FI69261B - SFAERISKT MAONGBLADIGT VERKTYG - Google Patents

Description

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C (45) Patent granted kjpJ Patent mo Malat 10 01 100G

(51) Kv.lk.> t.CI. 'B 23 D 77/1 b FINLAND —FINLAND (21) Patent application— PatentansSknlng 772329 (22) Filing date - Ansöknlngsdag 01.08.77 (H) (23) Starting date —Glltighetsdag 01.08. 77 (41) Tullut {ulklseksl - Blivit offentlig j 02.02.79

National Board of Patents and Registration publication n date— 3Q Qö gc

Patent and registration authorities '' Ansökan utlagd och utl.skriften publicerad J · J · J

(32) (33) (31) Privilege requested — Begärd priority (71) Kaiiningradsky Tekhnichesky Institut Rybnoi Promyshlennosti i Khozyaistva, Sovetsky Prospekt 1, Kaliningrad, USSR (SU) (72) Lev Aronovich Gik, Kaliningrad, USSR (SU) (7) This invention relates to tools for machining boreholes and holes, and more particularly to spherical multi-blade tools. (5 * 0 Spherical multi-blade tool - Sfäriskt mängbladigt Verktyg)

The invention can be most effectively utilized when machining relatively deep holes (at least ten times the depth of the diameter) and when machining holes to a high accuracy class (i.e., second or third).

In addition, the invention can be used in the machining of holes with chamfered walls.

Today, strict requirements are usually set for the accuracy of the machining of the holes (the accuracy class must even be second or third class) and for the roughness of the machined surface, which must not exceed R = 0.16-1.25 μπι. The machining of such holes

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the beam is usually performed either using blade-held or free plates equipped with two opposite blades. With such tools, a cutting depth of up to 0.1-0.2 mm is obtained and the surface finish roughness R = exceeds 1.25 μm, which a.

These holes must be post-processed either plastically by deformation 69261 or by grinding. When machining relatively deep boreholes or holes, said previously known tools would not ensure the required accuracy due to their relatively rapid change in dimensions due to wear. In order to achieve the required values, attempts have recently been made to use rotating tools equipped with different types of round blades. These are, for example, circular plate-shaped cutters in which the diameter of the cutting blade is equal to the diameter of the hole to be machined. The axis of rotation of the blade is inclined with respect to the axis of the hole to be machined at an angle of C0 to 15-20 °, so that its circular blade contacts the machined surface in two directly opposite areas, one for cutting and the other for smoothing or smoothing the machined surface. The dimensional stability of these tools has been emphasized compared to said conventional tools, but it has been found that the difficulties associated with centering such a tool in a hole affect the accuracy of machining. This disadvantage, together with the unresolved problem of chip reduction, has virtually prevented the use of these tools in industry.

In addition, rotating planar countersinks or units are known in which rotating, circular cutters extend at sharp and obtuse angles relative to the axis of the hole to be machined. However, such tools take up a lot of space and, in practice, are suitable for machining relatively large holes, e.g. more than 200 mm in diameter.

Attempts are now being made to use spherical multi-blade tools for this purpose in finishing drillings and holes.

Today, spherical multi-blade tools are already known, the end of which is made in the form of a block or unit, in which two cutting blades are placed on a spherical surface on the meridian part thereof. Due to the relatively rapid dimensional change of the blades over the blades, these units tend to lose their machining accuracy. To improve dimensional stability, in improved forms of the tools, blades are attached to segments rotated by an independent drive in the opposite direction relative to the axial feed direction of the tool. But even in this case, the dimensional stability of the tool has not been sufficiently improved. In addition, the latter tool has a complex structure and cannot be used

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3 69261 more than two blades, which affects the production efficiency of the machining work.

Such a spherical multi-blade tool for machining bores and holes is known, in which the spherical end carrying the blades is mounted on a bearing neck of a holder or arm. The blades extend along the meridian planes of the spherical head and the spherical end itself is rigidly attached to a bearing neck coaxial with the holder or arm.

During machining work, this spherical head performs the cutting in the same, relatively small areas of the blades without changing the blades because the head cannot be rotated by the bearing neck. Thus, only parts of the spherical head blades are used which are subject to high heat as well as rapid wear. This results in premature wear of the entire tool, not to mention how this affects productivity and machining accuracy.

