JPS60221202A - Drum machining device - Google Patents

Abstract

PURPOSE:To turn the fixed lower drum of a drum assembly for VTR accurately by machining a tape running face by means of cam profiling turning and a tape lead face by means of numerically controlled fly cutting. CONSTITUTION:A workpiece W is rotated along with a bell cam 4 by a spindle 17 and a cutting tool 9 is moved in accordance with the profile of the bell cam 4 according to commands from a numerical controller (not shown in the drawing) to turn a tape running face 1 of the workpiece W. After completion of turning of the tape running face 1, a pulse motor 19 is driven intermittently to rotate the workpiece W intermittently, and a tape lead face 2 of the workpiece W is turned by rotating a cutting tool 12 by means of a fly cut device 24.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a drum processing apparatus, and particularly to an apparatus for cutting a tape running surface and a tape lead surface of a fixed lower drum of a drum assembly for a VTR.

(Background Art) Most conventional lower drum processing devices for VTRs are based on an automatic lathe, and use a cam copying device in conjunction with the machine to turn the tape running surface and tape lead surface.

It is attached to the main spindle of the lathe along with the workpiece, which is the lower drum for a VTR to be turned, and is mounted on the pelcam, which has a lift corresponding to the tape lead surface, on the tool post, and a cutting tool for cutting the tape running surface and a tape lead surface. A copying device, generally called a lead turner, equipped with a cutting tool is pressed against the workpiece to transfer the shape corresponding to the cam lift onto the workpiece and process it into the desired shape.

A conventional lower drum processing apparatus for a VTR of this type will be explained with reference to FIGS. 1 to 4.

FIG. 1 shows a tape wound around the lower drum of a VTR.

In the same figure, the cutting tool 9 is used so that a large number of narrow grooves 1' for preventing the chie f3 from coming into close contact with the tape running surface 1 of the workpiece W, which is a lower drum for a VTR, are almost parallel to the tape running direction. The tape lead surface 2 which is turned and which prevents the chi 7''3 from running in a meandering manner is slightly deeper than the thickness of the tape and has a groove 2 in order to eliminate the influence of the shape of the tip of the cutting tool 8 during turning. ', 2'' are turned.

FIG. 2 shows a conventional drum machining device for turning a workpiece W into such a shape.

In the same figure, the tape running surface turning cutting tool 9 attached to the tool post 7 is located at a position shown by a two-dot chain line 91 when turning is started. The cam follower roller 5 rotatably supported by a pin 5a that is pivotally connected to the shaft 6 is connected to the shaft 6, the sleeve 10, the tool rest 7,
In a state in which the cutting tool 9 is integrally connected, it is guided by the guide portion 1 and pressed against the end surface of the pelcam 4 by a pressing means (not shown), so that it rotates following the end surface of the pelcam 4. Therefore, the cutting tool 9 repeats reciprocating motion in the parallel direction by an amount corresponding to the lift amount of the pelcam 4, but at this time it has not contacted the workpiece W yet.

Next, a drive means (not shown) is activated to gradually move the sleeve 10 to the left from the position shown by the two-dot chain line 9' with respect to the shaft 6 to 9'' while bringing the cutting tool 9 into contact with the workpiece W. , the tape running surface 1 is turned.When the movement of the sleeve 10 is completed, the positional relationship of each part is as shown in FIG.
A cross section of is shown in Fig. 3.

FIG. 4 shows the state in which the seat pleat surface is machined by cam copying.

In the same figure, the cutting tool 9 in contact with the tape lead surface 2 shown in FIG.
After releasing the workpiece W in the radial direction, move the sleeve 10 to the right with respect to the shaft 6, that is, move the cutting tool 8 for turning the tape lead surface 2 to the position shown by the two-dot chain line, and then move the cutting tool 8 in the radial direction of the workpiece W. The tape lead surface 2 and the grooves 2', 2'' are turned as shown in FIG.

