RU2268135C1 - Non-rigid screw rolling-out method - Google Patents

Abstract

FIELD: plastic metal working, possibly plastic surface deforming of screws of screw pumps.

SUBSTANCE: method comprises steps of imparting rotation to worked blank and imparting lengthwise feed motion to deforming tool including body and holder movably joined with body and having deforming members. In order to enhance efficiency and quality of working rolling out process is performed by means of several deforming members. Tool is provided with two discs having central openings; one disc is rigidly secured with tool body and other disc is rigidly secured to end of first disc by means of spacing sleeves and screws. Holder carrying deforming members is freely mounted between discs with the aid of three tension springs. Holder includes rings inserted into its end grooves for limiting motion in axial direction of deforming members freely mounted in recess of holder opening. In order to prevent rotation of holder, it is provided with handle arranged in periphery and resting upon roller with pivot fixed between discs. Said tension springs are mounted on spacing sleeves.

EFFECT: enhanced efficiency and quality of working.

5 dwg

Description

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

A known method, implemented by a three-roller device for rolling in non-rigid shafts, which can be upgraded for rolling screws, consisting of a holder with rollers, pivotally connected to the housing, which is mounted on the support of the machine [1].

The disadvantage of this method is the limited application, narrow specialization (only for cylindrical surfaces) and low productivity, while to obtain high quality it is necessary to create large working forces, and this requires the use of rollers with a large radius of the profile, which negatively affects the overall dimensions and not always feasible.

The objective of the invention is the expansion of technological capabilities by providing a rolling treatment of the screw surfaces of the screws with a large step, as well as reducing costs, increasing productivity and improving the quality of production, thanks to the use of the same machine on which the helical surface of the workpiece was pre-treated.

The problem is solved by the proposed method of rolling in non-rigid screws predominantly with a large step, in which rotational movement is reported to the workpiece, and a longitudinal feed movement is transmitted to a deforming tool comprising a housing and a holder with deforming elements movably connected to the housing, while rolling is carried out by many deforming elements moreover, the tool is equipped with two disks with central holes, one of which is rigidly connected to the housing, and the other di ck is rigidly attached to the end face of the first disk with spacer sleeves and screws, while a holder carrying deforming elements with rings that are inserted into the end grooves of the holder and axially limit the deforming elements are freely installed between the disks by means of three extensions in the form of tension springs freely located in the groove of the hole of the holder, while to prevent rotation of the holder, it is equipped with a handle located on the periphery, which rests on a roller with an axis fixed between the disks, rum, the stretch-mentioned springs are fixed to the spacers.

The essence of the method is illustrated by drawings.

Figure 1 presents a deforming tool for rolling in non-rigid screws, a longitudinal section along G-G in figure 2; figure 2 is a right view along A (rotated) in figure 1; figure 3 - element B in figure 1; figure 4 is a General view of the deforming tool according to figure 2; 5 is a diagram of a processing by rolling in a screw pump of a screw pump on a lathe.

The proposed method relates to surface plastic deformation (PPD) treatment - rolling in non-rigid screws mainly with a large pitch, for example, oil pump screws, a multi-element tool with free rollers or balls set to a predetermined size.

The deforming tool comprises a body 1 of a welded structure, with which the tool is mounted, for example, on a support of a lathe. In the housing you can distinguish: half disk 2, located vertically, two mutually perpendicular horizontal strips 3 for fixing the housing in the tool holder of the caliper and stiffeners 4.

Deforming elements, such as balls 5, are located in the hole of the holder 6, movably mounted in the housing 1 using two disks 7 and 8. The disks 7 and 8 have central holes for the passage of the workpiece. The disk 7 is rigidly connected to the half-disk 2 of the housing 1 by screws 9, and the other disk 8 is rigidly attached to the end of the disk 7 using spacer sleeves 10 and screws 11. Between the disks 7 and 8 in a sliding fit (H7 / h6) with a clearance is freely installed with three extensions in the form of tension springs 12 holder 6. The springs 12 are fixed at one end to the holder 6, and the other to spacer sleeves 10.

Rings 13 are inserted into the end grooves of the holder 6, which limit in the axial direction and prevent the deforming elements 5, freely located in the groove of the opening of the holder 6, from falling out.

To prevent rotation of the holder 6 in contact with the rotating workpiece, it is equipped with a handle 14 located radially on the periphery of the holder 6. The handle 14 is supported on a roller 15 with an axis 16 fixed between the disks 7 and 8.

Assembly of the deforming tool is carried out in the following sequence.

