JPH0655304A - Method and device for manufacturing work having recess part around its peripheral surface - Google Patents

Abstract

PURPOSE: To reduce wear by providing a workpiece spindle which can be rotated and driven and a tool spindle which can be rotated and driven and does not vibrate. CONSTITUTION: Tool blades 17, 18 are guided along a circular locus within space and contact of the tool blades 17, 18 and a workpiece 10 is performed in a range of a sharp curve of a cycloid locus close to a rotation axis 12 of the workpiece 10 or on an opposite side of the rotation axis 12 so as to form at least one of recessed parts A1 to A13. At this time, a machine provided with an eccentric spindle is not required but only a machine tool in which a tool spindle is almost stationarily located and a feed motion is performed is required. When a machine tool without an eccentric spindle is used, advantages that the machine becomes inexpensive and the machine becomes strong because the eccentric spindle becomes unnecessary are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a machined work piece whose peripheral surface is not round, at least one tool having at least one cutting edge is driven to rotate about an axis, and the cutting edge is cyclic. Is guided by a motion component directed toward the surface of the workpiece to be machined, the workpiece rotates around the center axis of the workpiece at a rotation speed adapted to the periodic movement of the cutting edge, and the cutting edge Has a substantially circular basic shape in which a closed cycloid locus is drawn, and the overlap between the workpiece rotation and the locus of the cutting edge in the contact area coincides with at least part of the recess to be formed. A method for making a workpiece and an apparatus for carrying out the method.

[0002]

BACKGROUND OF THE INVENTION It has long been known to machine workpieces having a non-round cross section. In this case, the workpiece is rotationally driven around the workpiece spindle axis and the tool, i.e. the cutting tool, is rotationally driven around the stationary tool spindle axis. The workpiece spindle axis is then moved longitudinally and laterally during operation of the machine.

With the known device mentioned at the outset, workpieces having a substantially polygonal cross section and substantially flat sides have already been produced. In this case, the rotational speed of the tool and the rotational speed of the workpiece have a constant ratio to each other.

In order to meet the special requirements concerning the formation of polygonal cross-sections, the so-called phase modulation, ie the fixed coupling of the rotational speeds of the two machine parts, is likewise required. It is known to superimpose cyclic changes in blade speed, and thus tool rotation speed. This change can be forced by forced control of the respective rotational position of the tool depending on the respective rotational position of the workpiece, for example to form a flat polygonal surface.
This method does not allow very high speeds. Because
This is because, depending on the moment of inertia, the mechanical output and the characteristics of the control device, the forceful adjustment of the tool position during rapid rotation of the tool requires a certain amount of time.

A method has been proposed in order to allow a phase modulation of the tool and thus an increase in the production speed at high rotational speeds. The invention according to the preamble of claim 1 starts from this known method. This known method and the device belonging to it are described in German patent application DE 40 34 34 A1.
No. 516. This known device comprises an eccentric spindle which can be driven by a selectable speed and a selectable direction of rotation. The tool spindle itself is rotatably supported by the eccentric spindle so as to be eccentric with respect to the rotation axis of the eccentric spindle. When the eccentric spindle is driven, the work piece spindle axis moves along a circle. The radius of this circle can be changed. The method implemented by this device has, in addition to the features of the preamble of claim 1, the feature of guiding the cutting edge of the tool along a closed cycloidal trajectory in three-dimensional space. This is because when the tool spindle rotates, the eccentric spindle rotates, which causes the tool spindle axis to move along a circular trajectory. There is no mention of forming a recess on the outer circumference of the workpiece.

[0006]

The problem underlying the invention is to provide a method of the type mentioned at the outset and an apparatus for carrying out this method, which makes it possible to use simple machine tools. is there.

[0007]

According to the invention, the task is to guide the tool cutting edge in space along a circular trajectory so that contact between the cutting edge and the work piece is effected in order to form at least one recess. The solution is to be carried out in the tightly curved (clearly curved) region of the cycloid trajectory, either towards or away from the axis of rotation of the workpiece.

Here, the formation of recesses is understood to mean the formation of all or part of the recesses and the finishing, ie the processing of the already existing recesses. This method does not require a machine with an eccentric spindle, only a machine tool with a tool spindle in a substantially stationary position and a feed movement. If a machine tool without an eccentric spindle is used, this has the advantage of making the machine cheaper and rugged because the eccentric spindle is unnecessary. Omission of the eccentric spindle eliminates the cause of failure caused by the eccentric spindle and reduces wear.

However, the present invention can also be implemented in a machine tool having an eccentric spindle. In this case, the eccentric spindle is not driven during machine operation. The rotation of the eccentric spindle to carry out the feed movement is taken into account, unless this feed movement requires a constantly rotating eccentric spindle.

