JPH04250902A - Spindle sliding type automatic lathe - Google Patents

Abstract

PURPOSE:To ease long stroke working by pressing down a work by means of a steady rest device at a place between a rotary main spindle, which is at a retreated position, and a fixed, guide bush. CONSTITUTION:Steady rest devices 21, 22, each of which is provided with a work holder which can freely elongate or retreat toward the periphery of a work 12, are provided between a rotary main spindle 11, which is at a retreated position, and a fixed, guide bush 13. At the time of long stroke working, the steady rest devices 21, 22 firmly press the work 12 down at a place between the rotary main spindle 11 and the fixed, guide bush 13, and, when the rotary main spindle 11 approaches the steady rest devices 21, 22, the steady rest devices 21, 22 are retreated from the moving range of the rotary main spindle 11.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is a sliding spindle type automatic lathe, which is particularly capable of long stroke machining in which the rotating spindle chucks the workpiece and moves it in the axial direction, and the workpiece is supported by a fixed guide bush near the tool post. This paper relates to the improvement of a main-spindle sliding type automatic lathe.

0002

2. Description of the Related Art A main shaft sliding type automatic lathe equipped with a rotary main shaft that can chuck a workpiece and is slidable in the axial direction is well known, and is mainly put into practical use as an NC-controlled automatic lathe.

[0003] In this type of lathe, the workpieces are successively fed to the rotating main shaft by a material feeding device, and the rotating main shaft reciprocates through a predetermined stroke as necessary to rotate the workpieces and feed them to the tool post. A fixed guide bush supports the workpiece in the vicinity of the turret, thereby making it possible to perform highly accurate machining while eliminating rotational runout of the workpiece.

0004

[Problems to be Solved by the Invention] However, when long stroke machining is performed using this type of main shaft sliding type automatic lathe, the span between the rotating main shaft and the stationary guide bushing becomes significantly large. In long stroke machining with a span of more than 10 times the diameter,
A phenomenon occurs in which the workpiece undergoes rotational run-out between the rotating main shaft and the fixed guide bush, resulting in an arched shape. When such a bowing phenomenon occurs, a problem arises in that a significantly large error occurs in the machining dimensions, and the life of the cutting tool is significantly shortened.

[0005] In recent years, such long stroke machining has been widely desired, for example in printers and other OA machines.
Long shafts for equipment or shafts for special motors are required to be machined with long, small diameter and high precision, and there is a strong demand for long stroke machining using a sliding spindle type automatic lathe with high machining efficiency. In practice, there is a limit to such long stroke machining due to the arching phenomenon.

On the other hand, workpiece steady rest devices are well known in various conventional lathes, and various steady rest devices have been proposed that hold down the machining tip of the workpiece or prevent the workpiece from swinging from the material feeding device to the main shaft. There is.

However, in the past, no device has been proposed for providing a steady rest between the rotating main shaft and the stationary guide bush in a main shaft sliding type automatic lathe.

[0008] Conventionally, a technology similar to such a steady rest device was developed in Utility Model Application Laid-Open No. 1983-11 for cam-type feed lathes.
It is known as No. 106879.

According to this automatic lathe, the workpiece is chucked by the main shaft and fed into the guide bush, and a material support device is fixed to the main shaft.

However, such conventional devices have various drawbacks as described below.

In other words, since the support member is fixed to the main shaft, there is a limit to its protrusion length that contributes to steady rest, and it is impossible to correctly swing the long stroke workpiece required in recent years between the rotating main shaft and the fixed guide bush. I couldn't stop it and support it.

Furthermore, in the conventional apparatus, in order to perform short stroke machining, the tip of the supporting member enters into the guide bush, and as a result, the diameter of the workpiece that can be machined is extremely limited.

Furthermore, in the past, since the supporting member was a bearing cylinder, there was the trouble of having to replace it every time the diameter of the workpiece changed.

The present invention has been made in view of the above-mentioned conventional problems, and it is possible to prevent the arching phenomenon from occurring between the rotating main shaft and the fixed guide bush when performing long stroke machining with a sliding main shaft automatic lathe. The objective is to provide an improved device.

[0015]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a bushing which is provided between the rotational main shaft in the retracted position and the guide bush, and which is extendable and retractable toward the outer periphery of the workpiece. It is characterized by having a steady rest device equipped with a work holder.

[0016]

[Operation] Therefore, according to the present invention, when performing long stroke machining, at least one steady rest device is provided between the rotating main shaft in the retracted position and the fixed guide bush. It reliably prevents the arching phenomenon that causes rotational shake of the workpiece, enabling highly accurate machining.