The disk 1 is attached to the casing 1, welded from individual elements (half-disk 2, planks 3 and stiffeners 4) with screws 9. The holder 6 is separately assembled. The holder is assembled by installing deforming elements 5 in the trench, fixing them with rings 13, which are freely inserted into the end grooves of the holder, fixing the stretch springs 12 and screwing the handle 14.

The general assembly of the deforming tool is completed by installing the disk 8 and fastening it with the help of rollers 10 with screws 11 with the preliminary installation of the holder 6 assembly between the disks 7 and 8 and the axis 16 with the roller 15, while the springs 12 are tensioned and fixed on the rollers 10.

At the end of the assembly, a check is made and, if necessary, adjustment of the gaps between the disks 7 and 8 and the holder 6 by installing washers (not shown) between the rollers 10 and the disk 7 or 8 with the aim of free lateral displacement of the holder 6 relative to the disks 7 and 8. without radial play the assembled tool on the deforming elements in the inner diameter d should not exceed 8 ... 10 microns.

Work on the proposed method is carried out in the following sequence.

When finishing with surface plastic deformation - rolling in a shaft with a variable cross-section 17 (for example, a screw of a screw pump having a profile and dimensions D, D ₁ , t shown in Fig. 5) with a deforming tool, a screw stock that has undergone preliminary, for example, turning, fasten in the chuck 18 of the spindle 19 of the front headstock 20, bring the tool and enter the free end of the screw blank into the hole of the tool, and tighten the center 21 of the tailstock 22. The rotational movement V _{s is} reported to the screw being machined. The speed of rotation of the workpiece is set depending on the required performance, design features of the workpiece and equipment. Usually the speed is 30 ... 150 m / min.

The deforming tool is informed of a longitudinal feed S _pr in one direction of not more than 0.1 ... 3.0 mm / rev. The optimal supply S _CR ⁰ is determined by the formula:

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 another screw size in the tool, it is enough to replace the holder and deforming elements.

Example. The left screw N41.1016.01.001 of the screw oil pump ЭВН5-25-1500, which had the following dimensions, was processed by rolling in: 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 processing by rolling was carried out on a mod screw-cutting lathe. 16K20, the peripheral speed of the workpiece - v _s = 84.78 m / min (1.41 m / s), n _s = 1000 rpm, the longitudinal feed S _pr ° was determined by the formula S _pr ° = k · S _e mm / about and took S _pr ° = 13 · 0.03 = 0.39 mm / rev, where k = 13 is the number of balls in the tool, the diameter of the balls is 7.94 mm. The breaking-in force was about ≈1700 N, the depth of the riveted layer was in the range 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 a lubricant-cooling fluid during the run-in.

The required roughness and accuracy of the helical surface was achieved after T _m = 3.13 min (against T _m ^bases = 16.75 min according to the basic version with traditional grinding using a grinding head, followed by polishing with an abrasive tape ЛВТ 2200 × 55 Э4, 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 when controlling 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 of rolling in non-rigid screws with a floating multi-element tool are:

- the possibility of rolling in non-rigid screws with an increase in machining accuracy (by 10 ... 20%) due to the rigid design of the holder (shape deviation no more than 10 ... 30 microns);

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

- ensuring a constant contact force of the deforming elements and the work surface;

- reduces the error of the previous processing;

- the multi-element tool 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 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 method of rolling in screw surfaces is easy to implement, and the deforming tool is not complicated in design and reliable in operation. The structural layer obtained on the surface of the workpiece has increased hardness and, accordingly, wear resistance and resistance to fatigue failure.

Using the proposed method allows to increase the processing productivity of 1.5 ... 2.0 times and to ensure high accuracy.

Information sources

1. Reference technologist-machine builder. In 2 vols. T.2 / Ed. A.G. Kosilova and R.K. Meshcheryakova. - 4th ed., Revised. and add. - M .: Mechanical Engineering, 1985. P.387, Fig. 6 - prototype.

Claims (1)

A method of rolling in non-rigid screws, mainly with a large step, in which rotational movement is reported to the workpiece, and a longitudinal feed movement, which is characterized in that several rolling-forming elements, is run, is supplied to a deforming tool comprising a body and a holder with deforming elements movably connected to the body. moreover, the tool is equipped with two disks with central holes, one of which is rigidly connected to the housing, and the other disk is rigidly attached to the end face the first disk with the help of spacer sleeves and screws, while between the disks, a holder carrying deforming elements with rings that are inserted into the end grooves of the holder and axially limit the deforming elements freely located in the trough holes of the holder, while to prevent rotation of the holder, it is equipped with a handle located on the periphery, which is supported by a roller with an axis fixed between the disks, while the said stretch -pruzhiny fixed on the spacers.

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