The object of the invention is achieved by a spherical multi-blade tool characterized in that the blades are inclined with respect to the meridian planes of the spherical head, which head is mounted on the neck so as to rotate freely about this geometric axis extending at an acute angle to the tool shank and the drilled axis.

Due to the fact that the spherical head can rotate on a bearing neck whose geometric axis extends at an acute angle CK with respect to the axis of the holder or arm, the working areas of the spherical head blades change continuously with respect to the hole or bore to be machined, swinging these parts within a spherical band , which is equal to 2 £ ^. . This means that the dimensional stability of the tool is improved compared to previous tools at least as much as there are such working parts along each blade within the spherical band. In addition, each working part of the spherical head becomes used during a very short cut, when said continuous change of these parts takes place, even during fractions of only a second, so that it does not have time to overheat. This improves the cutting conditions and further improves the dimensional stability of the tool as well as the quality of the surface to be machined. Multiple improvements in tool dimensional accuracy in turn lead to better machining accuracy, and in addition, better dimensional accuracy makes it possible to increase efficiency and productivity.

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The fact that the blades are oblique to the meridian plane of the spherical head provides the required conditions for machining all or part of the perimeter of the hole, depending on a predetermined angle of inclination of the blades, the spherical head rotating on the bearing neck only due to contact between the head and a different knob is needed to rotate the head. In addition, the application area of the tool is larger because it can machine chamfered holes. In addition, the dimensional stability of the tool has been further improved due to the fact that the blades are longer and are limited by a spherical band defined by a central angle = 2.

Po. a somewhat surprising side effect of the invention is that the chips become kinematically reduced during the cutting operation due to a regular change in the value and direction of the blade inclination angle with respect to the cutting speed vector during each turn of the head. This effect is particularly advantageous when machining relatively deep boreholes or holes and the chips must be removed with certainty.

The planar portions of the spherical head should form the blades and each blade should extend at least along a portion of the arc of the circle. When the blades have this structure, the tool is easier to manufacture, as is its sharpening and re-sharpening. It is useful to place the blades of the spherical head on its spherical surface along the helical line. This increases the working length of the blades, improves the dimensional stability of the tool, improves its working conditions, e.g. by making the incision smoother.

The blades may form a section of protrusions projecting spherically on its meridian planes and having a profile corresponding to the desired profile of the hole to be machined, the grooves extending at the spherical end at an angle to its meridian planes.

The described structure of the blades allows the tool to be used to machine beveled holes, e.g. to plan the teeth of internal gears.

In addition, it is advantageous that the front or guide surfaces of the blades are in the same direction, which makes tool making, sharpening and re-sharpening easier. Alternatively, the front or guide surfaces of the blades may be in different directions. In this case, the tool is subjected to uniform, symmetrical loads during work, which improves machining accuracy.

In addition, the rear or rear surfaces of the blades can be chamfered to a rear angle of up to -15 °, resulting in additional machining of the bore or hole by smoothing, which improves surface quality and protects the blades from cavities.

The spherical head can also be made in the form of laminated discs which are mounted on the bearing neck to rotate relative to each other. In this case, during each machining operation, each blade can be rotated at its own best speed by contact between it and the hole to be machined, which improves the cutting conditions by slowing down the sliding speeds and which improves the dimensional stability of the tool.

To expand the range of application of the tool for semi-finishing or finishing boreholes or holes, and to increase the cutting power, the bearing neck should be staggered so that it has eccentric necks. When this structure is on, all of its blades can be made to perform the cut simultaneously throughout the work, making it possible to remove a relatively large machining margin from the bore or hole and increase the machining speed.

Po. the invention will be described in more detail by means of its embodiments and with reference to the accompanying drawings, in which Figure 1 shows a general perspective view of a spherical multi-blade tool with blades in opposite directions, Figure 2 shows a cross-sectional view of a spherical multi-blade tool with spherical surface planar parts Fig. 3 shows a general view of a spherical multi-blade work platform in which, according to the invention, the blades (shown schematically) are arranged around a spherical end along a helical line; Fig. 4 shows a general view of a spherical end, in which, according to the invention, the blades are formed by cuts and grooves in the projections or protrusions made in the spherical end; Fig. 5 shows a cross-sectional view of a spherical end in which, according to the invention, the front surfaces of the blades are in the same direction; Fig. 6 shows a cross-sectional view of a spherical end in which, according to the invention, the front surfaces of the blades are in opposite directions; Fig. 7 shows a partial longitudinal sectional view of a spherical multi-blade tool in which, according to the invention, the spherical head includes a lamination formed by discs; Fig. 8 shows a general view of a spherical multi-blade tool with a stepped structure; Fig. 9 shows a cross-sectional view along the axis of the bearing neck of the tool of Fig. 8; and Fig. 10 shows the tool of Fig. 8 as seen from the end surface of the spherical head.

