JP4609337B2 - Turret lathe - Google Patents

Description

  The present invention relates to a turret lathe used for spherical machining of a workpiece such as a ball joint.

  Conventionally, when a workpiece is processed into a spherical shape, a method is adopted in which the workpiece is processed into a spherical shape with a lathe and then rolled with a rolling machine. As shown in FIG. 9, the spherical machining method using the lathe is performed by feeding the workpiece 81 held by the chuck 80 while changing the cutting amount of the cutting tool 81, thereby moving the cutting edge of the cutting tool 81 into an arc orbit. Move it up.

In addition, a lathe that performs spherical processing on a workpiece by attaching a tool to the turret tool post so as to be able to turn around a turning axis orthogonal to the main shaft supporting the workpiece, and cutting the workpiece while turning the tool around the turning axis. Has been proposed.
JP 2000-308901 A

  The above-mentioned method using a lathe and a rolling machine together uses a plurality of machines, so it takes time to change the workpiece, so the work efficiency is poor, and errors are likely to occur when changing the workpiece, so the machining accuracy is difficult. .

  Further, the lathe described in Patent Document 1 has a problem that the entire turret device including the peripheral part is enlarged because the turning drive means for turning the tool is provided on the outer peripheral part of the turret. Furthermore, since the tool turns around the turning axis in the tangential direction (for example, the vertical direction) of the turret index clearance, the tool protrudes greatly outward in the radial direction of the turret depending on the turning position, thereby increasing the turret index clearance. This causes a problem that the lathe itself must be enlarged.

An object of the present invention is to provide a turret lathe which can stably machine a spherical shape with a stable load applied to a workpiece tool.
Another object of the present invention is to reduce the turret index clearance and suppress the increase in the size of the lathe.
Still another object of the present invention is to make it possible to change the turning speed of the tool according to the type of workpiece and various machining conditions by making it possible to adjust the reduction ratio of rotation input from the turret.

A turret lathe according to the present invention includes a main shaft capable of supporting a workpiece, and a turret capable of mounting a plurality of tools around the workpiece and turning and indexing one tool toward a workpiece supported by the main shaft. A lathe, wherein at least one of the tools is mounted on a tool turning unit mounted around a turret, and the tool turning unit is configured to have a tool for processing the workpiece into a spherical shape. The tool tip is swung on an arc trajectory while maintaining a posture toward the center of the spherical surface of the work, and the turret incorporates a swivel drive mechanism that drives the tool swivel unit.
According to the turret lathe of the present invention, the work can be processed into a spherical shape by turning the cutting edge of the tool on an arc locus by the tool turning unit. At this time, since the tool maintains a posture toward the spherical center of the workpiece, the load applied to the tool of the workpiece is stable and can be processed with high accuracy. Since the turning drive mechanism for driving the tool turning unit is built in the turret, the turret device does not increase in size.

In this invention, the tool turning unit may turn the tool around a tool turning center line orthogonal to the turning center line of the turret.
With this configuration, the tool turning unit prevents the turret index clearance from increasing because the tool turret radial position does not change even if the tool blade tip is turned on an arc locus.

In the present invention, the turning drive mechanism includes a drive shaft having an axis perpendicular to the turning center line of the turret, and the tool turning unit includes a rotation transmission shaft coupled to the drive shaft, and the rotation transmission shaft. The drive-side gear provided on the drive-side gear, the driven-side gear that meshes with the drive-side gear, and the blade tip is directed to the center direction of the driven-side gear at a position that is attached to the driven-side gear and deviates from the center position of the driven-side gear And a tool holder on which a tool can be mounted.
According to this configuration, the tool turning unit can be removed from the turret by releasing the coupling between the drive shaft and the rotation transmission shaft. For this reason, it is possible to replace with a tool turning unit having a different transmission ratio (reduction ratio) between the driving side gear and the driven side gear according to the processing conditions, and spherical processing can be performed in an optimum state.

  A turret lathe according to the present invention includes a main shaft capable of supporting a workpiece, and a turret capable of mounting a plurality of tools around the workpiece and turning and indexing one tool toward a workpiece supported by the main shaft. A lathe, wherein at least one of the tools is mounted on a tool turning unit mounted around a turret, and the tool turning unit is configured to have a tool for processing the workpiece into a spherical shape. The tool tip is swung on an arc trajectory while maintaining a posture toward the center of the spherical surface of the workpiece, and the turret has a built-in swivel drive mechanism that drives the tool swivel unit. The load is stable, it can be accurately processed into a spherical shape, and the turret device does not become large.

