JP4027486B2 - NC lathe with gear cutting device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an NC lathe provided with a gear cutting device for processing gear teeth on a tool post, and in particular, the tool post is provided with a rotary drive shaft for driving a rotary tool mounted on a turret. The present invention relates to a lathe in which a cutting device is detachably attached to a turret.
[0002]
[Prior art]
NC lathes that enable drilling, tapping, grooving, etc. by attaching a rotating tool such as a drill or milling cutter to the turret mounted on the turret are well known. There is also known a composite lathe capable of performing gear cutting immediately on a workpiece after turning by mounting. A hob cutter is usually used as a gear cutting tool in this type of apparatus, and machining is performed while synchronously rotating the hob cutter and the main shaft for rotating the workpiece at a rotation ratio corresponding to the lead angle of the hob cutter. Therefore, in this type of apparatus, a synchronous control means for the electric motor that rotates the gear cutting tool and the spindle motor is required.
[0003]
The gear cutting device is provided on the gear cutting stand separately from the turret. For example, the structure proposed in Japanese Patent Laid-Open Nos. 56-56337 and 56-62721 has sufficient rigidity and versatility for the gear cutting device. The equipment must be large, the motor for the gear cutting tool must be provided separately from the motor for the rotary tool of the turret, or a device for transmitting the spindle rotation to the gear cutting tool must be provided, There is a disadvantage that the apparatus becomes complicated and expensive because a means for retracting the gear cutting apparatus must be provided when performing turning or the like.
[0004]
On the other hand, the device in which the gear cutting device proposed in Japanese Patent Laid-Open No. 2-152718 is mounted on the turret and the gear cutting tool is also driven by the electric motor for driving the rotary tool simplifies the device structure. Therefore, there is an advantage that the device can be provided at a low cost, but the rigidity of the gear cutting device tends to be insufficient, and the crossing angle between the workpiece and the gear cutting tool cannot be changed. There is a problem that various kinds of gear cutting devices have to be prepared, the rotation transmission system to the gear cutting tool becomes complicated, and the processing accuracy is lowered due to accumulation of errors in the transmission portion.
[0005]
[Problems to be solved by the invention]
An object of the present invention is to solve the problems of the conventional apparatus as described above, and it is possible to perform high-precision gear cutting with a simple structure, and according to the lead angle of the gear cutting tool and the like. It is an object of the present invention to provide an NC lathe provided with a gear cutting device that can also change the crossing angle with the workpiece.
[0006]
[Means for Solving the Problems]
The NC lathe according to the present invention includes a tool turret 9 that rotates around an axis in the Z-axis direction to index a tool, a rotary drive shaft 14 that is disposed in the Z-axis direction to drive a rotary tool mounted on the turret, in NC lathe and a gear cutting device that is detachably mounted on the turret, gear cutting apparatus, a gear cutting tool axis 34 intersecting at right angles to the rotation transmitting shaft 27 and the X-axis of the X-axis direction, hobs Gear cutting tool 33 fixed to the shaft, detachable rotation transmission means 18 and 30 linking the rotation transmission shaft to the rotation drive shaft, and gear cutting tool housing for supporting the gear cutting tool shaft so as to freely rotate. and a 32, gear cutting tool housing is of also being adjustable in position fixed to the shaft about the axis rotation transmission.
[0007]
In this specification, the Z-axis direction is a direction parallel to the main axis of the lathe, and the X-axis direction is a direction parallel to the cutting feed direction of the tool post. The Y-axis direction is a direction that intersects the Z-axis and the X-axis at right angles. The Z axis, the X axis, and the Y axis form coordinate axes that are orthogonal to each other in the three-dimensional space.
[0008]
The gear cutting operation in the NC lathe provided with the above means is the same as the gear cutting operation in the hobbing machine except for the indexing operation of the gear cutting tool by the rotation of the turret. That is, when gear cutting is performed, the turret 9 is indexed so that the rotation transmission shaft 27 faces the X-axis direction, the tool post 6 is advanced to a predetermined cutting position, and then the spindle motor and the tool drive motor are rotated by a predetermined rotation. Cutting is performed by moving the tool post 6 in the Z-axis direction while rotating synchronously at a ratio. The turret 9 is equipped with a turning tool and a rotating tool necessary for processing each workpiece at a tool mounting station arranged on the circumference thereof, and the necessary tools are indexed to perform turning, milling, drilling, and the like. The rotation of the milling cutter and drill when milling or drilling is performed by a tool-driven motor.
