JPH0885002A - Composite processing lathe - Google Patents

Abstract

PURPOSE: To shorten the processing time by constituting a turret of a tool rest in such a manner that the turret is provided with both a revolving shaft inclined between the X-axis (and Z-axis) in a moving plane and a tool-attaching surface part, in which an attaching hole for a fixed tool is made on the central side of the revolving shaft, while another attaching hole for a rotating tool is made on the outer side of the revolving shaft, thereby minimizing a tool moving stroke when the direction of the tool is changed. CONSTITUTION: In the composite processing lathe, in which lathing and milling are carried out by a fixed tool 21 and a rotating tool 22, respectively, which are placed on a turret 15 of a tool rest, the turret 15 is provided with a revolving shaft 34 inclined by an angle of 45 deg. formed between the X-axis and the Z-axis in a moving plane. In addition, a tool attaching surface part, in which an attaching hole for the fixed tool 21 is arranged on the central side of the revolving shaft 34, while another attaching hole for the rotating tool 22 is arranged on the outer side of the revolving shaft 34, are formed on the turret 15. The revolving shaft 34 is rotated by the action of an index motor 31 via a driving gear 32 and a revolving gear 33. On the other hand, the rotating tool 22 is rotated by the action of a mill revolving shaft motor 37 via a plurality of transmitting gears 38, a transmitting shaft 39, a bevel gear 40, etc.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite machining lathe having both functions of turning and milling, and more particularly to a tool post having a fixed tool mounting hole and a rotary tool mounting hole separately provided on a common tool mounting surface. .

[0002]

2. Description of the Related Art A composite processing lathe refers to a lathe having a turning function and a milling function added, and the milling includes milling, drilling, tapping and the like. As a tool post of a conventional combined machining lathe, a tool provided with a drum type swivel head (hereinafter, referred to as a turret) and a horizontal tool (hereinafter, also referred to as H direction) and a vertical tool (hereinafter, also referred to as V direction), or a book There is a 2-position HV turret proposed by the applicant (see JP-A-59-227343). In both cases, the positions of the tool edges in the horizontal direction and the vertical direction are greatly separated from each other, and the tool axis is also considerably separated from the turret rotation center line. For example, in the 2-position HV turret 3 shown in FIG. 9, the tool cutting edges 1a and 2a in the V direction and the H direction are largely separated from each other, and the tool axes are also greatly separated from the turret rotation center line t. In position.

In such a drum turret or a two-position HV turret, the position of the cutting edge of the tool is largely changed by changing the direction of the tool, and therefore the axial movement distance becomes long to return to the original machining position. That is, machining idle time is generated and the machining program becomes complicated. Further, since the tool edge is located far from the turret rotation center line, the moment load due to turning is large, which is disadvantageous in terms of rigidity. Therefore, in order to secure the rigidity, it is necessary to apply a large force to the turret clamp device, which makes the machine large. Further, the further the tool edge is from the turret rotation center line, the worse the positioning accuracy due to the rotational indexing of the turret.

Further, in the conventional tool post, a dummy tool is attached to a tool shaft of a fixed tool (hereinafter referred to as a turning tool) or a rotary tool, which is not used, in order to prevent intrusion of cutting water or cutting chips. ing. Then, the dummy tool must be replaced every time the turning process and the milling process are changed, so remove the unused tool and install the dummy tool, then remove the dummy tool of the one you are using and install the tool that you are using. To do. Therefore, the automatic tool changer (hereinafter referred to as ATC) has to make two reciprocating movements at the same place, resulting in a long tool change time and a machining idle time. Further, when a dummy tool is attached, when the ATC is used, the dummy tool is also placed in the tool magazine, so that the number of usable tools is reduced.

Further, in the case of processing an inclined surface with a conventional tool rest, the turret is positioned at an arbitrary angle by a turret having a swivel centerline perpendicular to the centerline of the work, and the inclined surface is moved by the feed shaft. We are processing. In this case, since the rotary tool axis and the turret rotation center line are orthogonal to each other, it is difficult to compactly house the rotary tool drive system in the tool rest main body, and it is also difficult to perform wiring processing. Further, in order to give such a conventional turret a function of processing an inclined surface, a complicated structure is required.

