RU2409462C1 - Device for vibration rolling of shafts and screws - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to metal forming, in particular to surface plastic deformation of shafts and screws. Proposed device comprises support element arranged in the casing to accommodate deforming elements, i.e. balls. Said support elements represents a helical coil spring with seats that embraces rolled billet. Support element is arranged in casing central bore on elastic bush. One end of said spring is rigidly attached to casing end face. Aforesaid deforming balls are arranged in seats inner surface.

EFFECT: expanded process performances, higher efficiency and accuracy.

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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.

A device for hardening processing is known, consisting of a vibrator of reciprocal longitudinal vibrations of a deforming element and a cam driven in rotation from an electric motor through a stepless gearbox and designed to excite transverse oscillatory movements of this deforming element [1].

A device for shock vibratory rolling, comprising 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 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 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 tool for surface treatment of parts by vibro-rolling, in which the balls are moved 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].

Also known is a 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 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 detecting,

The problem is solved by using the proposed device for processing parts such as shafts and screws by vibro-rolling, comprising a housing and a support element installed in the housing with deforming elements - balls placed in it, and the support element is made elastic in the form of a coil spring, covering the workpiece, one end which is rigidly attached to the end of the housing, and the supporting element itself is located in the Central hole of the housing on the elastic sleeve, while on the inner erhnosti supporting element - springs mounted in the sockets deforming elements - balls.

The essence of the design and operation of the device is illustrated by drawings.

Figure 1 presents a diagram of the processing of vibratory rolling of the screw of the proposed 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; in Fig.6 - shows the longitudinal movement of 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 the maximum value T _max in Fig.7 - shows the longitudinal movement of S _pr 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 device relates to a multi-tool with installed on a given size free deforming elements - balls 1 and serves for vibration processing by surface plastic deformation (PPD) - rolling shafts and non-rigid screws 2 mainly with a large pitch, for example, oil pump screws.

The proposed device 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 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 deforming elements on the workpiece.

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.

The device operates 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 _ol , while the device runs over the workpiece and deforming elements - the balls are pressed against the work surface with the force developed by the elastic supporting element - spring 5 and elastic sleeve 6, necessary for applying microrelief.

In this case, the supporting element - the spring 5 is untwisted, and the coils tend to decrease in diameter - are compressed, and deformation elements - balls are applied microrelief on 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 move 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 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 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 movements of the deforming elements - balls provide additional crushing on the lines of the trajectory of their movement and form additional protrusions and depressions, i.e. complicate the microrelief on the surface of the workpiece.

The 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 is informed of a longitudinal feed S _{PR of} not more than 0.1 ... 3.0 mm / rev. The optimal supply S _pr ^about is determined by the formula:

S _CR ^about = k S _E ,

where k is the number of deforming elements;

S _E - feed to 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.

Example. The screw left H41.1016.01.001 of the screw oil pump ЭВН5-25-1500, which had the following dimensions, was processed by vibro-rolling: the total length was 1282 mm, the length of the screw part was 1208 mm, and 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 S _pr ^about = 48 · 0.03 = 1.44 mm / about, 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 size by which the size has changed after running-in - 0.01 ... 0.02 mm; Sulfofresol (5% emulsion) served as the lubricating-cooling fluid during the run-in.

The required roughness and accuracy of the helical surface was achieved after T _m = 1.13 min (against _Tm ^bases = 16.75 min according to the basic version with traditional grinding using a grinding head, followed by polishing with an abrasive tape LVT 2200 × 55 E4, 5-8 -10 GOST 12439-79 on a 1K62 lathe at Livhydromash JSC). 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 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.

The proposed device 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 device allows to increase processing productivity by 1.5 ... 2.0 times and to ensure high accuracy.

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

Claims (1)

A device for processing parts such as shafts and screws by vibro-rolling, comprising a housing and a support element installed in the housing with the deforming elements - balls placed in it, characterized in that the support element is made elastic in the form of a coil spring covering the workpiece, one end of which is rigidly attached to the end of the housing, the support element is located in the Central hole of the housing on the elastic sleeve, while on the inner surface of the support element is a spring in the sockets installed We deforming elements - balls.

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