RU2412041C1 - Method of vibration rolling of shafts and screws - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to metal forming, particularly, to surface plastic deformation of shafts and screws. Billet is revolved relative to lengthwise axis. Deforming device consists of case accommodating support elements that houses straining balls. Support element is made up of helical coil spring embracing processed billet and having seats on inner surface. Said support element is arranged in base central bore on elastic sleeve. One end of said spring is rigidly secured to case face. Starting balls are arranged in aforesaid seats.

EFFECT: expanded process performances, higher accuracy of processing.

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Description

The invention relates to the processing of metals by pressure, in particular to the processing of surface plastic deformation (PPD) of shafts and screws, for example screw pumps with a large pitch.

There is a method of hardening processing and a device that implements it, consisting of a vibrator of reciprocal longitudinal vibrations of a deforming element and a cam driven into rotation from an electric motor through a stepless gearbox and designed to excite transverse vibrational movements of this deforming element [1].

A known method of shock vibratory rolling and a device containing a housing, a separator with a deforming element, a support in the form of a smooth roller mounted rotatably in the housing, while it is equipped with a support drive and an elastic element, one end of which is mounted on the housing and the other on the separator [2].

The disadvantages of the known methods and devices is that they do not use additional movement along the movement of the tool, namely, a change in the longitudinal feed of individual deforming elements, which reduces the quality of applying the microrelief on the part and the degree of its relief. With regard to obtaining such an additional movement of the deforming elements of the tool, the obvious technical solutions suggest the presence of complex drives to implement such a movement, which complicates the design of the device and the possibility of obtaining additional movement. In addition, the methods and devices are characterized by limited control capabilities in the creation of hardened layers and regular microrelief of the treated surface, low efficiency, insufficient depth of the hardened layer and insufficiently high degree of hardening of the treated surface.

A known method of surface treatment of parts by vibro-rolling and a tool in which the movement of the balls is carried out at a variable speed in the direction of movement of the tool relative to the part, the tool contains a holder with a ball [3].

There is also a known method and tool for processing flat surfaces of parts by vibro-rolling, comprising a drive holder, on which a ball is placed in the support element eccentrically to the axis of the holder [4].

The disadvantages of the known methods and tools [3, 4] is that they do not use additional movement along the eccentric movement of the tool, namely, the change in the speed of the tool along the arc described by the tool, which reduces the quality of applying the microrelief on the part and the degree of its relief. As for obtaining such an additional movement of the tool, the obvious technical solutions suggest the presence of complex drives to implement this movement, which complicates the design of the tool and the possibility of obtaining additional movement.

The objective of the invention is to expand the technological capabilities of surface plastic deformation processing by controlling the depth of the hardened layer, the degree of hardening and the microrelief of the surface with minimal energy consumption and the complexity of manufacturing tooling by using an elastic support element made in the form of a helical coil spring with deforming elements placed in it - balls, as well as cost reduction, increased productivity, and improved fabrication quality the detection.

The problem is solved by the proposed method, intended for processing parts such as shafts and screws by surface plastic deformation - vibro-rolling, including a message to the workpiece of rotational movements relative to the longitudinal axis, and to the deforming device containing the housing and the support element installed in the housing with the deforming elements placed therein - balls, longitudinal displacements, moreover, the supporting element is made elastic in the form of a helical coil spring, covering the machined th preform, one end of which is rigidly attached to the end of the housing, and the support member located in the central hole of the housing by an elastic sleeve, wherein the inner surface of the support member - the spring nests - set the deformation elements - balls.

The essence of the proposed method is illustrated by drawings.

Figure 1 presents a diagram of the processing of vibratory rolling of the screw of the proposed method using the developed device, a longitudinal section; figure 2 is a section along aa in figure 1; figure 3 - installation of the device and the workpiece before processing; figure 4 - supporting element in the form of a helical coil spring with deforming elements - balls inside, a partial longitudinal section; figure 5 is a section along BB in figure 4; figure 6 shows the longitudinal movement S _PR device from right to left, while the spring of the support element increases in length and the pitch of the turns increases to a maximum value of T _max ; Fig. 7 shows a longitudinal movement S _{pr of the} device from left to right, while the spring of the support element decreases in length and the pitch of the turns decreases to a minimum value of T _min .