In addition to the above, there is a tool rest that selectively mounts a turning tool and a rotary tool in a common tool hole to perform respective machining. As a result, the tool post can be made compact, and there is an advantage that a large machine can be combined with a small machine. However, with a common mounting hole,
Since the rotary tool is rotated at several thousand RPM, a considerable amount of heat is generated and thermal displacement occurs in the mounting portion. When a turning tool is installed in the mounting hole that has undergone this thermal displacement, the cutting edge position changes,
There is a problem that this error appears on both sides of the workpiece diameter and reduces the accuracy of turning. Further, since the rotary tool is supported by bearings and the turning tool is mounted in this floating state, there is also a problem that the mechanism for ensuring rigidity becomes complicated.

[0007]

[Problems to be Solved by the Invention]

(1) The present invention, in a combined machining lathe having both functions of turning and milling, when changing the orientation of the tool between the horizontal direction and the vertical direction, the tool moving stroke is minimized and the machining time is reduced. Shortened, improved processing accuracy,
We also provide a combined machining lathe with a simplified machining program. (2) Further, the present invention provides a tool post of a multi-tasking lathe, which has a small moment load due to turning, is advantageous in terms of rigidity, and can perform highly accurate machining. (3) Further, the present invention provides a multi-tasking lathe with good blade edge positioning accuracy by rotationally indexing a turret. (4) Further, the tool machining stroke is reduced to make the tool rest compact, and to provide a combined machining lathe capable of machining a relatively large work. (5) Further, the rotary tool and the turning tool are mounted in separate tool mounting holes to prevent thermal displacement caused by the operation of the rotary tool from affecting the turning tool, and a cooling means is provided as necessary. Thus, a combined machining lathe capable of reliably blocking the influence of heat is provided. (6) Further, the present invention provides a multi-tasking lathe equipped with a cover means capable of quickly closing an unused tool mounting hole instead of a dummy tool when the turning and milling processes are switched. (7) Further, the present invention provides a combined machining lathe capable of imparting a highly accurate inclined surface machining function to a turret by slightly modifying the structure.

[0008]

A spindle head provided on a frame, a spindle rotatably provided in the spindle head for holding a work, and moving on the frame in a direction parallel to and perpendicular to the spindle axis. A combined machining lathe that comprises a tool post for performing turning and milling respectively with a fixed tool and a rotary tool provided on the swivel head of the swivel head, the swivel head being an X-axis in a moving plane. A swivel axis that is inclined with an angle of 45 ° formed between the Z axis, a tool mounting surface portion in which mounting holes for a fixed tool are arranged on the center side of the swivel axis, and mounting holes for a rotary tool are arranged on the outer side, and the swivel axis A machining lathe comprising a first indexing position in which the swivel head is swiveled around the axis and the tool mounting surface is parallel to the spindle axis, and a driving means for positioning the tool mounting surface in a second indexing position orthogonal to the spindle axis. By To solve the serial first to fifth issues. The sixth problem is solved by providing a shutter for selectively and automatically closing the fixed tool mounting hole and the rotary tool mounting hole of the turret in the combined machining lathe. The seventh problem is solved by providing the composite processing lathe with positioning means capable of fixing the turret at an arbitrary position around the turning center line.

[0009]

1 is a side view of an embodiment of a combined machining lathe according to the present invention. A carriage base 12 is attached to a horizontal surface 11 a of a bed 11 that supports the lathe body. The carriage base 12 has a longitudinal feed in the Z-axis direction and a lateral feed in the Y-axis projection line direction on a horizontal plane,
A carriage 13 is placed. Carriage 13 X
The sliding surface 13a in the axial direction is inclined at a constant angle with respect to a vertical surface including the Z axis passing through the center line of the spindle, and the tool rest 14 is slidably mounted on the sliding face 13a. A turret (swivel head) 15 equipped with a tool is attached to the lower side. The spindle head, that is, the spindle head 16 and the tail stock 17 are attached to the bed inclined surface 11b on the left side of the drawing. AT at the rear of the lathe body (right side in the figure)
A C magazine 18 is arranged. Bed slope 11
A carrier 19 for processing chips is arranged below b.

FIG. 2 is a view as seen from the direction of arrow A, showing the front surface of the tool rest portion of FIG. On the left side of the bed inclined surface 11b in the figure, a spindle 16a (tip portion) on which a work W is mounted is arranged, and on the opposite side, a tail stock 17 is arranged. A carriage 13 is placed on the carriage base 12 on the bed horizontal surface 11a, and a tool rest 14 is placed on the carriage. A turret 15 capable of turning around an inclined turning center line is attached to the lower part of the tool rest, and mounting holes for a turning tool 21 and a rotary tool 22 are provided on the lower surface of the turret 15.

