RU2288816C1 - Screws diamond-abrasive working with use of former - Google Patents

Abstract

FIELD: machine engineering, namely working of precise screws of hard-to-form materials.

SUBSTANCE: apparatus includes probe engaging with former and being in the form of roller and tool such as diamond-abrasive disc. In order to enlarge manufacturing possibilities, to improve quality, efficiency and accuracy of working former is mounted at side of end of worked screw. Thickness of former is equal to pitch of worked screw thread. Probe is mounted in separate strut on movable plate of support diametrically opposite relative to diamond-abrasive disc and it is spaced in lengthwise direction by distance equal to pitch of screw. Radius of working surface of probe in its longitudinal section is equal to radius of peripheral working surface in longitudinal section of diamond-abrasive disc. Diamond-abrasive disc has separate drive unit and it is mounted in strut on movable plate of support with possibility of cross motion relative to said plate. Probe is in the form of movable rest that may be forced to worked screw by compression spring acting upon movable plate of support with force equal to cutting force of diamond-abrasive disc.

EFFECT: enlarged manufacturing possibilities, improved quality, enhanced efficiency and accuracy of working screws.

6 dwg

Description

The invention relates to mechanical engineering to the fields of machine tool engineering and mechanical engineering technology, can be used for finishing diamond abrasive machining of screw surfaces of precision screws from hard materials.

A device for diamond abrasive machining of screws on a copy, containing a probe in contact with the copier and having the shape of a roller, and a diamond-abrasive tool in the form of a circle [1].

The known device has significant disadvantages. This is a limited application: only for machining screw surfaces of screws; the complexity and complexity of the settings after editing as the circle becomes blunt and greasy, as well as the rapid loss and long-term restoration of the profile shape of the peripheral shape of the circle, which reduces the accuracy, quality and productivity of fine diamond abrasive processing. In addition, the inability to vary the longitudinal feed, which should be strictly defined and equal to the pitch of the machined screw, does not allow to establish the optimal cutting conditions.

A known method and device for grinding screws with a single-disc disk grinding wheel, which includes setting the wheel at an angle α _{in the} lifting turn of the machined screw and communicating to it an independent rotational movement and longitudinal feed, and the details of rotation and translational movement kinematically associated with the longitudinal feed of the wheel equal to the pitch of the screw being machined, using a circle one degree of hardness higher and one grain number less than with conventional grinding, a height equal to half a step o the screw being machined, and additionally tilt it at an acute angle α _APC to a plane perpendicular to the axis of rotation of the circle to create an axially offset cutting layer, which is determined by the formula

where α _in = arc tg [t / (2D)] is the angle of elevation of the turn of the screw being machined, deg;

t is the pitch of the screw, mm; D is the pitch diameter of the screw, mm;

D ^and - the outer diameter of the grinding wheel, mm [2].

The application of the known method and device for abrasive processing improves the quality, increases processing productivity and reduces the consumption of abrasive, while the method and device have significant disadvantages. This is a limited application: only for machining screw surfaces of screws; the complexity and complexity of the settings after editing as the circle becomes blunt and greasy, as well as the rapid loss and long-term restoration of the profile shape of the peripheral shape of the circle, which reduces the accuracy, quality and productivity of fine diamond abrasive processing. In addition, the inability to vary the longitudinal feed, which should be strictly defined and equal to the pitch of the machined screw, does not allow to establish the optimal cutting conditions.

A known method and device for processing cams having a smooth transition of curved surfaces along the machined surface and a copy of a small thickness, which is attached to the end face of the workpiece. On this copy, a small area is processed with a blade tool; Further, the probe roller moves along the previously processed surface area.

The disadvantages of the known method and device are the low accuracy of processing non-rigid workpieces due to the large one-sided cutting forces and the pressing forces of the probe, which lead to deflection and barrel-shaped. At the same time, the limitations of the method and device, which are realized mainly when working with a blade tool, do not allow using it, for example, when machining with diamond-abrasive wheels.

The objective of the invention is to expand the technological capabilities of processing on the copy and the machined surface, simplicity and minimal laborious settings after editing, the ability to set the optimal cutting conditions, as well as improving the quality, productivity and accuracy of processing.

The problem is solved by the proposed device for diamond abrasive machining of screws according to the copier, containing a probe in contact with the copier and having the shape of a roller, and a tool in the form of a diamond-abrasive wheel, while the copier is fixed from the side of the end of the machined screw, its thickness is equal to the pitch of the machined screw and the probe is mounted on a separate stand on a movable support plate diametrically opposite to the diamond-abrasive wheel at a distance in the longitudinal direction equal to the pitch of the screw being machined, than the radius of the working surface in the longitudinal section of the probe is equal to the radius of the peripheral working surface in the longitudinal section of the diamond-abrasive wheel, which has an individual drive and is mounted on a rack on a movable plate of the caliper with the possibility of lateral movement relative to it, while the probe is made in the form of a movable rest pressing the compression spring to the screw being machined, acting on the movable plate of the caliper with a force equal to the cutting force of the diamond-abrasive wheel.

The essence of the method is illustrated by drawings.

Figure 1 shows a diagram of the processing of the initial portion of the screw by copy using the proposed device with the installation of the machined screw in the chuck of the lathe with the back center pressed with a new diamond-abrasive tool, top view; figure 2 is a section aa in figure 1, the device for attaching the probe to the caliper; figure 3 is a section bB in figure 1, the fastening device of a diamond-abrasive tool; figure 4 - element In figure 1; figure 5 - element G in figure 1; Fig.6 is a diagram of the processing of the subsequent section of the screw on the previously processed section of the proposed device with the maximum worn diamond-abrasive tool, top view.

