JP4585096B2 - Machine tool swivel indexing device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a swivel indexing device used for a part that supports a tool unit or a work holding unit of a machine tool so as to be swiveled. The present invention relates to an indexing position by means of a three-piece face gear coupling (face gear coupling). It is related with the above-mentioned device which fixes.
[0002]
[Prior art]
As an apparatus for fixing the indexing position of the swivel member with high rigidity and high accuracy, a face gear coupling called a carbic coupling or a hearth coupling is widely used. In order to facilitate understanding of the present invention, referring to FIGS. 3 and 4 schematically showing an example in which a face gear coupling is used to fix the turret index position of the turret lathe, a two-piece type and a three-piece type are shown. The face gear coupling fixing structure and its features will be briefly described.
[0003]
FIG. 3 shows a structure using a two-piece type face gear coupling. The turret (swivel member) 1 is supported on a tool post (non-moving member) 4 by a bearing 3 and 3 with a pivot shaft 2 which is substantially integral therewith so as to be pivotable and axially movable. A rotating face gear 5 and a fixed face gear 6 are fixed to the back surface of the turret 1 and the end face of the tool post 4 facing the turret 1 respectively. A hydraulic cylinder for moving the turret 1 in the axial direction is formed between the bearings 3 and 3 by a piston 7 provided on the turning shaft 2 and a cylinder 8 formed in the shaft hole of the tool post 4. The indexing device for indexing and turning the turret 1 is not shown in the figure.
[0004]
In this two-piece type face gear coupling, one of the rotating face gear 5 and the fixed face gear 6 is moved in the axial direction to engage and disengage both the face gears 5, 6, thereby turning members (in the figure). (Turret) fixed state and free rotation state are realized. Therefore, in the two-piece structure, it is necessary to move either the rotating face gear or the fixed face gear in the axial direction by an amount corresponding to the tooth height, but the swiveling member is moved in the axial direction as shown in FIG. And the rotation transmission mechanism to a turning member becomes complicated. On the other hand, when any one of the face gear couplings 5 and 6 is mounted so as to be movable in the axial direction with respect to the turning member or the stationary member, the turning member 1 itself does not have to move in the axial direction. The rigidity and accuracy of the part that is mounted so as to be movable in the axial direction is significantly lower than that of the face gear coupling, resulting in the loss of the characteristics of high rigidity and high accuracy when using the face gear coupling. .
[0005]
FIG. 4 shows a turret support structure when a three-piece face gear coupling is used. The fixed face gear 11 fixed to the tool post 4 and the rotary face gear 5 fixed to the turret 1 are on the same plane. The connecting face gear 12 facing both of them is arranged so as to be axially movable by a hydraulic cylinder or the like (not shown). In the three-piece type, the rotating face gear 5 is fixed by the fixed face gear 11 via the connecting face gear 12 by moving the connecting face gear 12 forward and meshing with the rotating face gear 5 and the fixed face gear 11. When the connecting face gear 12 meshes with the fixed face gear, the position of the connecting face gear 12 is defined by the fixed face gear 11, so that even if the rigidity and accuracy of the supporting portion of the connecting face gear 12 are low, this causes the rotating face gear 12 to rotate. The position accuracy and rigidity of the are not reduced.
[0006]
According to the above description, the three-piece type face gear coupling is considered to be perfect, but in reality, the fixed face gear 11 and the rotary face gear 5 are completely flush with each other in terms of assembly accuracy and processing accuracy. It is impossible to place it above, and the axial entry and exit due to errors occurs. When the connecting face gear 12 meshes with either one of the face gears, the forward movement stops, so that there is a gap or lack of meshing force with the other face gear, which results in the indexing position accuracy or rigidity of the turning member. Reduce. Therefore, in reality, as in the case of the two-piece type, a hydraulic cylinder is provided that presses the turret 1 toward the connecting face gear with a pressing force that is a half of the pressing force of the connecting face gear 12. A structure is employed in which the rotating face gear 5 is pressed against the meshed connecting face gear 12. Unlike the two-piece type, the axial movement of the turret 1 at the time of pressing is in units of microns or sub-microns corresponding to the error, so this movement is absorbed by the elastic deformation of the member, and the turret 1 is supported. This means that the structure and drive structure are not complicated.