FIG. 3 is a front view showing the arrangement of main components of the combined machining lathe shown in FIG. A built-in main shaft 16a with a C-axis function is arranged on the left side in the figure on the Z-axis, and a tailstock 17 is arranged on the opposite side. A turret 15 is provided at the lower part of the tool rest 14 between the X-axis and the Z-axis in the moving plane so that the turret 15 can be swung around a turning center line T inclined by about 45 ° from the vertical line. Tool mounting surface 1 at the bottom of the turret
5a is provided with respective mounting holes for the turning tool 21 on the center side and the rotary tool 22 on the outer side with reference to the turning center line T. As a result, the turning tool 21 can be mounted by matching the clamp surface on the turning center line T, and the rotary tool 22 can be mounted by matching the cutting edge on the turning center line T. Although the drawing shows a state in which the turning tool 21 and the rotary tool 22 are mounted for the sake of description, any one of the tools is selectively mounted during processing. The swiveling operation of the turret 15 is performed by a driving means described later, and is placed at a first indexing position where the tool mounting surface 15a is parallel to the spindle axis Z and a second indexing position where the tool mounting surface 15a is orthogonal to the spindle axis Z. Can be positioned. In the state of the turret 15 in the first positioning position shown by the solid line, these tools 2
Although 1 and 22 are oriented in the V direction for side surface machining of the work W, the 180 degree turret 15 is centered around the turning center line T.
By swiveling, these tools move to the second positioning position and are oriented in the H direction as shown by the dotted line. As will be described later, this turret 15 has
It is possible to have a B-axis function of performing processing by fixing at an arbitrary position within 180 degrees from the V direction to the H direction around the turning center line T.

FIG. 4 is an explanatory view showing a drive mechanism of the turret 15 of FIG. A state in which the rotary tool 22 is mounted on the lower side of the turret 15 and the turning tool 21 is mounted on the upper side of the turret 15 is shown. First, the turning mechanism of the turret 15 will be described. The rotation of the index motor 31 is transmitted from the turret drive gear 32 to the turret turning gear 33, and the cylindrical turret turning shaft 34 attached to the turret turning gear is rotated,
The turret 15 fixed to the turret rotation shaft is rotated 180 degrees from the V direction to the H direction. The turret 15 is fixed by a coupling mechanism 36 having a coupling cylinder 35. When the B-axis function described later is added, the coupling mechanism 36 including the coupling cylinder 35 is removed, and the index motor 31 is replaced with a servo motor. By this servo motor, positioning is performed at an arbitrary angle between 180 ° from the V direction to the H direction.

Next, the rotating mechanism of the rotary tool 22 will be described.
The rotation of the mill rotation shaft motor 37 rotates the mill rotation transmission shaft 39 via the plurality of transmission gears 38, and the rotation is transmitted to the idle rotation shaft 42 via the idle gear 41 connected to the bevel gear 40 at the tip thereof. . When rotating the rotary tool 22, the drive gear 43 of the idle rotary shaft 42 is connected to the gear 45 of the mill rotary shaft 44 to rotate the rotary tool 22.