  When the tool turning unit turns the tool around the tool turning center line orthogonal to the turning center line of the turret, the maximum radius of the turret device can be reduced, and the enlargement of the lathe can be suppressed.

  The turning drive mechanism includes a drive shaft having an axis perpendicular to the turning center line of the turret. The tool turning unit includes a rotation transmission shaft coupled to the drive shaft, and a drive provided on the rotation transmission shaft. The side gear, the driven gear that meshes with the drive gear, and the tool attached to the driven gear so that the cutting edge is directed away from the center position of the driven gear so that the cutting edge faces the center direction of the driven gear. When it is composed of a tool holder that can be mounted, the rotation speed reduction ratio input from the turret can be adjusted, so the tool turning speed can be changed according to the type of workpiece and various machining conditions. Spherical processing can be performed in the state.

  An embodiment of the present invention will be described with reference to FIGS. In this turret lathe, as shown in the plan view of FIG. 1, a headstock 2 and a turret tool post 6 are installed on a bed 1. The spindle stock 2 is provided with a spindle 3, and the spindle 3 is rotationally driven by a spindle motor 4 installed on the bed 1 below the spindle stock 2. The main shaft 3 has a main shaft chuck 5 and can grip the workpiece W.

  The turret tool post 6 is installed in the tool post moving mechanism 7 and is movable in two orthogonal axes (X-axis direction and Y-axis direction). The tool post moving mechanism 7 includes a feed base 9 installed on the bed 1 through a guide 8 so as to be able to move forward and backward. The turret tool post 6 is orthogonal to the feed base moving direction (X-axis direction). It is movably installed in the direction (Z-axis direction). The tool post moving mechanism 7 includes a feed base advance / retreat mechanism 10 for moving the feed base 9 forward and backward, and a turret advance / retreat mechanism 11 installed on the feed base 9 for moving the turret tool post 6 back and forth. Each of the feed base advance / retreat mechanism 10 and the tool rest advance / retreat mechanism 11 includes a feed screw mechanism 12, 13 such as a ball screw mechanism and a drive source 14, 15 such as a servo motor for rotating the screw shaft.

  The turret tool post 6 includes a turret 16 whose front shape is a polygonal drum shape, and each planar peripheral surface portion of the turret 16 is a tool station S. Each tool station S is equipped with various tools such as tools. In this embodiment, the turret 16 has a regular decagonal drum shape and has ten tool stations S. Then, a spherical machining tool 65 is mounted on at least one of the tool stations S via the tool turning unit 17. The turret 16 can be indexed by driving an indexing mechanism to be described later so that an arbitrary tool station S is at a position corresponding to the spindle 3.

  FIG. 2 is a view showing the internal structure of the turret tool post 6. A turret tool post 6, a fixed frame 22, a hollow turning shaft 24 provided so as to be turnable with respect to the fixed frame 22 and having the turret 16 at the tip, and a hollow non-turning shaft 26 inserted through the turning shaft 24. And a non-rotating member 27 that is provided at the tip of the non-rotating shaft 26 and supports the drive shaft 28. A drive transmission shaft 29 is inserted into the non-turning shaft 26, and rotation is transmitted from the drive transmission shaft 29 to the drive shaft 28 via the transmission mechanism 30.

  A guide 35 is provided on the outer periphery of the non-rotating member 25 along the circumferential direction, and the guide 35 guides the movement of the rotary tool 36 attached to the turret 16 in accordance with the turning of the turret 16 while keeping the rotation angle constant. . A mesh coupling 34 is provided between the turret 16 and the fixed frame 22. The mesh coupling 34 is a three-piece coupling, and includes a first joint tooth 31 provided at the rear portion of the turret 16, a second joint tooth 32 provided on the fixed frame 22, and the first and second joints. It has the 3rd joint tooth | gear 33 which can be engaged / disengaged in both teeth 31 and 32. FIG. The third joint teeth 33 are driven back and forth by the engagement / disengagement drive source 40.

The fixed frame 22 is installed in a fixed state on the support base 52. The non-rotating shaft 26 is connected to the fixed frame 22 by connecting members 38 and 39 at the rear end. Each of the connecting members 38 and 39 includes a bolt and a positioning pin.
The turret 16 is rotatably supported on the outer periphery of the non-rotating shaft 26 via a bearing 42 in the portion of the rotating shaft 24. A gear portion 43 having a gear portion 43 such as a ring gear on the outer periphery of the rear portion of the turret 16 and provided on a turret drive shaft 44 driven by a turret indexing motor (not shown) is connected to the gear portion 43 of the turret 16. Are engaged.

