 mm thick, 25 mm high, nests for balls in the form of a tube made of 12X17 steel with an outer diameter of 10 mm, a wall thickness of 0.5 mm, and normal manufacturing accuracy - a pipe 10 × 0.5 - 12X17 GOST 9941 -72. Balls with a diameter of 8.73 mm (from bearing No. 110 GOST 8338-75) are inserted into the nests - tubes with a length of 15 mm. The ends of the tubes are rolled. The angle β of the installation of the socket to the straight line connecting the longitudinal axis of the mandrel with the center of the outlet of the socket was taken equal to β = 8 °.

To ensure the required quality and dimensional accuracy of processing, the main time was 0.65 min, which is 2.4 times faster than with separate hardening and impact plastic deformation.

In this case, the depth and microhardness of the hardened layer (white zone) were 0.17 ... 0.19 mm and 8 ... 9 GPa, respectively, with a gradual decrease in microhardness in depth to the initial state - 2.3 ... 2.7 GPa . With a twofold increase in the rotation speed of the hardened billet, the depth of the hardened layer was 0.12 ... 0.14 mm. Thus, the tool allows you to increase the productivity of the process.

With a decrease in the disk inclination angle to 1 ° 10 ^I (to α = arc tg (V _fr / D) = 6 °), the depth of the hardened layer decreased to 0.12 ... 0.15 mm. An increase in the disk inclination angle to 22 ° (α = arc tg (V _beats / D) leads to a slight increase in the depth of the hardened layer (from 0.17 ... 0.19 to 0.18 ... 0.20 mm).

The proposed method is simple to implement, and the tool is simple in design and reliable in operation. The structures of the white layers obtained on the surface of the hardened billet have increased hardness and, accordingly, wear resistance and resistance to fatigue fracture. The method allows to increase the processing productivity of 1.5 ... 2.0 times.

The proposed method and tool design expand technological capabilities by providing periodic, combined and sequential effects on the machined flat and surface of rotation of friction surface hardening before impulse-impact plastic deformation with axially shifted working surface.

The method of oscillating combined processing allows to increase wear resistance, improve quality and accuracy, reduce the complexity of processing and tool consumption, as well as increase productivity.

Information sources

1. RF patent 2228254, MKI B 24 D 5/00, 24 V 39/00. Combined tool. Stepanov Yu.S., Kirichek A.V., Afanasyev B.I. and others. Application No. 2003105759/02, declared 02/27/2003, publ. 05/10/2004. Bull. No. 13 is a prototype.

Claims (1)

A method of oscillating combined treatment of surfaces of revolution, comprising communicating rotational motion of a workpiece and rotational motion and feed motion along a machined surface to a combined tool located at an acute angle α to a plane perpendicular to the axis of rotation, characterized in that they use a combined tool containing a mandrel coaxially mounted on a device for treating metal surfaces with balls and a device for friction surface control parts equipped with fasteners on the mandrel, located in pairs from the ends of the combined tool, oblique washers and a washer gasket installed between the above devices, while the device for treating metal surfaces with balls is made with left and right covers connected at the periphery by an elastic shell with nests for balls moreover, each socket is made in the form of a tube with rolled ends, in which a ball is installed with the possibility of free movement, and placed between the said wings with a set of spacer washers, the total height of which is not less than the height of the elastic shell, and the device for friction surface hardening contains a disk of material with a low coefficient of thermal conductivity and with a working surface on its periphery, located at an acute angle α to a plane perpendicular to the axis of rotation, this provides smooth adjustment of the amplitude of the oscillation of the combined tool by changing its angle of inclination α using oblique washers and washers, and said angle of inclination bosom α is determined by the formula arctg (V _beats / D) ≥α≥arctg (V _fr / D), where In _beats - the height of the elastic shell with balls, mm; D is the outer diameter of the tool, mm; α is the acute angle of inclination of the tool to a plane perpendicular to the axis of rotation, deg; In _FR - the height of the disk device for friction surface hardening.

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