JPS5933493B2 - Attachment device for end face machining on automatic lathe with hobbing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is an automatic lathe with a hobbing device for manufacturing high-precision small-diameter gears. The end face drilling method relates to a two-axis end face machining attachment device that also has a processing mechanism.

In a movable spindle type automatic lathe for bar processing, turning is performed by moving the tool post, various bits on the locking arm, an attachment table for end face processing equipped with tools such as drills and reamers, and the headstock etc. It is well known that this is done, and as a means to improve the machining efficiency of the white side of the attachment, which is positioned opposite to the headstock, the attachment base has a two-axis structure, and the spindles are shifted within the machining cycle. Some systems have also been put into practical use that enable complex machining, such as reaming after drilling a pilot hole, by appropriately switching between the two methods.

By the way, the present inventor has previously developed a new automatic lathe equipped with a hobbing device.

As will be described later, during hob cutting, the rotation of the main spindle by the turning rotation mechanism is interrupted, and the main spindle and hob cutter spindle as well as the free end of the workpiece are moved to the attachment table position in order to be supported by the hob tooth cutting rotation mechanism. The trimming spindles arranged in the machine are rotated synchronously, and the hobbing device is traversed to perform the specified hobbing process, but unlike fixed trimmers, the workpiece itself is scratched. There is no risk of this, and factors that degrade accuracy such as twisting and deflection of the workpiece can be avoided, so it is possible to significantly improve tooth splitting accuracy as well as improve productivity of small diameter gears.

If such an automatic lathe is to be equipped with both a steady rest trimming mechanism and the above-mentioned two-axis attachment table function capable of compound machining, synchronous rotation on the trimmer side is required to move the attachment table in accordance with the machining cycle. It is expected that the gears in the transmission system will completely disengage.

Therefore, there is no problem when synchronous rotation with other mechanisms is not required, such as when reaming or drilling, but as mentioned above, during hobbing, the trimming spindle rotates completely synchronously with the hob cutter spindle, etc. If the gears of the synchronous rotation transmission system have to be meshed each time, there is a risk that the teeth may interfere with each other or skim. The necessary completely synchronous rotation cannot be obtained,
As a result, the accuracy of hob tooth splitting will be reduced.

In view of these points, this invention was made as a means to make the above-mentioned automatic lathe with a hobbing device more effective. A driven gear and an idle gear are arranged so as to be able to swing as a rotation center, thereby making it possible to selectively swing the two units with respect to the machining center position. In addition, by keeping the three drive gears in mesh at all times, we are able to eliminate the misalignment that affects tooth splitting accuracy as in the past, and we also set the rotation center of the idle gear to be different from the swing center of the tritu unit. As a result, the change in the butt crush of the gear due to the change in the height direction of the hob unit is compensated, and the butt crush of the hob unit at the center position of the workpiece processing is maintained appropriately, so that the hob unit is perfectly synchronized when the hob is young. This is what I did.

Hereinafter, one embodiment of the present invention will be described in detail based on the drawings.

First, the power transmission system of an automatic lathe equipped with an attachment device for end face machining according to the present invention will be explained based on FIG.
13 is a guide bush, 13 is an attachment device for end face machining that is located at a position facing the main shaft and has a trimming function to support the free end of the workpiece with a steady rest, and 14 is a hobbing device.

15 is a turning camshaft provided parallel to the main spindle 11, and 16 is a gear-cutting camshaft. Both camshafts 15 and 16 are connected to variable speed motors, which are the same driving source, through electromagnetic clutches. They are connected to each other and rotated alternately by the action of the electromagnetic clutch in accordance with turning and gear cutting.

As is well known, the turning cam shaft 15 is provided with a large number of cams, and this group of cams performs the feeding operation of each cutting tool, the feeding of the headstock, and the opening/closing operation of the chuck during turning processing. The gear cutting cam shaft 16 is also provided with a plurality of cams, and this group of cams feeds the hob cutter into the workpiece in the tooth depth direction and feeds the workpiece in the lateral direction, that is, traverses the workpiece.

24 is a motor for rotating the hob cutter spindle 25, and the rotation of this motor 24 is transmitted to the cutter spindle 25 via a belt 26, variable speed gear trains 27, 28, and a constant velocity ball joint 29.

In synchronization with this cutter spindle 250 rotations, the motor 2
4 is transmitted to the transmission gear train downstream of the headstock by means of the transmission gear train 28.degree. 30, the worm 31, and an intermediate shaft 33 having a worm wheel 32 that meshes with the worm 31.

Further, on the spindle 11 of the headstock 10, a cone-shaped clutch 34, a pawl clutch, a clutch 35, and a movable clutch body 36 for switching these clutches are coaxially provided. By operating a lever (not shown), it slides on the main shaft spindle 11 to selectively switch between the two clutches 34, 35.