[0009]
The crossing angle between the workpiece and the gear cutting tool is changed by changing the mounting angle around the rotation transmission shaft 27 of the gear cutting tool housing 32 by the gear module to be processed or the spiral angle. The gear cutting tool housing 32 is structured to be fastened with a bolt 31 or the like to the mounting housing 25 fixed to the turret case 9a or the turret, and when changing the crossing angle between the workpiece and the gear cutting tool, the bolt 31 is loosened, This is done by changing the mounting angle of the gear cutting tool housing 32.
[0010]
In addition to the means of claim 2, that is, the means of claim 1, the rotary drive shaft 14 passes through the hollow turret indexing shaft 8 and projects to the center of the turret 9 on the side opposite to the tool post. The apparatus includes a mounting housing 25 that supports the rotation transmission shaft 27 so as to freely rotate. When the gear cutting device is mounted on the turret 9, the projecting end of the rotation drive shaft 14 and the base end of the rotation transmission shaft are engaged with each other. According to the means provided with the pair of bevel gears 18 and 30, it is easy to increase the rigidity of the gear cutting device in the state where it is mounted on the turret, and the rotation transmission system extending from the tool driving motor 43 to the gear cutting tool 33. Therefore, it is possible to realize gear cutting with high accuracy. The gear cutting device can be mounted at a position close to the indexing rotation center of the turret, so that the rigidity can be improved and the rotational inertia of the turret can be reduced, and the gear cutting device does not occupy the tool station of the turret. It does not reduce the number of tools that can be mounted on the.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
1 and 2 are views showing a first embodiment of the NC lathe according to the present invention, and FIG. 3 is a view schematically showing the entire configuration of the lathe. A lathe spindle 1 is pivotally supported by a spindle stock 2. A chuck 3 is attached to the tip of the lathe and driven by a spindle indexing motor 4 to enable low-speed rotation and index positioning. High-speed rotation of the main shaft is performed by the same motor or a separate main shaft motor for turning. The movable table 5 is slidable along a guide in the Z-axis direction provided on a bed (not shown), and is screwed with a feed screw in the Z-axis direction (not shown). The tool post 6 is slidable along a guide provided on the movable table 5 in the X-axis direction, and is screwed into a feed screw in the X-axis direction (not shown) to give cutting feed.
[0012]
A hollow indexing shaft 8 is supported on the bearing housing 7 provided on the tool post 6 so as to be axially movable and rotatable. A turret case 9a is fixed to one end of the bearing housing 7 and a gear 10 and a speed reducer are connected to the other end. It is connected to an indexing motor 12 via a gear train 11. A hydraulic cylinder device is formed between the index shaft 8 and the bearing housing, and a surface gear joint is provided on the rear surface of the turret case 9a and the side surface of the bearing housing opposite to the turret case 9a. It has been. The surface gear joint is engaged and disengaged by switching the hydraulic pressure to the hydraulic cylinder device 13. The indexing motor 12 performs indexing of the turret with the face gear joint detached, and a predetermined index position is fixed by fitting the face gear joint.
[0013]
A rotary drive shaft 14 is pivotally supported on the index shaft 8 so as not to move in the axial direction. The distal end of the rotary drive shaft 14 passes through the turret 9 and projects to the front surface of the turret, and the proximal end is connected to the tool drive motor 43 via the pulley 15 and the toothed belt 16.
[0014]
As shown in FIG. 2, a gear sleeve 19 having bevel gears 17 and 18 formed at both ends is fitted to the tip of the rotary drive shaft 14, and one of the bevel gears 17 is located in the turret case 9a. The other is located at the tip of the rotary drive shaft 14 protruding from the turret case. The bevel gear 17 in the turret case is meshed with a bevel gear 21 formed at the base end of the tool drive shaft 20 that is pivotally supported so as to always face the X-axis direction in the turret case. Although a detailed description is omitted here, an inner case 22 fixed to the turret bearing housing is housed in the turret case 9a, and the tool drive shaft 20 is supported by the inner case. Therefore, the tool drive shaft 20 does not rotate even when the turret case 9a rotates, and always faces the X-axis direction. When the rotary tool is indexed at the tool index position of the tool drive shaft 20, the tool drive shaft 20 The rotary tool shaft is engaged with the rotary tool shaft so that the rotation of the tool drive shaft is transmitted to the rotary tool shaft. Of the two-layer bearings shown on the outside of the gear sleeve 19, the small-diameter bearing 23 is a bearing for allowing relative rotation between the inner case 22 and the rotary drive shaft 14. Reference numeral 24 denotes a bearing for allowing relative rotation between the inner case 22 and the turret case 9a. A mounting housing 25 of the gear cutting device is fixed to the front surface of the turret case with bolts 26. In the mounting housing 25, a rotation transmission shaft 27 is supported by bearings 28 and 29 in the radial direction of the turret and directed to the X-axis direction when the gear cutting tool is indexed to the machining position. The bevel gear 30 formed at the base end meshes with the bevel gear 18 on the protruding end side of the gear sleeve 19.