FIG. 5 shows the tool mounting surface 15a of the turret 15.
FIG. 6 is an explanatory diagram of a slide cover type shutter 51 that prevents cutting water, cutting chips, and the like from entering a mounting hole of a tool that is not used. (A) and (B) show the state of the shutter 51 when the turning tool 21 is used. In this state, the rubber packing 5 provided on the lower surface of the tip of the shutter
2 is closely attached to the periphery of the mounting hole 22a of the unused rotary tool, and a hole 51a corresponding to the mounting hole 21a of the turning tool is provided. The turning tool 21 is mounted in the mounting hole 21a through this hole 51a. When machining is performed by the turning tool 21 in this state, the mounting hole 22 of the unused rotary tool
Since a is closed by the rubber packing 52 of the shutter 51, invasion of cutting water, cutting chips, etc. is reliably prevented. Next, the case of using the rotary tool 22 will be described. (C),
(D) shows a side view and a plan view of the shutter 51 in this case, respectively. When shifting from the state of using the turning tool to the state of using the rotary tool, the shutter 51 is slid in the direction of the arrow (D) after the turning tool is pulled out by the ATC (not shown), and at this time, the mounting hole for the rotary tool is attached. 22
The packing 52 that was in close contact with a is lifted in the vertical direction with respect to the tool mounting surface 15a of the turret 15 by a cam groove (not shown) on the lower surface of the shutter, and slides on the tool mounting surface. Next, when it comes to the position of the removed mounting hole of the turning tool 21, the packing 52 comes into close contact with the periphery of the mounting hole 21a of the turning tool due to the spring function of the shutter 51. Then, the rotary tool 22 is mounted by the ATC in the rotary tool mounting hole 22a after the shutter 51 is moved. Also in this case, since the turning tool mounting hole 21a is closed by the packing 52, intrusion of cutting water, cutting chips, etc. is reliably prevented. Tool mounting surface 1 of this shutter 51
The lift operation and the slide operation with respect to 5a are performed by one actuator cylinder (not shown) provided on the turret surface.

The operation of the composite working lathe of the present invention constructed as above will be described. First, in the turning process, when the turning tool 21 moves between the work side surface and the work end surface,
As described in the configuration of the turret drive mechanism of FIG. 4, the rotation of the index motor 31 is driven by the drive gear 32 and the swing gear 3.
3. The turret 15 is turned by being transmitted to the turning shaft 34. At this time, as shown in FIG. 3, since the clamping surface of the turning tool 21 facing the V direction is on the turret turning center line T, after turning 180 degrees around the turret turning center line T and turning in the H direction. However, the turning tool 21 is in the immediate vicinity of its original position. Therefore, the movement control of the tool cutting edge to the end face machining position is extremely easily performed. For example, compared with the conventional turret 3 as shown in FIG. 9, the position control of the tool edge is significantly improved in the case of the present invention.

Further, since the distance from the cutting edge position of the turning tool 21 to the turret rotation center line T is extremely small, the moment during turning is small, which is advantageous in terms of rigidity of the turret 15, and the working accuracy is improved. When the direction of the tools 21, 22 is changed by the turning of the turret 15, the tool moving stroke is small, so that the turret 15 can be downsized, and the conventional drum type turret and 2-position H can be used.
Unlike the case of the V turret, since the tool cutting edge of the turret 15 always faces the turret turning center line T, the turning area of the turret 15 is small, and the turret 15 can be made compact also in this respect. Therefore, a relatively large work can be processed by the compact tool post, the rigidity of the tool post is improved, and highly accurate work can be performed.

Further, since the turning tool 21 is mounted in the mounting hole independent of the rotary tool 22, the influence of thermal displacement due to the operation of the rotary tool 22 can be minimized. In addition, since the rotary tool 22 whose rigidity is not relatively strong is arranged outside the turret 15 and the turning tool 21 is arranged on the base side of the turret 15, heat is dispersed on the base side having a large heat capacity to allow the turning tool 21 to rotate. Has the effect of reducing the effect on
Further, if necessary, a cooling means can be provided between both tool mounting holes, so that the turning tool 21 is prevented from being deteriorated in accuracy due to heat. Furthermore, the problem that the turning tool suffers from the disadvantage of the bearing support of the rotary tool in terms of rigidity is eliminated.

Next, the case of milling will be described. As described in the configuration of the turret drive mechanism in FIG. 4, the rotation of the mill rotation shaft motor 37 is transmitted to the idle rotation shaft 42 via the transmission gear 38, the transmission shaft 39, the bevel gear 40, and the idle gear 41, and the drive gear 43 thereof. Is the gear 4 of the mill rotary shaft 44
5, the rotary tool 22 is rotated. Rotating tool 2
When 2 is moved from the work side surface to the work end surface, as shown in FIG. 3, since the cutting edge position of the rotary tool 22 oriented in the V direction is on the turret rotation center line T, 180 degrees around the turret rotation center line T. Even after turning and directing in the H direction, the tool edge of the rotary tool 22 is almost at the original position. Therefore, the position control of the tool edge position is easier and more accurate than in the case of the turning tool 21.

Further, since the unused tool mounting hole is covered by a slide cover type shutter instead of the dummy tool, it is not necessary to replace the dummy tool each time the lathe turning process and the milling process are changed. Since the shutter operates instantly when the tool is changed, the tool change time is very short and the machining idle time is eliminated. In addition, ATC
When using, it is not necessary to put dummy tools in the tool magazine, and all usable tools can be installed.