[0007]
3 and 4, when the index position is fixed by the face gear coupling, the turret 1 is positioned not only in the turning direction but also in the axial direction with high accuracy, but can turn. The axial position of the turret 1 when it is in a different state is different from the axial position when it is fixed. In the case of FIG. 3, axial movement corresponding to the tooth height of the face gear occurs, and in the case of FIG. 4, axial movement in units of micron or submicron occurs.
[0008]
[Problems to be solved by the invention]
In the case of the turret, since the workpiece is not processed without fixing the index position, the axial movement of the turret when the turret can turn does not affect the processing accuracy of the workpiece. However, when machining is performed with the indexing position fixed as in the spindle of a machining center, or when machining is performed while turning, the indexing position is fixed and released. The movement in the axial direction with respect to when this occurs causes a reduction in the machining accuracy of the workpiece. FIG. 5 shows an example of a compound lathe in which a rotary tool unit 16 capable of turning and indexing positioning around the Y axis is mounted on the tool post 15. The rotary tool unit 16 of this lathe is arranged around the Y axis. Machining may be performed with the angle fixed at a predetermined indexing position, or machining may be performed while turning at a low speed around the Y-axis, or machining while stopped at an angle other than the specified indexing angle. May be performed. In FIG. 5, 17 is a headstock, 18 is a spindle supported by the headstock, 19 is a chuck attached to the tip of the spindle, 20 is a work held by the chuck 19, and the tool post 15 is usually Like the lathe, it can move in the Z-axis and X-axis directions.
[0009]
Machine tools are basically required to have high accuracy and high rigidity. For the fixing of the indexing position of the rotary tool unit 16 of the composite lathe as described above, it is desirable to employ a face gear coupling because of its high rigidity and high accuracy. However, even if the three-piece type is used, when the conventional structure is used as it is, when the indexing position is fixed with the face gear coupling and the machining is performed, the fixing is released and the rotary tool unit 16 is moved to the Y axis. When processing is performed while turning around, a phenomenon occurs in which the processing position moves in units of microns or submicrons in the Y-axis direction. This movement appears as a workpiece machining error. In order to correct this error by the NC device, it is necessary to perform Y-axis control, and it is not realistic to add the Y-axis feed device of the rotary tool unit 16 and its control device only for this correction. .
[0010]
Therefore, the present invention effectively uses the feature of the face gear coupling that the swiveling member does not move in the axial direction when the swiveling member is fixed by the face gear coupling and when the fixing is released, and that it has high rigidity and high accuracy. It is an object of the present invention to obtain a swivel indexing device that is simple in structure and can be exhibited in a compact manner.
[0011]
[Means for Solving the Problems]
A turning index device for a machine tool according to the present invention includes a rotating face gear 26 fixed to the turning members 16 and 25, and a fixed face gear 35 fixed to a stationary member in the same plane and in the same direction as the rotating face gear. In a swivel indexing device for a machine tool provided with a connecting face gear 40 that faces the two face gears 26 and 35 and simultaneously meshes with the two face gears 26 and 35 when the two face gears 26 and 35 are advanced, 35 and the stationary member 28 are fixed by alternately fixing a plurality of positions on the circumference of the laminated thin plate ring 29 interposed therebetween to the stationary member 28 and the fixed face gear 35, and the above-mentioned The above-described problem is solved by providing a pressing spring 36 that biases the fixed face gear 35 that is fixed toward the connecting face gear. Further, by providing the stopper 38 for limiting the expansion / contraction stroke of the pressure spring 36, the durability and operation stability of the apparatus are improved.
[0012]
Here, the laminated thin plate ring is a laminated body of a plurality of ring-shaped metal thin plates, and the positions in the circumferential direction are alternately fixed to the immovable member 28 and the fixed face gear 35, so that between the two fixing positions. By utilizing the bending of the thin metal plate in the direction perpendicular to the plane, the fixed face gear 35 can be moved slightly in the axial direction, and a plurality of thin metal plate rings are laminated to obtain a large rigidity in the circumferential direction. It is what I did.
