RU2306217C1 - Spring tool for strengthening - Google Patents

Abstract

FIELD: plastic working of metals, namely finishing-strengthening operations.

SUBSTANCE: tool has disc holder to outer surface of which cylindrical springs provided with deforming turns are secured. Cylindrical springs are coiled to rings; their deforming turns are turned out and arranged in lengthwise plane of cylindrical springs. Holder has annular grooves where coiled to rings cylindrical springs are mounted with tightness. Each annular groove has bottom shaped according to configuration of inner surface of coiled to ring cylindrical spring at forming recesses and with possibility of arranging each deforming turn of coiled to ring cylindrical springs in respective its own recess. Each deforming turn is rigidly secured to shaped bottom.

EFFECT: enlarged manufacturing possibilities, enhanced efficiency due to using multi-member tool, improved quality of worked surface.

6 dwg, 1 tbl, 1 ex

Description

The invention relates to mechanical engineering technology, in particular to the production of equipment for finishing and hardening processing of steel and alloy billets by surface plastic deformation with deforming elements in the form of coil spring coils.

Known spring tool for hardening, containing a disk holder, on the outer surface of which are fixed cylindrical springs with deforming coils [1].

The disadvantages of the known tool are: narrow technological capabilities that do not allow to process shaped surfaces, and low productivity due to the small number of deforming elements, as well as hardening to a small depth due to the fact that the drop-shaped contact of the deforming element with the workpiece is longitudinal and of considerable length .

Known rotating spring tool for dynamic hardening by surface plastic deformation, in which on the outer surface of the disk holder fixed coiled coil ring [2]. Separate turns of the spring during the working rotation of the tool holder play the role of deforming elements that interact with the machined surface of the rotating workpiece mounted on a screw-cutting lathe.

The disadvantages of the known tool are: narrow technological capabilities that do not allow to process shaped surfaces with small radii of curvature, and low productivity due to the small number of deforming elements, as well as hardening to a small depth due to the teardrop-shaped contact of the deforming element with the workpiece longitudinally and of considerable extent.

The objective of the invention is to expand the technological capabilities of surface plastic deformation through the use of a multi-element rolling tool, as well as increasing the roughness parameter of the treated surface, increasing its hardness to a considerable depth due to the periodic, combined and sequential force impact on the treated surface of the deforming elements and due to the transverse drop-shaped arrangement, significant extent of contact deforming element of the workpiece, increasing the productivity by increasing the contact area of the deforming elements with the surface being treated, the duration of work and tool life, as well as cheaper manufacturing tool and reducing process cost.

The problem is solved using the proposed spring tool for hardening, containing a disk holder, on the outer surface of which are fixed coil springs with deforming coils, and the coil springs are rolled into rings, their deforming coils are deployed and located in the longitudinal plane of the coil springs, the holder is made with ring grooves , coil springs rolled into rings are fitted with an interference fit, each annular groove is made with a shaped bottom according to the config walkie-talkies of the inner surface of a coil spring coiled into a ring, with the formation of niches and with the possibility of arranging each deforming coil of coil springs coiled into rings in its niche, each said deforming coil being rigidly attached to the shaped bottom.

Features of the design of the tool are illustrated by drawings.

Figure 1 shows the proposed tool for hardening with deforming elements in the form of coils, deployed along a spring, rolled into a ring, a partial longitudinal section; figure 2 is a cross section aa in figure 1; figure 3 is a General view of the tool on the left in figure 1; figure 4 is a diagram of the interaction of a single deforming coil with the workpiece, a cross section; in Fig.5 is a view B in Fig.4, a drop-shaped trace of a deforming coil on the machined surface of the workpiece; figure 6 - diagram of the hardening process of the screw of the proposed tool.

The proposed tool 1 is used for finishing by surface plastic deformation by hardening the surfaces of revolution and flat surfaces of the workpiece.

The main deforming element of the reinforcing tool 1 are round turns 2 of a coil spring 3, which is rolled into a ring. In this case, the deforming coils 2 are deployed and located in the longitudinal planes of the springs 3. The springs 3 rolled into rings are fixed on the outer surface of the disk holder 4, which contains many annular grooves having a shaped bottom 5, with a depth of not more than half the outer diameter of the coil, determined by the formula:

h≤0.5 · d,

where h is the depth of the annular groove, mm;

d is the outer diameter of the coil of the spring, mm

The bottom 5 of the annular grooves is configured to configure the inner surface of the annular springs 3 with the possibility of arranging each coil 2 in its niche.

In the annular grooves with a high interference are the rings of springs 3, each coil 2 of which is rigidly attached to the shaped bottom 5 in a known manner, for example, by embossing, spot welding, etc.

Processing is performed on turning, grinding and milling machines; when processing, for example, a screw (see Fig. 6), it is informed of a rotational movement with a frequency of V _s , the tool is given a rotational movement with a frequency of V _{and a} longitudinal feed movement S, _etc. Preload spring tool carry out the transverse movement of the caliper S _pop .

A feature of the contact interaction of a set of deforming elements with the workpiece surface being processed is the implementation of force action with slippage. At the same time, a regular microrelief is formed on the treated surface in the form of peculiar drop-like processing traces, which provide good lubrication and increase efficiency. Due to the transverse arrangement of the deforming coil of the tool spring relative to the screw blank, the coil is contacted on some extended surface of the workpiece (see Figs. 4-5). Due to the consistent force on the work surface of the deforming elements and the significant length of the drop-shaped contact of the deforming element with the workpiece, its hardness is increased to a considerable depth compared to processing with a tool with a longitudinal arrangement of a turn (as in the prototype).