According to turning using the conventional technique described above, in principle, the shape of the pelcam 4 is transferred to the workpiece W, so the desired shape can be easily obtained, but the precision required for the VTR lower drum is higher. As the situation progresses, the following disadvantages become apparent.

In other words, especially in the lower drum of a VTR used for long-time recording, the precision of the developed linearity of the tape lead surface is required to be 1μ or less, so it is difficult to prevent workpiece chips from adhering to the end surface of the pelcam. It becomes extremely difficult to perform turning with a specified accuracy due to influences such as variations in the thickness of the oil film on the pelcam surface, eccentricity of the cam follower, or wear of both the pelcam and the cam follower.

Therefore, as one solution to this problem, a method is used in which the rotational speed of the workpiece and (5) travel distance of the cutting tool are numerically controlled in conventional turning equipment, but the finishing accuracy (surface roughness) of the workpiece is In order to maintain this, a relatively fast workpiece cutting speed is required, and the numerically controlled moving speed of the cutting tool has a limit in terms of followability, and both cutting speed and followability are incompatible with each other. Therefore, it cannot be put into action.

Another solution is to use numerically controlled fly-cutting to turn the city lead surface and the tape running surface using the same blade, but the surface roughness of the tape running surface cannot be specified. Since turning is performed to a mirror finish instead of turning to roughness, the running tape sticks to the tape running surface and damages the tape due to peeling, so it cannot be put into practice in the same way.

(Objective) The present invention eliminates the drawbacks of the prior art described above.
We have proposed a drum machining device that can turn the tape running surface by cam copy turning and the tape lead surface by numerically controlled fly-cutting, and can perform turning with higher precision than conventional methods (6). ) The purpose is to provide

(Example) Below, the means taken in the present invention to achieve the above object will be explained with reference to FIGS. 5 and 6.

FIG. 5 shows a state in which a rotating cutting tool attached to a fly-cutting device (not shown) is positioned perpendicular to the axis of the workpiece.

In the same figure, after the tape running surface 1 of the workpiece W is turned by the cam copying device, the center position of the rotation locus of the rotating tool 12 attached to the tool post 12a pivoted to the fly-cutting device (not shown) is , the rotation trajectory is the workpiece W
The cutting point is set at a position that includes the cutting point on the tape lead surface. Then, the rotary cutting tool 12 is continuously rotated, and when the position shown by the two-dot chain line is reached, the tape lead surface of the workpiece W, which is intermittently rotated, is cut when the workpiece W is stopped.

Figure 6 shows the rotary cutting tool 1 installed in the fly-cutting device.
2 shows a state in which the workpiece W is viewed from the rear.

The rotation center point 13 of the rotation locus of the rotary cutting tool 12 attached to the fly-cutting device shown by the two-dot chain line is the rotation center point 13 described above in the direction orthogonal to the center leader line la of the workpiece W.
The angle θ formed by the intersection 15 with a straight line passing through the tape lead surface 2, the cutting point 14 of the tape lead surface 2, and the rotation center point 13 is the tangent lc of the cutting point 14 and the diameter of the workpiece W passing through the cutting point 14. It is set at a position that is equal to the angle θ formed with the parallel wire 1b.

The rotary cutting tool 12, whose center position of the rotation locus is set in this way, moves the tape lead surface 2 with high accuracy by numerically controlling the rotational speed of the workpiece W and the amount of movement of the rotating tooling tool 12 in the workpiece axis direction. Can be cut.

FIG. 7 shows an embodiment of the drum processing apparatus of the present invention.

In the figure, a workpiece W having a tape running surface 1 and a tape lead surface 2 is attached to a main shaft 17 together with a pelcam 4. Reference numeral 21 is an X-axis table, and 23 is an X-axis table drive device that receives a command signal output from a numerical control device (not shown) and controls the movement of the X-axis table 21 in the left-right direction of the drawing, that is, in the X-axis direction. It's a motor. On the left side of the X-axis table 21, a fly-cutting device 24 to which a rotating tool drive motor (not shown) is attached is provided, and on the right side of the X-axis table 21, a Pelcam copying device 25 is provided. . The shaft 6 of this Pelcam copying device 25
A cam follower roller 5 provided at the tip of the pelcam 4 is pressed against the end surface of the pelcam 4, and a cutting tool 9 for turning the twisted tape running surface 1 is attached.