The proposed method and device are used for vibration processing by surface plastic deformation (PPD) - rolling of shafts and non-rigid screws 2 mainly with a large pitch t, for example, screws of oil pumps. The method includes communicating to the workpiece rotational movements with a speed of V _З relative to the longitudinal axis, and to a deforming device comprising a body and a support element installed in the body with the deforming elements placed therein - balls 1, longitudinal displacements S _ave .

A device that implements the proposed method comprises a housing having a base 3 and a cover 4, which are connected by screws. In the central hole of the housing there is a support element 5 with the deforming elements - balls 1. located therein. The support element 5 is made elastic in the form of a coil spring and acts as a separator.

The supporting element - spring 5 - covers the workpiece 2, and in the free state, its inner diameter along the vertices of the deforming elements - balls D _AND - is less than the diameter of the workpiece D ₁ .

One end 5k of the supporting element - the spring 5 - is rigidly attached to the end of the housing. In Fig.3, the end 5k of the supporting element - the spring 5 - is rigidly attached to the end face of the base 3 (see Fig.2).

The supporting element 5 is located in the Central hole of the housing on the elastic sleeve 6, which is made, for example, of rubber by vulcanization or other elastic material. The elastic sleeve 6 allows you to compensate for the change in the diameter of the workpiece during the processing of screws. In addition, the elastic sleeve 6 allows you to change its rigidity when connecting and tightening the cover 4 with the base 3, thereby changing the force of action of the deforming elements 1 on the workpiece 2.

On the inner surface of the supporting element - the spring 5 - in the sockets 7 are installed deforming elements - balls 1 - and are held in them.

Work on the proposed method is as follows.

A device mounted, for example, on a support of a lathe (not shown), is led to a workpiece that is fixed in the chuck 8 of the spindle 9 of the headstock 10, and the elongated rear center 11 of the tailstock 12 is inserted into the opening of the device and the workpiece is pressed by the back center 11.

Turn on the rotational movement of the workpiece V _З and the longitudinal feed S _{pr to the} device, while the device runs into the workpiece and deforming elements - balls - are pressed against the work surface with the force developed by the elastic supporting element - spring 5 - and the elastic sleeve 6 necessary for applying the microrelief.

In this case, the supporting element - spring 5 - tends to unwind, and the turns tend to decrease in diameter - are compressed - and by deforming elements - balls - a microrelief is applied to the surface of the workpiece.

Due to the unevenness of the surface of the workpiece, as well as different hardness and roughness of its individual sections, the deforming elements - balls - are moved in the longitudinal direction along the surface of the workpiece, then decreasing, then increasing the step T of the spring of the supporting element, compressing and expanding its coils. The diameter of the workpiece varies from D ₁ to D, as a result of which the relative speed of movement of the deforming elements - balls - on the surface varies.

In Fig.6, with a longitudinal movement S _{pr of the} device from right to left, the spring of the support element increases in length and the pitch of the turns increases to a maximum value of T _max . When changing the direction (see Fig. 7) of the longitudinal feed S _{pr of the} device from left to right, the spring of the support element decreases in length and the pitch of the turns decreases to a minimum value of T _min .

Such additional longitudinal and transverse movements of the deforming elements - balls - provide additional crushing on the lines of their movement paths and form additional protrusions and depressions, i.e. complicate the microrelief on the surface of the workpiece.

определяют по формулеThe speed of rotation of the workpiece V _Z set depending on the required performance, design features of the workpiece and equipment. Typically, the speed is 30 ... 150 m / min. The device reports a longitudinal feed S _ol not more than 0.1 ... 3.0 mm / rev. Optimum feed

determined by the formula

,

,

where k is the number of deforming elements;

S _E - feed on one deforming element, accepted for balls no more than 0.01 ... 0.05 mm / rev.

When switching to processing a different size of the shaft or screw in the device, it is enough to replace the support element and deforming elements.