Therefore, during turning, the motor 24 for driving the hob cutter spindle is stopped, the claw clutch 35 is disengaged, and the cone clutch 34 is engaged, so that the main spindle 11 is connected to the pulley 38, which also serves as the clutch member. It is rotated by its own drive motor.

On the other hand, during hob gear cutting, the cone clutch 34 is disengaged and the pawl clutch 35 is engaged, as shown in the figure, contrary to the above.

The rotation in synchronization with the 250 rotations of the hob cutter spindle mentioned above is the transmission gear train 39, 40, 41 and 42°43.
．． 52 to the master gear 3T meshing therewith, and as a result, the main shaft spindle 11 is rotated synchronously with the hob cutter spindle 25.

Further, the synchronous rotational force of the hob cutter spindle 25 is transmitted to the synchronous shaft 46 via a transmission gear train 44° 45 downstream of the main shaft spindle.

The synchronous shaft 46 extends from the rear stage of the headstock to the rear stage of the attachment device 13, and a gear 47 on the shaft connects to a gear 51 on the trimming spindle 50 via an idle gear 48.
Since the trimmer spindle 50 is in mesh with the hob cutter spindle 25, the trimmer spindle 50 is also rotated synchronously with the hob cutter spindle 25.

In other words, the motor for driving the hob cutter spindle and the motor for driving the main spindle are driven alternately in accordance with the turning/gear cutting cycle, and when the hob is young, the hob cutter spindle 25, main spindle 11, and trimmer spindle are driven alternately. 50 are synchronously rotated by the above-mentioned transmission system, and the hobbing device is traversed by the gear cutting camshaft drive system in accordance with the rotation, thereby performing predetermined gear cutting.

Next, the structure and operation of the end face machining attachment according to the present invention will be explained based mainly on the drawings from FIG. 3 onwards.

As described above, the end face processing attachment device 13 is disposed at a position facing the headstock 10 in the same manner as a conventionally known attachment table, and as shown in FIG.
0 is a rotating shaft 71 parallel to the main spindle.
A pair of spindle holders, that is, a drill unit 72 and a drill unit 73 for cutting an end face, each having a rotation center at a rotation center 71b, are arranged so as to be swingable.

Both units) 72 and 73 are pulled in the direction of arrow A shown in FIG. 4 by tension springs (not shown), and in the state shown in the figure, the drill unit
3 comes into contact with the stopper 76, and the trimming unit 72 comes into contact with a positioning member (not shown) provided on the side surface of the drill unit due to the above-mentioned spring force, so that the respective swingable positions are achieved. The drill spindle 14 is aligned with the main spindle 11, that is, the machining center position.

The rotating shafts 71a, 71b both have an eccentric structure on the same axis, and these rotating shafts 71a, 7
Both spindles 50, 74 are rotated by rotating 1b.
It is possible to make fine adjustments in the height direction.

That is, since both the rotating shafts 71a and 71b have the same structure, only the rotating shaft 71a will be explained based on FIG. 4 and FIG. On the other hand, the intermediate portion 71d between the shaft bearing portions 71c and 71c is fitted into the shaft hole of the base 70.

The axial center of the bearing part 71c and the axial center of the intermediate part 71d are slightly eccentric, and by rotating these, the entire tritu unit moves up and down with respect to the base 70,
The trimming spindle 50 is aligned with the main spindle 11.

On the other hand, a tilting lever 77 is pivotally supported on one side of the base 70, the floor part of one end of which comes into contact with a contact part 78 protruding from the side of the drill unit 73, and the other end of the tilting lever 77 with a follower part. is in pressure contact with the cam 19 on the turning camshaft 15.

And by this cam 190 rotations, both units) 72, 73
both swing in the direction of arrow A, and the drill unit 72 is aligned with the machining center position, contrary to the previous state, and at this time, the drill unit 72 and the drill unit 73 are each moved by a stopper (not shown). The direction of the swinging force is determined.

That is, the above-mentioned tritu unit 72 and drill unit 7
3 is configured to be able to swing back and forth between the processing center position and the standby position by the action of a tilting lever 77, and both units) 72.73
can be selectively positioned with respect to the processing center position.

The drill unit 73 is mainly used for drilling the end face of a workpiece, and as shown in FIG. 6, the drill spindle 74 is equipped with a collet chuck 80 for holding tools at its tip and is slidable in the axial direction. At the same time, the guide shaft 81 is biased in the forward direction by a tension spring 82 included in the guide shaft 81, and cutting feed is applied by the spring force.

A guide block 83 for spindle feeding is fixed to the rear end of the guide shaft 81, and a cam follower pivotally supported on the base 10 is attached to the block 83 as shown in FIGS. 3 and 5. One end of the lever 84 is in contact with it.

