RU2268134C1 - Floating apparatus for rolling-out non-rigid screws - Google Patents

Abstract

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

SUBSTANCE: apparatus includes body designed for mounting in support of machine tool and holder with deforming members jointly secured to body. In order to enhance efficiency and quality of working, apparatus is provided with two discs having central openings. One of said discs is rigidly secured to body, other disc is rigidly secured to end of first disc by means of pacing sleeves and screws. Holder carrying deforming members is freely mounted between discs with use of three tension springs. Holder includes rings inserted in its end grooves for limiting in axial direction motion of deforming members freely arranged in recess of holder opening. In order to prevent rotation of holder, it is provided with handle arranged in periphery and supported by means of roller with pivot mounted between discs. Said tension springs are mounted in spacing sleeves.

EFFECT: enhanced efficiency and quality of working.

5 dwg, 1 ex

Description

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

Known three-roller device for rolling in non-rigid shafts, consisting of a holder with rollers, pivotally connected to the housing, which is mounted on the support of the machine [1].

A disadvantage of the known device is the limited use, 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 profile radius, which negatively affects the overall dimensions and not always feasible.

The objective of the invention is to expand the technological capabilities of the tool by providing the processing of rolling in the screw surfaces of the screws with a large step, as well as reducing costs, increasing productivity and improving the quality of production by using the proposed device on the same machine on which the helical surface of the workpiece was pretreated.

The problem is solved by using the proposed floating device for rolling in non-rigid screws, comprising a housing, with which the device is mounted on a machine support, and a holder with deforming elements, pivotally connected to the housing, while it is equipped with two disks with central holes, one of which is rigidly connected to the case, and the other disk is rigidly attached to the end face of the first disk using spacer sleeves and screws, and between the disks is freely installed using three extensions in the form of tensioning toolholder 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 groove of the holder’s opening, while to prevent the holder from rotating, it is provided with a handle located on the periphery that rests on the roller with an axis fixed between the disks, in addition, the said spring springs are mounted on spacer sleeves.

The essence of the device is illustrated by drawings.

Figure 1 presents a floating device 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 device according to figure 2; figure 5 - diagram of the processing by rolling the screw of the screw pump of the proposed device on a lathe.

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

The device comprises a housing 1 of a welded structure, with which the device 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, for example, 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 openings 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 a davrazhka 6, and the other end are fixed 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.

The assembly of the device is carried out in the following sequence.

To the housing 1, welded from separate elements: half-disk 2, strips 3 and stiffeners 4, the disk 9 is attached with screws 9. The holder 6 is separately assembled. The holder is assembled by installing deforming elements 5 in the groove, fixing them with rings 13, which freely inserted into the end grooves of the holder, fixing the stretch springs 12 and screwing the handle 14.

The general assembly of the device is completed by installing the disk 8 and fastening it using the 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 device for deforming elements on the inner diameter d should not exceed 8 ... 10 microns.

The operation of the device is as follows.

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), the device is fixed by the proposed device in the cartridge 18 of the spindle 19 of the headstock 20, the device is brought in and the free end of the screw blank is introduced into the opening of the device and pressed by 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 device 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:

S _pr ° = 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 screw size in the device, 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 device, 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 value 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 screw 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 LVT 2200x55 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 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 floating multi-element device 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;

- 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 screws;

- the formation of a certain macro- and microgeometric shape of the treated surface, a decrease in the roughness parameter — smoothing of the surface, 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 rolling in screw surfaces with a 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.

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 floating device for rolling in non-rigid screws, comprising a housing intended for mounting on a machine support and a holder with deforming elements pivotally connected to the housing, characterized in that it is provided with two disks with central holes, one of which is rigidly connected to the housing, and the other the disk is rigidly attached to the end face of the first disk using spacer sleeves and screws, and between the disks is freely mounted using three stretch marks in the form of tension springs holder, carrying deforming elements, with rings that are inserted in the end grooves of the holder and axially limit the deforming elements freely located in the groove of the holder’s opening, 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, this said spring springs are mounted on spacer sleeves.

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