  The first joint tooth 31 and the second joint tooth 32 of the meshing coupling 34 are provided in a concentric ring shape, and are provided rearward at the same axial position. These joint teeth 31 and 32 are formed by meshing teeth arranged in the circumferential direction, and the cross-sectional shape of each tooth in the circumferential direction is formed in a trapezoidal shape, for example. The third joint teeth 33 are ring-shaped members having a radial width that meshes with both the first and second joint teeth 31 and 32.

  The engagement / disengagement drive source 40 of the meshing coupling 34 is composed of a fluid pressure cylinder such as a hydraulic cylinder built in the fixed frame 32 and has a piston 41 that can move back and forth. The third joint teeth 33 of the meshing coupling 34 are provided in front of the piston 41. The piston 41 is a ring-shaped member, and is fitted to the inner peripheral surface portion of the stepped cylindrical surface of the fixed frame 22 so as to freely advance and retract. The fluid pressure chambers 53a and 53b before and after the fluid pressure is applied to the piston 41 are provided in the fixed frame 22 on the outer peripheral side of the piston 41, and communicate with the fluid passages 54a and 54b (see FIG. 3), respectively.

In FIG. 2, a drive transmission shaft 29 is a shaft for driving the tool turning unit 17 or another rotary tool 18, and is connected to a tool rotation drive source such as a motor via a transmission mechanism (not shown) at the rear end. ing. The drive transmission shaft 29 has a rear portion supported by a support base 52 via a bearing 46 and a front portion supported by a non-rotating shaft 26 by a bearing 47.
The drive shaft 28 is rotatably supported by the non-rotating member 27 by bearings 48 and 49 at predetermined positions, and extends in a direction orthogonal to the turning center line O1 of the turret 16, that is, in the radial direction of the turret 16. A transmission mechanism 30 that transmits rotation from the drive transmission shaft 29 to the tool transmission shaft 28 includes a pair of bevel gears 50 and 51 that are provided on both shafts 29 and 28 and mesh with each other.
The drive transmission shaft 29, the transmission mechanism 30, and the drive shaft 28 constitute a turning drive mechanism that drives the tool turning unit 17. This turning drive mechanism is built in the turret 16.

  As shown in FIGS. 4 and 5, the tool turning unit 17 includes a rotation transmission shaft 61 coupled to the drive shaft 28 by a coupling means 60 described later, and a drive provided so as to rotate integrally with the rotation transmission shaft 61. It comprises a side gear 62, a driven side gear 63 that meshes with the drive side gear 62, and a tool holder 64 attached to a support shaft 63 a of the driven side gear 63. The tool holder 64 can be mounted with a tool 65 at a position deviated from the center position of the driven gear 63 so that the cutting edge faces the center direction of the driven gear. The drive side gear 62 and the driven side gear 63 are both spur gears, and the driven side gear 63 has more teeth than the drive side gear 62, and transmits the rotation by decelerating from the rotation transmission shaft 61 to the support shaft 63a. It is supposed to be.

  The housing 66 that accommodates the drive side gear 62 and the driven side gear 63 is fixed to the peripheral surface of the turret 16 by a plurality of (four in this embodiment) bolts 67. The bolt hole 68 of the housing 66 through which the bolt 67 is inserted is a hole that is larger than the bolt diameter, and the mounting angle of the housing 66 with respect to the turret 16 can be adjusted by changing the insertion position of the bolt 67 in the bolt hole 68. It is.

  As shown in FIG. 6, the coupling means 60 forms a linear groove-like concave portion 28 a on the tip surface of the drive shaft 28, and the linear convex portion 61 a meshing with the concave portion 28 a is transmitted to the rotation of the tool turning unit 17. It is formed at the end of the shaft 61 on the rotation input side. Although the drive shaft 28 is fixed in position, the concave portion 28a and the convex portion 61a of the coupling means 60 can be freely engaged and disengaged in the rotational direction of the turret 16 due to the linear shape thereof.