Then, the drill spindle γ4 is moved forward and backward by the rotation of the cam 850 on the turning camshaft 15.

Further, the drill spindle 74 is equipped with an automatically rotatable pulley 86 at its center, and this pulley 86 is connected to a turning plate 88 at the rear end of the spindle via a celery pin 87, and connected to a motor (not shown) by a belt 89. By rotating the drill spindle 74 in conjunction with the feeding operation by the aforementioned cam, drilling can be performed with the headstock fixed.

Incidentally, reference numeral 90 denotes a set screw for making the pulley 86 and thus the drill spindle 74 non-rotatable, which allows the rotation of the drill spindle 40 to be stopped and drilling by, for example, a flat saw.

FIG. 7 shows the details of the trimming unit 72, in which the trimming spindle 50 is equipped with a steady rest trimmer 91 at the tip, is configured to be slidable in its axial direction like the aforementioned drill spindle 74, and is further provided with a guide. a configuration biased in the forward direction by a tension spring 93 within the shaft 92;
Also, the configuration in which the rotation of the cam 96 on the turning camshaft 15 causes forward and backward movement via the guide block 94 and the cam follower lever 95 is completely (same) as that of the drill spindle 74.

At the rear end of the trimming spindle 50, there is a gear 5 at the rear end.
1 is fixed, and this gear 51 is the idle gear 48.
As shown in FIG.
It is designed to rotate in sync with the

As shown in FIG. 5, the synchronous shaft 46 and the processing center are on the same perpendicular line orthogonal to these,
The lines connecting the axes of these champions, including the center of the figure, are arranged in a roughly dogleg shape.

Further, the idle gear 48 is connected to a support frame 100 in the form of an abbreviation.
The frame 10 is rotatably supported by the frame 10.
0 is the bolt 102, 10 for the synchronous shaft frame 101
2 so that the rotational position can be adjusted.

By swinging about the synchronizing shaft 46, the idle gear 48 rolls on the gear 4T, and has the function of supplementing the backlash adjustment for the gear 51, which will be described later.

On the other hand, the gear 51 on the trimming spindle 50 is rotated to the idle gear 48 in accordance with the swinging operation by the above-mentioned tilting lever 77.
The rotating shaft 71a, which is the center of swing of the trim unit 72, and the center of rotation of the idle gear 48 are set to be slightly shifted from each other.

That is, as shown in FIG. 8, if 0 is the rotation center of the idle gear 48, P is the swing center of the tritu unit 72, and Q is the rotation center of the main spindle 110, that is, the workpiece machining center position, then the rotation center of the idle gear 48 is 0. is set at a position slightly closer to the processing center Q than the perpendicular line passing through the swing center P of the tritu unit 72.

In the hobbing process described above, when the trimming spindle 50 (the rotation center of the gear 510) is aligned with the processing center Q, the gear 51 and idle gear 48
When the back crush between the two positions is optimal and the trimming spindle 50 moves to the standby position S (that is, when the machining center Q and the center of the drill spindle 14 coincide)
The above-mentioned backlash is set to be expanded to the extent that both gears do not come out of mesh.

This means the following:

That is, when the axis of the trimming spindle 50 is misaligned with respect to the main spindle 11 (ζ), accurate hobbing cannot be expected unless it is corrected.

Therefore, when the rotating shaft 71a of the above-mentioned tritu unit 720 is operated and aligned, the gear 51
This results in fluctuations in the backlash between the idle gear 48 and the idle gear 48, and it is necessary to return this fluctuation in backlash to an optimal state by some method.

Therefore, if the idle gear 48 is slightly oscillated about the synchronization shaft 46 while the trimming spindle 50 is located at the processing center, the optimum state of the polishing described above can be reproduced.

Therefore, the tritu unit 72 and the drill unit 7
3 undergoes repeated rocking motion due to the operation of the tilting lever 17,
Since the idle gear 48 and the gear 51 are always meshed, there is no risk of tooth interference or tooth spillage.
Further, when the hob is young, the butt crush between the two gears is reproduced in an optimal state, so the meshing state of the gears does not affect the tooth splitting accuracy.

Next, a series of operations of the automatic lathe including the attachment device according to the above configuration will be explained based mainly on FIG. 1.

First, to explain the case where only the Tritsu unit is used, as is well known in the art, when the turning camshaft 15 is rotated by a turning cycle start signal, cutting feed is given to each cutting tool to perform the turning process in the pre-hobbing stage. It will be done.

Simultaneously with the completion of this turning process, both the trimmer unit 72 and the drill unit 73 are swung, and the trimmer spindle 50 is aligned with the center position of the process and is extended to a predetermined position.