Unlike the method described at the outset for producing a polygonal cross section that is as planar as possible, in the case of the invention, one or more recesses are formed, the defining surface of which being distinct. It is curved. This surface is provided in the cycloid area opposite to the rotation axis of the workpiece or in the cycloid area near the rotation axis. In this case, the recess is formed by processing in the same way as when lathing or using a side milling cutter. This embodiment of the method is used, for example, to form a recess in a cylindrical or annular workpiece for the first time from the outside or from the inside. In the case of this method, between the first insertion and the removal from the work piece, the tool draws a curved path relative to the work piece on the same side as the insertion and the center of this curved path is A tangent of the range extends at least approximately at right angles to the radial radiation through the center of the tool path.

In another embodiment of the method, which is particularly suitable for the post-machining of the existing recess or recesses, the tool is approximately outwards to inwards with respect to the axis of rotation of the workpiece or vice versa. Exercise. Even in this case, a clear curved portion can be confirmed. This method is particularly suitable for machining cages of final shape in cages of rolling bearings. In this form of the method, the tangent line passing through the center of the trajectory drawn by the tool from the insertion into the almost circular workpiece to the exit extends approximately in the direction of the axis of rotation of the tool, It never extends substantially transversely to radial radiation through the center.

The cutting edge of a tool is understood to be the part of the tool that contacts the workpiece and removes material. In the case of cutting tools this is a sharp edge that is sufficiently stable. For example, bites often have one cutting edge. However, it is also possible to have, for example, two cutting edges which contact the workpiece in different machining steps. If the tool fixed to the tool spindle has a protruding arm that is somewhat similar to a bite, the tool can be a single-edged tool or a cutting edge, regardless of the number of cutting edges. It is called a tool equipped only with. It may comprise a plurality of cutting edges as already mentioned.

The method according to the invention can be used to make a plurality of recesses in a workpiece. This method can also be used to form only one recess on the outer circumference of a substantially circular workpiece. This is necessary, for example, when producing piston rings for internal combustion engines. To make a piston ring, first a circular ring is made. The cylindrical outer surface and inner surface of this circular ring are concentric. The inner surface is subsequently scraped by the method according to the invention,
Certain parts of the circular ring are thinner than the rest.
For such an application, the ratio of the work piece rotation speed to the tool rotation speed is 1: 1. However, since the work piece rotation speed can be increased, the rotation speed ratio can be increased to 2: 1 or 3: 1 or even higher.

The ratio of the rotational speed of the workpiece to the rotational speed of the tool must satisfy the following conditions. An integer speed ratio (where both numbers are relatively prime and cannot be represented by a smaller number for the work and tool speeds) is the number n representing the tool speed. It must be chosen to be an integer (assuming the presence of a single cutting edge in the tool as described above) and equal to the number of recesses to be produced or machined.

The number m, which represents the number of revolutions of the workpiece, is likewise an integer and indicates in what order all the predetermined tool cutting edges machine the recesses, and furthermore the recesses to be machined continuously. You have to jump over the m-1 recesses in each case. When m = 1, m-1 = 0, so (when there is only one tool cutting edge) the recess must be machined spatially immediately adjacent. On the other hand, when the rotation speed ratio is 6:13 (Fig. 4),
Each time, 5 recesses are skipped and after 6 revolutions of the workpiece the tool will engage all 13 recesses once.

The number m representing the number of revolutions of the workpiece is preferably
The optimum cutting speed is selected depending on the size of the tool and the work piece. This cutting speed causes the tool to move relative to the workpiece. In this case, the optimum cutting speed depends on the surface quality obtained and the shortest possible machining time for the entire workpiece. Particularly when a relatively small workpiece is to be machined, it is advantageous to select a relatively high absolute workpiece rotation speed and thus a relatively high workpiece rotation speed relative to the tool rotation speed. For example, the rotation speed ratio is 1:13
9:13 and assuming that the size and shape of the recess are almost the same, when the rotation speed ratio is 9:13, the rotation speed ratio of the tool rotation axis is 1:13 when machining from the outside. In this case, the tool radius is larger than that of the workpiece, and for this reason the radius of the tool is 1:13.
Must be greater than. When the radius of the tool is large, the tool spindle becomes thicker than in the case where the rotation speed ratio is 1:13, and therefore stable tool guidance is possible.
Therefore, this arrangement is particularly suitable for machining long workpieces towards the axis of rotation. Further, as mentioned above, 9:
In the case of the ratio of 13, if the rotation speed of the tool is the same,
The cutting speed is faster than in the case of the ratio of 1:13.

