RU2328368C2 - Method of combined processing by grinding and surface plastic deformation - Google Patents

Abstract

FIELD: mechanical engineering.

SUBSTANCE: workpiece is imparted rotary and spring tool is imparted longitudinal feed. Spring tool is used containing the case with bores accommodating freely running rolling bearings and working abrasive-diamond-containing and deforming elements. Working abrasive-diamond-containing and deforming elements are made in the form of ellipse coils curled up to make a ring. The external working surface of the abrasive-diamond containing and deforming elements has deforming sites and abrasive-diamond sites opposite to the latter. The former is made so that to envelope the workipiece and to make an interference fit with the latter. Here, the aforesaid spring is arranged in the case freely and can be unscrewed to allows the workpiece superficial plastic deformation or grinding.

EFFECT: extended process performances, higher efficiency and lower costs.

2 cl, 7 dwg, 1 ex

Description

The invention relates to mechanical engineering technology, in particular to finishing combined abrasive-diamond processing and surface plastic deformation of workpieces of shafts and screws made of steels and alloys with a multi-element abrasive-diamond and deforming tool in the form of a coil spring.

A known method of grinding with an abrasive-diamond tool containing a housing, on the periphery of which elastic abrasive-diamond-containing work elements made in the form of a helical spring are rigidly fixed in grooves [1].

The disadvantages of this method, implemented by a spring tool, are: narrow technological capabilities, low productivity in relation to the finishing, finishing processing of screws and other parts such as shafts due to the small contact patch of the working elements with the surface being treated, and also the low quality of processing.

A known method of grinding with an abrasive-diamond tool containing a housing, in the grooves of which are installed working abrasive-diamond-containing elements made in the form of a helical spring, and the grooves are located radially in the housing [2].

The disadvantages of this method, implemented by a spring tool, are: narrow technological capabilities, low processing quality and productivity in relation to finishing, finishing processing of screws and other parts such as shafts due to the small contact patch of the working elements with the treated surface.

The objective of the invention is the expansion of technological capabilities, which consists in improving the roughness parameter of the processed surface due to the sequential actions of a large number of abrasive-diamond and deforming elements, in increasing productivity by increasing the contact spot of these elements with the treated surface and the possibility of using large feeds, in reducing the cost of the process and cheaper manufacture of the tool due to its compactness and simplicity of design, if possible and process slozhnofasonnye body rotational runout and neutralize the workpiece surface, which adversely affect the quality of the processing, in the discharge process of the system nodes: machine - tool - tool - workpiece from one side applied force especially when processing nonrigid workpieces.

The problem is solved by the proposed method of combined processing by grinding and surface plastic deformation, including the message of the rotational motion of the workpiece and rotational motion and longitudinal feed of the spring tool, using a spring tool containing a housing with holes in its side walls, which are mounted on freely rotating bearings and working abrasive-diamond-containing and deforming elements in the form of ellipsoid coils rolled into there are a coil springs, the outer working surface of which is made with deforming sections and opposite opposite to the last abrasive-diamond sections deposited on the said outer working surface of ellipsoidal turns in an arc, the central angle α of which is 90 ° <α <180 °, a coil spring rolled into a ring in contact with the ends of the bearings, the distance between which is equal to the length of the major axis of the ellipsoid coil, is installed in the housing freely, covers the workpiece and is installed on the last yagom for radial feed in grinding or static load during plastic deformation of the surface, wherein the rotation is performed on the individual motor via gear ring rolled into a helical spring and its screwing to ensure plastic deformation of the surface or sanding the workpiece. In addition, the turning of a coil spring screwed into the ring is carried out using a mandrel with a groove on its outer surface made of a width equal to at least the length of the small axis of the ellipsoid coil and a depth equal to half the length of the large axis of the ellipsoid coil and the sleeve, made with the possibility of installation in the indicated groove.

Features of the method are illustrated by drawings.