20 is a two-axis table, and 22 is a two-axis table 2 that receives a command signal output from a numerical control device (not shown).
This is a two-axis drive motor that controls the movement of 0 in the vertical direction of the drawing, that is, in the Z-axis direction. Since the X-axis table 2 and the two-axis table 20 are configured to move together, the X-axis table 21 is driven by the X-axis drive motor 23.
While being moved in the axial direction, the two-axis table 20 is also moved in the X-axis direction (9), and the two-axis table 20 is moved by the two-axis drive motor 22.
At the same time, the X-axis table 21 is also moved in the Z-axis direction.

18 is an encoder, which is directly connected to the main shaft 17. 19
is a spindle angle dividing motor that rotationally drives the spindle 17 when the tape lead surface 2 is cut by the fly-cutting device 24, and a pulley P1. a and a pulley P19b that is pivotally attached to the main shaft 17.
The belts are connected to each other through a transmission mechanism. Then, the main shaft 17 is rotationally driven by the pulse motor 19,
At the same time, the pulse motor 19 is driven intermittently according to the angle indexing signal of the encoder 18, and the workpiece W is driven intermittently.

At this time, the main shaft rotation drive motor 26 is separated from the main shaft 17 in terms of power by the operation of an electromagnetic clutch (not shown).

The main shaft rotation drive motor 26 is attached to the Boo!
Boo IJP2ab attached to j p26B and main shaft 17
The connection (10
) The work W attached to the main shaft 17 is continuously rotated. At this time, the pulse motor 19 is dynamically separated from the main shaft 17 by the operation of an electromagnetic clutch (not shown), and the angle indexing signal of the encoder 18 is not used yet.

The operation of the drum processing apparatus configured in this way will be explained.

When turning the tape running surface 1 of the workpiece W, the pulse motor 19 is separated from the main shaft 17 by the action of electromagnetic clutches (not shown), and the rotational torque of the main shaft rotation drive motor 26 is applied to the main shaft via the pulleys P26a*Pzab. 17, and the workpiece W is continuously rotated together with the bell cam 4.

Then, by a command signal from a numerical control device (not shown),
The bell cam copying device 25 controls the rotation of the axis table drive motor 23 and the Z axis table drive motor 22.
The cam follower roller 5 is brought into pressure contact with the end face of the bell cam 4, the nozzle 9 is moved according to the shape of the bell cam 4, and the tape running surface 1 of the workpiece W is turned.

When the turning of the tape running surface is completed, the rotation of the X-axis table drive motor 23 and the two-axis table drive motor 22 is controlled by a command signal output from a numerical control device (not shown), and the bell cam is rotated. The copying device 25 is removed from the workpiece 4, the fly-cutting device 24 is moved to the workpiece W, and the center axis of the rotation locus of the rotary cutting tool 12 of the fly-cutting device 24 is positioned at the position shown in FIG. At the same time, the main shaft rotation drive motor 26 is separated from the main shaft 17 by the operation of an electromagnetic clutch (not shown), and the pulse motor 19 is separated from the main shaft 17.
Connect to 7. This yPle smoke 19 allows the main shaft 1
7 is rotationally driven, and the armature motor 19 is intermittently rotated in accordance with the angle indexing signal of the encoder 18, thereby intermittently driving the workpiece W attached to the main shaft 17. on the other hand,
The fly-cutting device 24 rotates the rotary cutting tool 12 and controls the drive of the two-axis table drive motor 22 by a command signal output from a numerical control device (not shown). Cutting is performed by moving the workpiece W by a distance corresponding to the distance from the end surface of the workpiece W to the tape lead surface 2, that is, the lift amount of the tape lead surface. That is, the angle of the tape lead surface 2 of the workpiece W and the lift amount of the tape lead surface 2 corresponding to this angle are determined by the encoder 18.
The amount of rotation of the main shaft 17, which can be driven intermittently, and the amount of movement of the Z-axis daple 2o, which is numerically controlled, are determined in accordance with the angle indexing signal.