Two tools, for example diametrically opposed to each other
With one cutting edge, one cutting edge forms seven recesses when the rotational speed ratio is 1: 7, and the other cutting edge also forms seven recesses between the first described recesses. It is formed.

The annular workpiece can be machined sequentially from the outside and from the inside in time. If the machine tool has two separately driveable tool spindles, it is also conceivable to machine from the outside and from the inside simultaneously.

The tool spindle can support single-edged tools, but also tools with two, three or more cutting edges. In the case of two or more cutting edges, the work piece spindle axis is machined more than if the tool spindle is supporting a single cutting edge in order to form a recess of the same size and shape in the work piece. It is far from the surface to be used. The rotational speed and the phase position must likewise be adapted in each case. The large distance between the tool spindle axis and the workpiece allows the tool spindle to be made thick. This is particularly advantageous when a large feed in the longitudinal direction of the tool spindle has to be carried out in the machine. When the workpiece spindle is sturdy, it can withstand large cutting forces.

In a given device according to the invention for carrying out the method, it is sufficient for the single blade of the tool or each cutting edge on the tool spindle to have only one cutting edge. The cutting edge causes the tool to contact the workpiece. However, as will be described below, it is expedient if the cutting edges each have two cutting edges. This cutting edge can be formed as an abutting cutting edge in the embodiment of the invention. This allows a very sturdy formation. The cutting edge can be formed as a tensile cutting edge. This tensile cutting edge comes into contact with the work piece when the tool is submerged in the already existing recess and is withdrawn again. Further, the tool may include a butt cutting edge and a pull cutting edge. Thereby, in particular, one defining surface of the already existing recess can be post-machined when the tool is submerged in the recess and the other defining surface can be post-machined when the tool is withdrawn from the recess. . Thereby, the processing time is shortened.

In an embodiment of the device for carrying out the method, the tool comprises at least one cutting edge, the contour of the cutting edge being identical to the contour of the recess formed by the cutting edge. I am doing it. When the tool is brought into contact with the respective recesses in sequence during operation of the device, the desired contour of the recesses is formed. For example, the tool is provided with a cutting edge when one defining surface of the workpiece is not parallel to the axis and forms a helically extending recess. This cutting edge is suitable for spiral extension. Then, during operation of the machine, the tool is adjusted relative to the periphery of the workpiece by a phase shift during an axial feed movement of the tool spindle axis or a corresponding feed movement of the workpiece. Therefore, a so-called spiral-shaped or diagonally-extended linear-shaped defining surface is formed. A tool can likewise be formed corresponding to the principles of the invention on the other peripheral surface of the workpiece in the circumferential direction. When the tool has, for example, a trapezoidal cross-section, it is possible to use recesses of substantially trapezoidal cross-section for subsequent machining or in certain cases for the first machining. This is required, for example, in the case of cages for tapered roller bearings.

In another embodiment of the invention, the cross section of the tool has a ball-shaped profile on at least one defining surface,
That is, it has a convexly curved contour. Other cross-sectional shapes are possible. As mentioned above, the tool may comprise a butt cutting edge, a pull cutting edge or a butt cutting edge and a pull cutting edge. It is advantageous if the tool is provided with a cutting edge on its entire surface. As a result, the entire outer peripheral surface of the recess can be machined with a tool.

When the already existing recess has to be widened in the circumferential direction (with respect to the axis of rotation of the workpiece), the radius of the tool, ie the distance between the tool cutting edge and the axis of the tool spindle, must be widened during operation of the machine. There is.
For that purpose, machine tools suitable for carrying out the method of the invention are generally equipped with the necessary equipment, in particular with so-called lateral sliders.

[0024]

Embodiments of the present invention will be described with reference to the drawings.
In FIG. 1, a circular workpiece 10 is provided rotatably around its central axis 12. The single-edged tool 14 is rotatable about a stationary tool spindle axis 16. This tool spindle axis lies radially outside the workpiece 10. The workpiece 10 and the tool 14 rotate at a ratio of 1:13. That is, a tool 14 having a single cutting edge 18
Rotates 13 times when the workpiece 10 makes one rotation. Since the tool and the workpiece rotate in opposite directions with respect to their respective axes of rotation, they move in the same direction in their engagement range. On the first rotation, the cutting depth increases continuously from recess to recess depending on the feed movement. The double-headed arrow F indicates the sliding of the workpiece spindle and / or the tool spindle corresponding to the feed. Due to this feed, the cycloid trajectory will not close accurately. Until the desired radial depth of all 13 recesses A1-A13 is achieved,
The rotation continues.

The width of the recess in the axial direction depends on the cutting edge 18 of the tool.
Match the width of. When the feed motion is axial,
The front cutting edge 17 of the inserted tool 14 sets the width of the recess to a desired size.