[0015]
A gear cutting tool housing 32 is fixed to the mounting housing 25 with bolts 31. The fixed surface is a surface orthogonal to the rotation transmission shaft 27, and a circular fitting portion coaxial with the rotation transmission shaft 27 is provided between the mounting housing 25 and the gear cutting tool housing 32. Therefore, by changing the angle of the gear cutting tool housing 32 around the rotation transmission shaft 27 by changing the insertion hole of the bolt 31 on the gear cutting tool housing side to an arc-shaped long hole concentric with the rotation transmission shaft 27, the mounting housing 25 can be fixed. As shown in FIG. 1, a gear cutting tool shaft 34 having a gear cutting tool (hob cutter) 33 fixed at the center thereof is supported by bearings 35, 36 disposed on both sides of the gear cutting tool 33. Has been. The gear cutting tool 33 is arranged so that the center thereof is on the extension line of the rotation transmission shaft 27. A helical gear 37 is fixed to one end of the gear cutting tool shaft 34, and a second rotation transmission shaft 39 having a gear 38 attached to one end is meshed with the helical gear, and the gear cutting tool shaft 34. In parallel with the gear cutting tool housing 32. A bevel gear 40 is formed at the inner end of the second rotation transmission shaft 39, and this bevel gear 40 meshes with a bevel gear 41 formed at the tip of the rotation transmission shaft 27 on the mounting housing side.
[0016]
As understood from the above configuration, if the tool driving motor 43 is rotated while the gear cutting device 42 is mounted on the turret case 9a, the gear cutting tool 33 rotates. If the spindle motor 4 and the tool drive motor 43 are synchronously rotated at a constant rotation ratio by the NC device while being indexed to the machining position, a spur gear or a helical gear is machined on the work gripped by the chuck 3. Can do. The crossing angle θ between the center axis of the work necessary for gear cutting shown in FIG. 4 and the center axis of the gear cutting tool adjusts the fixing position around the rotation transmission shaft 27 of the gear cutting tool housing 32 with respect to the mounting housing 25. Can be set. At this time, no matter what angle the mounting angle of the gear cutting tool housing is set, there will be no problem in the rotational drive system of the gear cutting tool 33. This is achieved by arranging the rotation transmission shaft 27 in the X-axis direction and adopting a configuration in which the rotation is transmitted to the gear cutting tool shaft 34 via a gear.
[0017]
An NC lathe is known to be provided with a turret that is movable in the Y-axis direction. The NC lathe F of the present invention can displace the position where the teeth of the gear cutting tool 33 and the workpiece contact by adopting a configuration in which the turret can be moved and positioned in the Y-axis direction. If such a displacement operation is appropriately performed, it is possible to avoid local wear of the cutting blade of the gear cutting tool 33, and it is possible to extend the life of the gear cutting tool.
[0018]
FIG. 5 shows a second embodiment in which the gear cutting device 42a is mounted on the rotating tool mounting station of the turret. The main difference from the first embodiment is that there is no mounting housing, the gear cutting tool housing 32 is directly fixed to the turret case 9 with bolts 31, and the rotation transmission shaft 27 in the X-axis direction is toothed. It is supported by a tool shaft holder 44 provided substantially integrally with the cutting tool housing 32, and when the gear cutting device 42a is indexed by the turret, the base end of the rotation transmission shaft 27 is the inner case of the turret described above. It is a point which fits and is driven by the tool drive shaft 20 pivotally supported by. The above differences will be described in detail below.