Figure 1 shows a diagram of the proposed processing process in the grinding mode of the outer surface of the screw pump screw and a spring device that implements it, for sequential grinding and surface plastic deformation, a partial longitudinal section BB in figure 2; figure 2 is a section aa in figure 1; figure 3 - section bb of the annular spring in figure 2; figure 4 - section GG in figure 2, is rotated, the annular spring is turned out to work in grinding mode; figure 5 - cross section GG in figure 2, rotated, the annular spring is turned out to work in the mode of surface plastic deformation; Fig.6 is a diagram of the turning of the annular spring during the transition from the grinding mode (see Fig.1-4) to the surface plastic deformation mode, the intermediate position is the dropping of the annular spring into the groove; Fig.7 is a diagram of the unloading of the annular spring during the transition from the grinding mode (see Fig.1, 4) to the surface plastic deformation mode, the final position is the annular spring turned out to work in the surface plastic deformation mode.

The proposed method is intended for sequential processing by grinding and surface plastic deformation (PPD) of the outer surfaces of rotation of the workpieces of parts such as shafts and screws with a large pitch, for example, screw pumps.

The processing is performed on turning, rotary machines with the message of the rotational movement of the workpiece - V _З , rotational motion - V _And and the longitudinal feed motion - S _pr tool.

The proposed method is intended for sequential grinding and RPM and is implemented by a spring device containing a box-shaped body 1, inside which a tool is located - a spring 2. The body 1 has through holes in two opposite walls for the workpiece 3 to pass through.

A tool with working abrasive-diamond-containing and deforming elements made in the form of ellipsoidal coils having a small a and large b axis, combined in a coil spring 2, rolled into a ring.

The outer working surface of the ellipsoidal coils of the spring 2 on one side of the minor axis a of the ellipse is made with an abrasive-diamond layer 4 deposited on the working part of the surface of the coils along an arc length with a central angle α in the range 180 °> α> 90 °. On the other diametrically opposite side of the turns, their outer working surface is used as a deforming 5.

A ring of coil spring 2 with ellipsoidal coils with abrasive-diamond and deforming sections is freely installed inside the housing 1 so that the holes in the annular spring and in the housing are aligned.

The spring 2 is made of steel of circular cross section and is installed with an interference fit on the workpiece 3, covering it, and with the possibility of rotation on it.

The inner diameter D _{and the} rings of the spring 2 in the idle state are less than the diameter D _{Z of} the workpiece 3 by the amount of double preload, the latter provides a radial feed S _P during grinding and a static load P _ST during RPM, i.e. D _S > D _AND .

Due to the fact that the process of finishing abrasive-diamond processing requires high speeds, the device is equipped with an individual electric motor 6, which through the gear 7 forcibly rotates the annular spring 2 with a speed of V _AND . The gear 7 is made of an elastic elastic material, for example rubber, and in engagement with the spring ring 2, which is a gear wheel, in which the turns of the annular spring play the role of the teeth, it allows transmitting a torque sufficient for grinding and PPD.

The proposed method is used to work both in grinding mode and in RPM mode. Work in the grinding mode (see Fig.1-4) is carried out when the abrasive-diamond layer 4 on the coil of the spring is located on the inner side of the ring of the spring 2, and work in the PPD mode is carried out when the deforming elements of 5 turns are on the inner side spring rings 2.

Therefore, when switching from the grinding mode to the PPD mode and vice versa, the annular spring 2 turns out.

The ability to unscrew the spring 2 is ensured by its free location both on the workpiece 3 and in the housing 1, while in the housing the spring 2 is installed against the holes in the side walls, in which freely rotating plain bearings 8 are mounted with their ends, the distance between which is equal to a large length b the axis of the ellipsoidal coil in contact with the spring 2.

Bearings 8 are located in the bushings 9, which are pressed into the holes in the side walls of the housing 1.