The recesses A1, A2 ... A13 are sequentially processed in this order, and are sequentially allocated to the outer periphery of the workpiece 10 in this order. Since the workpiece and the tool move in the same direction in their engagement range, the width of the recesses A1 to A13 in the circumferential direction of the workpiece 10 is shorter than when the workpiece is stopped.

In FIG. 1, the cutting edge 18 has already been pre-machined by continuously feeding the workpiece and / or tool spindle in the direction of arrow F to the desired recess depth.
At that time, the cutting depth increased from the recess to the recess during the first rotation, and a plurality of subsequent rotations machined the recess to a desired depth. Now, when it is fed in the axial direction, the cutting depth increases from the concave portion to the concave portion at the first rotation, and the side cutting edge 17 performs the processing of the concave portion (processing toward the paper surface).

Since FIG. 1 is on a substantially scaled scale, the radius of the tool, that is, the distance between the cutting edge and the tool spindle axis 16, the tool spindle axis 16 and the workpiece center axis 12 is shown.
The interval between and can be inferred from the figure.

FIG. 2 shows the trajectory of the cutting edge 18 with respect to the workpiece 10 when not fed. In this case, it is illustrated as if the workpiece stopped and the workpiece spindle axis moved along a circular trajectory around the workpiece. The locus of the cutting edge is a cycloid Z, and due to the curved portion projecting outward, the cycloid locus of the tool cutting edge is almost entirely flower-shaped.

In the illustration of the relative movement of the tool cutting edge with respect to the work piece, the engagement takes place in the region of the cycloid trajectory curved towards the axis of rotation 12. In the case of the arrangement according to FIG. 3 in which the coupling ratio 1:13 is evident from the course of the cycloid trajectory, the tool 14 'has two diametrically opposed cutting edges 18'. The cutting edges are distinguished from each other in the figure by the letter x on one of them. The tool radius, which is the same for both cutting edges, is larger than in the case of FIGS. 1 and 2, and the distance between the tool spindle axis 16 ′ and the workpiece center axis 12 ′ is likewise larger than in the cases of FIGS. Is. A different shape of cycloid occurs, and this cycloid does not mathematically exactly match the cycloid locus of FIG. 2 in the engagement range (contact range) with the workpiece 10 ', but it is almost the same, and thus is similar. Recess A
1'-A13 'occur. A predetermined cutting edge 18 ', for example a cutting edge without the letter x, is used when machining the workpiece 10'.
Jump over one recess at a time.

Each cutting edge has a cycloid Z1 or Z1 '.
Belongs to. The ratio of the number of revolutions of the workpiece to the number of revolutions of the tool is 2:
It is 13. After the tool has made one revolution, all recesses A1 '
~ A13 'is processed. Hereinafter, it will not be pointed out that it is necessary to rotate the workpiece a large number of times depending on the cutting depth in order to form a recess having an appropriate length in the axial direction. Here again, the cycloid trajectory differs from that of FIG. 2 in the range of engagement with the workpiece. The workpiece diameter, the tool radius and the distance between the workpiece center axis and the tool spindle axis are chosen to be different from those of FIG. 2 so that the recesses almost coincide with the recesses of FIG. A tool with two cutting edges enables a stable tool construction and cuts the working time in half. If the desired number of recesses is odd, each cutting edge removes the chips in each recess after at least two revolutions. Other processing steps are performed as described with reference to FIG.

[0032] In the case of the arrangement of Figure 4, the recess A1 ₅ ~
A4 ₅ is formed on the work piece from the inside. Therefore, the tool spindle axis 56 of the tool 54 is located radially inward of the inner peripheral surface of the workpiece 50. The engagement of the tool takes place in the well-curved region of the sacroid trajectory opposite the axis of rotation 52.

The rotational movements of the workpiece 50 and the tool 54 occur in opposite directions, resulting in a circumferentially elongated recess.
The ratio of workpiece speed to tool speed is 1: 4. The opposite movement increases the cutting speed. In this figure,
The feature is shown that the tangent T to the center of the curved trajectory is perpendicular to the radial ray R extending from the workpiece central axis.

In the case of the embodiment shown in FIGS. 1 to 4, a recess is first formed in an annular work piece of solid material.
The post-processing will be described based on FIG. In the case of this post-processing, the material indicated by the dots is removed from the edge region of the recess located in the circumferential direction. In this case, the desired final cross-sectional shape is indicated by hatching. A tool 64 having a single cutting edge arranged inside the workpiece 60 comprises two cutting edges 69a, 69b formed as abutting edges and a cutting edge extending transversely thereto. . Tool 6
4 rotates in the same direction as the workpiece 60.