In the tool post of the present invention, by adopting a tool having a short taper shank capable of withstanding both loads of turning and milling, the tool mounting holes of the turret and the tool magazine are unified, and the tool exchange time is improved. It can be further shortened.

Further, as shown in FIG. 1, the tool rest 14 of the present invention can be moved in the Z-axis direction and the Y-axis projection line direction on the horizontal plane by the carriage base 12, and the inclined lateral feed surface of the cage 13 is provided. Since it is configured to be movable on the X-axis along the Y-axis, it is possible to perform Y-axis control with high precision and high rigidity by performing Y-axis control by synthesizing two linear axes on the inclined surface and the horizontal plane. In this case, since the main component force of turning is not directly received by the Y-axis, turning rigidity is high and there is no overhang of the tool rest 14, so that stable accuracy can be maintained. Further, the tool rest 14 does not hinder the operator and the workability is good. FIG. 6 shows an example of the work W that has been subjected to such Y-axis processing. (A)
Shows various processing examples on the side surface of the work W, and (B) and (C) show groove processing and corner surface processing on the end surface of the work W, respectively.

Next, the tool rest 14 of the combined machining lathe of the present invention
Is the turret 1 as described for the turret drive mechanism in FIG.
B-axis machining is possible only by removing the coupling mechanism 36 of No. 5 and replacing the index motor 31 with a servomotor. With such a configuration, the turret 15 is rotationally controlled and positioned to an arbitrary position between 180 degrees in the V direction and the H direction about the turret rotation center line T, and a synchronization function with the feed shaft is provided. Can be processed into inclined surfaces. In this case also, since the distance from the turret rotation center line T to the tool blade edge is small, it is possible to perform processing while maintaining high rigidity, so that the processing accuracy is improved.

FIG. 7 is an explanatory view of the operation of B-axis machining. As an example, a case where the oblique slot S is formed on the cylindrical work W by B-axis processing will be described. First, for comparison, (A) shows a state in which the machining of the reference hole R in the work W is completed by the X-axis feed of the rotary tool 22. (A ') is a perspective view seen from a direction in (A). Next, in order to process the diagonal slot S on the side opposite to the reference hole R of the work W, as shown in (B), the turret 15 is swung, and rotational indexing is performed to a required angle between the V direction and the H direction. Be done. (B ') is a perspective view seen from the b'direction in (B), and (B ") is a side view seen from the b" direction. The turret 15 is indexed so that the rotary tool 22 has an inclination angle with the work W that matches the angle θ of the oblique slot S. Next, as shown in (C), the work W is rotated by C-axis indexing of the main shaft, and the side opposite to the reference hole R comes to a position facing the rotary tool 22. Since the cutting edge position of the rotary tool 22 deviates from the machining position by s only by the C-axis indexing, the deviation s is corrected by moving the turret 15 in the Y-axis this time, as shown in (D). In this way, when the machining start position of the rotary tool 22 is determined,
After that, as shown in (E), the machining of the oblique slot S is completed by the cutting feed h-g-h-g. In this case, cutting h
Is performed by X-, Y-, and Z-axis composite feed, and cutting g is performed by Z-axis feed. FIG. 8 shows an example of B-axis machining. (A) shows an example of processing of an inclined surface on the end surface of the work W, (B) shows an example of processing of an oblique hole on the cylindrical surface of the work W, and (C) shows an example of processing of various inclined surfaces on the end surface of the work W.

[0024]

As described above, according to the combined machining lathe of the present invention, when the direction of the tool is changed between the horizontal direction and the vertical direction, the tool axis movement is minimized and the machining time is shortened. As a result, the processing accuracy is improved and the processing program is simplified. Further, since the turning tool clamping surface is on the turret rotation center line, the moment load due to cutting is small, which is advantageous in terms of rigidity, and high-precision machining can be performed.
Since the turning tool cutting edge is close to the turret rotation center line and the rotating tool cutting edge is on the turret rotation center line, the positioning accuracy of the cutting edge by rotary indexing of the turret is good. Furthermore, since the tool movement stroke is small, the tool rest can be made compact, and relatively large workpieces can be machined. Since the rotary tool and the turning tool are installed in separate tool mounting holes, thermal displacement due to the operation of the rotary tool does not affect the turning tool, and by providing cooling means as necessary,
Further, it is possible to reliably block the influence of heat and prevent a decrease in turning accuracy. In addition, the tool mounting holes that are not used when changing processes are instantly covered with a slide-cover type shutter, so there is no need to replace the dummy tool each time the machining process of turning and milling is changed, and machining idle time is reduced. Disappear. Furthermore, when using the ATC, it is not necessary to put dummy tools in the tool magazine, and all usable tools can be mounted. With a slight modification of the structure, it is possible to give the turret the function of processing inclined surfaces, and by driving the turning of the turret with a servo motor, the inclination of the tool can be changed continuously, and the accuracy can be improved. Highly inclined surfaces can be easily processed.