The annular spring 2 is turned out using the technological sleeve 10 and the mandrel 11. The technological mandrel 11 has a profile and an outer diameter identical and equal to the outer diameter of the workpiece. Technological mandrel 11 is a continuation of the workpiece 3. The end face of the mandrel 11 in contact with the workpiece can be made, for example, in the form of a direct center 12, a reverse center (not shown), or other design. From this end, on the outer surface of the mandrel 11, a groove 13 is made with a width of at least a - the length of the small axis of the ellipsoid coil and a depth of not more than b / 2 - half the length of the major axis of the ellipsoid coil (Fig.6).

Technological sleeve 10 is designed to be installed in the groove 13, completely filling it, has a profile and an outer diameter identical to and equal to the outer diameter of the workpiece being processed, being a continuation of the latter.

The turning of the spring ring 2 during the transition from the grinding mode to the HID mode and vice versa is carried out as follows.

The housing 1 with a spring 2 located on the workpiece 3 in the position, for example, grinding, i.e. abrasive-diamond elements located inside the ring in contact with the workpiece (see figure 1), brought in the longitudinal direction to the groove 13 of the technological mandrel 11, while the groove 13 is free. Since the annular spring 2 is installed on the workpiece with an interference fit, then under the action of elastic forces, the turns are tilted and fill the groove 13 (see Fig.6). With further longitudinal advancement of the device from left to right, according to Fig.6, the coil of the spring abuts against the right end of the groove 13 and, pushed by the end of the left bearing 8, flips relative to the Central axis of the spring (see Fig.7). The annular spring 2 is on the technological mandrel 11 deforming elements inside the ring, in contact with the outer surface of the mandrel. The annular spring 2 is ready to perform processing of the workpiece PPD. Before moving the device in the longitudinal direction onto the workpiece in the groove 13, the technological sleeve 10 is inserted. Having a profile and an outer diameter identical to and equal to the external diameter of the workpiece, the technological sleeve 10 facilitates the unimpeded advancement of the annular spring from right to left in the longitudinal direction for the workpiece RPM.

A device that implements the proposed method is mounted, for example, on a support of a lathe (not shown), the workpiece, for example screw 3, is fixed in the chuck 14 of the spindle 15 of the headstock 16 and is pressed by the center 12 of the technological mandrel 11, which is installed, for example, in the back grandmas 17.

The axial movement of the forcibly rotating spring 2 is transmitted from the housing 1 of the device through freely rotating sliding bearings 8, made in the form of oil-bearing bronze bushings, which contact the ends of the spring 2 with their ends.

After the workpiece 3 is fixed in the cartridge 14, the device is led to the free end of the workpiece and, using the manual longitudinal feed of the support, the workpiece is introduced into the central hole of the housing 1 and into the hole of the annular spring 2, overcoming the resistance of the latter, and then the workpiece is pressed by the back center of the technological mandrel 12 If the finishing operation of the proposed device they want to start with grinding, then the annular spring 2 is introduced into the processing in the position when the abrasive-diamond elements are inside the ring, ie in grinding mode. Before entering into contact of the tool with the workpiece include the movement of rotation of the workpiece V _s , the rotational movement of the spring V _AA and the longitudinal feed S _pr device.

Elastic abrasive-diamond-containing elements of the spring 2 with their working surfaces come into contact with the workpiece and carry out grinding.

Having elasticity, the abrasive-diamond-containing elements of the spring 2 provide a more elastic clamp to the machined complex-shaped surface, thereby achieving a more uniform cutting of the layer from the complex-shaped processing surface, which is very important when removing thin layers.

The presence of an elastic element, which is an abrasive-diamond-containing spring 2, provides a constant grinding force at any point on the machined complex shaped surface.

Contact abrasive diamond-containing tools with the surface to be processed during grinding is carried out by a large number of individual abrasive diamond pads, for example, toroidal shape. Through the free space between these sites, polished dust and sludge are easily removed, which almost eliminates the salinity of the working surface of the tool and increases its durability.

At the end of grinding, the device is brought to the groove in the technological mandrel and the annular spring is turned out by abrasive-diamond elements to the outside, and by deforming elements inside the ring, while springing onto the technological mandrel (see Fig. 7).