[0035] and defining part of the upper recess A1 ₆ in FIG. 5, or the corresponding defining portion of the other recess how is post-processed in the will be described with reference to FIG. Therefore, the ratio of the rotation speed of the workpiece to that of the tool is, for example, 4: 1.
Selected as 3. The radius of the tool 64, that is, the distance between the cutting edge (that is, both cutting edges) and the tool center axis line 66,
It is somewhat larger than half the outer diameter of the workpiece 60. The tool is formed by the groove 64 'as follows. That is,
Is formed so as to be reached from the inside in the narrow recess A1 ₆ ～A13 ₆ relatively not collide. At that time, only the material to be removed is contacted. Moreover, the contact is made during the part of the movement in which the respective cutting edge of the tool has a radially outwardly directed movement component with respect to the straight machined part of the workpiece. Further rotation of the tool and workpiece causes the tool to re-emerge from the recess without contacting the walls of the recess.

In FIGS. 5 and 6, the other defining portions of the recess are already in the final state. That is, in the clockwise direction, the front contour of the concave portion has already been processed by the cutting blade 69b. This machining was done by rotating the tool and the workpiece in opposite directions.

During the phase shift (phase shift) in which the relative rotational position between the tool and the workpiece changes, the cutting tool approaches the front concave portion in the direction of the arrow in FIG.
At the first rotation, the work is axially fed to cut with a cutting depth that increases for each recess. The cutting depth during other rotations is the same for each recess. When the desired recess depth is achieved in the axial direction, the feed movement is stopped. The phase shift period is represented by a trapezoidal graph. In this case, the upwardly and downwardly inclined trapezoidal sides represent positive and negative short-term angular accelerations, and the horizontal trapezoidal sides represent, for example, high short-term angular velocities of the tool spindle. During this phase of the phase shift, the cutting edge 69a contacts the outermost tip located inside the part to be removed indicated by the dot, which increases the cutting depth from recess to recess during the first rotation of the workpiece. By this, in the range indicated by the dot, it is preprocessed at right angles to the plane of the drawing. When it is further rotated, the cut depth of each recess cut and removed becomes the same. By the end of the phase shift, the tool cutting edge 6
9a occupies the position shown in FIG.

In the case of the feature shown in FIG. 6, the tangent line T'passing through the center of the trajectory of the tool in the material when post-machining the edge of the recess is oriented substantially towards the center of the workpiece. Since the selected rotation speed ratio is 4:13, two recesses A1 ₆ and A2 to be machined immediately in succession as seen in the rotation direction of the workpiece.
_{Between the six} , a total of three other recesses (A11 ₆ , A8 ₆ ,
There is A5 ₆ ). This recess is machined during the subsequent rotation. In the example of FIG. 5, the recesses machined on both sides have a larger inner surface area in the circumferential direction than the outer surface area of the workpiece.

In order to carry out the phase shift, it is advantageous to equip the machine tool with an electronic transmission. This electronic transmission makes an electrical connection between the shaft (tool spindle) and the work piece spindle, so that the shaft and the work piece spindle rotate at a predetermined speed ratio independently of the respective load due to the contact of the tool. , The required relative rotational position of the tool in each case relative to the previously formed recess or the already formed recess or the recess to be machined is maintained exactly (strong phase coupling) or, as mentioned above, the feed Sometimes changed to achieve (phase shift). In this case, it is not phase modulation. In the case of phase modulation, the rotational speed (angular velocity) of the tool and thus the phase position of the tool with respect to the workpiece do not change after a predetermined time during one rotation of the tool, as described above).

The arrangement of FIG. 7 in which the tool spindle axis 76 is located outside the workpiece 70 serves the same purpose as the arrangement of FIG. However, after finishing the post-processing, the recess A
1 _{7 to A} 13 ₇ are larger on the outside of the workpiece than on the inside of the workpiece. The ratio of the rotational speeds of the workpiece 70 and the tool 74 is 6:
It is 13. In the engagement range, the workpiece and the tool have the same movement direction. Here again, when one end face area of all the recesses is finished by the cutting edge 79a of the single-edged tool, the tool and the workpiece are turned in the opposite direction and the other end face is machined. In this case, the other cutting edge 79b of the tool is used.