  The guide 35 (FIG. 4) is a member that guides the tool turning unit 17 or the rotary tool 18 attached to the turret 16 to the drive shaft 28 while turning the turret 16 while keeping the orientation constant. The guide 35 has a discontinuous portion 35 b in which the drive shaft 28 is interposed at a circumferential position corresponding to the drive shaft 28. The guide 35 has a guide groove 35a on the outer periphery for engaging the convex portion 61a of the rotation transmission shaft 61 movably in the circumferential direction. Specifically, the guide 35 is formed by two disc-shaped guide plates 59 facing each other with a gap sandwiching the convex portion 57a, and the outer peripheral portion between the two guide plates 59 becomes the guide groove 35a. The guide plate 59 is disposed around the turret axis and is fixed perpendicular to the turret axis. These guide plates 59 have an opening 59a through which the non-rotating member 27 enters, and the discontinuity 35b is formed at one place in the circumferential direction.

The operation of this turret lathe will be described. When the tool turning unit 17 attached to the turret 16 is indexed to the machining position Q where the drive shaft 28 is located, the convex portion 61a of the rotation transmission shaft 61 meshes with the concave portion 28a of the drive shaft 28, and drive transmission is performed. Rotation drive by a tool rotation drive source (not shown) is enabled via the shaft 29 and the drive shaft 28.
In this case, the concave portion 28a and the convex portion 61a are formed in a straight line, and the convex portion 61a of the rotation transmission shaft 61 is engaged with the concave portion 28a waiting at a predetermined position only by rotating the turret 16. When the turret 16 is rotated, the end on the rotation input side of the rotation transmission shaft 61 is detached from the drive shaft 28. However, the rotation angle is maintained by the guide 35 being guided by the guide 35 so as to be sandwiched. Therefore, when the convex portion 61a of the rotation transmission shaft 61 is next engaged with the concave portion 28a of the drive shaft 28, the mutual directions are matched, and the meshing is performed smoothly and reliably.

  In this way, by simply rotating the turret 16, the rotation transmission shaft 61 of the tool turning unit 17 is connected to the drive shaft 28 and can be immediately driven. Therefore, the clutch operation after the turret rotation is unnecessary, and the rotary tool indexing time of the turret 16 is shortened.

  Next, the clamping operation by the coupling 34 of the turret 16 will be described with reference to FIG. When turning the turret 16, as shown in FIG. 3 (B), the third joint teeth 33 of the coupling 34 are retracted together with the piston 41 and separated from the first and second joint teeth 31 and 32. To do. When the turning of the turret 16 is completed, the third joint tooth 33 of the coupling 34 is advanced together with the piston 41 and meshed with the first and second joint teeth 31 and 32 as shown in FIG. The piston 41 moves backward when the working fluid is supplied to the front fluid pressure chamber 33a, and moves forward when the working fluid is supplied to the rear fluid pressure chamber 53b.

As described above, when the meshing state is established, the first joint teeth 31 provided on the turret 16 and the second joint teeth 32 provided on the fixed frame 22 are fixed to each other via the third joint teeth 33. become. Therefore, the rotation angle of the turret 16 is fixed with respect to the fixed frame 22, and rigidity in the rotation direction is obtained at the time of processing, and high processing accuracy is obtained.
Since the coupling 34 is a three-piece coupling, it is not necessary to move the turret 16 back and forth when engaging and disengaging the mesh, and only the piston 41 needs to be advanced and retracted. Therefore, the engagement / disengagement drive source 40 of the coupling 34 does not become large, and a compact configuration is obtained. Further, since the turret 16 does not move back and forth, the front and rear direction rigidity is high, and this enables high-precision processing.

  When spherical processing is performed on the workpiece W gripped by the spindle 5, the tool turning unit 17 is indexed to the processing position Q as described above, and then the tip of the cutting edge 65a of the tool 65 is in contact with a predetermined position of the workpiece W. The turret tool post 6 is positioned. When the output of a tool rotation drive source (not shown) is turned on in this state, the rotation transmission shaft 61 rotates in a predetermined direction via the turning drive mechanisms 28, 29, and 30 in the turret 16, and the rotation transmission shaft 61 The rotation is decelerated and transmitted to the support shaft 63a of the gear 63 through the pair of gears 62 and 63. Thereby, the tool 65 together with the tool holder 64 revolves on the arcuate locus C with the axis of the support shaft 63 as the tool revolving center line O2. By performing cutting with the tool 65 while turning the tool 65 in this way, the spherical portion Wa of the workpiece W is processed into a spherical surface centered on the tool turning center line O2 of the tool 65 as shown by a solid line in FIG. Is done. At the time of this spherical processing, the tool 65 maintains a posture almost toward the center of the spherical surface of the workpiece W, so that the load applied to the tool 65 of the workpiece W is stable and can be processed with high accuracy.