[0013]
Further, as the pressure spring, a disc spring is suitable because it has a large urging force and a short stroke, which is advantageous for making the apparatus compact. If the expansion / contraction stroke of the spring is large, the spring force is reduced due to fatigue or permanent deformation occurs. Therefore, in order to minimize the expansion / contraction stroke of the pressure spring, the extension position of the spring is defined by the stopper 38. The urging force of the pressure spring 36 is set to approximately one half of the pressing force of the connecting face gear 40 against the rotating and fixed face gears 26, 35. As a result, the fixed face gear and the connecting face gear, and the connecting face gear and the rotating face gear mesh with each other with substantially the same force, and the meshing rigidity is maximized.
[0014]
The stopper 38 is provided at a position where the extension of the pressure spring 36 is stopped at a position where the fixed face gear 35 protrudes slightly (for example, 0.1 mm) from the rotating face gear 26 toward the connecting face gear 40.
[0015]
When the turning members 25 and 16 are indexed and the connecting face gear 40 is rotated and advanced toward the fixed face gears 26 and 35 by the hydraulic cylinder 42 or the like, the connecting face gear 40 first meshes with the fixed face gear 35 to be connected. With the axial center and phase of the face gear 40 accurately positioned by the fixed face gear 35 and the fixed face gear 35 being slightly pushed in, the connecting face gear 40 and the rotating face gear 26 mesh with each other, and the turning member 25 and 16 are fixed. The pressing spring 36 may be provided so as to urge the fixed face gear 35 in principle, but urges the laminated thin plate ring 29 at a fixing portion between the laminated thin plate ring 29 and the fixed face gear 35. Such an arrangement is advantageous for making the apparatus compact.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows an example in which the rotary tool unit 16 of the composite lathe shown in FIGS. 5 and 6 is supported by the turning indexing device of the present invention. The rotary tool unit 16 has a built-in tool drive motor and a chuck opening / closing cylinder, and holds a rotary tool such as a milling cutter or a drill with a tool chuck 21 protruding from one end of the case (see FIG. 6). A swivel base 22 is fixed to the lower surface of the rotary tool unit 16, and this swivel base is mounted on the tool rest 15 with a swivel bearing 23 so as to be pivotable about the Y axis and not movable in the axial direction. A cylindrical part 24 having a built-in rotary joint for supplying hydraulic pressure to the chuck cylinder protrudes from the center of the swivel base 22, and a rotary face gear 26 is fixed downward to a fixed flange 25 portion at the base of the cylindrical part 24. Yes.
[0017]
The inner ring of the slewing bearing 23 is fixed to the outer periphery of the upper end of a short support cylinder 27 fixed to the tool post 15, and a ring-shaped inner flange 28 is fixed to the upper end of the support cylinder, and the inner diameter side of the inner flange The laminated thin plate ring 29 is fastened to the lower surface in a state of being clamped by washers 31 and 32 with an upward fixing bolt 30 provided at a portion that divides the circumference into eight equal parts (see FIGS. 1 and 2).
[0018]
The laminated thin plate ring 29 has a structure in which eight thin stainless steel plate rings having the same shape are stacked, and this ring is provided with bolt holes at positions equally dividing the circumference into 16 equal parts. Upward bolts 30 are inserted every other, and the laminated thin plate ring 29 is fixed to the inner flange 28 at eight positions around the circumference of the ring.
[0019]
Downward bolts 34 having short cylindrical spring guides 33 formed at the heads are inserted into the other eight bolt insertion holes of the laminated thin plate ring with the laminated thin plate ring 29 sandwiched between the washers 31 and 32. Downward bolts fasten the fixed face gear 35 to the lower surface of the laminated thin plate ring 29.
[0020]
That is, upward bolts 30 and downward bolts 34 are alternately inserted into bolt insertion holes provided by dividing the circumference of the laminated thin plate ring 29 into 16 equal parts, and the laminated thin plate ring 29 is fixed by the upward bolt 30. Fixed to a certain inner flange 28, downward bolts 34 fix the fixed face gear 35 to the laminated thin plate ring 29.
[0021]
An appropriate number of disc springs 36 are inserted into the short cylindrical spring guide 33 at the head of the downward bolt 34, and this disc spring group is arranged at eight locations on the inner lower surface of the inner flange 28. The disc spring 37 expands and contracts between the stepped hole 37 provided and the washer 31 on the upper surface of the laminated thin plate ring 29. The disc spring 37 urges the fixed face gear 35 downward at the mounting position thereof, that is, at eight positions on the circumference of the laminated thin plate ring 29. The step provided on the inner diameter side of the support cylinder 27 is a stopper. 38, the lower end position of the fixed face gear 35 is defined by contacting the shoulder 39 of the fixed face gear biased downward.