In addition, the arrangement of deforming coils transverse relative to the workpiece-screw being processed contributes to a smoother entry of the coils into contact with the workpiece and out of contact, thereby reducing process vibrations and improving the quality of the processed surface.

Example. The left screw H41.1016.01.001 of the screw pump EVN5-25-1500 was processed, which had the following dimensions: total length - 1282 mm, length of the screw part - 1208 mm, cross-section diameter of the screw - d = ⌀27 ^-0.05 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. Processing was carried out on a mod screw-cutting machine. 16K20 using the proposed spring tool, which was mounted on the spindle of a special head with an individual drive, which in turn was installed on a support of a lathe.

The deforming elements were coil springs from heat-treated steel grade 65G, which were made of wire with a diameter of 3 mm. The diameter of the springs is 30 mm, the number of turns is 30 with a pitch of 12 mm. The turns were turned by their planes along the longitudinal axis of the springs and the working surfaces of the turns were polished to R _a = 0.08 ... 0.16 μm. On the outer surface of the holder, grooves were grooved and shaped bottoms of grooves were milled for laying in them with interference ring springs in the amount of 5 pieces. The turns were fastened in the grooves of the holder using spot welding. To reduce vibration and imbalance, the holder assembly was balanced with ring springs. The preload of the spring tool was carried out as a result of the lateral movement of the support of the lathe by 0.75 ... 1.5 mm (from the point of contact of the springs with the workpiece). The frequency of rotation of the tool was regulated using an individual drive built into the tool head. Before finishing hardening treatment, the screws from one installation were pre-machined to ensure R _a = 3 ... 4 μm. Since the screw is a non-rigid structure, when hardening, we use a movable rest, installed against the tool (not shown in Fig. 6). After processing with a spring tool, surface roughness was measured on a profilograph-profilometer of the Caliber plant mod. 201, and microhardness - on the PMT-3 device. The results are shown in table 1.

1. The results of hardening treatment of screws made of 18KhGT steel with a spring tool with a rotation frequency of V _and = 8.8 m / s (n _and = 1400 rpm) Workpiece rotation frequency V _s , m / s (n _s , rpm) Longitudinal feed of the tool, S _ol , mm / rev Actual size after hardening, mm R _a , μm Microhardness, Nμ, MPa 0.01 26,994 1.4 3120 0.14 (100) 0,075 26,992 1,0 3080 0.15 26,996 0.65 2970 0.01 26,990 0.9 3040 0.70 (500) 0,075 26,990 0.6 2960 0.15 26,988 0.5 2920 0.01 26,984 0.3 2930 0,025 26,986 0.35 2860 1.40 (1000) 0.04 26,988 0.4 2790 0,075 26,990 0.48 2720 0.15 26,990 0.57 2600 0.3 26,996 1.15 2540 Note. Initial data: R _a = 3.5 μm; Hμ = 2000 MPa; d = 27,000 mm.

As follows from the data presented in table 1, when the processing conditions are close to optimal (tool rotation speed V _and = 8.8 m / s, workpiece rotation frequency V _s = 1.40 m / s, longitudinal feed of the tool S _CR = 0 , 01 ... 0.04 mm / rev), R _a = 0.3 ... 0.4 μm and hardening of the surface layer to 30 ... 40% were provided.

The required roughness and accuracy of the helical surface was achieved after T _m = 31.2 min (against T _m ^{bases of} 65.9 min according to the basic version with traditional grinding, followed by polishing with a diamond belt on a 1K62 lathe at Livhydromash JSC). The control was also 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 results obtained indicate a significant decrease in roughness and an increase in the microhardness of the surface layer. After processing, the diameter of the workpiece decreased by 0.02 ... 0.06%, and the parameter of surface roughness decreased to 0.3 ... 0.4 μm. The average value of the surface microhardness after hardening by the proposed spring tool is 2.8 ... 2.9 GPa, i.e. 30 ... 40% higher than the original.

The proposed spring tool allows you to expand the technological capabilities of surface plastic deformation due to the force of action with a multi-element rolling tool, increase the roughness parameter of the treated surface, increase its hardness to a considerable depth due to the periodic, combined and sequential impact of deforming elements on the treated surface and due to the transverse arrangement of the drop-shaped, significant the length of the contact deforming about the element with the workpiece, to increase productivity by increasing the contact spot of deforming elements with the work surface, the duration of the work and the service life of the tool, as well as reduce the cost of manufacturing the tool and reduce the cost of the process.

Information sources

1. Patent SU 1738617 A1, IPC B24V 39/00. 06/07/1992 - a prototype.

2. Nikiforov A.V., Sakharov V.V. Technological capabilities and prospects of finishing and hardening with an elastic tool (Mashinostroit. Pr-in. Ser. Progressive technology. Processes in engineering: Obzor. Inform. / VNIITEMR. Issue 5). - M., 1991 - S. 31 ... 37.

Claims (1)

A spring hardening tool containing a disk holder, on the outer surface of which are fixed coil springs with deforming coils, characterized in that the coil springs are rolled into rings, their deformation coils are deployed and located in the longitudinal plane of the coil springs, the holder is made with ring grooves, rolled into rings, coil springs are installed in them with an interference fit, each annular groove is made with a shaped bottom according to the configuration of the inner surface rolled into a ring of a coil spring with the formation of niches and with the possibility of arranging each deforming coil coiled into rings of coil springs in its niche, each said deforming coil being rigidly attached to the shaped bottom.

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