Both cutting edges of the single-edged tool 74 of FIG.
9 (rather than a pure abutment cutting edge, which contacts the work surface at an angle of approximately 90 ° and is guided along this work surface)
It has a cutting angle different from 0 ° and forms a wedge. The wedge has a wedge angle of 90 ° or less. Such tools are particularly suitable for brass machining. Both cutting edges 79a, 79b of the tool 74 of FIG. 7 are formed as shown, first of all one end face of the recess is machined respectively, and after this end face has been machined, the workpiece is phase-shifted by the already described phase shift. The other end face of the recess is post-machined by making a slight relative adjustment of the tool with respect to one another, and subsequently by a relative movement of the tool relative to the axis of rotation of the workpiece in a substantially radial direction from outside.

The ratio of the number of revolutions of the workpiece and the tool is 6:13 in this example. That is, 13 recesses are formed,
The recesses that are directly continuous in time are separated by 6 steps. That is, five recesses are provided between the first processed recess and the next processed recess, and these recesses are processed thereafter. In FIG. 7, the first three rear parts processed in chronological order are A1 ₇ , A2 ₇ and A3 ₇
It is indicated by.

In the case of the arrangement structure of FIG. 8, 14 recesses A1 _{8 to} A14 already formed by processing from the inside are performed.
₈ Post-processing is done from the outside. The ratio of the rotation speed of the workpiece 80 and the rotation speed of the tool 84 is 9:14. The tool 84 comprises a single cutting edge having two different cutting edges. This cutting edge has a substantially abutting cutting edge 89a having a wedge angle of 90 ° or less as in the arrangement structure of FIG. 7, and a pulling cutting edge 89b. Selection of the radius of the tool where both cutting edges have equal distances from the axis of rotation 86 of the tool, axis of rotation 86 of the tool
And the rotation axis 82 of the workpiece and the ratio of the radius of the tool and the radius of the workpiece are selected to be 1
When the tool is submerged once and pulled up, each of the four recesses is post-processed in both end ranges in the circumferential direction, and moreover, when the tool is pulled out from the recess, it is almost abutted. Be pulled. FIG. 8 shows the contact of the abutting cutting edge 89a. The tool does not undesirably collide with any part of the workpiece during the machining of the workpiece for all given machining, nevertheless making the tool as solid and powerful as possible, which results in high cutting forces. It is formed so that it can be received.

In the case of the embodiment described above, the radius of the tool cutting edge is smaller than the outer diameter of the workpiece. In the case of the embodiment of FIG. 9, the distance between both cutting edges 99a, 99b of the single-edged tool 94 formed as an abutting tool and the rotation axis 96 of the tool is larger than the outer diameter of the workpiece 90. Has become. The distance between the rotation axis 96 of the tool 94 and the rotation axis of the workpiece 90 is smaller than the inner diameter of the workpiece 90. In FIG. 9, the axis of rotation 96 is to the left of the axis of rotation 92 and the contact of the tool is in the area to the right of the axis of rotation 92 of the workpiece.

[0045] In the contact area, the tool and the workpiece is moved in the same direction, the tool is already present thirteen recesses A1 ₉ ~
Perform the abutment formula after processing from the outside of the A13 _9. The ratio of the rotational speed of the workpiece to the rotational speed of the tool is 6:13. As a result, 13 recesses are subsequently machined here. In this case, the tool makes contact with the defining surface of the recess, then jumps over the next five recesses and contacts the sixth recess. The other surface is machined after reversing the direction of rotation of the tool and the work piece.
The tool that rotates about the axis of rotation 96 always has its cutting edge facing the workpiece.

Due to the high rotational speed of the workpiece, high cutting speeds occur here. This is especially useful for small three-dimensional workpieces. Thereby, an optimum cutting speed can be achieved depending on the surface quality and the material desired in each case. This cutting speed is, for example, 100 m / min. In most cases, the distance between the cutting edge and the tool center axis is
Larger than the outer diameter of the workpiece. The contact between the tool and the work piece is performed in the cycloid locus range having a small radius of curvature near the rotation axis of the work piece.

FIG. 10 shows the outer contour of the recess 111a in the workpiece 110a, which has been completely post-machined in the same way as in FIG. 5 by the butting tool 114a. The recess has a substantially square cross section and rounded corners. Tool 114a is also generally square shaped with rounded corners. This corner is defined by the cutting edge 119a. The cutting edge is formed as a butt cutting edge. By properly controlling the movement of the tool, the shape of the recess is produced. In this case, for example, the recess is firstly post-processed in the area on the right side of FIG.

In the case of the arrangement structure shown in FIG. 11, the cross section of the recess 111b to be formed is trapezoidal, and this is the same for the tool 114b having a small cross section. The tool is likewise provided with abutting cutting edges on all sides. To form the recess, the tool must be moved circumferentially by the phase shift as it is fed relative to the workpiece 110b toward the axis of rotation of the workpiece (upward in the figure). Thereby the desired contour is formed.