Here, a spherical multi-blade tool is presented, in which a spherical head 1 (Fig. 1) carrying the blades 2 is mounted on a bearing neck 3 of a holder or arm 4.

The spherical end 1 has a housing or body 5 formed as a rotating body with a central bore 6 for mounting the head 1 on the bearing neck 3. The tool blades 2, formed by the cut between their front or guide surfaces 7 and the rear or rear surfaces 8, are arranged as intended. on the spherical surface A and are either integral with the body 5 of the spherical head 1 or are attached thereto in any suitable known manner.

The bearing neck 3 of the arm 4 is preferably cylindrical and provided with a means for holding the spherical end 1 axially, e.g. a nut 9, which cooperates with the threaded end of the bearing neck 3. In order to achieve self-positioning of the tool in the machined bore or hole 10, the spherical head 1 can be placed on the bearing neck 3 so that there is a gap 11 between the bearing neck 3 and the central bore 6 of the body 5, or the bearing neck 3 itself can be mounted on the arm 4 with limited radial displacement. which can be done with any suitable lightened tool heads, as is well known to those skilled in the art.

The tool arm 4 is preferably designed as a rotating body and has either a rear part (not shown in Figure 2) for attaching it to the tool holder or flanges for attaching it to a face plate (also not shown), a spindle, or a machining tool (not shown) rear stop, support or slide.

According to the invention, the blades 2 are oblique to the spherical

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69261 to the meridian plane of its end 1 (which is the plane of the drawing in Fig. 2). A spherical head 1 is mounted on a bearing neck 3 to rotate about this geometric axis 0-0. The bearing neck 3 is in turn placed at an acute angle cX with respect to the axis L-L of the arm 4. In order for the spherical head 1 to rotate on the bearing neck 3, the body 5 of the head 1 has suitable bearings 12, which can be either plain or plain bearings, and which are designed to receive radial and longitudinal loads during the cutting work.

The tool blades 2 consist of planar parts of the spherical head 1 (Fig. 2) and each blade extends at least by a part of the arc BC of the circle. When the blades 2 have this structure, the tool is easier to manufacture as well as its sharpening and post-sharpening, which in this case can be done in general purpose machines, i.e. e.g. general tool grinding machines without the use of any specially designed equipment.

The blades 2 of the spherical head 1 can also be placed on its spherical surface along the helical line DE (Fig. 3). This improves the dimensional stability and durability of the tool and its conditions in connection with the incision in the bore or hole 10.

Po. in a further developed form of the invention for machining chamfered holes, the spherical end 1 is provided with protrusions 13 (Fig. 4) extending along its meridian planes and grooves 14 extending at an angle to these meridian planes, the projections 13 corresponding to the profile of the machined the desired profile of the holes. In this case, the tool blades 2 consist of cuts between the projections 13 and the grooves 14. The guide or front surfaces 7 of the tool blades 2 formed by the grooves 14 and the rear surfaces 8 of the blades 2 formed by the protrusions 13 are shaped in the same way as the work surfaces of the planing device. In addition, the grooves 14 may divide the protrusions 13 into a plurality of parts, each of which is a tooth 15 which is either a sharpened or back-cut tooth.

In order to facilitate the manufacture of the tool, its sharpening and re-sharpening, the front surfaces 7 of its blades 2 (Fig. 5) are in the same direction. This makes tool sharpening easier to automate.

Alternatively, the front surfaces 7 of the tool blades 2 can be oriented in different directions, e.g. in opposite directions (Fig. 6), whereby the tool is subjected to symmetrical loads throughout the work, which improves the machining accuracy. In this case, the front surfaces 7 and the rear surfaces 8 of the blades 2 can be made in the same shape as the surfaces of the planing device.