[0017]The steady rest device according to the present invention includes:
Since it has a work holder that can be evacuated from the work,
Even when the rotating main shaft moves in the axial direction, the steady rest device does not become an obstacle to machining, and highly efficient machining can be performed without waste.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 schematically shows a preferred embodiment of the main shaft sliding type automatic lathe according to the present invention.

A rotating spindle 11 is built into the headstock 10 which is provided on a table (not shown) so as to be slidable in the Z-axis direction. Gives driving force.

Therefore, the workpiece 12 rotates and moves in the Z-axis direction while being chucked by the rotating main shaft 11.

The leading end of the workpiece 12 is supported by a guide bush 13 fixed to a table, and this fixed guide bush 13 is arranged near a tool post 14. Therefore, the tool 15 fixed to the tool post 14 performs desired machining on the workpiece 12 in the vicinity of the support portion of the fixed guide bush 13, making it possible to perform high-precision machining without rotational run-out. In the present invention, the fixed guide bush 13 is fixed so as not to move in the direction of the main axis (Z), and of course includes a rotary guide bush with a built-in ball bearing or the like and whose inner ring rotates together with the workpiece.

A characteristic feature of the present invention is that a steady rest device is provided between the rotating main shaft 11 in the retracted position and the fixed guide bush 13, and in the embodiment, two sets of steady rest devices 21 are provided. , 22 are provided, and the workpiece 12 to be machined with a long stroke can be supported with steady rests at predetermined intervals.

FIG. 2 shows the steady rest device shown in FIG. 1, which includes cylinders 23 and 24 arranged diametrically opposite each other with the workpiece 12 in between, and each cylinder 23 and 24 is attached to the workpiece 12, respectively. It has work holders 25 and 26 that can be extended and retracted. Each of these cylinders 23, 2
4 may be hydraulic or pneumatic, and work holders 25 and 26 may be used as necessary depending on the diameter of the workpiece to be used.
It is also good to have a built-in stopper for adjusting the position.

According to the linear motion cylinders 23 and 24, when the work holders 25 and 26 provide a steady rest for the work 12, their tips touch the outer periphery of the work 12, as shown in FIG. The workpiece 12 is driven to a position where the workpiece 12 is in contact with the workpiece 12 or close to the workpiece 12 with a slight gap, and in this state, the workpiece 12 is sandwiched from both sides to ensure steady resting.

Returning to FIG. 1, the steady rest device 21 mentioned above
, 22, it is possible to reliably eliminate the arching phenomenon even though the workpiece 12 has a long stroke, and in the figure, the rotating main shaft 11 moves from the solid line position to the chain line position in the figure to obtain the maximum long stroke. becomes possible.

A further feature of the present invention is that when the rotating spindle 11 moves through the maximum long stroke, the steady rest devices 21 and 22 sequentially move the work holder from the passing position of the rotating spindle 11 or the headstock 10. It can be retracted from the movement area of the rotary main shaft 11 very easily by retracting the linear motion cylinders 23 and 24 shown in FIG. 2 described above.

In FIG. 1, each steady rest device 21, 22
The retraction of is controlled by the steady rest controller 27.

That is, the movement of the headstock 10 is monitored by position sensors 28 and 29 fixed to the table, and in order to operate these sensors 28 and 29, a dog 30 is provided on the headstock 10. There is. If each position sensor 28, 29 is configured with a limit switch, for example, the first sensor 28 detects that the rotating main shaft 11 approaches the first steady rest device 21, and the steady rest controller 27 detects that the rotating main shaft 11 approaches the first steady rest device 21. A retreat command is sent to the direct-acting cylinders 23 and 24 of the first steady rest device 21, and both work holders 25 and 26 are retreated from the passage area of the rotating main shaft 11 and the headstock 10.

Similarly, when the rotating main shaft 11 approaches the second steady rest device 22, the second sensor 29 detects the position of the dog 30, and the steady rest controller 27 moves the second steady rest device 22. Evacuate.

[0031] Therefore, by the retracting operation of the steady rest device, the rotating main shaft 11 can move by the maximum long stroke, and the workpiece 12 can be efficiently machined with a desired long stroke without waste.

Of course, in the present invention, the steady rest controller 27 can also be incorporated into the NC controller of the main shaft sliding type automatic lathe, and the position sensors 28 and 29 can also be installed in each steady rest device 21 by the NC controller.
, 22, it becomes unnecessary.