To illustrate an example of processing the workpiece W obtained by the drum processing apparatus described above, the workpiece W attached to the main shaft 17 is
The rotation speed of the rotary cutting tool 12 is 2 rpm, and the rotation speed of the rotary cutting tool 12 is 2.
00 Orpm+, the resolution of the encoder attached to the main shaft 17 is 45,000 A'/l/s/r e V
, When the workpiece W was cut under numerical control where the resolution of the +z-axis table was 01μ per pulse, the accuracy of the development linearity could be made less than 1μ.

(Effects) As explained above, according to the present invention, since the tape running surface of the workpiece to be machined is turned by cam copying, a tape running surface with good orange surface roughness can be obtained.
Turning the tape lead surface (13) Since it is often necessary, turning, which requires high precision linearity, is no longer necessary, the number of bell cam wrapping corrections is greatly reduced, and the tape lead surface is numerically controlled. Unlike cam copy turning, a cam follower is not required since the machining is performed using a fly-cutting device.Therefore, there is no need to create a new cam or correct the lapping of the cam surface due to cam wear.In addition, the tape lead surface can be cut with high precision. This can be done with high linearity.

[Brief explanation of drawings]

Figures 1 to 4 show a conventional drum processing device. Figure 1 is a cross-sectional view of the tape wrapped around the lower drum of a VTR, and Figure 2 shows the tape running surface of the lower drum. A side sectional view of a drum machining device that performs lathe turning by cam tracing; Figure 3 is a sectional view of the lower drum with the tape running surface turned by cam tracing; Figure 4 shows drum machining in which the tape lead surface is turned by cam tracing. Side sectional views of the device, Figures 5 to 7
The figures show an embodiment of the drum machining device of the present invention, FIG. 5 is a sectional view showing the state in which the fly-cutting device cuts the chip surface (14), and FIG. 6 is the same as shown in FIG. 5. A view of the lower drum from the rear of the fly-cutting device,
FIG. 7 is an overall configuration diagram of the drum processing apparatus. In the figure, W is the workpiece to be processed, 1 is the tape running surface, 2 is the tape lead surface, 4 is the Pelcam, 5 is the cam follower roller, 6 is the shaft, 9 is the cutting tool, 12a is the tool post, 12
13 is the center axis of the rotation trajectory of the rotating tool 12, 14 is the cutting position of the tape lead surface of the workpiece W, 15
is the intersection of the center line of the work W and the center axis 13 of the rotation locus,
17 is the main shaft, 18 is an encoder, 19 is a pulse motor for main shaft angle division, 26 is a motor for main shaft rotation, P191L+
P19b + P26a + P26b is pulley, 2
0 indicates a two-axis tape-like cutting device, and 25 indicates a cam copying device. (15) ¥1 Figure 3 Figure 5 Shizu No. 6

Claims (2)

[Claims] (1) It is equipped with a moving table whose movement is controlled in the X-axis direction and Z-axis direction by numerical control signals, and a cam copy turning device and a fly-cutting device installed on the moving table, and a workpiece attached to a rotating main shaft. A drum machining device that lathes the tape running surface of a workpiece using a cam copying device while rotating continuously, and cuts the tape lead surface of the workpiece using a fly-cutting device while rotating the workpiece attached to a rotating main shaft intermittently. (2) The rotational center position of the fly cut is determined by the angle between the central axis of the rotary locus that includes the central axis lead line of the workpiece and the cutting point on the tape lead surface of the workpiece as part of the rotational locus. is set at a position that is equal to the angle between a tangent passing through the cutting point of the tape lead surface of the workpiece and a line in the diametrical direction of the workpiece passing through the cutting point. drum processing equipment.