Then the center of the technological mandrel is diverted from the workpiece, the technological sleeve 10 is installed, filling the groove, and the PPD is processed. When PPD include the movement of rotation of the workpiece V _s and the longitudinal feed S _pr device. The rotational movement of the spring V _And can be omitted, because the magnitude of the tool speed does not significantly affect the surface plastic deformation process.

The elastic deforming elements of the spring 2 come into contact with the workpiece by their working surfaces and, under the action of P _ST, carry out surface plastic deformation of microroughnesses, smoothing them, the surface layer and harden it.

Having elasticity, the deforming elements of the spring 2 provide a more elastic clamp to the machined complex-shaped surface, thereby achieving a more uniform treatment of complex-shaped surfaces.

The presence of an elastic element, which is spring 2, provides a constant force of the PPD at any point on the machined complex shape surface.

The contact of the deforming tool with the surface to be treated during PPD is carried out by a large number of individual deforming areas, for example, a toroidal shape.

The elastic elements of the tool - the coil of the spring, are made of steel: alloyed ShH15, HVG, 9X, 5XHM, carbon tool U10A, U12A. Hardness of the working surface of coils made of HRC 62 ... 65 steels. The working surface of the deforming elements 5 turns of the spring 2 is polished to Ra = 0.08 ... 0.16 μm.

The productivity of the process of abrasive-diamond and hardening processing is determined by the diameter of the coil of springs and the diameter of the wire from which the springs are made. When processing screw blanks, the diameter of the coil of the springs is dictated by the dimensions of the depression of the screw surface, namely, the diameter of the coil of the springs must be such that it contacts all points of the bottom of the cavity in the longitudinal section of the screw (see Fig. 1).

A device with a large diameter of the coil of the spring and the diameter of the wire allows you to process with a large longitudinal feed S _CR both during grinding, and when PPD. However, in this case, when PPD it is necessary to create large working forces P _article , which reduces the quality of the surface. The spring parameters depend on the value of the permissible working force P _st . It is most expedient to process the initial surfaces of the 7 ... 11th level by grinding and PPD.

When grinding and PPD, roughness parameters of Ra = 0.2 ... 0.8 μm are practically achieved with the initial values of these parameters 0.8 ... 6.3 μm. The degree of reduction in surface roughness depends on the material, working force or interference, feed, initial roughness, device design, etc.

PPD after grinding should be carried out so that the desired results are achieved in one pass. Do not use the reverse stroke as a working stroke, as repeated passes in opposite directions can lead to excessive deformation and peeling of the surface layer.

The workpiece speed V _s does not have a noticeable effect on the results of processing PPD, but affects the grinding process and is selected taking into account performance requirements, design features of the workpiece and equipment. Typically, the speed V _s is 30 ... 150 m / min. The value of the PPD force is selected depending on the purpose of the processing. The optimal force P _article (N), corresponding to the maximum endurance limit, is determined by the formula: P _article = 500 + 1.66 D ² , where D is the diameter of the workpiece being rolled in, mm.

The proposed method, implemented by a multi-element abrasive-diamond and deforming spring tool for sequential grinding and PPD, provides a constant contact force of the abrasive-diamond and deforming elements with the treated surface and almost does not reduce the error of the previous processing, being a copy.

Sulfofresol (5% emulsion) serves as a lubricant-cooling fluid during grinding and PPD by the proposed method. Cast iron processing is recommended without cooling.

Example. The left screw H41.1016.01.001 of the screw pump EVN5-25-1500 (see figure 1) was processed, which had the following dimensions: total length - 1282 mm, length of the screw part - 1208 mm, cross-section diameter of the screw - ⌀27 ^{-0 , 05} mm, eccentricities - 1.65 mm, 3.3 mm, pitch - 28 ^{± 0.01} mm, roughness R _a = 0.4 μm; single-helical screw surface, left direction; material - steel 18HGT GOST 4543-74, hardness HB 207-228, weight - 5.8 kg. The allowance on the side of 0.2 mm. Processing was carried out on a mod screw-cutting machine. 16K20 using a spring device with a tool in the form of a spring with abrasive-diamond and deforming elements. The spring was made in the form of a ring with a diamond layer on the surface of ellipsoidal coils having a small axis a - 18 mm and a large axis b - 25 mm, the length of the arc of the diamond layer had a central angle α = 135 °, the diameter of the coil wire was 5 mm, and the thickness of the diamond bearing a layer of 1.0 mm, the diamond content at a 100% concentration is 56 carats, on a rubber-containing bond (analogue is the diamond endless seamless tape ALSHB used at the base enterprise). The working surface of the deforming elements of the spring was polished to Ra = 0.08 ... 0.16 μm.