[0022]
As described above, this specified position is a position where the tooth surface of the fixed face gear 35 protrudes downward by a slight amount of 0.1 mm or less from the tooth surface of the rotating face gear 26.
[0023]
In this way, the connecting face gear 40 is mounted upward facing the rotating face gear 26 and the fixed face gear 35 that are mounted downward in a positional relationship adjacent to each other. It is fixed to a cylinder case 42 that forms a hydraulic cylinder device with a piston 41 fixed to the outer periphery of the cylindrical portion 24. In this hydraulic cylinder device, by alternately supplying hydraulic pressure to both sides of the piston, the cylinder case 42 moves up and down, and the connecting face gear 40 is rotated and pressed against and separated from the fixed face gears 26 and 35.
[0024]
An upper shaft 43 coaxial with the swivel axis of the swivel base 22 protrudes from the upper portion of the rotary tool unit 16, and a large-diameter bevel gear 44 and a brake disk 45 are fixed to the upper end portion of the upper shaft (see FIG. 6). The large-diameter bevel gear 44 meshes with the small-diameter bevel gear 47 of the servo motor 46 mounted on the tool post side, and is provided in the direction of the rotary tool unit 16 by the reciprocating rotation and positioning stop of the servo motor 46. The tool held by the tool chuck 21 is turned around the Y axis and indexed. On the other hand, the rotation of the brake disc 45 can be fixed by a disc brake 48 mounted on the tool post side, and the rotary tool unit 16 is located at a position other than the index position of the three-piece face gear coupling 49 described above. Used when fixing the direction of
[0025]
According to the rotary indexing structure of the rotary tool unit of this embodiment described above, the rotary tool unit 16 is turned around the Y axis by the servo motor 46, when the turning direction is fixed by the disc brake 48, and at the face. Even when the gear coupling is fixed at a predetermined index angle, the position of the tool in the Y-axis direction is held at the same position. Accordingly, there is no possibility of causing a machining error in the Y-axis direction when machining is performed while the rotary tool unit is turning, and when machining is performed at a fixed position, and more accurate machining can be realized.
[0026]
Note that the accuracy and rigidity at the time of fixing differ between when the direction of the rotary tool unit is fixed by the disc brake 48 and when the direction of the rotary tool unit is fixed by the face gear coupling 49. In machining, for example, high machining accuracy is often required at a specific division position, for example, every 15 degrees. Therefore, it is meaningful to fix the turning angle by the brake and the face gear coupling.
[Brief description of the drawings]
FIG. 1 is a side view showing a cross section of a swivel base in FIG. 6 according to an embodiment of the present invention. FIG. 2 is a cross-sectional perspective view schematically showing a fixing structure of a laminated thin plate ring. FIG. 4 is an explanatory view of a three-piece type face gear coupling having a conventional structure. FIG. 5 is a schematic perspective view showing an example of a composite lathe equipped with a rotary tool unit that rotates around a Y axis. Side view showing a part of the turret part of 5 in cross section [Explanation of symbols]
16 Rotary tool unit
25 Fixed flange
26 Rotating face gear
28 Ring-shaped bowl
35 Fixed face gear
36 Belleville spring
38 Stopper
40 Connecting face gear

Claims (2)

A rotating face gear (26) fixed to the swivel members (16, 25), a fixed face gear (35) fixed to the stationary member in the same plane and in the same direction as the rotating face gear, and the two faces In a swivel indexing device for a machine tool provided with a connecting face gear (40) that simultaneously meshes with the two face gears (26, 35) when facing the gear (26, 35),
The fixed face gear (35) and the stationary member (28) are arranged at a plurality of locations on the circumference of the laminated thin plate ring (29) interposed between the stationary member (28) and the stationary face gear (35). And a pressing spring (36) that is fixed by alternately fixing to the connecting face gear and biases the fixed face gear (35) fixed toward the connecting face gear. Swivel indexing device. The turning index device for a machine tool according to claim 1, further comprising a stopper (38) for restricting an expansion / contraction stroke of the pressure spring (36).

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