  When the vertical position of the tool turning center line O2 is inappropriate, it is processed into a rugby ball shape with sharpened ends as shown by a two-dot chain line in FIG. It is processed into a spherical shape (B). In that case, by changing the insertion position of the mounting bolt 67 in the bolt hole 68 of the housing 66, the mounting angle of the housing 66 with respect to the turret 16 is adjusted, and the vertical position of the tool turning center line O2 is set to an appropriate position. It can be corrected.

  Since the tool turning unit 17 turns the tool 65 around the tool turning center line O2 orthogonal to the turning center line O1 of the turret 16, even if the cutting edge 65a of the tool 65 turns on the arc locus C, Turret radial position does not change. For this reason, it can prevent that a turret index clearance becomes large. This prevents the lathe itself from becoming large.

  Moreover, since the turning drive mechanism 31 for driving the tool turning unit 17 is built in the turret 16, the turret device does not increase in size. For this reason, it is possible to provide the tool turning unit 17 in every other tool station S. Therefore, in the case of this embodiment having ten tool stations S, five tool turning units 17 can be provided for one turret 16.

  Further, the tool turning unit 17 can be detached from the turret 16 by releasing the coupling between the drive shaft 28 and the rotation transmission shaft 61. For this reason, it is possible to replace with a tool turning unit in which the reduction ratio between the drive side gear 62 and the driven side gear 63 is different according to the type of workpiece W and machining conditions, and spherical machining can be performed in an optimum state. it can.

  In this embodiment, a tool rotation drive source (not shown) is provided outside the turret 16, but a tool rotation drive source 70 may be provided inside the turret 16 as shown in FIG. . In the example of FIG. 8, the tool rotation drive source 70 is a motor, and the output shaft of the motor is a rotation transmission shaft 61. Thus, providing the tool rotation drive source 70 inside the turret 16 has an advantage that the power transmission mechanism is simplified.

It is a top view of the turret lathe concerning one Embodiment of this invention. It is sectional drawing of the turret tool post of the same turret lathe. It is operation | movement explanatory drawing of the meshing coupling. It is a fracture front view of the turret and tool turning unit of the turret tool post. (A) is a partially broken plan view of the tool turning unit, and (B) is a side view thereof. It is a perspective view of a transmission coupling mechanism. It is a figure which shows the shape of the workpiece | work processed by the spherical surface. It is a fracture front view of a turret and a tool turning unit of a turret lathe according to a different embodiment of the present invention. It is explanatory drawing which shows the method of the conventional spherical surface processing.

Explanation of symbols

DESCRIPTION OF SYMBOLS 3 ... Main shaft 6 ... Turret tool post 7 ... Tool post moving mechanism 9 ... Feed base 16 ... Turret 17 ... Tool turning unit 28 ... Drive shaft (turn drive mechanism)
29 ... Drive transmission shaft (turning drive mechanism)
30 ... Transmission mechanism (turning drive mechanism)
31 ... Rotation drive mechanism 61 ... Rotation transmission shaft 62 ... Drive side gear 63 ... Drive side gear 63a ... Support shaft 64 of driven side gear ... Tool holder 65 ... Tool 66 ... Housing 67 ... Bolt 68 ... Bolt hole C ... Arc-shaped locus O1 ... Turret turning center line O2 ... Tool turning center line S ... Tool station W ... Workpiece

Claims (3)

A turret lathe comprising a spindle capable of supporting a workpiece, and a turret capable of mounting a plurality of tools around the workpiece and turning and indexing one tool toward the workpiece supported by the spindle,
At least one of the tools is mounted on a tool turning unit mounted around the turret, and the tool turning unit is configured so that the tool is approximately at the center of the spherical surface of the workpiece in order to machine the workpiece into a spherical shape. The tool's cutting edge is swung on an arc locus while maintaining a posture toward
The turret is a turret lathe having a built-in turning drive mechanism for driving the tool turning unit.   The turret lathe according to claim 1, wherein the tool turning unit turns the tool around a tool turning center line orthogonal to a turning center line of the turret.   The turning drive mechanism includes a drive shaft having an axis perpendicular to the turning center line of the turret, and the tool turning unit includes a rotation transmission shaft coupled to the drive shaft, and a drive-side gear provided on the rotation transmission shaft. And a driven gear that meshes with the drive gear, and a tool that can be mounted on the driven gear so that the cutting edge faces the center of the driven gear at a position that is off the center position of the driven gear. The turret lathe according to claim 1 or 2, comprising a simple tool holder.

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