[0019]
In the gear cutting device 42a of the second embodiment, a tool shaft holder 44, which is substantially integral with the gear cutting tool housing 32, is mounted by being inserted into the rotary tool mounting station of the turret 9, and the angle around the rotation transmission shaft 27 with respect to the turret 9 Is fixed to the outer periphery of the turret 9 with the fixing screw 31. A fitting projection 47 protrudes from the base end of the rotation transmission shaft 27 supported by the tool shaft holder 44 with bearings 45 and 46, and the gear cutting device 42a is indexed to the machining position. Then, it is fitted into the fitting groove 48 at the tip of the tool drive shaft 20 described above. A bevel gear 49 is formed at the outer diameter side end portion of the rotation transmission shaft 27, and this bevel gear is supported by the gear cutting tool housing 32 in parallel with the gear cutting tool shaft 34. It meshes with a bevel gear 40 formed at the inner end. Thereafter, the rotation of the second rotation transmission shaft 39 is transmitted to the gear cutting tool shaft 34 via the helical gears 37 and 38, and the rotation of the gear cutting tool 33 fixed at the center of the gear cutting tool shaft is the first. It is the same as that of an Example.
[0020]
The configuration of the second embodiment has the advantage that the gear cutting device can be configured more compactly than that of the first embodiment, but the rotation transmission system from the tool drive motor 43 to the gear cutting tool 33 becomes complicated. There is a problem that the slight backlash between the rotation transmitting elements is accumulated to reduce the gear cutting accuracy, and the gear cutting device protrudes further to the outside of the outer periphery of the turret 9, so that the rotational inertia at the time of indexing the turret increases. Furthermore, since the gear cutting device occupies at least one, usually a plurality of tool mounting stations of the turret, there are disadvantages such as a reduction in the number of tools that can be mounted on the turret. Even in the second embodiment, the rotation transmission function from the tool drive shaft 20 to the gear cutting tool shaft 34 is not impaired by adjusting the mounting angle of the gear cutting tool housing 32 to the turret 9. The crossing angle θ between the workpiece and the gear cutting tool 33 can be freely adjusted.
[Brief description of the drawings]
FIG. 1 is a cross-sectional side view of an essential part of a first embodiment. FIG. 2 is a sectional front view of an essential part of a first embodiment. FIG. 3 is a plan view schematically showing an overall configuration of a lathe. Explanatory drawing which shows the crossing angle of the workpiece | work and gear cutting tool in a cutting process [FIG. 5] Sectional side view of the principal part of 2nd Example [Explanation of a code]
8 Indexing shaft 9 Turret
14 Rotary drive shaft
18 Bevel gear
25 Mounting housing
30 Bevel gear
32 gear cutting tool housing
33 Gear cutting tool
34 Gear cutting tool shaft

Claims (3)

A tool turret that rotates around an axis in the Z-axis direction to index a tool, a rotary drive shaft that is arranged in the Z-axis direction to drive the rotary tool mounted on the turret, and a tooth that is detachably mounted on the turret NC lathe equipped with a cutting device
The toothed system,
A rotation transmission shaft that faces the X-axis when the gear cutting tool is indexed to the machining position ;
A gear cutting tool housing fixed so that its position can be adjusted around the rotation transmission shaft;
A gear cutting tool shaft that is rotatably supported by the gear cutting tool housing and intersects the rotation transmission shaft at a right angle;
The gear cutting tool, the center of which is positioned on the extension line of the rotation transmission shaft and fixed to the gear cutting tool shaft;
A detachable rotation transmission means for connecting the rotation transmission shaft to the rotation drive shaft, and a bevel gear pair for linking the gear cutting tool shaft to the rotation transmission shaft ;
An NC lathe equipped with a gear cutting device, wherein the crossing angle of the workpiece and the gear cutting tool is changed by changing the mounting angle of the gear cutting tool housing around the rotation transmission shaft . The rotation drive shaft passes through a hollow turret indexing shaft and protrudes to the center of the turret on the side opposite to the tool post, and the rotation transmission shaft is pivotally supported by a mounting housing fixed to the turret, A gear cutting tool housing is fixed to the mounting housing so that the position of the gear cutting tool can be adjusted, and when the gear cutting device is mounted on the turret, the projecting end of the rotation drive shaft and the base end of the rotation transmission shaft An NC lathe equipped with a gear cutting device according to claim 1, further comprising a bevel gear pair that meshes and connects the two. The gear cutting tool housing is substantially integrally provided with a tool shaft holder that is inserted into a rotating tool mounting station of the turret, and the rotation transmission shaft is pivotally supported by the tool shaft holder so as to be freely rotatable. It is fixed to the outer periphery of the rotation transmission shaft so that the position of the rotation transmission shaft can be adjusted. When the gearing device is indexed by the turret, the shaft of the rotation transmission shaft is always oriented in the X-axis direction in the turret case. The NC lathe provided with the gear cutting device according to claim 1, wherein the NC lathe is driven by being fitted to a supported tool drive shaft.

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