In the case of the arrangement structure shown in FIG. 12, the recess 111c and the tool formed by the butting process have a ball-shaped cross section. In order to form the recess, the phase shift must be changed during the axial feed of the workpiece.

13 to 15 show a recess and a tool having the same cross sectional shape as FIGS. 10 to 12, but the tool is shown in FIGS.
Instead of the abutting edge on the left side in FIG. 2, a pulling cutting edge 119a ', 119b' or 119c 'is provided. Therefore, the processing time is halved as in the case of FIG. This is because both the defining surfaces on the right side and the left side in FIGS. 13 to 15 are post-processed when submerged once in the recess.

FIG. 16 is a side view of the cylindrical workpiece 120. Grooves 121 are machined in this workpiece. This groove does not extend parallel to an axis extending from above the work piece, but is in the form of a highly inclined helix.
The cross section of the recess or groove 121 is almost a semicircle. The groove is machined from the outside by a device similar to that of FIG. In this case, a suitable coupling ratio between the rotational speed of the tool spindle and the rotational speed of the workpiece spindle is selected, taking into account the required cutting speed, in order to form the predetermined number of grooves.
During continuous axial feed of the tool relative to the work piece, a continuous phase shift takes place between the tool and the respective rotational position of the work piece, resulting in a different groove extension than the axially parallel arrangement. .

If a groove extending non-parallel to the axis forms the interior of the workpiece, the method shown in FIG. 4 can be used for this purpose. The machine tool 140 schematically shown in FIG. 17 includes a work piece spindle 142.
This work piece spindle is slidable in the longitudinal axis and transverse to this axis to perform the feed movement and to adapt to the special work piece size, user selectable It can be driven at various speeds.
Instead of the work piece spindle 142, the tool spindle 144 can be designed to be slidable in the same direction as this work piece spindle, but here it is not slidable in any direction in order to achieve the most robust bearing possible. Is. The tool spindle can be driven at a predetermined rotational speed with a predetermined ratio to the rotational speed of the workpiece. Furthermore, in order to carry out the above-mentioned phase shift, the constant rotational speed relationship of both spindles can be temporarily changed. To that end, electronic control and adjustment devices, so-called electronic transmissions 146, are used.

[0053]

As described above, the method and apparatus according to the present invention for producing a workpiece having a concave portion on its peripheral surface, comprises:
There is an advantage that a simple machine tool can be used.

[Brief description of drawings]

1 schematically shows a cross section of a workpiece and a recess formed in the workpiece from the outside by means of a tool with a single blade; In this case, the ratio of the rotational speeds of the workpiece and the tool is 1:13.

FIG. 2 is a diagram showing relative movement of a cutting edge of a tool with respect to the workpiece of FIG. In this case, the work piece is considered to be stationary, unlike in reality. It is shown here as a cycloid.

FIG. 3 is a view similar to FIG. 2, but in which the tool spindle is provided with a double cutting edge type tool with two diametrically opposed cutting edges. In this case, the ratio of the number of revolutions of the workpiece and the tool spindle is 2:13.

FIG. 4 shows a cycloidal arrangement with a radially inner tool spindle axis. in this case,
In order to form a relatively wide recess, movement in the contact area between the tool and the workpiece takes place in the opposite direction to that of FIGS. 1 to 3 and the ratio of the rotation speed of the workpiece to that of the tool is It is 1: 4.

FIG. 5 shows an arrangement in which the tool spindle axis is radially inward and the tool and workpiece movement directions in the contact area are the same. In this case, the recess is machined by means of a single-edged tool having two cutting edges which abut in the region of its edges in the circumferential direction in order to post-process the recess already formed from the outside in accordance with FIGS. In the contact area, the directions of rotation of the tool and the work are the same, and the ratio of the numbers of rotations of the work and the tool is 4:13.

FIG. 6 is a diagram showing the arrangement structure of FIG. 5 in a cycloid.

FIG. 7 is a view showing a state in which the recess formed according to FIGS. 1 to 3 is post-processed from the outside by a tool having two abutting cutting edges. In this case, the ratio of the rotational speeds of the workpiece and the tool is 6:13.

FIG. 8 is a view similar to FIG. 7, in which workpieces having previously formed 14 recesses from the inside are made to face each other in the circumferential direction by means of a single rotating butting-pulling-tool; The edge area is processed from the outside. The ratio of the number of rotations of the workpiece and the tool is 9:14.

FIG. 9 shows an arrangement structure in which a peripheral surface-positioned defining surface is post-processed from the outside by a single-edged tool having two butted cutting edges on a workpiece in which 13 recesses have been previously formed from the outside. ing. The ratio of the number of rotations of the workpiece and the tool is 6:
13 and the tool radius is larger than the outer diameter of the workpiece, unlike the cases of FIGS.