In order to improve the quality of the machining and to protect the blades 2 from damage, the rear surfaces 8 of the blades 2 are provided with chamfers 16, whereby the rear angle is at most about -15 °. This angle is preferably 0 °, which improves the manufacturing accuracy of the tool.

The spherical end 1 of the tool may consist of a lamination formed by the discs 17 (Fig. 7), whereby some of the discs may have a rounded profile to provide a machinable bore or hole 10. In this case, thanks to the independent rotation of each blade 17, the minimum sliding speeds of the tool blades 2 against the bore or hole 10 to be machined adjust themselves, which improves the dimensional stability and durability of the tool.

In the latter variant, the bearing neck 3 of the arm or holder 4 may have a stepped structure with several individual, eccentric necks or lower bearing necks 19 (Fig. 8), providing simultaneous execution of all tool blades 2 during cutting, whereby cutting can be accelerated and cutting depth increased, not to mention the expansion of the application area of the tool at all, when the tool can be used not only for finishing but also for semi-finishing. The value of the eccentricity "e" and its direction are chosen so that the tips P of the blades 2 of the discs 17 (Figs. 9 and 10) are in the same plane perpendicular to the axis LL of the bore or hole 10 to be machined around its circumference, with deviations from this plane within the limits set by the pre-set division.

The spherical multi-tool presented here performs machining in the following manner.

The tool arm 4 is mounted either at its rear end or at its flange, as the case may be, on the end plate, spindle, stern or support of the machining tool. A force is applied to the operator of the machining tool to rotate the workpiece and / or the tool about the same axis L-L and to provide a predetermined axial feed. The tool is inserted into a machined bore or hole 10 in the workpiece, where the spherical end 1 of the tool is self-positioning either due to the use of a clearance 11 between the central bore 6 and the bearing neck 3 or because the bearing neck 3 has a radial

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9 69261 freedom (relief) on the arm 4. Contact with the workpiece causes the spherical head 1 to rotate on a bearing neck 3 whose geometric axis 0-0 extends at an acute angle o (relative to the axis LL of the arm 4, whereby the parts of the blades 2 of the head 1 contact the machined bore or to the surface of the hole 10, continuously changing within the limits of the imaginary spherical band FGIK due to these parts oscillating or swinging relative to the surface of the bore or hole 10 within an angle of 2 CjL In the position shown in Figure 2, those parts or dimension is and associated with points F and I, when the spherical head 1 has rotated about 0 ° about the axis 0-0, the parts associated with points G and K become working, etc. This means that the dimensional stability and durability of the tool are improved at least compared to the previously known tool. as many as there are parts of length 1, which is the arc of each different blade 2 n BC or DE length or dimension within the limits of the spherical band FGIK of head 1. This continuous change of the working parts of the tool blades 2 also results in a considerable decrease in temperature in the cutting zone, by about 200-300 ° C, due to the short time the blade part contacts the surface of the bore or hole to be machined, followed by relatively longer cooling. Together, these factors result in more efficient, qualitatively better and more accurate machining work.

The inclination of the tool blades relative to the meridian plane of the spherical head 1 provides for cutting between them and the cutting speed vector and chip removal when oscillating or swinging relative to the surface of the bore or hole 10 to be machined. This oscillation is the result of the superimposition of the various rotations performed by the spherical head 1 and the bore or hole 10 about the axes 0-0 and LL, which are inclined at an acute angle o to each other. Thus, the conditions for drilling or drilling 10 either for machining the circumference or part thereof, depending on the preselected angle of inclination of the blades 2, during rotation of the spherical head 1 by the bearing neck 3, initiated by contact of the head with the bore or hole 10 to be machined, without the need for a separate drive mechanism. in addition, the dimensional stability and durability of the tool are improved by increasing the dimension or length of the blades 2 within the limits of the spherical band FGIK and the kinematic shredding of the shavings by regularly varying the value and direction of the blade angle 2 relative to the cutting speed vector. 1 during each round.