The device was fixed on the support of the machine. Cutting fluid - sulfofresol. The peripheral speed of the workpiece - V _s = 21 m / min (0.35 m / s), n _s = 250 rpm, the speed of abrasive-diamond processing - V _AA = 5 m / s, n _AA = 1600 rpm at the opposite direction of rotation of the workpiece and the spring, the longitudinal feed S _ol = 0.25 mm / rev, the required roughness and accuracy of the screw surface was achieved after T _m = 11.5 min (against T _m ^bases = 106.5 min according to the basic version with traditional grinding with a grinding head, followed by polishing with a diamond tape on a 1K62 lathe and surface plastic deformation with a traditional sha Ikov obkatnikom at JSC "Livgidromash"). As a result of plastic deformation of microroughnesses and the surface layer, the surface roughness parameter increased to Ra = 0.4 μm with the initial value of Ra = 3.2 μm. The surface hardness increased by 30 ... 80% with a riveted layer depth of 0.3 ... 3 mm. The residual compressive stresses reached 400 ... 800 MPa on the surface.

The control was carried out by an indicator bracket with an indicator ICh 10 B cells. 1 GOST 577-68. The cumulative error between any non-adjacent steps was not more than 0.1 mm, the clearance during the control by the straightedge of the protrusions forming in diameter was not more than 0.07 mm, which is permissible according to the technical specifications.

The proposed method extends the technological capabilities of the processes of abrasive-diamond processing and surface plastic deformation, increases the roughness parameter of the treated surface, increases its hardness to a significant depth, increases productivity by increasing the contact spot of a large number of abrasive-diamond and deforming elements with the treated surface, and also reduces the cost of the process and reduces the cost of manufacturing equipment.

Information sources

1. German patent No. 665083, cl. 67 p. 1, 1940.

2. A.S. USSR No. 852528, M. cl. 3, B24D 7/06. Abrasive diamond tool. Fedoseev L.A. 2420368 / 25-08, 09.11.76; 08/07/81. Bull. No. 29 is a prototype.

Claims (2)

1. A method of combined processing by grinding and surface plastic deformation, comprising communicating rotational motion to the workpiece and rotational motion and longitudinal feeding to a spring tool, characterized in that they use a spring tool containing a housing with holes in its side walls, in which freely rotating sliding bearings are mounted and working abrasive-diamond-containing and deforming elements in the form of ellipsoid coils of a coil spring coiled into a ring, outer the working surface of which is made with deforming sections and oppositely located last abrasive-diamond sections deposited on the said outer working surface of ellipsoidal turns in an arc, the central angle α of which is 90 ° <α <180 °, the coil spring coiled into the ring contacts the ends of the bearings , the distance between which is equal to the length of the major axis of the ellipsoidal coil, is installed in the housing freely, covers the workpiece and is mounted on the latter with an interference fit to ensure radial minutes during grinding or filing static load during plastic deformation of the surface, wherein the rotation is performed on the individual motor via gear ring rolled into a helical spring and its screwing to ensure plastic deformation of the surface or sanding the workpiece. 2. The method according to claim 1, characterized in that the turning of the coil spring screwed into the ring is carried out using a mandrel with a groove on its outer surface, made of a width equal to at least the length of the small axis of the ellipsoid coil, and a depth equal to half the length of the large axis of the ellipsoid turn, and bushings, made with the possibility of installation in the specified groove.

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