The proposed device is intended for diamond-abrasive machining of screws 1 according to copy 2. The device includes a message to tool 3 in the form of a diamond-abrasive wheel of independent rotational movement V _and , which is provided by an individual engine, and the machined screw 1 - independent rotation of V _З and longitudinal feed S _pr . _Pop S traverse cam tool 2 is provided, the thickness of which is equal _to l t step machined screw 1 and the surface treated. The copier 2 is fixed at the end of the machined screw and aligned with it in such a way that it is a continuation of the machined screw.

The probe, having the shape of a roller 4, initially in contact with the copier 2, and then with the machined surface of the screw, is installed in a diametrically opposite place relative to the tool 3 at a distance in the longitudinal direction equal to the pitch t of the machined screw 1.

The radius R _{u of the} working surface in the longitudinal section of the probe roller 4 is equal to the radius R _{and the} peripheral working surface in the longitudinal section of the diamond-abrasive tool 3. To increase the accuracy of processing, it is necessary to reach the minimum values of the radii R _u and R _and .

The probe 4, which acts as a movable lunette, is loaded with a clamp force P _u to the workpiece, equal to _the cutting force P developed by the tool 3.

Work using the proposed device for diamond abrasive processing of screws on a copy is made in the following sequence.

A copier 2 is installed from the end onto the machined screw 1, which has previously passed roughing, so that the base of the machined screw is not disturbed and the longitudinal axis of the screw coincides with the axis of the centers of the machine on which the machining is performed. To the machined screw installed, for example, in the chuck 5, equipped with cams 6, and the machined screw pressed by the rear center 7 of the lathe, the probe 4 is fed in the form of a roller using the handwheel 8, which is mounted on the screw 9 of the transverse support 10 of the machine. The screw 9 acts on the movable plate 11 through the spring 12, creating a certain force P _u on the probe roller 4. Next, using the handwheel 13, which is mounted on the screw 14, connected to the upper movable plate 15, a diamond-abrasive tool 3 mounted on the screw is fed the spindle of the tool head 16, which is mounted on the upper movable plate 15. The tool head 16 contains an individual drive for rotating the tool 3, the latter is mounted on the output shaft of the drive. On the dial (not shown) with the handwheel 13, the grinding depth is set and the longitudinal feed S _{ave is} turned on.

When finishing the screw 1 according to the proposed method according to the copier 2, a small initial portion is polished, equal to the step length t; Further, the roller 4 of the probe is mixed along the previously processed portion of the surface of the workpiece.

In an industrial test of the device, the left screw H41.1016.01.001 of the screw pump EVN5-25-1500 was processed, which has 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. Side allowance - 0.25 mm. Processing was carried out on a modernized mod screw-cutting lathe. 16K20 with a tool grinding head and probe, installed respectively in front and behind the workpiece, on the transverse support of the machine with an abrasive one-thread disc disk type PP 200 × 16 × 32 GOST 2424-83 44A 8-16 VM1-VM2 8-12 K. When editing, the peripheral worker the surface of the circle is profiled torus with a radius R _and = 5 mm, the speed of the new tool v _i = 31.42 m / s, n _i = 3000 rpm, the peripheral speed of the workpiece v _d = 15.1 m / min, n _d = 160 rpm, longitudinal feed S _ol = 2 mm / rev. A copier made with a thickness l _k = 28 mm equal to the pitch of the screw being machined was mounted on the screw being machined on a cylindrical neck provided by the screw structure and was chamfered with the workpiece.

The required roughness and accuracy of the helical surface was achieved after T _m = 7.6 min (against T _m ^bases = 16.5 min according to the basic version with traditional grinding of screws on the modernized lathe 1K62 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.

Thanks to the use of the proposed device for diamond-abrasive machining of screw surfaces of screws by copier and machined surface, technological capabilities have expanded, quality has improved, machining productivity has increased due to the choice of optimal processing modes, dressing has been simplified, the setup time has been reduced, and the abrasive consumption has been reduced.

Information sources

1. RF patent 2176179, MKI ⁷ V 23 G 1/36. A method of grinding screws with a single-thread disc grinding wheel. Stepanov Yu.S., Afanasyev B.I. and other Application No. 99122990/02, application. 10/29/99, publ. 11/27/2001. Bull. No. 33.

2. Reference technologist-machine builder. In 2 vols. T.1 / Ed. A.G. Kosilova and R.K. Meshcheryakova. - 4th ed., Revised. and add. - M .: Engineering, 1986. P.232, Fig. 17, b - prototype.

Claims (1)

A device for diamond abrasive machining of screws according to the copier, containing a probe in contact with the copier and having the shape of a roller, and a tool in the form of a diamond abrasive wheel, characterized in that the copier is fixed on the side of the end of the machined screw, its thickness is equal to the pitch of the machined screw, and the probe is mounted on a separate stand on a movable support plate diametrically opposite to the diamond-abrasive wheel at a distance in the longitudinal direction equal to the pitch of the screw being machined, and the radius of the working surface in the longitudinal section of the probe is equal to the radius of the peripheral working surface in the longitudinal section of the diamond-abrasive wheel, which has an individual drive and is mounted on a stand on a movable support plate with the possibility of lateral movement relative to it, while the probe is made in the form of a movable lunette with the possibility of clamping to the screw being machined a compression spring acting on the movable plate of the caliper with a force equal to the cutting force of the diamond-abrasive wheel.

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