[Brief description of drawings]

FIG. 1 is a side view of an embodiment of a combined machining lathe according to the present invention.

FIG. 2 is a view taken in the direction of arrow A showing the front surface of the tool rest portion of FIG.

FIG. 3 is a front view showing an arrangement of main components of the combined machining lathe shown in FIG. 1.

FIG. 4 is an explanatory view of a drive mechanism of the turret of FIG.

5A is a side view and FIG. 5B is a plan view of a shutter when a turning tool is used, and FIG. 5B is a side view and FIG. 5C is a plan view when the rotary tool is used. .

FIG. 6 is an explanation of Y-axis machining carried out by the multi-tasking lathe of the present invention by various machining examples of the side surface (A) of the work, examples of groove processing of the end face (B) and examples of side surface corner surface machining (C). It is a figure.

FIG. 7 is an explanatory view of the action of B-axis machining, (A),
(A ') Finishing machining of the reference hole, (B), (B'),
(B ") is the turret angle index, (C) is the spindle C
Axis indexing, (D) shows machining start position correction by Y-axis movement, and (E) shows cutting feed.

FIG. 8 is an explanation of B-axis machining by (A) end face inclined surface machining example, (B) side surface oblique hole machining example, and (C) end face various machining example of a work carried out by the combined machining lathe of the present invention. It is a figure.

FIG. 9 is a front view of a conventional 2-position HV turret.

[Explanation of symbols]

 11 Bed (frame) 14 Turret (turret) 15 Turret (swivel head) 16 Spindle head (spindle head) 16a Spindle 21 Turning tool (fixed tool) 22 Rotary tool 21a Turning tool mounting hole (fixed tool mounting hole) 22a Rotating tool mounting hole 31 To 45 driving means (including 34 turning axis) 51 shutter T turning center line W work

Claims (6)

[Claims] 1. A spindle head provided on a frame, a spindle that is rotatably provided in the spindle head to hold a work, and a tool rest that moves on the frame in a direction parallel to and perpendicular to the spindle axis. A combined machining lathe that performs turning and milling with a fixed tool and a rotary tool provided on the swivel head of the tool post, respectively, wherein the swivel head has an X-axis and a Z-axis in a moving plane. And a tool mounting surface portion in which mounting holes for a fixed tool are provided on the center side of the swivel axis and each mounting hole for a rotary tool is disposed on the outer side of the swivel axis, and swivel about the swivel axis. A composite machining lathe comprising: a first indexing position at which a head is pivoted to make a tool mounting surface parallel to a spindle axis and a driving means for positioning a tool mounting surface at a second indexing position orthogonal to the spindle axis. 2. A first slide that moves on the frame in the Z-axis direction, a second slide that moves on the first slide in the Y-axis direction, and a first slide that moves on the second slide in the X-axis direction. The combined machining lathe according to claim 1, comprising three slides. 3. The combined machining lathe according to claim 1, further comprising a shutter for selectively automatically closing the fixed tool mounting hole and the rotary tool mounting hole of the swivel head. 4. The packing is a slide cover that slides on the tool mounting surface of the swivel head by an actuator, and a packing having a shape matching the hole diameter at the rotary tool mounting hole position on the lower surface of the tip of the slide cover. The combined machining lathe according to claim 3, further comprising a hole having a diameter slightly larger than the hole at the fixed tool mounting hole position. 5. The combined machining lathe according to claim 1, further comprising a positioning means capable of fixing the turning head at an arbitrary position around a turning center line thereof. 6. The combined machining lathe according to claim 1, wherein both the fixed tool and the rotary tool have a short taper shank.