FIG. 3 shows another embodiment of the steady rest device according to the present invention.

Work holders 31 and 32 sandwiching the work 12
are provided on arms 35 and 36 that are rotatably supported on support shafts 33 and 34, respectively, and are connected to linear motion cylinders 37 and 3.
8 moves each arm 35, 36.

According to the steady rest device shown in FIG.
It is possible to transmit to 2.

Furthermore, as shown by the chain lines in FIG. 3, the arms 35 and 36 are connected to rotary actuators 39
, 40 is also possible.

FIG. 4 shows still another embodiment of the steady rest device according to the present invention, in which one work holder 41
is driven by a linear cylinder 42 as in the above embodiment, but the other work holder 43 is fixed to a rack 44, and this rack 44 is driven by a linear cylinder 42.
are interlocked by a rack 45 and a pinion 46,
According to the embodiment shown in FIG. 4, it is possible to simultaneously hold and hold the workpiece 12 with only one direct-acting cylinder 42 for a pair of steady rest devices. A further steady rest device is shown in FIG. 5, in which a single linear cylinder 5
1, the pair of arms 52, 53 are simultaneously moved, and the work holders 54, 55 provided on these arms 52, 53 are moved in a scissor motion.

As described above, according to the present invention, various types of steady rest mechanisms can be employed, and in any case, when the work holder gets in the way of the rotating main shaft, it can be quickly evacuated.

In each of the embodiments described above, the work holders come into contact with or come close to the work 12 with the flat portions of their tips, but in the present invention, the tips of the work holders 61 and 62 are formed with V-grooves as shown in FIG. Work 12 by doing
The holding work can be further stabilized.

Similarly, FIG. 7 shows an embodiment in which the tips of the work holders 63 and 64 have concave shapes that match the outer shape of the work 12.

FIG. 8 shows an embodiment in which three rollers 65, 66, and 67 are used as work holders for the work 12. In this case as well, the work 12 is pressed at three points on its outer periphery, so it is very easy to use. A stable steady rest can be achieved.

Furthermore, FIG. 9 shows that the belt 71 is
, 72 as a work holder, each belt 71, 72 is rotatably provided by a pair of pulleys 73, 74 and 75, 76, and as the work 12 rotates, the belts 71, 72 rotate. It is possible to move the workpiece 12 and provide a desired steady rest while reducing the load on the workpiece 12.

In the present invention, the steady rest device is arbitrarily set based on the relationship between the workpiece diameter and the machining stroke.
When the ratio of the workpiece diameter to the machining stroke is large, it is preferable to install a large number of steady rest devices.

[0044]

[Effects of the Invention] As explained above, according to the present invention,
In a sliding spindle automatic lathe, the workpiece is held down by a steady rest device between the rotating spindle in the retracted position and the fixed guide bush, making long stroke machining extremely easy. Since it is retracted from the movement area as the machine moves, it does not interfere with the progress of machining, and good machining can be performed without impeding the high efficiency characteristics of the automatic lathe.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram schematically showing a preferred embodiment of a main shaft sliding type automatic lathe according to the present invention.

FIG. 2 is a side view of the steady rest device in FIG. 1;

FIG. 3 is an explanatory diagram showing another embodiment of the steady rest device according to the present invention.

FIG. 4 is an explanatory diagram showing still another embodiment of the steady rest device according to the present invention.

FIG. 5 is an explanatory diagram showing still another embodiment of the steady rest device of the present invention.

FIG. 6 is an explanatory diagram showing another embodiment of the work holder in the present invention.

FIG. 7 is an explanatory diagram showing still another embodiment of the work holder in the present invention.

FIG. 8 is an explanatory diagram showing an embodiment in which the work holder of the present invention is a three-point support roller.

FIG. 9 is an explanatory diagram showing an embodiment in which the work holder according to the present invention is a belt.

[Explanation of symbols]

10 Headstock 11 Rotating main shaft 12 Work 13 Fixed guide bush 14　Turret 15 Tools 21, 22 Steady rest device 25, 26 Work holder 27 Steady rest controller

Claims (1)

[Claims] 1. A main shaft sliding type automatic lathe including a rotating main shaft that chucks a workpiece and is slidable in the axial direction; and a fixed guide bush that supports the workpiece near a tool rest. 1. A main shaft sliding type automatic lathe, comprising a steady rest device provided between the rotating main shaft and the guide bush and including a work holder that can extend and retract toward the outer periphery of the work.