Next, the headstock 10 moves forward slightly while holding the workpiece in accordance with the hobbing process, and the free end of the workpiece is pressed against and supported by the steady rest trimmer 91 of the trimmer spindle 50, which is already waiting at a fixed position. Ru.

In this state where both ends are supported, the main spindle 11, the trimmer spindle 50, and the hob cutter spindle 25 are rotated synchronously, and at the same time, two-dimensional feed is applied to the hobbing device 14 by the rotation of the gear cutting camshaft 16, and a predetermined feed is applied to the hobbing device 14. Hobbing is performed.

During this hob cutting, the workpiece is supported at both ends and rotated completely synchronously as described above, so that causes of accuracy deterioration such as twisting and deflection due to cutting resistance are avoided.

When the hobbing process is completed, each power transmission system is switched again to the turning process side, the trim unit 72 is retreated to the initial position, and the finishing cutting and parting are performed by the respective bits, completing one machining cycle. finish.

Note that the trimming spindle 50 can be replaced with a reaming spindle, and in that case, reaming can be performed by inserting and supporting an identical reaming spindle without the rotation transmission gear 51 in a non-rotatable manner.

In addition, when the reamer spindle and the drill spindle 74 are used together, the drill spindle 74 holds a drill for the prepared hole, and the pulley 86 on the drill spindle 74 is connected to the motor that is the dedicated drive source described above, and the turning If each spindle is moved back and forth in conjunction with the rocking motion of the tritu unit 72 and drill unit 73 by 150 rotations of the camshaft to perform a compound operation, holes can be drilled on the end face of the workpiece using a drill and reamer at the same time as the conventional turning process. can be done.

Note that when only one spindle is used, it is not necessarily necessary to swing both spindle holders, and it is also possible to fix a desired spindle by changing the cam.

As is clear from the above description, the attachment device of the present invention is configured to be able to swing the trimming unit and the end face processing unit so as to selectively position them with respect to the processing center position, and to synchronize the hob when the hob is young. The gear train that controls rotation transmission is configured to always mesh regardless of the above-mentioned oscillating motion comparison, so there is no interference between teeth or tooth loss as in the conventional case, and completely synchronous rotation is achieved when the hob is young. This ensures that failures due to poor meshing and deterioration in tooth splitting accuracy can be eliminated.

In addition, since the center of rotation of the Tritsu unit is set slightly offset from the center of rotation of the idle gear, the backlash between the driven gear of the Tritsu unit and the idle gear at least at the processing center position is always properly reproduced and maintained. Therefore, it is possible to manufacture gears with high tooth splitting accuracy through completely synchronous rotation.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing the power transmission system of an automatic lathe with a hobbing device equipped with an attachment device according to the present invention, Fig. 2 is a front explanatory diagram showing the overall configuration of the automatic lathe, and Fig. 3 is an explanatory diagram of this automatic lathe. A plan view of the attachment device in the invention,
Figure 4 is the right side view of Figure 3, and Figure 5 is the same side view of Figure 3.
6 is a sectional view of only the drill unit, FIG. 7 is a sectional view of the drill unit, and FIG. 8 is a pitch circle schematic diagram showing the relationship between the driving/driven gear and the idle gear. 13... Attachment device for end face processing, 72
... Trimming unit, 73 ... Drill unit (end face processing unit), 71 a y 7 l
b... Rotating shaft, 50, 74... Trimming spindle, 47... Drive gear, 48...
... Idle gear, 51 ... Driven gear.

Claims (1)

[Scope of Claims] 1. A device that is installed in an automatic lathe equipped with a hobbing device, and is rotated synchronously with the free end of the workpiece supported by a steady rest during end face processing such as drilling and hobbing, the main shaft being An end face processing unit and a steady rest trim unit that are arranged side by side so as to be able to swing around an axis parallel to the spindle and each has a rotatable spindle, a driven gear fixed to the trim spindle, and a driven gear that is fixed to the trim spindle. A synchronous rotation gear train consisting of a drive gear for driving and an idle gear interposed between the drive and driven gears, and both units are configured to be able to selectively swing relative to the processing center position. At the same time, when the above-mentioned Tritsu unit is at the processing center position, the backlash between the driven gear and the idle gear is optimal, and when it is at the standby position, the rotation center of the above-mentioned idle gear is set so that the rotation center of the above-mentioned idle gear is the same as that of the Tritsu unit. An attachment device for end face processing in an automatic lathe with a hobbing device, characterized in that the attachment device is set differently with respect to the center of rotation. 2. An attachment device for end face machining in an automatic lathe with a hobbing device according to claim 1, wherein the idle gear is configured to be able to adjust its oscillating position about the same axis as the rotation center of the drive gear. . 3. An attachment device for end face machining in an automatic lathe with a hobbing device according to claim 1, wherein the end face machining unit and the trim unit are provided with a position adjustment mechanism in the height direction.