Both when using tool blades 2 formed by planar portions of a spherical head 1 and extending along a portion of the arc of a circle BC (Fig. 2), that the blades 2 are positioned on the spherical surface of the head 1 along a helical line DE (Fig. 3) of a bore or hole 10 the machining takes place in a flat part perpendicular to the axis LL of the arm H and extending through the center of the spherical band FGIK, the deviations from this plane part taking place within a predetermined division of the machining allowance or feed of the blades 2. In the first case, a multi-blade tool is used simultaneously with a conical countersink, Calvi or planer; in the second case, even a single-blade tool can be used, the blade of which contacts the circumference of the bore or hole 10 to be machined at many points, which makes the incision of the tool smoother and improves its dimensional stability.

When chamfered holes 10 are to be machined, a tool is used in which the blades 2 are formed by intersections of protrusions 13 and grooves 14 projecting at a spherical end in the direction of its meridian planes and having a profile corresponding to the desired profile of the hole 10 and extending at an angle to these meridian levels. The spherical end 1 of the tool is brought into contact with the machined hole 10 along an arc of up to 360 °, whereby the axis 0-0 of the bearing neck 3 is placed either transversely to the axis of the hole 10 or cut and the cutting work is performed continuously due to oscillation of the protrusions 13 relative to the hole 10 surface. The work is continued by feeding either the tool or the workpiece axially until the hole 10 has been machined to the desired length or depth.

When using a tool in which the front surfaces 7 of the blades 2 are in the same direction, each blade 2 makes a cut during the first half turn of the spherical head during the entire work and smooths the surface of the workpiece hole 10 during the second half of this turn, this smoothing being performed by chamfers 16 on the back surfaces 8 and having a back angle of 0 to about -15 °.

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To improve machining accuracy, a tool can be used in which the front surfaces of the blades 2 are in different, e.g. opposite, directions. Although still, as in the previous case, each blade 2 cuts the head 1 during the first half turn and smooths during the second half turn, symmetrical loads are applied to the spherical end 1 during machining due to the opposite control of the front surfaces 7 of the blades.

The dimensional stability and durability of the tool can be further improved by using a spherical head 1, which is a lamination formed by discs 17 mounted on a bearing neck 3 to rotate relative to each other. In this case, the discs 17 are rotated by their contact with the surface of the bore or hole 10 of the workpiece to be machined independently of each other, whereby the minimum friction rate between the blades 2 and the bore or hole 10 becomes self-adjusted. In addition, if the discs 17 are mounted on a bearing neck 3 having eccentric necks or lower bearing necks 19, then each disc performs independently and all the discs together perform the machining bore or hole 10 without smoothing the surface thereof.

This increases the machining speed and expands the scope of the tool, as the tool can then be used for both finishing and semi-final machining work.

Claims (9)

12 69261 A spherical multi-blade tool for machining bores and holes, wherein a spherical head (1) carrying blades (2) with cutting edges on a spherical surface is mounted on a neck portion (3) formed at the end of the tool shank (4), characterized in that the blades (2) ) are inclined with respect to the meridian planes of the spherical head (1) mounted on the neck portion (3) to rotate freely about this geometric axis (0-0) extending at an acute angle (OC) with respect to the tool shank (4) and the axis of the machined bore (LL). ). A spherical multi-blade tool according to claim 1, characterized in that the blades (2) are formed by planar parts forming a spherical head (1) and each blade (2) is arranged to extend along at least a part of the arc (BC) of the circle. Spherical multi-blade tool according to Claim 1, characterized in that the blades (2) are arranged on the spherical surface (1) along a helical line (DE). Spherical multi-blade tool according to Claim 1, characterized in that the blades (2) are formed at an angle of at most 90 ° to the meridian planes of the protrusions (13) corresponding to the desired shape of the machined hole (10) arranged parallel to the spherical end (1). from the intersections between the fitted grooves (14). Spherical multi-blade tool according to Claim 1, characterized in that the guide surfaces (7) of the blades (2) are in the same direction. Spherical multi-blade tool according to Claim 1, characterized in that the guide surfaces (7) of the blades (2) are in different directions. Spherical multi-blade tool according to Claim 1, characterized in that the trailing surfaces (8) of the blades (2) are provided with chamfers (16) with an angle of at most about -15 °. Spherical multi-blade tool according to Claim 1, characterized in that the spherical head (1) is formed by superimposed blades (17), the circumferential surfaces of which form the blades (2) and in that the blades (17) are arranged so that they can rotate relative to one another. Il 69261 Spherical multi-blade tool according to Claim 8, characterized in that its neck part (3) is stepped and has a plurality of eccentric necks (19).