, где k=48 - количество шариков в устройстве, диаметр шариков 7,94 мм. Усилие вибронакатывания составляло около ≈700 Н, глубина наклепанного слоя находилась в пределах 0,15…0,20 мм; величина, на которую изменился размер после обкатки 0,01…0,02 мм; смазывающе-охлаждающей жидкостью при вибронакатывании служил сульфофрезол (5%-ная эмульсия).Example. The left screw H41.1016.01.001 of the screw oil pump ЭВН5-25-1500, which had the following dimensions, was processed by vibration rolling: the total length was 1282 mm, the length of the screw part was 1208 mm, the cross-section diameter of the screw was D ₁ = 27 ^-0.05 mm, D = 30.3 mm, eccentricity e ₁ = 1.65 mm, e = 3.3 mm, pitch t = 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. Preliminary processing by turning and finishing by vibro-rolling was carried out on a mod screw-cutting lathe. 16K20, the peripheral speed of the workpiece V _З = 84.78 m / min (1.41 m / s), n _З = 1000 rpm, the longitudinal feed was taken

where k = 48 is the number of balls in the device, the diameter of the balls is 7.94 mm The force of vibro-rolling was about ≈700 N, the depth of the riveted layer was in the range of 0.15 ... 0.20 mm; the value by which the size has changed after a run-in of 0.01 ... 0.02 mm; Sulfofresol (5% emulsion) served as a lubricant-cooling fluid during vibro-rolling.

по базовому варианту при традиционном шлифовании с помощью шлифовальной головки, с последующим полированием абразивной лентой ЛВТ 2200×55 Э4, 5-8-10 ГОСТ 12439-79 на токарном станке 1К62 на АО "Ливгидромаш"). Контроль проводился скобой индикаторной с индикатором ИЧ 10 Б кл. 1 ГОСТ 577-68. Накопленная погрешность между любыми не соседними шагами была не более 0,1 мм, просвет при контроле лекальной линейкой образующих по диаметру выступов не более 0,07 мм, что допустимо по ТУ.The required roughness and accuracy of the helical surface was achieved after T _m = 1.13 min (against

according to the basic version with traditional grinding using a grinding head, followed by polishing with an abrasive belt ЛВТ 2200 × 55 Э4, 5-8-10 GOST 12439-79 on a lathe 1K62 at JSC "Livhydromash"). 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 advantages of the proposed method, implemented by a multi-element device, are:

- the possibility of vibro-rolling of non-rigid shafts and screws with an increase in processing accuracy of 10 ... 20%, shape deviation of not more than 10 ... 30 microns;

- allows vibro-rolling at maximum feeds in comparison with the known single-element or three-element devices;

- reduces the error of the previous processing;

- multi-element device allows for multi-pass processing, due to which a higher quality of processing is achieved;

- allows you to unload the machine components from a one-sided application of force and handle non-rigid shafts and screws;

- the formation of a certain macro- and microgeometric shape of the treated surface, a decrease in the roughness parameter — smoothing of the surface, a change in the structure of the material — surface hardening — and the creation of a certain stress state — all this favorably affects the wear resistance.

A device operating according to the proposed method is not complicated in design and reliable in operation, and the method of vibro-rolling of cylindrical and screw surfaces by the device is simple to implement. The layer structures obtained on the surface of the hardened billet have increased hardness and, accordingly, wear resistance and resistance to fatigue failure. Using the proposed method and device can improve processing productivity by 1.5 ... 2.0 times and ensure high accuracy.

The method allows to increase the degree of relief without complicating the design of the tool.

Information sources

1. A.S. USSR 366062, IPC V24V 39/00. The method of hardening the surface of metal parts. G.M. Azarevich. 1616331 / 25-8. 12/07/1970; 01/10/1973.

2. A.S. USSR 1238952, IPC V24V 39/00. Device for shock vibratory rolling. Yu.G. Schneider, B.N. Bukin, G.R. Kruglov. 3818752 / 25-27. 12/04/1984; 06/23/1986.

3. A.S. USSR 313647, IPC V24V 39/02, 1971.

4. A.S. USSR 1232463, IPC V24V 39/06, 1986.

Claims (1)

A method of surface plastic deformation processing by vibro-rolling of shafts and screws, comprising communicating to the workpiece rotational motions relative to the longitudinal axis and longitudinal displacements to a deforming device comprising a housing and a support element installed in the housing with deforming elements placed therein - balls, characterized in that the support element is used, made elastic in the form of a helical coil spring, covering the workpiece, one end of which is rigidly attached lyayut to the end of the housing, and the support member is disposed in the central hole of the housing by an elastic sleeve, wherein the inner surface of said spring nests mounted deforming elements - balls.

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