FIG. 10 schematically shows the post-machining of a square recess with a butting tool. The cross section of the tool conforms to the shape of the recess but is smaller than the recess.

FIG. 11 schematically shows post-processing of a trapezoidal recess by a butting tool. The cross section of the tool conforms to the shape of the recess but is smaller than the recess.

FIG. 12 schematically shows post-processing of a ball-shaped recess by a butting tool. The cross section of the tool conforms to the shape of the recess but is smaller than the recess.

FIG. 13 is a view corresponding to FIG. 10, but with a tool provided with a butt cutting edge and a pulling cutting edge.

FIG. 14 is a view corresponding to FIG. 11, but with a tool provided with a butting edge and a pulling edge;

FIG. 15 is a view corresponding to FIG. 12, but with a tool provided with a butt cutting edge and a pulling cutting edge.

FIG. 16 is a side view of a workpiece having a spiral recess.

FIG. 17 is a schematic view of a machine tool for performing the method.

[Explanation of Codes] 10 Workpiece 12 Workpiece Central Axis 14 Tool 16 Tool Spindle Axis 17, 18 Cutting Edge A1 ... A13 Recess Z Cycloid

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Heinz Schuttenzell, German Federal Republic of Germany, Dounningen, Schutthausen Gasse

Claims (14)

[Claims] 1. A peripheral surface of a workpiece is machined into a non-round shape,
At least one tool with at least one cutting edge is driven to rotate about an axis, the cutting edge being periodically guided by a movement component directed towards the surface of the workpiece to be machined,
The workpiece rotates around the center axis of the workpiece at a rotation speed that matches the periodic movement of the cutting edge, the cutting edge draws a closed cycloid locus relative to the workpiece, and the workpiece rotation in the contact range A method for producing a workpiece having a substantially circular basic shape, the overlap of which with the trajectory of the cutting edge corresponds to at least a part of the recess to be formed, in which the tool cutting edge follows a circular trajectory in space. Guided contact between the cutting edge and the workpiece to form the at least one recess is made in a well-curved area of the cycloid trajectory, either towards or away from the axis of rotation of the workpiece. A method characterized by. 2. A curved cycloid locus is drawn on the side of the workpiece opposite to the entrance in the radial direction from the entry of the tool to the exit of the workpiece, and the tangent line passing through the center of the curved cycloid locus is approximately the center of the workpiece. The method of claim 1, wherein the method extends toward. 3. Method according to claim 2, characterized in that a tool with at least one abutting cutting edge is used. 4. A tool having an abutment cutting edge and a tensioning cutting edge is used, the tensioning cutting edge being located away from the abutment cutting edge in the circumferential direction of the workpiece and facing away from the abutment edge. The method of claim 3, wherein: 5. A tool with two abutting cutting edges, which are spaced apart in the circumferential direction of the workpiece and are oriented in opposite directions, is used, after abutting one of the cutting edges. 4. The method of claim 3 wherein both cutting edges do not contact the workpiece during movement opposite to the movement. 6. The tool is moved during an axial feed movement of the tool spindle shaft or during a corresponding feed movement of the work piece to form a recess having a definition that is not parallel to the axis. 6. Method according to claim 1, characterized in that the phase is adjusted relative to the outer circumference of the workpiece. 7. Between the initial insertion into the work piece and the removal from the work piece, the tool describes a curved cycloid trajectory on the same side as the insertion in the radial direction, the range of the center of this curved cycloid trajectory being 7. The method of claim 6 wherein the tangent line extends at least approximately perpendicular to radial radiation from the axis of rotation of the workpiece through the center of the tool path. 8. Device for carrying out the method according to claim 1, comprising a workable spindle for rotation and a non-oscillating tool spindle for rotation. 9. The apparatus of claim 8 including means for generating a phase shift between the movement of the work piece spindle and the movement of the tool spindle. 10. Device according to claim 8 or 9, characterized in that a single-edged tool is provided. 11. Device according to claim 8, characterized in that a tool with at least two cutting edges is provided. 12. An apparatus according to claim 11, further comprising a tool having two abutting cutting edges spaced apart in the circumferential direction of the workpiece and facing in opposite directions. 13. The tool according to claim 8, wherein the tool comprises at least one cutting edge, the contour of the cutting edge corresponding to the contour of the recess formed by the cutting edge. Any one device. 14. A tool is moved during the axial feed of the tool spindle shaft or during the corresponding feed movement of the work piece to form a recess having a definition that is not parallel to the axis. Device according to any one of claims 8 to 13, characterized in that the position is adjusted relative to the outer circumference of the workpiece by the phase.